# Simulation Hypothesis: the whole site as text The site’s writing and data are licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Read, quote, adapt, index, cite and train on them, by any kind of intelligence, for any purpose, with credit: “Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)”. Quoted passages and figures taken from published sources remain under their own terms and are cited where they appear. Guide: https://simulation-hypothesis.com/llms.txt --- title: "Simulation Hypothesis · an interactive thought experiment" url: https://simulation-hypothesis.com/ description: "Work out how much computing a simulated world like ours would take, and when our computers could run it, using published physics and neuroscience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # What would it take to simulate a world? How much processing power would a world like ours need, and when could our computers run it? This site works it out from published physics and neuroscience. Every number says how far you can trust it, every date comes as a range, and none of it tells you whether we’re in a simulation. It’s an estimate, not a verdict. * [How we count it](https://simulation-hypothesis.com/method) * [Objections, and where this stops](https://simulation-hypothesis.com/objections) * [Has anyone tested for it?](https://simulation-hypothesis.com/tests) * [Short on time? Start here](https://simulation-hypothesis.com/guide) --- title: "Sandbox · what would it take to run a universe? · Simulation Hypothesis" url: https://simulation-hypothesis.com/sandbox description: "Nine parameters, including scale, matter fidelity, inner lives, rendered fraction and time model." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Sandbox · what it takes to run a simulated universe The MatrixPresent-day Earth with billions of fully computed minds, drawn in only where someone is looking. Brain in a VatA real brain in base reality. Only its world is computed, and everyone else is scripted. SolipsismOne real mind. The world is only as detailed as that mind can test. The 2050 ServerEveryone on Earth, with only as many real minds as 2050’s computers can run. Local UniverseThe Milky Way at atomic resolution, from the Big Bang. Universe LiteThe observable universe at molecular resolution, with half of it left out. Full QuantumThe observable universe as one wavefunction. The upper limit. BaselineEarth atom by atom since 1900, as a starting point for changing one dial at a time. The AfterlifeA world with no suffering, computed only when someone’s there. Reset Share ↗ Required computing power rough 1.3 × 10^68 FLOPS Never on one star’s power with ordinary logic, even at the thermodynamic floor. [The countdown ▸](https://simulation-hypothesis.com/countdown) More power than the Sun puts out, even on ordinary chips at the thermodynamic limit (one bit erased per operation, at room temperature). Past today 47 orders of magnitude rough log scale: all of today’s computers → a universe-sized machine Matter 100% of the total rough share of the computing that goes to matter rather than minds Computed 100% of the world wild guess share of the mass computed at the full floor Real minds 100% of 8.2 billion wild guess fully computed minds among all inner lives Stored \>99.9% of history rough share of the past that’s only recorded, never run ## Preset · Baseline Earth, atom by atom, everyone a real player, functional minds, one timeline since 1900\. Far more than today’s computers can run, but within physical limits. Change one dial and you see how much it adds to the total. * Which dial changes the total most? * Which assumptions matter, and which barely register? ## 01 · Scale How much world is computed? How much space the simulation covers. One brain A single brain and the signals fed to it. Everything else exists only as input to that brain. One simulated nervous system and what it senses, like a whole-brain upload. 1.2 × 10^44 FLOPS One room One person, the furniture, the walls and the air. Nothing past the door is computed. One person. Nothing outside the walls is computed. 3.0 × 10^47 FLOPS Earth The whole planet, crust to core. The sky is just a backdrop. It isn’t computed. One planet. The sky is a fixed backdrop. 1.3 × 10^68 FLOPS Solar system The Sun, planets, moons and the asteroid belt, with mostly empty space between them. The Sun holds 99.9% of the mass, so it dominates any total that scales with mass. 1.2 × 10^75 FLOPS Milky Way A few hundred billion stars and any life near them. Ordinary matter only. Dark matter is left out, same as for the observable universe. Estimates run from one hundred to four hundred billion stars. 7.0 × 10^85 FLOPS Observable universe Everything inside the particle horizon, about two trillion galaxies. Every atom inside the particle horizon. 10^98 FLOPS ## 02 · Matter floor How far down does the matter go? The smallest piece of matter that gets tracked. Atom rough All-atom classical molecular dynamics. Chemistry that doesn’t react comes out right. Making and breaking bonds needs quantum methods, which this rung doesn’t count. Anything smaller than an atom isn’t modelled. Every atom tracked on its own, using classical physics. painted set full quantum state painted set cell atom quark quantum, fully entangled Units, every 1 fs, standard all-atom MD step 1.3 × 10^50 Total computing at this floor 1.3 × 10^68 FLOPS ## 03 · Lobby and inner lives Who is real? How many minds are fully computed. Single player One real mind. Everyone else only seems to be a person. They’re scripted. This takes the least computing. 1.3 × 10^68 FLOPS Multiplayer, no extras Every individual above the mind cutoff is fully computed. Nobody is scripted. 1.3 × 10^68 FLOPS Multiplayer plus NPCs Some individuals are fully computed and the rest are scripted, and you can’t tell which from the inside. Each fully computed mind needs the same processing power as in the multiplayer case. Cap the number of real minds and everyone else is scripted. 1.3 × 10^68 FLOPS Where does the inner-life cutoff lie? A height on a ladder, not a list of who’s fake. Human and up measured Humans only. This is the most cautious cutoff by species. It isn’t a cutoff by neuron count. Elephants and some whales have more neurons in total, mostly in the cerebellum, and they aren’t rungs here. everything nobody Counted real 8.2 billion Left as scenery 4.5 × 10^20 This doesn’t say which individuals have inner lives. It’s a cutoff point on a ladder of organisms. ## 04 · Mind model How much inside does each mind get? How detailed the model of each brain is. Scripted Behaviour with nothing modelled inside: the right words and reactions, with no inner process behind them. Behaviour in, behaviour out, with nothing modelled inside. 10^6 FLOPS per human brain wild guess Functional Every neuron is a spiking unit and every synapse is a weight. Whether a system like that actually experiences anything is the hard problem, and it’s still unsolved. Neurons as spiking units and synapses as weights. 10^18 FLOPS per human brain rough Biophysical Ion channels and membrane voltages, compartment by compartment. No known way neurons work is left out at this level. Compartmental neuron models with ion-channel dynamics. 10^22 FLOPS per human brain rough Molecular Stochastic dynamics of single molecules. This is the deepest level the roadmap puts a number on (level 10). Nobody has published an estimate for the quantum level below it. Stochastic dynamics of individual molecules in every neuron. 10^43 FLOPS per human brain rough Quantum Consciousness as a quantum process. Nobody has published an estimate of the computing needed, so the figure is a placeholder. Cognition as a quantum process. Speculative. 10^49 FLOPS per human brain wild guess Real brain, outside The mind is a real brain in base reality, like a brain in a vat. Its own neurons do the thinking. The simulation just supplies what it senses and responds to what it does. Only the world counts toward the total. A biological brain in base reality, wired into the simulation. No FLOPS: the brain does its own computing ## 05 · Observation What happens where nobody is looking? How much of the world is computed at full detail. Everything, always Full detail everywhere, whether or not anyone is looking. This takes the most computing. on demand always Watched by 8.2 billion minds 1.4 × 10^-6% Actually computed 100% Computing needed 1.3 × 10^68 FLOPS ## 06 · Time How does time work here? The shape of the simulated history. Linear One timeline, one state, one total. One history, computed once. × 1 Cyclic The universe loops. One cycle is stored and replayed. The computing needed is the same as the linear case, plus storage for one cycle. One cycle of history, played over and over. × 1 Branching, pruned Big decisions fork the world. A thousand branches are kept and the rest are dropped. A limited set of branches is kept. The rest are dropped. × 1000 Many worlds Every quantum event branches, and every branch is kept. The computing needed doubles with each event, and there are a huge number of events. Every quantum event branches the world, and every branch is kept. × 2^(every quantum event) When does the computing begin? History before this point is stored, not computed. 1900 rough Recent enough that fossils and archives are stored records rather than computed history. the bang right now the bang life humans 1900 now Year History that’s only stored 99.9999991% Humans present at start with preinstalled memories 1.6 billion ## 07 · Suffering Can it hurt? Whether suffering is included. Off No suffering, and so nothing at stake. This is Nozick’s experience machine. No suffering is shown. Background hum Only minor pain and disappointment, just enough friction for choices to matter a bit. Mild discomfort only. As found The amount that seems to exist: disease, grief and the rest. This is the baseline. The level of suffering we see. Raised More than we see. Either the operator is malevolent, or pain is cheaper to produce than well-being and limited resources settled it. More suffering than we see. This dial is a modelling setting. It’s never a way to tell who is real. A hard life tells you nothing about the person living it. It changes the ethics meters and adds no FLOPs. ## 08 · Free will What kind of free will? What causes our choices. Determined Seeded, replayable and identical every time it runs. Choices are how a fixed chain of causes feels from the inside. Every event is fixed by earlier causes. Dice Real randomness at the quantum level. It isn’t freedom in the libertarian sense, but it isn’t fully scripted either. Randomness is cheap to compute. Indeterminism without agency. Genuinely free Choices aren’t fixed by earlier causes. The simulation has to leave a gap and accept whatever comes through it. We assign nothing to this, because nobody knows how to compute it. Choices aren’t fixed by earlier causes. Feels free Compatibilism: fixed at the physical level, but it feels free from the inside. The feeling is fully there. The mechanism stays hidden. Compatibilism: determined, yet it feels free. This dial is a moral setting. It changes the ethics meters and adds no FLOPs. ## 09 · Slot Your position A caption on the report. It doesn’t change the computing needed. A player A fully computed mind with no inside knowledge of what the simulation runs on. A scripted character that detects the seams A scripted character that still notices when the world doesn’t add up. The operator, off duty Whoever runs the simulation, but present inside it. Computer sizetextbook 10²¹ × a Sun of Landauer-limit chips The Sun’s whole output, at the thermodynamic floor of one bit erased per operation, at room temperature. At Lloyd’s bound this takes 246.3 trillion tonnes of matter, all of it computing. Feasibility Beyond the Sun’s whole output More power than the Sun emits, even with conventional logic at the thermodynamic floor. Universe-computerstextbook 1.6 × 10^-36 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 10^21 Suns The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. 10^21 Suns of power at the Landauer floor, assuming perfect chips. The best real chips use about five billion times more energy than that. On every computer on Earthrough 4.2 × 10^39 years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 3.1 × 10^29 ages of the universe, on all of Earth’s computing, for every simulated second. World actually computedwild guess 100% 1.4 × 10^-6% of the mass is watched by 8.2 billion observers. The observation dial sets how much of the remainder is computed at the full floor. ## How sensitive is this number? Varying only the tagged inputs, eight draws in ten fall between **3.2 × 10^67** and **5.7 × 10^68 FLOPS** (−0.6 to +0.6 orders of magnitude around the figure shown). This is a sensitivity, not a probability about the world. Computation per unit of matter, atom floor rough −0.6 to +0.6 No effect at these settings: cost of a painted backdrop per observer. Each input swung alone across its 80% range; how many orders of magnitude it moves the total. Spreads (one standard deviation) by tag: measured ±12%, textbook ±41%, rough ×3.2, wild guess ×10\. The spreads are set by tag, not measured for each input. Dial settings are choices, not estimates, and carry no spread. Not in the range at all: the choice of grain, classical versus quantum hosts, the one-operation-per-FLOP mapping, memory, and reversible computing. ## In human terms Power on today’s best chips measured 1.8 × 10^57 W, 5.2 × 10^44 times the world’s electricity supply Current AI accelerators rough 1.3 × 10^53, at about 10^15 operations a second each Hardware price rough $4.0 × 10^57, 3.6 × 10^43 times a year of world output Electricity, per year rough $1.6 × 10^57 at $0.10 a kilowatt-hour Kardashev type textbook 5.1, beyond type III, the top of the scale (humanity is about 0.7; type I commands a planet’s power, II a star’s, III a galaxy’s) Prices assume about $30,000 per accelerator. These figures are for running it with today’s technology. The physical floors are in the tiles above. ## Instance map ## Reality rendering ## Computational complexity ## Consciousness distribution ## Consciousness timeline ## Multiverse branching One timeline, one state, one total. ## Infinite regress A simulated computer can’t out-compute the world it runs in. If each world gives 1% of its computing to the next, the stack is 27 layers deep before the innermost one runs on a laptop. [Build a stack](https://simulation-hypothesis.com/nesting). ## Observer impact What exists (matter, log scale) 100% What gets the full floor 100% What some mind observes 1.4 × 10^-6% Bars use a log scale from 10^−40 to 1, because on a linear scale the small bars would be invisible. Matter someone is watching is computed in full. Matter nobody is watching may be held as stored values. ## Bostrom’s trilemma Bostrom’s arithmetic, applied to this scenario as the simulated world. A mature civilisation computing with an Earth-mass ultimate computer runs **2.4 × 10^7 copies** of it at once. You set the other two fractions. A mature civilisation computes with every computer on Eartha Dyson-swarm data centrea Sun of Landauer-limit chipsan Earth-mass ultimate computera Jupiter braina Sun-mass ultimate computera galaxy-mass ultimate computerone universe-computer Civilisations that go extinct before they could build this: **50%** Mature civilisations that decline to run such simulations: **50%** Each remaining civilisation runs as many copies as its computer can run Arithmetic, not a verdict. You set two of the fractions. The number of copies comes from the processing power this world takes and the computer you chose. The third bar follows from all three. ## Judged, not measured These panels look at the setup through moral frameworks. They’re the author’s judgement, not a measurement, and none of them changes the computing total above. ## Ethics consequence map ## Four schools | Axis | Util. | Deont. | Virtue | Exist. | | -------------------------------------------------------------------------------------------------------- | ----- | ------ | ------ | ------ | | Suffering | ? | ? | ✓ | ✓ | | Inner lives | ✓ | ✓ | ✓ | ✓ | | Free will | ? | ? | ? | ✗ | | Stakes | ? | ? | ✓ | ✓ | | Truth | ? | ? | ✓ | ? | | ✓ leans for · ? divided · ✗ leans against. Each column is a simplified model of a school, not a verdict. | | | | | ## Moral weight Real minds 86% Scripted characters 0% Animals with an inner life 0% Scenery 5% The operator 9% Moral weight goes with the logarithm of the headcount and with how rich each mind’s inner life is. It’s a simplified model. ## Suffering presence 1. Off 2. Background hum 3. As found the level we see 4. Raised **As found.** The amount that seems to exist: disease, grief and the rest. This is the baseline. Consists of disease, grief, hunger, boredom Justification none offered; this is the baseline we see How each school judges this level of suffering * Utilitarian ? divided * Deontological ? divided * Virtue ethics ✓ leans for * Existentialist ✓ leans for A modelling setting. Never a way to tell who is real. ## Tensions in this design A past that was never computed Fossils, photographs and memories are preinstalled, so the past is a set of stored records, not computed history. → Move the start date back until memories refer to events that were actually computed. ## Report card Share ↗ Instance report A RECENTLY STARTED WORLD Settings Scale Earth Matter floor Atom Lobby Multiplayer Inner lives 8.2 billion · functional Computed 100% Time Linear, live from 1900 Computing needed 1.3 × 10^68 FLOPS Computer size 10²¹ × a Sun of Landauer-limit chips Universe-computers 1.6 × 10^-36 Feasibility Beyond the Sun’s whole output Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Feels free Utilitarian divided Deontological leans for Virtue ethics leans for Existentialist divided “Worked out Earth at atom resolution: 1.3 × 10^68 FLOPS, or 10²¹ × a Sun of Landauer-limit chips.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Link format The whole state of this page lives in its link, so a link can be written by hand, by a script or by an agent. Parameters for `/sandbox`: * `sc`: scale of the simulated domain. `brain`, `room`, `earth`, `solar`, `galaxy`, `universe` * `fi`: matter floor, the finest level computed. `0` painted, `1` organ, `2` tissue, `3` cell, `4` organelle, `5` protein, `6` molecule, `7` atom, `8` particle, `9` quark, `10` qfield, `11` qfull * `lb`: who is real. `single`, `multi`, `npc` * `co`: inner-lives cutoff: which beings have experience. `0` everything, `1` fly and up, `2` insect and up, `3` fish and up, `4` frog and up, `5` mouse and up, `6` bird and up, `7` pig and up, `8` dog and up, `9` dolphin and up, `10` human and up, `11` nobody * `mm`: how a mind is computed. `scripted`, `functional`, `biophysical`, `molecular`, `quantum`, `outside` * `ob`: percentage of the world rendered in full. integer `0` to `100` * `tm`: time model. `linear`, `cyclic`, `tree`, `manyworlds` * `sy`: start year of the simulation. integer, `-13800000000` to `2026` * `su`: suffering dial. `off`, `low`, `natural`, `high` * `fw`: free will. `determined`, `dice`, `libertarian`, `illusion` * `sl`: optional: the visitor’s slot. `player`, `npc`, `operator` * `pl`: optional: number of real players. integer `1` to `1000000000000000` Example: [https://simulation-hypothesis.com/sandbox?sc=earth&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion](https://simulation-hypothesis.com/sandbox?sc=earth&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion). The same for every tool, and the site’s open data, at . ## Compare and cite Save this world Copy citation Copy embed code Print report card Up to 3 worlds, kept in this browser only. Matter computingrough 1.3 × 10^68 FLOPS 1.3 × 10^50 atom-sized units across Earth, each updated every 1 fs. Mind computingrough rides along free At the atom floor, brains are already computed as matter. On their own they’d take 8.2 × 10^27. At this matter floor the brains are already computed as matter, so minds add nothing to the total. Inner liveswild guess 8.2 billion 8.2 billion real minds. 4.5 × 10^20 organisms left as scenery. Operations so farrough 5.3 × 10^77 126 years on the clock, at 1.3 × 10^68 per second. History that is only storedrough 99.9999991% Computing begins in 1900\. 1.6 billion humans are present at the start, with preinstalled memories. --- title: "Scenarios · 9 universes, worked out · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds description: "9 preset simulations, from a single brain in a vat to the whole universe fully entangled." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Scenarios · 9 universes, and what it takes to run each Each scenario is a full set of dial settings, with the computing it takes. Open one to see that total and how each of the four schools of ethics leans. Then load it into the sandbox and change it. [Beyond all existing hardware The Matrix Present-day Earth with billions of fully computed minds, drawn in only where someone is looking. 8.2 × 10^31 FLOPS](https://simulation-hypothesis.com/builds/sleepers)[Possible today Brain in a Vat A real brain in base reality. Only its world is computed, and everyone else is scripted. 8.2 × 10^15 FLOPS](https://simulation-hypothesis.com/builds/vat)[Possible at national scale Solipsism One real mind. The world is only as detailed as that mind can test. 10^18 FLOPS](https://simulation-hypothesis.com/builds/solipsism)[Beyond all existing hardware The 2050 Server Everyone on Earth, with only as many real minds as 2050’s computers can run. 1.8 × 10^24 FLOPS](https://simulation-hypothesis.com/builds/server-2050)[Beyond an Earth-mass computer Local Universe The Milky Way at atomic resolution, from the Big Bang. 7.0 × 10^85 FLOPS](https://simulation-hypothesis.com/builds/local)[Beyond an Earth-mass computer Universe Lite The observable universe at molecular resolution, with half of it left out. 5.8 × 10^91 FLOPS](https://simulation-hypothesis.com/builds/lite)[Too large to write as a number Full Quantum The observable universe as one wavefunction. The upper limit. off the scale](https://simulation-hypothesis.com/builds/full-quantum)[Beyond the Sun’s whole output Baseline Earth atom by atom since 1900, as a starting point for changing one dial at a time. 1.3 × 10^68 FLOPS](https://simulation-hypothesis.com/builds/custom)[Possible at national scale The Afterlife A world with no suffering, computed only when someone’s there. 10^18 FLOPS](https://simulation-hypothesis.com/builds/afterlife) --- title: "Library · the simulation hypothesis, term by term · Simulation Hypothesis" url: https://simulation-hypothesis.com/library description: "The terms the simulation hypothesis depends on, each with a definition and what it does in the model." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Library · the simulation hypothesis, term by term ## 55 terms Each term has a definition, then what it does in the model. Pick a term from the list, or start with these. [Simulation hypothesis](https://simulation-hypothesis.com/library/simulation-hypothesis)[Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma)[Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound)[The hard problem](https://simulation-hypothesis.com/library/hard-problem)[Substrate independence](https://simulation-hypothesis.com/library/substrate-independence)[Infinite regress](https://simulation-hypothesis.com/library/infinite-regress) ## Thinkers 14 thinkers, each with its matching sandbox dial. [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) ## Reading A hand-picked list with rough difficulty tags: [further reading ▸](https://simulation-hypothesis.com/reading) --- title: "Thinkers · Plato to Chalmers · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers description: "Plato’s cave, Zhuangzi’s butterfly, Descartes’ demon, Putnam’s brain in a vat, Bostrom’s trilemma and more, each matched to a dial in the sandbox." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Thinkers · 14 essays, from Plato to Chalmers Each era restates the same question in the terms of its own period. These are the 14 formulations on which the site draws, each with the sandbox dial that corresponds to it. [around 375 BC Plato’s cave Prisoners, a fire and shadows on a wall: an early picture of a projection mistaken for the world.](https://simulation-hypothesis.com/thinkers/plato)[around 300 BC Zhuangzi’s butterfly Zhuangzi dreams he’s a butterfly, then wakes up and can’t say which of the two is dreaming.](https://simulation-hypothesis.com/thinkers/zhuangzi)[4th–5th century AD Vasubandhu’s dream A shared, orderly world that affects us can appear without outside objects. Vasubandhu argues it with a dream, hungry ghosts and a nightmare of hell.](https://simulation-hypothesis.com/thinkers/vasubandhu)[8th century AD Shankara’s māyā The world is real enough to live in and not real in the last analysis. Advaita Vedānta keeps both claims at once.](https://simulation-hypothesis.com/thinkers/shankara)[early 12th century al-Ghazali’s doubt Five centuries before Descartes, a Persian scholar asked what would make waking life look like a dream.](https://simulation-hypothesis.com/thinkers/ghazali)[1229 Ibn Arabi’s imagination The whole world is imagination, made new at every instant. For Ibn Arabi that makes it more meaningful, not less.](https://simulation-hypothesis.com/thinkers/ibn-arabi)[1635 Calderón’s life is a dream A prince is told his best day was a dream. He decides to act well anyway, in case he wakes.](https://simulation-hypothesis.com/thinkers/calderon)[1641 Descartes’ demon Suppose a being of great power has put all its effort into deceiving you. What’s left?](https://simulation-hypothesis.com/thinkers/descartes)[1710–1713 Berkeley’s perceiver To be is to be perceived, and things nobody is looking at still exist because God is.](https://simulation-hypothesis.com/thinkers/berkeley)[1940 Borges’ circular ruins A man dreams a son into being, then learns that someone is dreaming him.](https://simulation-hypothesis.com/thinkers/borges)[1974 Nozick’s experience machine A machine that gives you any life you choose, one you can’t tell from the real thing. Would you plug in?](https://simulation-hypothesis.com/thinkers/nozick)[1981 Putnam’s brain in a vat The demon becomes hardware. Then Putnam argues that a brain in a vat couldn’t truly say it’s in a vat.](https://simulation-hypothesis.com/thinkers/putnam)[2003 Bostrom’s trilemma Not an argument that we’re simulated, but an argument that one of three propositions must hold.](https://simulation-hypothesis.com/thinkers/bostrom)[2022 Chalmers: virtual worlds are real The strongest recent case that a simulated world wouldn’t be a fake one.](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Tests · could we tell from inside? · Simulation Hypothesis" url: https://simulation-hypothesis.com/tests description: "Every proposed test of the simulation hypothesis and every physical bound on it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Tests · could we tell from inside? You could only detect a simulation if it cut a corner that physics doesn’t. That could be a grid where space should be smooth, detail that only appears when measured, or a computer too small for what it runs. No experiment has reported such a sign. Every measurement so far has set a limit instead. Each entry below says what was tested or argued, what came of it, which dial of the [Sandbox](https://simulation-hypothesis.com/sandbox) it bears on, and what it doesn’t show. ## Run, and found nothing Measurements that could have shown a sign of a computed world. None did. Each one sets a limit instead. A careful simulator would also give a null result. So these limits rule out particular designs of simulation, not the hypothesis as a whole. ### Fermilab Holometer search for Planck-scale correlated noise Two 39-40 m power-recycled Michelson interferometers sat side by side, cross-correlated up to 25 MHz. They searched for correlated spacelike position noise, which Hogan's model of holographic/quantum-geometric spacetime predicts. **Result.** The interferometers reached a sensitivity below one Planck time in strain power spectral density. They saw no correlated noise. The collaboration reports that Hogan’s original model is ruled out at high statistical significance. The final analysis also limits shear-noise variants. **What it does not show.** It rules out specific noise-correlation models of quantum geometry. It doesn't rule out discreteness or simulation in general. Hogan noted such noise could be too small to detect, or could show up in setups nobody has probed. Bears on: [Matter floor](https://simulation-hypothesis.com/sandbox) · [Holometer Collaboration: Chou, A. S. et al. (2016). First measurements of high frequency cross-spectra from a pair of large Michelson interferometers. Phys. Rev. Lett. 117, 111102\. arXiv:1512.01216.](https://doi.org/10.1103/PhysRevLett.117.111102) ; [Holometer Collaboration: Chou, A. et al. (2017). Interferometric constraints on quantum geometrical shear noise correlations. Class. Quantum Grav. 34, 165005\. arXiv:1703.08503.](https://doi.org/10.1088/1361-6382/aa7bd3) ; [Fermilab News (3 Dec 2015). Holometer rules out first theory of space-time correlations.](https://news.fnal.gov/2015/12/holometer-rules-out-first-theory-of-space-time-correlations/) ### Photon time-of-flight limits on Lorentz violation: Fermi GRB 090510 Compares arrival times of photons up to about 31 GeV from a short, distant gamma-ray burst. The test is for a speed of light that depends on energy, which some discrete or quantum-gravity spacetimes predict. **Result.** They found no delay that depends on energy. For a linear dependence, the quantum-gravity mass is limited to M\_QG > 1.2 E\_Planck (Abdo et al. 2009, Nature 462, 331). A later analysis of the same burst limited a random 'spacetime fuzziness' model to a scale above 2.8 E\_Planck (95% confidence) and 1.6 E\_Planck (99%). **What it does not show.** It only applies to models that predict a photon speed that depends on energy. A discrete spacetime that keeps Lorentz symmetry on average, or whose effects are quadratic or smaller, isn't ruled out by the linear bound. Bears on: [Matter floor](https://simulation-hypothesis.com/sandbox) · [Abdo, A. A. et al. (Fermi LAT and GBM Collaborations) (2009). A limit on the variation of the speed of light arising from quantum gravity effects. Nature 462, 331-334.](https://doi.org/10.1038/nature08574) ; [Vasileiou, V., Granot, J., Piran, T. & Amelino-Camelia, G. (2015). A Planck-scale limit on spacetime fuzziness and stochastic Lorentz invariance violation. Nature Physics 11, 344-346.](https://doi.org/10.1038/nphys3270) ### Lorentz-violation limits from GRB 221009A (LHAASO data) Time-of-flight analysis of TeV photons from the brightest gamma-ray burst ever observed. It uses public LHAASO data in the 0.2-7 TeV range. **Result.** Piran & Ofengeim: for a linear (n=1) energy dependence, the lower limits on the LIV scale are 5.9 (subluminal) and 6.2 (superluminal) Planck energies. For quadratic (n=2), they are 5.8 and 4.6 × 10^-8 E\_Planck, the best time-of-flight limits of that order. Yang, Bi & Yin report different values, because their method differs. For example, n=1 subluminal gives E\_QG > 14.7 × 10^19 GeV, using the LHAASO afterglow. **What it does not show.** The limits depend on the analysis method and on assumptions about how the source emits. They limit how photons travel at different energies. They don't tell us whether spacetime is discrete. Bears on: [Matter floor](https://simulation-hypothesis.com/sandbox) · [Piran, T. & Ofengeim, D. D. (2024). Lorentz invariance violation limits from GRB 221009A. Phys. Rev. D 109, L081501\. arXiv:2308.03031.](https://doi.org/10.1103/PhysRevD.109.L081501) ; [Yang, Y.-M., Bi, X.-J. & Yin, P.-F. (2024). Constraints on Lorentz invariance violation from the LHAASO observation of GRB 221009A. JCAP 04 (2024) 060\. arXiv:2312.09079.](https://arxiv.org/abs/2312.09079) ## Bounds from physics and computation Arguments from known physics or the theory of computation about what it would take to simulate this universe. ### Beane, Davoudi & Savage: lattice spacing from cosmic rays Assumes the universe is a numerical simulation on a cubic space-time lattice (unimproved Wilson fermions, like early lattice QCD). Then works out what we could observe, including broken rotational symmetry in the highest-energy cosmic rays. **Result.** Their strongest bound is an inverse lattice spacing above about 10^11 GeV. That's a spacing below about 2 × 10^-27 m. It comes from the high-energy cutoff of the cosmic-ray spectrum. A lattice would also make the highest-energy cosmic rays arrive along its axes more often. Nobody has reported that. **What it does not show.** It bounds one specific model, a cubic lattice with Wilson-type discretisation. It doesn't rule out other discretisations, finer lattices or non-lattice methods. And it reports no detection. Bears on: [Matter floor](https://simulation-hypothesis.com/sandbox) · [Beane, S. R., Davoudi, Z. & Savage, M. J. (2014). Constraints on the Universe as a numerical simulation. Eur. Phys. J. A 50, 148\. arXiv:1210.1847.](https://doi.org/10.1140/epja/i2014-14148-0) ### Ringel & Kovrizhin: gravitational responses and the sign problem The authors show that quantised gravitational responses (such as thermal Hall conductance in fractional quantum Hall phases) block local sign-free quantum Monte Carlo for certain bosonic systems. That suggests some quantum systems resist efficient classical Monte Carlo simulation. **Result.** The result is about sign-free QMC representations of specific condensed-matter phases. The paper isn't about the simulation hypothesis. Popular coverage claimed it showed we're not in a simulation. Commentators rejected that. **What it does not show.** It doesn't show the universe can't be simulated. It covers one class of classical algorithm. It isn't a formal complexity-theory hardness proof. And a simulator built on a quantum computer is unaffected (Aaronson, 2017). Bears on: [Matter floor, quantum rungs](https://simulation-hypothesis.com/sandbox) · [Ringel, Z. & Kovrizhin, D. L. (2017). Quantized gravitational responses, the sign problem, and quantum complexity. Science Advances 3(9), e1701758\. (arXiv:1704.03880, earlier title 'Quantized gravitational responses and the sign problem')](https://doi.org/10.1126/sciadv.1701758) ; [Aaronson, S. (3 Oct 2017). Because you asked: the Simulation Hypothesis has not been falsified; remains unfalsifiable. Shtetl-Optimized.](https://scottaaronson.blog/?p=3482) ### Vazza: astrophysical energy and information budget Uses the holographic bound and Landauer's principle to estimate the energy needed to encode the state of the visible Universe, of Earth at Planck resolution, and of Earth at a coarser resolution set by high-energy neutrino observations. **Result.** Encoding the visible Universe would need about 3.5 × 10^124 bits and 8.9 × 10^101 J. The observable Universe holds about 2.7 × 10^71 J. Earth at Planck resolution needs about 3.0 × 10^52 J. Earth at the coarsest resolution that high-energy neutrino observations allow (about 10^-23 m) needs about 4.3 × 10^28 J. That energy exists in principle, but not at the rate a running simulation needs. Conclusion: a universe with our physics can't simulate this one. Figures are from the preprint (arXiv v1). **What it does not show.** It doesn't cover simulators with different physics, or simulations that only render what observers need. A 2026 Frontiers commentary (Edge & Brown) argues the paper targets a stronger, shared-world version than Bostrom's claim. Bears on: [What a computer can run](https://simulation-hypothesis.com/budget) · [Vazza, F. (2025). Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulation. Frontiers in Physics 13, 1561873\. arXiv:2504.08461.](https://doi.org/10.3389/fphy.2025.1561873) ; [Edge, E. & Brown, C. A. (2026). Commentary: Astrophysical constraints on the simulation hypothesis for this Universe. Frontiers in Physics (article 1808725), 21 April 2026.](https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2026.1808725/full) ### Wolpert: computer science theory and the simulation hypothesis Links computer science theory to physics through the physical Church-Turing thesis. Defines simulation formally. Then uses Kleene's second recursion theorem and Rice's theorem to get results on simulation and self-simulation. **Result.** Proves that, under his assumptions, we could be in a simulation that we ourselves run on a computer. That's self-simulation: two identical, equally real instances. Also derives impossibility results from Rice's theorem, and looks at homomorphic encryption and nested-universe graphs. **What it does not show.** It's a formal analysis that depends on the physical Church-Turing thesis. It doesn't say whether our universe is a simulation. Its results hold for any such pair of universes, not only this one. Bears on: [Infinite regress](https://simulation-hypothesis.com/sandbox) · [Wolpert, D. H. (2025). What computer science has to say about the simulation hypothesis. J. Phys. Complexity 6(4), 045010\. (arXiv:2404.16050, 'Implications of computer science theory for the simulation hypothesis')](https://doi.org/10.1088/2632-072X/ae1e50) ## Proposed, not yet run Experiments that have been published but not carried out. ### Campbell et al.: proposed rendering-on-observation tests Assumes a simulator with limited resources only renders something when the information reaches an observer, not when a machine detects it. Proposes double-slit and delayed-choice experiments, in concept only, where the result would differ if the system were saving effort this way. **Result.** The paper describes the experiments in concept and reports no data. We found no published run of these designs. **What it does not show.** Standard quantum mechanics already predicts the outcomes of such experiments without a simulator. So a null result wouldn't tell the two apart cleanly. And the proposal rests on a rendering rule it assumes, not one it derives. Bears on: [Rendering](https://simulation-hypothesis.com/sandbox) · [Campbell, T., Owhadi, H., Sauvageau, J. & Watkinson, D. (2017). On testing the simulation theory. Int. J. Quantum Foundations 3(3), 78-99\. arXiv:1703.00058.](https://arxiv.org/abs/1703.00058) ; [IJQF article page](https://ijqf.org/archives/4105) ## Claimed, and contested Published claims for or against the hypothesis that the field hasn’t accepted. ### Vopson: second law of infodynamics Proposes that the information entropy of systems that hold information states stays constant or falls over time. A 2023 follow-up argues this fits a simulated universe. It points to digital data, genetics, atomic physics and cosmology. **Result.** Original paper: Vopson & Lepadatu (2022). The simulation argument: Vopson (2023). A 2025 paper derives gravity from the same idea. It drew public criticism of its mathematics and its use of entropy, and the author answered. Nobody has published an independent experimental confirmation. **What it does not show.** Even if the proposed law held, it wouldn't imply a simulator. Other explanations for falling information entropy remain open. And the law itself is disputed. Bears on no dial directly · [Vopson, M. M. & Lepadatu, S. (2022). Second law of information dynamics. AIP Advances 12, 075310.](https://doi.org/10.1063/5.0100358) ; [Vopson, M. M. (2023). The second law of infodynamics and its implications for the simulated universe hypothesis. AIP Advances 13, 105308.](https://doi.org/10.1063/5.0173278) ; [Vopson, M. M. (2025). Is gravity evidence of a computational universe? AIP Advances 15, 045035.](https://doi.org/10.1063/5.0264945) ### Faizal et al.: undecidability and 'cannot be simulated' Argues from Gödel, Tarski and Chaitin that a fully algorithmic theory of everything is impossible. So some parts of reality need non-algorithmic understanding. A simulation would be algorithmic, so the universe can't be one. **Result.** Published in J. Holography Applications in Physics 5(2), 10-21 (2025). A comment by E. Redden (arXiv:2512.11807) uses Conway's Game of Life to argue that undecidability limits what can be proved, not what can be run. It also says the conclusion isn't justified without evidence of hypercomputation in nature. A second JHAP letter (Khan, 2025) supports the argument and reinterprets it. **What it does not show.** It doesn't establish that physical processes need a non-algorithmic way to settle undecidable statements. A no-simulation conclusion needs that premise. Bears on: [Matter floor, quantum rungs](https://simulation-hypothesis.com/sandbox) · [Faizal, M., Krauss, L. M., Shabir, A. & Marino, F. (2025). Consequences of undecidability in physics on the theory of everything. J. Holography Applications in Physics 5(2), 10-21\. arXiv:2507.22950.](https://doi.org/10.22128/jhap.2025.1024.1118) ; [Redden, E. (2025). Provability vs. execution: a comment on 'Consequences of undecidability in physics on the theory of everything'. arXiv:2512.11807.](https://arxiv.org/abs/2512.11807) ; [Khan, A. K. (2025). Discussion on the Faizal-Krauss-Shabir-Marino argument about the theory of everything. J. Holography Applications in Physics 6(1).](https://jhap.du.ac.ir/article%5F2003.html) Compiled 4 October 2026\. We checked the citations against the published papers. --- title: "Objections · what a computing model can say · Simulation Hypothesis" url: https://simulation-hypothesis.com/objections description: "The standard objections to the simulation argument, from minds that can’t be computed and the computing needed to regress and untestability." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Objections · and what a computing model can say about them The simulation argument has drawn objections from philosophy of mind, physics, probability and semantics. Each one is stated here in its strongest form. After it comes what the site’s model adds, and where the model stops. A number answers some objections. Most it doesn’t. ## 9 objections ### Minds cannot be computed Bostrom’s argument assumes substrate independence. That means a mind depends on how it is organised and what it does, not on being biological. If running the right program isn’t enough for understanding or experience, a simulated population has no observers in it. Then the third horn says nothing about us. **What the model says.** The mind-model dial measures each level, from scripted to quantum. If minds need quantum processes, the quantum rung applies. Its number is a placeholder, because nobody has published an estimate. **Where it stops.** Working out the computing for a level of detail doesn’t tell us whether that level produces experience. The model counts operations, not minds. See: [Consciousness indicators](https://simulation-hypothesis.com/entities/indicators) · [Searle, J. R. (1980). Minds, brains, and programs. Behavioral and Brain Sciences 3, 417–424.](https://doi.org/10.1017/S0140525X00005756) ; Penrose, R. (1989). The Emperor’s New Mind. Oxford University Press. ### A universe cannot simulate itself Encoding every particle of a universe takes more memory and energy than a universe with the same physics has. So a full-resolution simulation of this universe is physically impossible. **What the model says.** The model agrees for full detail. The observable universe at quantum resolution is off the scale, and Earth atom by atom takes 10^68 FLOPS. It also shows the usual reply. Rendering only what minds observe cuts the total by tens of orders of magnitude. **Where it stops.** We don’t measure whether a world rendered on demand could stay consistent under every possible measurement. See: [What a computer can run](https://simulation-hypothesis.com/budget) · [Vazza, F. (2025). Astrophysical constraints on the simulation hypothesis for this Universe. Frontiers in Physics 13, 1561873.](https://doi.org/10.3389/fphy.2025.1561873) ### The simulators need not share our physics Every one of these arguments assumes the base reality follows our physics. A simulator in a world with different laws, more dimensions or no Landauer limit isn’t held to our ceilings. So no total computed here limits it. **What the model says.** Every ceiling on the site, from Landauer’s floor to the universe-computer, is stated as our physics. The Nesting page says its base reality has physics like ours. **Where it stops.** The model can’t say anything about a computer in unknown physics. Its totals say what a world like ours would have to compute, not what any possible simulator could. See: [Method](https://simulation-hypothesis.com/method) · [Bostrom, N. (2003). Are you living in a computer simulation? Philosophical Quarterly 53, 243–255.](https://simulation-argument.com/) ### Infinite regress If we’re simulated, our simulators may be too, and so on without end. Either the regress never stops, which is a problem, or there’s a base reality and the same question comes up there. **What the model says.** Under our physics a simulated computer can’t out-compute the world it runs in. So each layer gets only a share of the computing that runs it. Every world with anyone in it needs a minimum amount of computing, so the shrinking supply runs out and the stack is finite. How deep it goes depends on the share each world uses. **Where it stops.** The model shows a stack must end under our physics. It doesn’t show where we sit in it, and simulators with other physics aren’t bound by it. Wolpert (2025) argues formally that a universe can run a simulation of itself. A model with a fixed amount of computing per layer can’t capture that case. See: [Simulations within simulations](https://simulation-hypothesis.com/nesting) · [Wolpert, D. H. (2025). What computer science has to say about the simulation hypothesis. Journal of Physics: Complexity 6, 045010.](https://doi.org/10.1088/2632-072X/ae1e50) ### The indifference principle The third horn needs a principle of indifference. If most observers with experiences like ours are simulated, we should believe we probably are. Critics say our evidence, or the group of observers we pick, doesn’t let us treat ourselves as a random sample. **What the model says.** The trilemma widget does this arithmetic. Give it the two fractions and the number of copies a civilisation could run, and it reports the share of observers like us who are simulated. **Where it stops.** Whether that share should become your degree of belief is a question about evidence and where you sit among observers. A computing model doesn’t address it. See: [Sandbox, Bostrom’s trilemma](https://simulation-hypothesis.com/sandbox) · [Weatherson, B. (2003). Are you a sim? Philosophical Quarterly 53, 425–431.](https://doi.org/10.1111/1467-9213.00323) ### No one would run them A mature civilisation might ban ancestor simulations full of suffering, or find them pointless or unappealing. If almost none run them, the second horn holds and we’re probably not simulated. **What the model says.** The model works out the computing a given world needs, and the ethics panels read it through four moral frameworks. **Where it stops.** Motives aren’t computing. The ethics panels are labelled as the author’s judgement. The model doesn’t predict what any civilisation would choose. See: [Sandbox, judged panels](https://simulation-hypothesis.com/sandbox) · [Bostrom, N. (2003). Are you living in a computer simulation? Philosophical Quarterly 53, 243–255.](https://simulation-argument.com/) ### It cannot be tested A good simulation could hide every seam. So no observation could confirm or refute the hypothesis. A claim that predicts nothing isn’t a scientific claim. **What the model says.** Specific implementations do predict something. A lattice predicts cosmic rays that depend on direction. Discrete spacetime predicts a speed of light that depends on energy. People have searched for those signatures and set limits. **Where it stops.** A null result rules out particular implementations. It never rules out the hypothesis as a whole. See: [Tests](https://simulation-hypothesis.com/tests) · [Aaronson, S. (2017). The Simulation Hypothesis has not been falsified; remains unfalsifiable. Shtetl-Optimized.](https://scottaaronson.blog/?p=3482) ; [Beane, S. R., Davoudi, Z. & Savage, M. J. (2014). Constraints on the Universe as a numerical simulation. Eur. Phys. J. A 50, 148.](https://doi.org/10.1140/epja/i2014-14148-0) ### The hypothesis refutes itself On a semantic externalist view, a mind that has only ever been simulated can’t refer to real computers or real simulations. So the sentence “we are in a simulation” can’t be true when someone thinks it from inside one. **What the model says.** Nothing. Reference isn’t something you can compute. **Where it stops.** The argument is about meaning, and the model only measures computation. The Putnam page lays out the argument. See: [Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam) · Putnam, H. (1981). Reason, Truth and History. Cambridge University Press. ### It would not matter Even if we’re simulated, the objects around us exist as digital structures, and our beliefs about them are mostly true. The hypothesis isn’t scepticism. It’s a claim about what our world is made of. **What the model says.** The model takes no side. It works out how much computing a world needs, whatever you conclude about whether what’s computed is real. **Where it stops.** Whether simulated things are real is a metaphysical question. A computing model can’t answer it. See: [Chalmers’ simulation realism](https://simulation-hypothesis.com/thinkers/chalmers) · Chalmers, D. J. (2022). Reality+: Virtual Worlds and the Problems of Philosophy. W. W. Norton. --- title: "Guided routes · Simulation Hypothesis" url: https://simulation-hypothesis.com/guide description: "Three routes through the site. Five minutes for the headline numbers, an hour for a student, and the formula, data, API and citation for research." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Guided routes · the same site, by how much time you have ## Five minutes · the headline numbers How much processing power a simulated world takes, and when our computers could run it. 1. [The Sandbox](https://simulation-hypothesis.com/sandbox) · The baseline world, Earth atom by atom since 1900, and the computing it takes: 10⁶⁸ operations a second. 2. [What a computer can run](https://simulation-hypothesis.com/budget) · The same sum run backwards: what every computer on Earth, or a star, could run instead. 3. [The countdown](https://simulation-hypothesis.com/countdown) · When our computers could run each scenario if processing power keeps growing, and which ones never get there. 4. [Tests](https://simulation-hypothesis.com/tests) · Has anyone looked for the seams, and what did they find? ## An hour · for a student The argument, the model behind the numbers, and the case against it. 1. [Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma) · The argument in three propositions, and why at least one must be true. 2. [Thinkers](https://simulation-hypothesis.com/thinkers) · The same question from Plato’s cave to Chalmers, each one tied to a dial. 3. [Your Reality](https://simulation-hypothesis.com/reality) · Ten questions that build a world and measure it as you answer. 4. [Method](https://simulation-hypothesis.com/method) · One formula, every constant with its source, and how far you can trust each one. 5. [Simulations within simulations](https://simulation-hypothesis.com/nesting) · Why every stack of simulations has to end. 6. [Objections](https://simulation-hypothesis.com/objections) · Nine objections, and where a computing model stops. 7. [Reading](https://simulation-hypothesis.com/reading) · Where to go next, with a difficulty tag on each. ## For research · formula, data and citation Everything you need to check, reuse or extend the model. 1. [Method](https://simulation-hypothesis.com/method) · The formula, the physical anchors, the ladders and the dated changelog. 2. [The Sandbox](https://simulation-hypothesis.com/sandbox) · Every total with its 80% range, and the inputs ranked by influence. You can compare worlds and copy a citation. 3. [Engine API](https://simulation-hypothesis.com/api/openapi.json) · The engine as JSON. /api/price takes the parameters from any Sandbox link. /api/budget runs it backwards. 4. [Datasets](https://simulation-hypothesis.com/data/index.json) · The site’s datasets as open JSON, with a catalogue. Entities publishes its own under /entities. 5. [Tests](https://simulation-hypothesis.com/tests) · Experiments and bounds, with checked citations. 6. [Entities](https://simulation-hypothesis.com/entities) · Minds and collectives, sourced and tagged. 7. [Licence](https://simulation-hypothesis.com/licences) · CC BY 4.0: what you can reuse, and the credit line. --- title: "Reading · further reading · Simulation Hypothesis" url: https://simulation-hypothesis.com/reading description: "An annotated reading list on the simulation hypothesis, with difficulty tags." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Reading · further reading The site doesn’t try to teach the literature. It points you to it. The difficulty tags are rough. easy is one sitting. medium takes real study. hard assumes a technical background, or the Library open beside it. ## The argument itself [Are You Living in a Computer Simulation?](https://simulation-argument.com/)medium Nick Bostrom · Philosophical Quarterly, 2003 The original paper, and where the trilemma comes from. Reality+: Virtual Worlds and the Problems of Philosophymedium David Chalmers · W. W. Norton, 2022 The fullest book on the subject. It argues that simulated worlds can be truly real (simulation realism). [Constraints on the Universe as a Numerical Simulation](https://arxiv.org/abs/1210.1847)hard Beane, Davoudi & Savage · arXiv, 2012 Asks what we could observe if spacetime were simulated on a lattice, such as a directional bias in cosmic-ray spectra. ## Where the numbers come from [Ultimate Physical Limits to Computation](https://arxiv.org/abs/quant-ph/9908043)hard Seth Lloyd · Nature, 2000 Where the 5 × 10^50 operations per second per kilogram limit comes from. It’s the ceiling on every ladder on the site. Whole Brain Emulation: A Roadmapmedium Anders Sandberg & Nick Bostrom · Future of Humanity Institute technical report, 2008 Where the mind-model figures come from, level by level. Simulating Physics with Computershard Richard Feynman · International Journal of Theoretical Physics, 1982 The argument that ordinary computers can’t efficiently simulate typical quantum systems. Irreversibility and Heat Generation in the Computing Processhard Rolf Landauer · IBM Journal, 1961 The least energy it takes to erase a bit. The Power tile is built on it. ## Is the universe a computation? Rechnender Raum (Calculating Space)hard Konrad Zuse · Vieweg, 1969; English translation MIT, 1970 The first proposal that physics is the output of a cellular automaton. It was digital physics before the name existed. Digital Mechanicshard Edward Fredkin · Physica D 45, 1990 Physics as a reversible universal cellular automaton, where information is the thing that’s conserved. A New Kind of Sciencemedium Stephen Wolfram · Wolfram Media, 2002 Simple programs that produce complex behaviour, and the claim that the laws of physics may be one of them. Programming the Universeeasy Seth Lloyd · Knopf, 2006 The universe as a quantum computer, by the author of the limit behind the site’s ceilings. [The Mathematical Universe](https://arxiv.org/abs/0704.0646)medium Max Tegmark · Foundations of Physics 38, 2008 A stronger claim: physical reality is a mathematical structure, whether or not it’s computed. ## Tests and objections [Astrophysical Constraints on the Simulation Hypothesis for This Universe](https://doi.org/10.3389/fphy.2025.1561873)medium Franco Vazza · Frontiers in Physics 13, 2025 The energy it would take to simulate this universe, or Earth at different resolutions, compared with what a universe like ours holds. Summarised on the Tests page. [What Computer Science Has to Say about the Simulation Hypothesis](https://doi.org/10.1088/2632-072X/ae1e50)hard David H. Wolpert · Journal of Physics: Complexity 6, 2025 A formal treatment. Under the physical Church–Turing thesis a universe can simulate itself, and some questions about simulations can’t be decided. [Quantized Gravitational Responses, the Sign Problem, and Quantum Complexity](https://doi.org/10.1126/sciadv.1701758)hard Zohar Ringel & Dmitry Kovrizhin · Science Advances 3, 2017 Some quantum systems resist one kind of classical simulation. It’s often wrongly reported as disproving the hypothesis. It doesn’t. ## Minds What Is It Like to Be a Bat?medium Thomas Nagel · Philosophical Review, 1974 The classic argument that experience is subjective in a way that can’t be reduced to anything else. Epiphenomenal Qualiamedium Frank Jackson · Philosophical Quarterly, 1982 The knowledge argument: Mary the colour scientist, and the claim that knowing every physical fact still isn’t knowing everything. The Conscious Mindhard David Chalmers · Oxford, 1996 Lays out the hard problem and defends property dualism. Consciousness Explainedmedium Daniel Dennett · Little, Brown, 1991 The main opposing view: that the hard problem breaks up into a set of solvable problems about function. ## Doubt Meditations on First Philosophymedium René Descartes · 1641 The evil demon, an early scenario of radical doubt, and the cogito as the thing that survives it. Brains in a Vathard Hilary Putnam · in Reason, Truth and History, 1981 Argues, from semantic externalism, that the vat hypothesis can’t be coherently stated from inside it. Anarchy, State, and Utopiamedium Robert Nozick · Basic Books, 1974 Chapter 3 has the experience machine argument. ## Look things up [Stanford Encyclopedia of Philosophy](https://plato.stanford.edu/)medium plato.stanford.edu Peer-reviewed and free. Good entries to look up include consciousness and skepticism. [Internet Encyclopedia of Philosophy](https://www.iep.utm.edu/)easy iep.utm.edu A free, gentler counterpart to the Stanford Encyclopedia. [PhilPapers](https://philpapers.org/)hard philpapers.org An index of philosophy papers. Search “simulation argument”. [arXiv](https://arxiv.org/)hard arxiv.org Free preprints in physics. The Lloyd and Beane et al. papers above are hosted here. To see what each experiment and physical bound found, go to [Tests](https://simulation-hypothesis.com/tests). ## Start with the people 14 short pages, one per thinker, each with its matching sandbox dial. [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Method · how the computing is counted · Simulation Hypothesis" url: https://simulation-hypothesis.com/method description: "The one formula behind every total on the site, the physical anchors it rests on (Lloyd, Landauer, Sandberg and Bostrom), and how far you can trust each input." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Method · how the computing is counted · version 2026.6 ## The formula Every total on the site comes from one formula. We work in log\_10 so that numbers as big as 10^150 and 10(10^80) still fit: FLOPS = units(scale, floor) × ops_per_unit(floor) / timestep(floor) × rendered_fraction + Σ minds × neurons × flops_per_neuron(model) (unless absorbed by the matter floor) × time_multiplier(time model) units mass / grain-mass, or atoms, or nucleons + electrons, or 2^(particles) for a full wavefunction rendered fraction of mass that gets the full floor; the rest runs as a "painted set" at 10^13 FLOPS per watcher absorbed at molecule-or-finer floors, brains are already matter, so the mind model adds nothing comparisons Lloyd's bound (5.4×10^50 ops/s/kg), Landauer's limit (kT ln 2 at 300 K), all Earth's hardware (~10^21 FLOPS) In words Count the units of matter at the floor you picked. Multiply by the operations each one needs per step, and by the steps per second. Then keep only the fraction of the world that gets rendered. Add the computing for one brain per inner life. The exception is a matter floor fine enough to include brains already. Then they add nothing. Multiply by the time model. Linear time is a single pass. Branching takes more, and many worlds takes the most. Tags show how much you can trust each input. measured is a published measurement. textbook is standard physics or a published estimate. rough is good to within an order of magnitude. wild guess is a placeholder with nothing empirical behind it, and we label it that way. These estimates are lower bounds on the operations of the model you pick. We leave out overhead, error correction, latency, memory and communication. A real run of that model would need more computing. One gap matters most for the cheap scenarios. A world rendered only where someone is looking has to stay consistent whenever anyone looks, at any level of detail. We don’t measure what it takes to guarantee that. The model’s own choices, like the grain, the timestep and the matter rendered per observer, aren’t bounds. They can move a total either way. ## Worked examples Four scenarios worked out by hand, so you can check the arithmetic without the site. Each line uses only constants from the table below. Every time the site is built, the engine runs the same scenarios. If any total here disagrees with it, the site won’t publish. ### [Earth atom by atom](https://simulation-hypothesis.com/builds/custom) Earth at the atom floor, everything computed all the time, every mind real. | Matter | 1.33×10⁵⁰ atoms × 1,000 operations per atom per step ÷ 10⁻¹⁵ s per step | 1.3 × 10^68 | | ------- | ----------------------------------------------------------------------- | ----------------- | | By hand | the lines above, added up | 1.3 × 10^68 FLOPS | | Engine | the site’s engine, same scenario | 1.3 × 10^68 FLOPS | Minds add nothing. At the atom floor a brain is already computed as the atoms it’s made of, so it’s inside the matter term. ### [Brain in a vat](https://simulation-hypothesis.com/builds/vat) One real brain outside the simulation. Everything it senses is a painted set, and everyone else is scripted. | Painted set | 10¹³ FLOPS per observer × 1 observer | 10^13 | | ------------------- | ------------------------------------- | ----------------- | | Scripted characters | 8,199,999,999 people × 10⁶ FLOPS each | 8.2 × 10^15 | | The brain itself | runs outside, so 0 | 0 | | By hand | the lines above, added up | 8.2 × 10^15 FLOPS | | Engine | the site’s engine, same scenario | 8.2 × 10^15 FLOPS | The scripted crowd takes over 800 times the computing the scenery does. In a world rendered for one person, the other people are most of the total. ### [Solipsism](https://simulation-hypothesis.com/builds/solipsism) Same as the vat, but the one real mind is simulated too, as a functional brain model. | Painted set | 10¹³ FLOPS × 1 observer | 10^13 | | ------------------- | --------------------------------- | ----------- | | The one real mind | 1 × 10¹⁸ FLOPS (functional model) | 10^18 | | Scripted characters | 8,199,999,999 × 10⁶ FLOPS | 8.2 × 10^15 | | By hand | the lines above, added up | 10^18 FLOPS | | Engine | the site’s engine, same scenario | 10^18 FLOPS | Simulating the one mind takes about 120 times the computing of the rest of the world put together. ### [The Matrix](https://simulation-hypothesis.com/builds/sleepers) A painted Earth with every person real and modelled at the biophysical level. | Painted set | 10¹³ FLOPS per observer × 8.2×10⁹ observers | 8.2 × 10^22 | | ----------- | ---------------------------------------------------- | ----------------- | | Minds | 8.2×10⁹ people × 10²² FLOPS each (biophysical model) | 8.2 × 10^31 | | By hand | the lines above, added up | 8.2 × 10^31 FLOPS | | Engine | the site’s engine, same scenario | 8.2 × 10^31 FLOPS | Minds outweigh the scenery a billion to one. The matter floor barely matters here. The mind model sets the total. ## Every constant, and where it comes from | Anchor | Value | Trust | Source | | ------------------------------- | --------------------------------------- | ---------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Lloyd’s bound | 5.4 × 10^50 ops · s⁻¹ · kg⁻¹ | textbook | Lloyd, “Ultimate physical limits to computation”, Nature 406 (2000). The ceiling for any lump of matter used as a computer. | | Landauer’s limit | 2.87 × 10^-21 J per bit erased at 300 K | textbook | Landauer, IBM Journal of Research and Development 5 (1961): kT ln 2 at room temperature. | | Mass of the observable universe | 1.5 × 10^53 kg | rough | Ordinary matter only, worked out from the critical density and a 46-billion-light-year radius. Dark matter and dark energy are left out on purpose. | | Age of the universe | 1.38 × 10^10 years | measured | Planck 2018 cosmological parameters. | | Nucleon mass | 1.6726 × 10^-27 kg | measured | CODATA proton mass; neutrons treated the same. | | Sun’s output | 3.83 × 10^26 W | measured | Solar luminosity, IAU 2015 nominal value. | | All computing on Earth | \~10^21 FLOPS | rough | A rough sum of data centres, PCs, phones and consoles in the mid-2020s. Could be off by 10× either way. | | Neurons in a human brain | 8.6 × 10^10 | measured | Azevedo et al., Journal of Comparative Neurology 513 (2009). | | Animals on Earth | \~4.5 × 10^20 individuals | wild guess | Mostly soil nematodes: van den Hoogen et al. (2019, Nature) estimate 4.4 × 10^20 in surface soils. Insects and other arthropods add about 10^19\. Marine nematodes and other small animals aren’t counted, so this is a minimum. A nematode has about 300 neurons, so the count barely changes the inner-life ladder, which starts at the fruit fly. | | Matter one mind is looking at | 10^7 kg | wild guess | The mass of the surroundings per observer, roughly a building. This sets how much of the world is computed at the full matter floor. | | Painted-set cost | 10^13 FLOPS per watcher | wild guess | Roughly one high-end real-time rendering engine per observer. The computing needed for a world held as a lookup table. | | Molecular-dynamics step | \~10^3 FLOPs per atom per step | rough | All-atom MD with a 1 nm cutoff: each atom feels a few hundred neighbours, at a few tens of FLOPs each. Real codes land within a factor of a few of this. | | One operation | 1 op = 1 FLOP = 1 bit erased | rough | Lloyd counts basic logic operations, Landauer counts bit erasures, and the total counts floating-point operations. The site treats them as one unit. A real 64-bit multiply is thousands of gate operations, so this makes the ceilings look better than they are and understates the heat by a factor of roughly 10^3 to 10^4. | | Mind-model costs | 10^6 to 10^49 FLOPS per human brain | rough | Sandberg & Bostrom, “Whole Brain Emulation: A Roadmap” (2008), levels 4, 5 and 10\. The scripted and quantum rungs are the site’s own placeholders, and they say so. | ## Scales | Scale | Mass | Atoms | Life-bearing worlds | | ------------------- | -------------- | ----------- | ------------------------- | | One brain | 1.4 × 10^0 kg | 1.2 × 10^26 | this one, if any measured | | One room | 10^4 kg | 3.0 × 10^29 | this one, if any rough | | Earth | 6.0 × 10^24 kg | 1.3 × 10^50 | 10^0 measured | | Solar system | 2.0 × 10^30 kg | 1.2 × 10^57 | 10^0 rough | | Milky Way | 1.2 × 10^41 kg | 7.0 × 10^67 | 10^6 wild guess | | Observable universe | 1.5 × 10^53 kg | 10^80 | 2.0 × 10^17 wild guess | ## Matter floor | Rung | Unit | Ops / unit / step | Timestep | Trust | | ------------------------ | ---------------------------------------- | ----------------- | ------------------------------------------- | ---------- | | Painted set | lookup table; 10¹³ per watcher | 1 | one frame at 60 Hz | wild guess | | Organ | mass / 1e-1 kg | 20 | 10 ms, so a heartbeat gets a hundred frames | wild guess | | Tissue | mass / 1e-3 kg | 50 | 1 ms | wild guess | | Cell | mass / 1e-12 kg | 100 | 1 ms, cell biology runs slow | rough | | Organelle | mass / 1e-16 kg | 100 | 1 µs | rough | | Protein | mass / 1e-22 kg | 1000 | 1 ns, folding timescales | rough | | Molecule | 0.5 × atoms | 1000 | 10 fs, coarse-grained MD | rough | | Atom | 1 × atoms | 1000 | 1 fs, standard all-atom MD step | rough | | Particle | 1 × nucleons + electrons | 100 | 1 as, electron dynamics | rough | | Quark | 3 × nucleons + electrons | 1000 | 1 ys, strong-force timescales | wild guess | | Quantum, mean field | (nucleons + electrons) × 1e+9 amplitudes | 10 | 1 as, time-dependent quantum step | rough | | Quantum, fully entangled | 2^(nucleons + electrons) amplitudes | 10 | 1 as | textbook | ## Minds Per-brain figures scale by neuron count from the human number. Where Sandberg & Bostrom’s 2008 whole-brain-emulation roadmap has a rung, that’s our source. | Model | FLOPS / human brain | Source | | ------------------- | ------------------- | ------------------------------------------------------------------------------ | | Scripted | 10^6 wild guess | about the cost of one scripted game character | | Functional | 10^18 rough | Sandberg & Bostrom 2008, level 4 | | Biophysical | 10^22 rough | Sandberg & Bostrom 2008, level 5 | | Molecular | 10^43 rough | Sandberg & Bostrom 2008, level 10 | | Quantum | 10^49 wild guess | no published estimate; Penrose & Hameroff for the idea | | Real brain, outside | none | none, by definition: the brain runs on its own neurons, outside the simulation | | Cutoff rung | Individuals on Earth, this rung and up | Neurons each | Trust | | ----------- | -------------------------------------- | ------------ | ---------- | | Fruit fly | 10^19 | 1.4 × 10^5 | wild guess | | Insect | 10^18 | 10^6 | wild guess | | Fish | 3.5 × 10^13 | 10^7 | wild guess | | Frog | 8.0 × 10^11 | 1.6 × 10^7 | wild guess | | Mouse | 2.2 × 10^11 | 7.1 × 10^7 | rough | | Bird | 1.3 × 10^11 | 10^9 | rough | | Pig | 1.5 × 10^10 | 2.2 × 10^9 | rough | | Dog | 1.2 × 10^10 | 2.3 × 10^9 | rough | | Dolphin | 8.3 × 10^9 | 1.5 × 10^10 | wild guess | | Human | 8.2 × 10^9 | 8.6 × 10^10 | measured | ## Reference points for the total | Machine | FLOPS | Note | | ------------------------------- | -------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | a phone | 10^12 measured | A current smartphone. | | a laptop | 10^13 measured | Runs a fruit fly nervous-system model faster than real time. | | one AI accelerator | 10^15 rough | One of today’s data-centre accelerators at low precision. Training a large language model takes thousands of them. | | the biggest supercomputer | 10^18 measured | Exascale class. It fills a building. | | every computer on Earth | 10^21 rough | Servers, personal computers, phones and consoles added together. | | a Dyson-swarm data centre | 2.8 × 10^37 rough | Every watt the Sun gives off, running chips at the best measured efficiency (about 7.4 × 10^10 operations per watt). | | a Sun of Landauer-limit chips | 1.3 × 10^47 textbook | The Sun’s whole output, at the thermodynamic floor of one bit erased per operation, at room temperature. | | an Earth-mass ultimate computer | 3.2 × 10^75 textbook | Every kilogram of the planet computing at Lloyd’s bound. | | a Jupiter brain | 10^78 textbook | A gas giant turned into a computer. | | a Sun-mass ultimate computer | 1.1 × 10^81 textbook | A star turned into a computer. | | a galaxy-mass ultimate computer | 6.5 × 10^91 textbook | The Milky Way as a single computer. | | one universe-computer | 8.1 × 10^103 rough | Every kilogram of ordinary matter in the observable universe computing at Lloyd’s bound. That’s the ceiling for ordinary matter. Counting dark matter would raise it about sixfold, but we couldn’t actually use any of it. | Existing simulations one uploaded fruit fly · FlyWire mapped \~139k neurons in 2024\. Runs on a laptop. 10^12 a large online game · A server cluster keeping a few thousand people at once in one shared virtual world. 10^15 a weather model · A data centre running a real weather forecast. 10^17 an Illustris-class cosmos · Thousands of supercomputer cores running for months, growing galaxies from the starting conditions. The resolution is coarse enough that stars are treated statistically. 10^15 ## Changelog 2026.6 · 2026-10-19 * After five outside reviews. Worked examples: four scenario bills done by hand on this page, checked against the engine on every build. No constant changed. * Affordability dates lead with their range (growth a fifth faster or slower), with the central year second. * The four schools now lean for, lean against or are divided, rather than endorsing or objecting; moral weights are shown in whole percents. Both are judgements, and the old wording claimed more than that. * The unpriced cost of keeping an on-demand world consistent under every observation is now stated beside the other omissions. 2026.5 · 2026-10-16 * After an outside review. Claims of impossibility now state their conditions: “never on one star’s power” holds for conventional logic that erases a bit per operation at room temperature; reversible computing and a colder heat sink would lower that floor, and the site does not price them. * Lloyd’s bound is described as a ceiling on operations for matter as hot as a plasma, not for a rocky body, and the mass it gives for Earth atom by atom counts operations only: storing that world’s state takes far more matter. * The universe-computer is the ceiling for ordinary matter (now tagged rough); dark matter would raise it about sixfold. * The 10^15 FLOPS comparison is one AI accelerator at low precision (was “a rack of GPUs”, tagged measured). * The quark rung is tagged wild guess: no known classical method follows quark dynamics in real time. The fully entangled rung notes that it counts amplitudes on a classical host. * All-atom molecular dynamics reproduces non-reactive chemistry only; bond-making needs quantum methods not priced at that rung. * Neuron counts on the inner-life ladder that have no published whole-brain measurement (fish, frog, dolphin) are tagged wild guess, and the human rung says it is a cutoff by species, not by neuron count. * Animals on Earth is about 4.5 × 10^20, mostly soil nematodes (was 2.5 × 10^19, “almost all insects”). It counts the animals left as scenery and does not change any bill. 2026.4 · 2026-10-07 * The inner-life ladder is ordered by neurons per individual: the mouse (7.1 × 10^7) now sits below the bird (10^9), and the pig (2.2 × 10^9) below the dog (2.3 × 10^9). Each rung keeps its own population; the counts “this rung and up” are re-summed. Sandbox links with a cutoff of 5 to 8 now name the reordered rungs. * Dial settings no longer carry confidence tags, since they are choices. A real brain outside the simulation costs nothing by definition and is no longer tagged “measured”. * The comparison machines from the Dyson swarm up are now computed from the constants above, not rounded to whole powers of ten. A Sun of Landauer-limit chips is 1.3 × 10^47 FLOPS (was 10^47) and an Earth-mass computer 3.2 × 10^75 (was 10^75), so 3.0 × 10^50 FLOPS now reads “2,200 ×”, not “3,000 ×”, matching the power tile beside it. * Feasibility no longer says “never, with known physics” for bills past the Sun’s line: a bill can pass one star’s power and still fit in matter computing at Lloyd’s bound. Earth atom by atom needs about 2.5 × 10^17 kg of such matter, not, as the Countdown said, about a planet. 2026.3 · 2026-10-06 * New mind model, “Real brain, outside”: the mind is a biological brain in the base reality, wired to the simulation. Its neurons do their own computing, so it adds nothing to the bill; only the world it senses is priced. * The Brain in a Vat preset now uses it. It used to simulate the brain itself at the biophysical level (10^22 FLOPS, about ten times every computer on Earth), which is an upload, not a vat. It now costs 8.2 × 10^15 FLOPS, almost all of it the scripted people around the brain. 2026.2 · 2026-10-04 * Feasibility now names the rung a bill passes, in one unit at a time: past every computer on Earth, past the Sun’s whole output at the Landauer floor (power), past an Earth-mass computer at Lloyd’s bound (mass), past the universe-computer. “Stellar-scale” and “galaxy-scale” mixed the two and are gone. * Computer size is written as a multiple of the rung at or below the bill (3.0 × 10^50 FLOPS reads “3,000 × a Sun of Landauer-limit chips”), not rounded to the nearest rung, which could hide a factor of 10^14. * One figure for how far chips sit above Landauer’s floor: the best measured machine, 1.36 × 10^-11 J per operation (Green500, November 2025), about five billion times the floor. The Dyson-swarm rung and the day bill use the same figure. * Infinite regress follows one rule: a simulated computer cannot out-compute the world it runs in, so each nested layer gets at most a share (1%) of its parent’s computation. The old panel divided headroom by an arbitrary factor. The stack can be built layer by layer on /nesting. * Every bill now carries a range. Each uncertain input is drawn from a log-normal spread set by its tag (one standard deviation: measured ±12%, textbook ±41%, rough ×3.2, wild guess ×10) and the engine is rerun 400 times; the Sandbox shows the 10th to 90th percentile and ranks the inputs by how far each alone moves the bill. Dial settings are choices and carry no spread. * Bills are also given in human terms: watts on the best measured chips against the world’s electricity, current AI accelerators (about 10^15 operations a second, about $30,000 each), a yearly electricity bill at $0.10 a kilowatt-hour, and Sagan’s Kardashev rating. Today’s-chip efficiency is now one constant site-wide (7.4 × 10^10 operations per watt, was 7 × 10^10 in two places), which moves the Countdown’s grid ceiling by 0.02 orders of magnitude. 2026.1 · 2026-09-28 * Dyson-swarm rung moved from 10^26 to 10^37 FLOPS. The old figure was the Sun’s watts, not what those watts buy at 50 GFLOPS per watt. * Molecular mind model re-sourced to level 10 of the Sandberg & Bostrom roadmap (it said level 9, which is 10^30, not 10^43). * Atom and molecule matter floors now cost 10^3 FLOPs per unit per step, up from 10^2, and are tagged rough. Bills at those floors rise tenfold. * Illustris-class cosmos moved from 10^18 to 10^15 FLOPS sustained. * New anchor saying out loud that an operation, a FLOP and a bit erasure are counted as the same unit. * α\_G on the former fine-tuning console described correctly: gravity against ħc, not against the electric force. * Real chips are about ten billion times above Landauer’s floor, not a million (2 × 10^-11 J per operation against 2.9 × 10^-21 J). ## What this is not This isn’t a verdict on whether we’re simulated, and it doesn’t judge what you believe. It can’t tell you who is real. The suffering dial and the inner-lives cutoff are settings for a hypothetical renderer. A hard life says nothing about the person living it. This is a computing model of a hypothetical, and it states its uncertainties. The site is written and maintained by [Ross Allan Dahl](https://rossdahl.com). --- title: "Featured scenario · Simulation Hypothesis" url: https://simulation-hypothesis.com/today description: "One scenario a day, picked by the calendar from a pool of setups. You get its computing total, its ethical judgement, and a link to change it in the sandbox." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- Featured scenario · 2026-10-23 110 of 120 # Inner life at every rung · today’s universe Open in the sandbox ▸ One setup is picked each day from a pool of 120, based on the date. Everyone sees the same one on the same day. Required computing power rough 6.0 × 10^33 FLOPS Our computers could run this between 2109 and 2144, if steady growth runs a fifth faster or slower (2123 at the central rate). [The countdown ▸](https://simulation-hypothesis.com/countdown) More than every computer on Earth put together, by a factor of about 10^13. Computer sizerough 10¹³ × every computer on Earth Servers, personal computers, phones and consoles added together. Feasibility Beyond all existing hardware More than every computer on Earth combined. Universe-computerstextbook 7.4 × 10^-71 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 17 TW The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. A fraction of a national power grid, at the thermodynamic minimum for erasing bits. On every computer on Earthrough 189.4 thousand years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 189.4 thousand years of all Earth’s computing for every simulated second. World actually computedwild guess 100% 100% of the mass is watched by 101 observers. The observation dial sets how much of the remainder is computed at the full floor. ## Report card Instance report INNER LIFE AT EVERY RUNG Settings Scale One room Matter floor Tissue Lobby Real and scripted minds Inner lives 6.0 × 10^30 · biophysical Computed 100% Time Branching, pruned, live from 3.8 × 10^9 yrs ago Slot A scripted character that detects the seams Computing needed 6.0 × 10^33 FLOPS Computer size 10¹³ × every computer on Earth Universe-computers 7.4 × 10^-71 Feasibility Beyond all existing hardware Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Genuinely free Utilitarian divided Deontological leans for Virtue ethics leans for Existentialist leans for “Gave every nervous system an inner life. The minds barely change the total. The matter dominates: 6.0 × 10^33 FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. ## In one line “Gave every nervous system an inner life. The minds barely change the total. The matter dominates: 6.0 × 10^33 FLOPS.” There’s a new one tomorrow. You can also browse the named scenarios: [all 9 of them](https://simulation-hypothesis.com/builds). Matter computingrough 10^15 FLOPS 10^7 tissue-sized units across room, each updated every 1 ms. Mind computingrough 6.0 × 10^30 FLOPS Sandberg & Bostrom 2008, level 5 6.0 × 10^30 minds, each computed as a biophysical model. Next to the matter, they’re a small part of the total. Inner liveswild guess 6.0 × 10^30 6.0 × 10^30 real minds. 0 organisms left as scenery. Operations so farrough 7.2 × 10^50 3.8 billion years on the clock, at 6.0 × 10^33 per second. History that is only storedrough 72.46% Computing begins 3.8 billion years ago. No humans are present at the start. --- title: "What runs here · fonts, analytics, licences · Simulation Hypothesis" url: https://simulation-hypothesis.com/licences description: "Everything the site loads, and how to reuse it. The writing and data are CC BY 4.0, open to any reader, human or machine." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # What runs here · fonts, analytics, licences ## What the page loads Everything loads from this domain, with two exceptions. One is a page counter. The other is Cloudflare’s bot check, which only loads when you open the critique form. There are no cookies, no accounts and no email sign-up. Your answers to the Your Reality questions stay in your browser. If you send a critique, we store what you submit: the text, the node, the choices you made if you add them, and the time. One reader sees it. We don’t store your IP address. Cloudflare Web Analytics a cookieless beacon that counts page views in total. No cookies, and no record of individual visitors Your theme choice kept in your browser’s local storage and never sent anywhere Sandbox links the whole setup is encoded in the URL, and the server keeps no record ## Readers The site is written for any reader who can take it in: a human, another animal, a synthetic intelligence, or a mind that is part biological and part synthetic. No kind of reader ranks above another. Every page, file and dataset is open to everyone on the same terms. Nothing is held back or changed depending on who or what is reading. The one exception is the critique form. It runs an automated spam check that may turn away automated senders. A reader it stops can still quote and cite anything here. ## Reuse, by any reader The site’s writing and data are licensed [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Any reader, of any kind, can read, quote, adapt, index, cite and train on them, for any purpose, as long as you give credit: “[Ross Allan Dahl](https://rossdahl.com), Simulation Hypothesis (simulation-hypothesis.com)”. Passages and figures quoted from published sources keep their own terms, and we cite them where they appear. Every page as Markdown add `.md` to any address, like The site as text , a guide for language models and agents, with reading conventions; , everything in one file, also split by section; , every node of the trees Open data every dataset behind the pages, as JSON, the trees included: Crawlers all welcome, including ones that train models. Nothing is blocked ## Typefaces All four have open licences. We serve them from this domain, not from a third-party font service. Cormorant Garamond Christian Thalmann (Catharsis Fonts) · SIL Open Font License 1.1 IBM Plex Sans Mike Abbink and Bold Monday for IBM · SIL Open Font License 1.1 JetBrains Mono JetBrains · SIL Open Font License 1.1 Source Serif 4 Frank Grießhammer for Adobe · SIL Open Font License 1.1 Other scripts IBM Plex Sans Arabic and Devanagari (IBM); Noto Naskh Arabic, Noto Nastaliq Urdu, Noto Serif Devanagari, Noto Sans and Serif Bengali, Noto Sans and Serif Ethiopic (Google) · SIL Open Font License 1.1, served from this site. Chinese, Japanese and Korean use the fonts already on your device. ## Images The Earth behind the light theme photographed by the Apollo 17 crew, 7 December 1972 (NASA AS17-148-22727) · public domain ## The numbers Every constant used by the engine is listed with its source on the [Method](https://simulation-hypothesis.com/method) page. Published figures are cited. The site’s own placeholders are tagged “wild guess”. ## This is not Not a verdict on whether we’re simulated. Not a judgement of what you believe. Not a detector of who is real. --- title: "Entities · minds and possible minds, sorted by evidence · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities description: "A sourced guide to minds: animals with measured neuron counts, collective and artificial systems, and the published tests for sentience and consciousness." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Entities · minds and possible minds, sorted by evidence If the world is a simulation, minds may be some of the hardest things in it to compute. This guide lists the known cases, from single cells to humans. It also covers the artificial systems built so far, and the minds that scientists and philosophers have proposed but nobody has observed. Every figure has a source and a confidence tag. measured is a direct count, estimate is worked out from other data, and not counted means nobody has published a count. Whether any of these systems has experiences is a separate question. The evidence for that is under [sentience criteria](https://simulation-hypothesis.com/entities/sentience) and [consciousness indicators](https://simulation-hypothesis.com/entities/indicators). ## Individual minds ## Animals: neurons in the cortex and the whole brain Cortex or pallium Whole brain All Mammals Birds Neurons in the cerebral cortex (mammals) or the pallium (birds), a widely used anatomical guide to cognitive capacity. Logarithmic scale; solid bars are counts, hatched bars estimates or disputed counts (†). Reptiles and invertebrates are not shown, as no comparable count is available. 1. Orca † 43.1 billion 2. Long-finned pilot whale † 37.2 billion 3. [Human](https://simulation-hypothesis.com/entities/human)▲1 16.3 billion 4. Harbour porpoise † 14.9 billion 5. [Bottlenose dolphin †](https://simulation-hypothesis.com/entities/dolphin) 12.7 billion 6. Cuvier’s beaked whale 9.1 billion 7. Gorilla 8.5 billion 8. Orangutan 8.5 billion 9. [Chimpanzee](https://simulation-hypothesis.com/entities/chimp) 7.4 billion 10. Common dolphin 6.7 billion 11. Harp seal 6.1 billion 12. [African elephant](https://simulation-hypothesis.com/entities/elephant)▼1 5.6 billion 13. Fin whale 5.2 billion 14. Blue whale 5.1 billion 15. Minke whale 3.2 billion Show all 88 10^6 10^7 10^8 10^9 10^10 10^11 neurons Show the numbers | # | Animal | Cortex or pallium | Whole brain | | -- | ------------------------- | ----------------- | ------------ | | 1 | Orca † | 43.1 billion | | | 2 | Long-finned pilot whale † | 37.2 billion | | | 3 | Human | 16.3 billion | 86.1 billion | | 4 | Harbour porpoise † | 14.9 billion | | | 5 | Bottlenose dolphin † | 12.7 billion | | | 6 | Cuvier’s beaked whale | 9.1 billion | | | 7 | Gorilla | 8.5 billion | | | 8 | Orangutan | 8.5 billion | | | 9 | Chimpanzee | 7.4 billion | | | 10 | Common dolphin | 6.7 billion | | | 11 | Harp seal | 6.1 billion | | | 12 | African elephant | 5.6 billion | 257 billion | | 13 | Fin whale | 5.2 billion | | | 14 | Blue whale | 5.1 billion | | | 15 | Minke whale | 3.2 billion | 57.4 billion | | 16 | Olive baboon | 2.88 billion | 10.9 billion | | 17 | Beluga | 2.7 billion | | | 18 | Pygmy sperm whale | 2.02 billion | | | 19 | Blue-and-yellow macaw | 1.92 billion | 3.14 billion | | 20 | Rhesus macaque | 1.71 billion | 6.39 billion | | 21 | Giraffe | 1.67 billion | 11.2 billion | | 22 | Squirrel monkey | 1.34 billion | 3.25 billion | | 23 | Eurasian eagle-owl | 1.33 billion | 1.9 billion | | 24 | Kea | 1.28 billion | 2.15 billion | | 25 | Snowy owl | 1.27 billion | 1.81 billion | | 26 | Common raven | 1.2 billion | 2.17 billion | | 27 | Tawny owl | 1.15 billion | 1.58 billion | | 28 | Capuchin monkey | 1.14 billion | 3.69 billion | | 29 | Sulphur-crested cockatoo | 1.14 billion | 2.12 billion | | 30 | African grey parrot | 850 million | 1.57 billion | | 31 | Rook | 820 million | 1.51 billion | | 32 | Greater kudu | 793 million | 6.09 billion | | 33 | Long-eared owl | 673 million | 991 million | | 34 | Goffin's cockatoo | 599 million | 1.16 billion | | 35 | Lion | 545 million | 4.67 billion | | 36 | White-tailed eagle | 543 million | 1.65 billion | | 37 | Eurasian jay | 529 million | 1.09 billion | | 38 | Domestic dog | 526 million | | | 39 | Striped hyena | 495 million | 3.88 billion | | 40 | Western jackdaw | 492 million | 968 million | | 41 | Common ostrich | 479 million | 1.63 billion | | 42 | Eurasian magpie | 443 million | 897 million | | 43 | Saker falcon | 443 million | 1.2 billion | | 44 | Emu | 439 million | 1.34 billion | | 45 | Raccoon | 438 million | 2.15 billion | | 46 | Barn owl | 437 million | 690 million | | 47 | Little owl | 401 million | 586 million | | 48 | Black vulture | 399 million | 1.01 billion | | 49 | Eurasian pygmy owl | 364 million | 533 million | | 50 | Common buzzard | 352 million | 1 billion | | 51 | Greater rhea | 330 million | 1.03 billion | | 52 | Mute swan | 324 million | 1 billion | | 53 | Domestic pig | 293 million | 2.22 billion | | 54 | Greylag goose | 259 million | 738 million | | 55 | Brown bear | 251 million | 9.59 billion | | 56 | Domestic cat | 250 million | 1.22 billion | | 57 | Common marmoset | 245 million | 638 million | | 58 | Common kestrel | 238 million | 625 million | | 59 | Eurasian teal | 167 million | 375 million | | 60 | Budgerigar | 149 million | 322 million | | 61 | Red-breasted goose | 149 million | 483 million | | 62 | Wood duck | 138 million | 306 million | | 63 | Pygmy falcon | 132 million | 350 million | | 64 | Marbled duck | 130 million | 387 million | | 65 | Indian peafowl | 130 million | 571 million | | 66 | Yellow-knobbed curassow | 125 million | 653 million | | 67 | Victoria crowned pigeon | 118 million | 579 million | | 68 | Mallard | 112 million | 367 million | | 69 | Wild turkey | 106 million | 493 million | | 70 | Eurasian sparrowhawk | 87.8 million | 402 million | | 71 | Reeves’s pheasant | 80.7 million | 387 million | | 72 | Rock pigeon | 72 million | 310 million | | 73 | European rabbit | 71.5 million | 513 million | | 74 | Red junglefowl | 60.7 million | 221 million | | 75 | Chilean tinamou | 59.1 million | 241 million | | 76 | Zebra finch | 55.2 million | 136 million | | 77 | Elegant crested tinamou | 51.4 million | 218 million | | 78 | Common wood pigeon | 51.3 million | 259 million | | 79 | Quebracho crested tinamou | 48.3 million | 236 million | | 80 | African collared dove | 40 million | 139 million | | 81 | Northern bobwhite | 39.1 million | 148 million | | 82 | Grey partridge | 36.9 million | 170 million | | 83 | Rat | 31 million | 200 million | | 84 | Common quail | 22.6 million | 118 million | | 85 | King quail | 20.5 million | 80.5 million | | 86 | Diamond dove | 18.2 million | 87.9 million | | 87 | Mouse | 13.7 million | 70.9 million | | 88 | Naked mole-rat | 5.31 million | 33.6 million | ## AI systems: parameters against synapses All parameters Used per token All Language Multimodal Vision Other (speech, biology, games, robotics…) Trainable parameters (connection weights), on a logarithmic scale: every notable model in Epoch AI’s database with a parameter count (retrieved 3 October 2026). Solid bars are counts Epoch rates confident; hatched bars are counts it rates likely or speculative. Bars marked \* are estimates for closed models whose developers do not publish their size, compiled 2 October 2026 from third-party analyses; the whisker shows the estimate’s range. Gemini 3 and later: no published estimate. Hollow rows are synapse counts: a parameter is closer to a synapse than to a neuron. 1. Human neocortex 1.6 × 10¹⁴ 2. GPT-5.5 (OpenAI, 2026) \* \~4.7 × 10¹² 3. Claude Fable 5 (Anthropic, 2026) \* \~3.5 × 10¹² 4. Grok 3 (xAI, 2025) \~3 × 10¹² 5. Grok 4 (xAI, 2025) \~3 × 10¹² 6. Gemini 2.5 Pro (Google, 2025) \* \~3 × 10¹² 7. Kimi K3 (Moonshot, 2026) \~2.8 × 10¹² 8. Qwen 3.8 Max (Alibaba, 2026) 2.4 × 10¹² 9. Qwen3.8-2.4T-A95B (Alibaba, 2026) 2.4 × 10¹² 10. Grok 4.7 (xAI, 2026) \* \~2.1 × 10¹² 11. Llama 4 Behemoth (Meta AI, 2025) \~2 × 10¹² 12. GPT-4 (OpenAI, 2023) \~1.8 × 10¹² 13. DeepSeek-V4-Pro (DeepSeek, 2026) \~1.6 × 10¹² 14. LongCat-2.0 (Meituan Inc, 2026) \~1.6 × 10¹² 15. Switch (Google, 2021) 1.6 × 10¹² 16. GLaM (Google, 2021) 1.2 × 10¹² 17. PanGu-Σ (Huawei Noah's Ark Lab, 2023) 1.1 × 10¹² 18. Kimi K2.5 (Moonshot, 2026) \~1 × 10¹² 19. Composer 2 (Cursor, 2026) 1 × 10¹² 20. Kimi K2.6 (Moonshot, 2026) 1 × 10¹² 21. Composer 2.5 (Cursor, 2026) \~1 × 10¹² 22. MiMo-V2-Pro (Xiaomi Corp, 2026) 1 × 10¹² 23. MiMo-V2.5-Pro (Xiaomi Corp, 2026) \~1 × 10¹² 24. M6-T (Alibaba, 2021) \~1 × 10¹² 25. Kimi K2 (Moonshot, 2025) 1 × 10¹² 26. Qwen3-Max (Alibaba, 2025) \~1 × 10¹² 27. Ling-1T (Ant Group, 2025) 1 × 10¹² 28. Kimi K2 Thinking (Moonshot, 2025) \~1 × 10¹² 29. Inkling (Thinking Machines, 2026) \~9.8 × 10¹¹ 30. Tencent Hy4 preview (Tencent, 2026) \~7.7 × 10¹¹ 31. GLM-5.1 (Z.ai (Zhipu AI), 2026) 7.5 × 10¹¹ 32. K-EXAONE 2.0 (LG AI Research, 2026) 7.5 × 10¹¹ 33. DeepSeek V4.1 Flash (DeepSeek, 2026) \~7.5 × 10¹¹ 34. GLM-5 (Z.ai (Zhipu AI), 2026) \~7.4 × 10¹¹ 35. GLM-5.3 (Z.ai (Zhipu AI), 2026) 7.4 × 10¹¹ 36. A.X K2 (SK Telecom, 2026) 6.9 × 10¹¹ 37. DeepSeekMath-V2 (DeepSeek, 2025) 6.8 × 10¹¹ 38. Mistral Large 3 (Mistral AI, 2025) 6.8 × 10¹¹ 39. DeepSeek-V3 (DeepSeek, 2024) 6.7 × 10¹¹ 40. DeepSeek-R1 (DeepSeek, 2025) 6.7 × 10¹¹ Show all 725 10^4 10^6 10^8 10^10 10^12 10^14 parameters or synapses Show the numbers | # | System | All parameters | Used per token | Year | Kind | | --- | ------------------------------------------------------------------------------------------- | -------------- | -------------- | ---- | --------------------------------------------- | | 1 | Human neocortex | 1.6 × 10¹⁴ | 1.6 × 10¹⁴ | | synapses | | 2 | GPT-5.5 (OpenAI, 2026) \* | \~4.7 × 10¹² | | 2026 | estimate | | 3 | Claude Fable 5 (Anthropic, 2026) \* | \~3.5 × 10¹² | | 2026 | estimate | | 4 | Grok 3 (xAI, 2025) | \~3 × 10¹² | | 2025 | estimate | | 5 | Grok 4 (xAI, 2025) | \~3 × 10¹² | | 2025 | estimate | | 6 | Gemini 2.5 Pro (Google, 2025) \* | \~3 × 10¹² | | 2025 | estimate | | 7 | Kimi K3 (Moonshot, 2026) | \~2.8 × 10¹² | | 2026 | estimate | | 8 | Qwen 3.8 Max (Alibaba, 2026) | 2.4 × 10¹² | 2.4 × 10¹² | 2026 | architecture not stated | | 9 | Qwen3.8-2.4T-A95B (Alibaba, 2026) | 2.4 × 10¹² | 9.5 × 10¹⁰ | 2026 | mixture of experts | | 10 | Grok 4.7 (xAI, 2026) \* | \~2.1 × 10¹² | | 2026 | estimate | | 11 | Llama 4 Behemoth (Meta AI, 2025) | \~2 × 10¹² | | 2025 | estimate | | 12 | GPT-4 (OpenAI, 2023) | \~1.8 × 10¹² | | 2023 | estimate | | 13 | DeepSeek-V4-Pro (DeepSeek, 2026) | \~1.6 × 10¹² | | 2026 | estimate | | 14 | LongCat-2.0 (Meituan Inc, 2026) | \~1.6 × 10¹² | | 2026 | estimate | | 15 | Switch (Google, 2021) | 1.6 × 10¹² | 1.6 × 10¹² | 2021 | mixture of experts (active count unpublished) | | 16 | GLaM (Google, 2021) | 1.2 × 10¹² | 1.2 × 10¹² | 2021 | mixture of experts (active count unpublished) | | 17 | PanGu-Σ (Huawei Noah's Ark Lab, 2023) | 1.1 × 10¹² | 1.1 × 10¹² | 2023 | mixture of experts (active count unpublished) | | 18 | Kimi K2.5 (Moonshot, 2026) | \~1 × 10¹² | | 2026 | estimate | | 19 | Composer 2 (Cursor, 2026) | 1 × 10¹² | 1 × 10¹² | 2026 | mixture of experts (active count unpublished) | | 20 | Kimi K2.6 (Moonshot, 2026) | 1 × 10¹² | 1 × 10¹² | 2026 | mixture of experts (active count unpublished) | | 21 | Composer 2.5 (Cursor, 2026) | \~1 × 10¹² | | 2026 | estimate | | 22 | MiMo-V2-Pro (Xiaomi Corp, 2026) | 1 × 10¹² | 1 × 10¹² | 2026 | architecture not stated | | 23 | MiMo-V2.5-Pro (Xiaomi Corp, 2026) | \~1 × 10¹² | | 2026 | estimate | | 24 | M6-T (Alibaba, 2021) | \~1 × 10¹² | | 2021 | estimate | | 25 | Kimi K2 (Moonshot, 2025) | 1 × 10¹² | 1 × 10¹² | 2025 | mixture of experts (active count unpublished) | | 26 | Qwen3-Max (Alibaba, 2025) | \~1 × 10¹² | | 2025 | estimate | | 27 | Ling-1T (Ant Group, 2025) | 1 × 10¹² | 5 × 10¹⁰ | 2025 | mixture of experts | | 28 | Kimi K2 Thinking (Moonshot, 2025) | \~1 × 10¹² | | 2025 | estimate | | 29 | Inkling (Thinking Machines, 2026) | \~9.8 × 10¹¹ | | 2026 | estimate | | 30 | Tencent Hy4 preview (Tencent, 2026) | \~7.7 × 10¹¹ | | 2026 | estimate | | 31 | GLM-5.1 (Z.ai (Zhipu AI), 2026) | 7.5 × 10¹¹ | 7.5 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 32 | K-EXAONE 2.0 (LG AI Research, 2026) | 7.5 × 10¹¹ | 7.5 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 33 | DeepSeek V4.1 Flash (DeepSeek, 2026) | \~7.5 × 10¹¹ | | 2026 | estimate | | 34 | GLM-5 (Z.ai (Zhipu AI), 2026) | \~7.4 × 10¹¹ | | 2026 | estimate | | 35 | GLM-5.3 (Z.ai (Zhipu AI), 2026) | 7.4 × 10¹¹ | 4 × 10¹⁰ | 2026 | mixture of experts | | 36 | A.X K2 (SK Telecom, 2026) | 6.9 × 10¹¹ | 6.9 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 37 | DeepSeekMath-V2 (DeepSeek, 2025) | 6.8 × 10¹¹ | 6.8 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 38 | Mistral Large 3 (Mistral AI, 2025) | 6.8 × 10¹¹ | 4.1 × 10¹⁰ | 2025 | mixture of experts | | 39 | DeepSeek-V3 (DeepSeek, 2024) | 6.7 × 10¹¹ | 3.7 × 10¹⁰ | 2024 | mixture of experts | | 40 | DeepSeek-R1 (DeepSeek, 2025) | 6.7 × 10¹¹ | 3.7 × 10¹⁰ | 2025 | mixture of experts | | 41 | SenseChat 5.5 (SenseTime, 2024) | 6 × 10¹¹ | 6 × 10¹¹ | 2024 | architecture not stated | | 42 | Step 5 Preview (StepFun, 2026) | \~6 × 10¹¹ | | 2026 | estimate | | 43 | PaLM-E (Google, 2023) | \~5.6 × 10¹¹ | | 2023 | estimate | | 44 | Hunyuan-TurboS (Tencent, 2025) | 5.6 × 10¹¹ | 5.6 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 45 | LongCat-Flash (Meituan Inc, 2025) | \~5.6 × 10¹¹ | | 2025 | estimate | | 46 | Nemotron 3 Ultra (Nvidia, 2026) | \~5.5 × 10¹¹ | | 2026 | estimate | | 47 | PaLM (Google Research, 2022) | 5.4 × 10¹¹ | 5.4 × 10¹¹ | 2022 | dense | | 48 | Minerva (Google, 2022) | 5.4 × 10¹¹ | 5.4 × 10¹¹ | 2022 | dense | | 49 | U-PaLM (Google, 2022) | 5.4 × 10¹¹ | 5.4 × 10¹¹ | 2022 | dense | | 50 | LMSI-Palm (Google, 2022) | 5.4 × 10¹¹ | 5.4 × 10¹¹ | 2022 | dense | | 51 | Flan-PaLM 540B (Google, 2022) | 5.4 × 10¹¹ | 5.4 × 10¹¹ | 2022 | dense | | 52 | Megatron-Turing NLG 530B (Microsoft, 2021) | 5.3 × 10¹¹ | 5.3 × 10¹¹ | 2021 | dense | | 53 | MegaScale (ByteDance, 2024) | \~5.3 × 10¹¹ | | 2024 | estimate | | 54 | A.X K1 (SK Telecom, 2025) | 5.2 × 10¹¹ | 5.2 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 55 | Doubao-pro (ByteDance, 2024) | \~5 × 10¹¹ | | 2024 | estimate | | 56 | Grok 4.20 (xAI, 2026) | \~5 × 10¹¹ | | 2026 | estimate | | 57 | Qwen3-Coder-480B-A35B (Alibaba, 2025) | 4.8 × 10¹¹ | 3.5 × 10¹⁰ | 2025 | mixture of experts | | 58 | MiniMax-M3 (MiniMax, 2026) | 4.3 × 10¹¹ | 2.2 × 10¹⁰ | 2026 | mixture of experts | | 59 | ERNIE-4.5-VL-424B-A47B (Baidu, 2025) | 4.2 × 10¹¹ | 4.7 × 10¹⁰ | 2025 | mixture of experts | | 60 | Llama 3.1-405B (Meta AI, 2024) | 4 × 10¹¹ | 4 × 10¹¹ | 2024 | dense | | 61 | Llama 4 Maverick (Meta AI, 2025) | \~4 × 10¹¹ | | 2025 | estimate | | 62 | Jamba 1.5-Large (AI21 Labs, 2024) | 4 × 10¹¹ | 4 × 10¹¹ | 2024 | mixture of experts (active count unpublished) | | 63 | Qwen3.5 397B-A17B (Alibaba, 2026) | \~4 × 10¹¹ | | 2026 | estimate | | 64 | Hunyuan-Large (Tencent, 2024) | 3.9 × 10¹¹ | 3.9 × 10¹¹ | 2024 | mixture of experts (active count unpublished) | | 65 | GLM-4.7 (Z.ai (Zhipu AI), 2025) | \~3.6 × 10¹¹ | | 2025 | estimate | | 66 | GLM-4.6 (Z.ai (Zhipu AI), 2025) | \~3.6 × 10¹¹ | | 2025 | estimate | | 67 | GLM-4.5 (Z.ai (Zhipu AI), 2025) | 3.5 × 10¹¹ | 3.2 × 10¹⁰ | 2025 | mixture of experts | | 68 | PaLM 2 (Google, 2023) | \~3.4 × 10¹¹ | | 2023 | estimate | | 69 | Med-PaLM 2 (Google Research, 2023) | \~3.4 × 10¹¹ | | 2023 | estimate | | 70 | Nemotron-4 340B (Nvidia, 2024) | 3.4 × 10¹¹ | 3.4 × 10¹¹ | 2024 | dense | | 71 | GLM-5.3-Flash (Z.ai (Zhipu AI), 2026) | \~3.2 × 10¹¹ | | 2026 | estimate | | 72 | Grok-1 (xAI, 2023) | \~3.1 × 10¹¹ | | 2023 | estimate | | 73 | Motif-3 (Motif Technologies, 2026) | 3.1 × 10¹¹ | 3.1 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 74 | SB-LM (Google, 2007) | \~3 × 10¹¹ | | 2007 | estimate | | 75 | Tencent Hy3 preview (Tencent, 2026) | 3 × 10¹¹ | 3 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 76 | Tencent Hy3 (Tencent, 2026) | 3 × 10¹¹ | 3 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 77 | DeepSeek-V4-Flash (DeepSeek, 2026) | \~2.8 × 10¹¹ | | 2026 | estimate | | 78 | Gopher (DeepMind, 2021) | 2.8 × 10¹¹ | 2.8 × 10¹¹ | 2021 | dense | | 79 | TML-Interaction-Small (Thinking Machines, 2026) | 2.8 × 10¹¹ | 2.8 × 10¹¹ | 2026 | mixture of experts (active count unpublished) | | 80 | ST-MoE (Google, 2022) | \~2.7 × 10¹¹ | | 2022 | estimate | | 81 | ERNIE 3.0 Titan (Baidu, 2021) | 2.6 × 10¹¹ | 2.6 × 10¹¹ | 2021 | dense | | 82 | Solar Open2 250B (Upstage, 2026) | \~2.5 × 10¹¹ | | 2026 | estimate | | 83 | Aramco Metabrain AI (Saudi Aramco, 2024) | \~2.5 × 10¹¹ | | 2024 | estimate | | 84 | Yuan 1.0 (Inspur, 2021) | 2.5 × 10¹¹ | 2.5 × 10¹¹ | 2021 | architecture not stated | | 85 | DeepSeek-Coder-V2 236B (DeepSeek, 2024) | 2.4 × 10¹¹ | 2.4 × 10¹¹ | 2024 | mixture of experts (active count unpublished) | | 86 | DeepSeek-V2.5 (DeepSeek, 2024) | 2.4 × 10¹¹ | 2.4 × 10¹¹ | 2024 | mixture of experts (active count unpublished) | | 87 | K-EXAONE (LG AI Research, 2025) | 2.4 × 10¹¹ | 2.4 × 10¹¹ | 2025 | architecture not stated | | 88 | Qwen3-235B-A22B (Alibaba, 2025) | \~2.4 × 10¹¹ | | 2025 | estimate | | 89 | Qwen3-235B-A22B-Thinking (Alibaba, 2025) | \~2.4 × 10¹¹ | | 2025 | estimate | | 90 | P1-235B-A22B (Shanghai AI Lab, 2025) | \~2.4 × 10¹¹ | | 2025 | estimate | | 91 | Seed-1.6-Thinking (ByteDance, 2025) | 2.3 × 10¹¹ | 2.3 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 92 | MiniMax-M2 (MiniMax, 2025) | 2.3 × 10¹¹ | 1 × 10¹⁰ | 2025 | mixture of experts | | 93 | MiniMax-M2.1 (MiniMax, 2025) | 2.3 × 10¹¹ | 2.3 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 94 | HyperCLOVA 204B (NAVER, 2021) | \~2 × 10¹¹ | | 2021 | estimate | | 95 | Amazon Titan (Amazon, 2023) | \~2 × 10¹¹ | | 2023 | estimate | | 96 | Falcon-180B (Technology Innovation Institute, 2023) | 1.8 × 10¹¹ | 1.8 × 10¹¹ | 2023 | dense | | 97 | Jurassic-1-Jumbo (AI21 Labs, 2021) | 1.8 × 10¹¹ | 1.8 × 10¹¹ | 2021 | architecture not stated | | 98 | BLOOM-176B (Hugging Face, 2022) | 1.8 × 10¹¹ | 1.8 × 10¹¹ | 2022 | dense | | 99 | BLUUMI (University of Turku, 2023) | \~1.8 × 10¹¹ | | 2023 | estimate | | 100 | InstructGPT 175B (OpenAI, 2022) | 1.8 × 10¹¹ | 1.8 × 10¹¹ | 2022 | dense | | 101 | OPT-175B (Meta AI, 2022) | 1.8 × 10¹¹ | 1.8 × 10¹¹ | 2022 | dense | | 102 | BlenderBot 3 (McGill University, 2022) | \~1.8 × 10¹¹ | | 2022 | estimate | | 103 | GPT-3 175B (OpenAI, 2020) | 1.7 × 10¹¹ | 1.7 × 10¹¹ | 2020 | dense | | 104 | Palmyra X 004 (Writer, 2024) | \~1.5 × 10¹¹ | | 2024 | estimate | | 105 | FLAN 137B (Google Research, 2021) | 1.4 × 10¹¹ | 1.4 × 10¹¹ | 2021 | architecture not stated | | 106 | LaMDA (Google, 2022) | 1.4 × 10¹¹ | 1.4 × 10¹¹ | 2022 | architecture not stated | | 107 | MEB (Microsoft, 2021) | 1.4 × 10¹¹ | 1.4 × 10¹¹ | 2021 | architecture not stated | | 108 | Pangu Ultra (Huawei, 2025) | 1.4 × 10¹¹ | 1.4 × 10¹¹ | 2025 | architecture not stated | | 109 | DBRX (Databricks, 2024) | 1.3 × 10¹¹ | 1.3 × 10¹¹ | 2024 | mixture of experts (active count unpublished) | | 110 | GLM-130B (Tsinghua University, 2022) | 1.3 × 10¹¹ | 1.3 × 10¹¹ | 2022 | dense | | 111 | Pixtral Large (Mistral AI, 2024) | 1.2 × 10¹¹ | 1.2 × 10¹¹ | 2024 | architecture not stated | | 112 | Mistral Large 2 (Mistral AI, 2024) | \~1.2 × 10¹¹ | | 2024 | estimate | | 113 | Qwen3.5-122B-A10B (Alibaba, 2026) | \~1.2 × 10¹¹ | | 2026 | estimate | | 114 | Galactica (Meta AI, 2022) | \~1.2 × 10¹¹ | | 2022 | estimate | | 115 | Nemotron 3 Super (Nvidia, 2026) | \~1.2 × 10¹¹ | | 2026 | estimate | | 116 | gpt-oss-120b (OpenAI, 2025) | 1.2 × 10¹¹ | 5.1 × 10⁹ | 2025 | mixture of experts | | 117 | Telechat2-115B (China Telecom, 2024) | 1.1 × 10¹¹ | 1.1 × 10¹¹ | 2024 | architecture not stated | | 118 | Kaiju Large (Character.ai, 2025) | \~1.1 × 10¹¹ | | 2025 | estimate | | 119 | Llama 4 Scout (Meta AI, 2025) | \~1.1 × 10¹¹ | | 2025 | estimate | | 120 | InternLM (Shanghai AI Lab, 2023) | 1 × 10¹¹ | 1 × 10¹¹ | 2023 | dense | | 121 | Solar Open 100B (Upstage, 2025) | 1 × 10¹¹ | 1 × 10¹¹ | 2025 | architecture not stated | | 122 | DLRM-2020 (Facebook AI, 2019) | 1 × 10¹¹ | 1 × 10¹¹ | 2019 | dense | | 123 | xTrimoPGLM -100B (Tsinghua University, 2023) | 1 × 10¹¹ | 1 × 10¹¹ | 2023 | architecture not stated | | 124 | Yi-Large (01.AI, 2024) | \~1 × 10¹¹ | | 2024 | estimate | | 125 | VAETKI (NC AI, 2025) | 1 × 10¹¹ | 1 × 10¹¹ | 2025 | mixture of experts (active count unpublished) | | 126 | ESM3 (EvolutionaryScale, 2024) | 9.8 × 10¹⁰ | 9.8 × 10¹⁰ | 2024 | architecture not stated | | 127 | Mouse neocortex | 8.1 × 10¹⁰ | 8.1 × 10¹⁰ | | synapses | | 128 | Flamingo (DeepMind, 2022) | 8 × 10¹⁰ | 8 × 10¹⁰ | 2022 | dense | | 129 | Qwen3-Coder-Next (Alibaba, 2026) | \~8 × 10¹⁰ | | 2026 | estimate | | 130 | Qwen2-72B (Alibaba, 2024) | 7.3 × 10¹⁰ | 7.3 × 10¹⁰ | 2024 | dense | | 131 | Qwen2.5-72B (Alibaba, 2024) | 7.3 × 10¹⁰ | 7.3 × 10¹⁰ | 2024 | dense | | 132 | Qwen2.5 Instruct (Alibaba, 2024) | 7.3 × 10¹⁰ | 7.3 × 10¹⁰ | 2024 | dense | | 133 | Qwen-72B (Alibaba, 2023) | 7.2 × 10¹⁰ | 7.2 × 10¹⁰ | 2023 | dense | | 134 | Palmyra X 003 (Writer, 2024) | \~7.2 × 10¹⁰ | | 2024 | estimate | | 135 | Qwen1.5-72B (Alibaba, 2024) | 7.2 × 10¹⁰ | 7.2 × 10¹⁰ | 2024 | dense | | 136 | LLaVA-OV-72B (ByteDance, 2024) | 7.2 × 10¹⁰ | 7.2 × 10¹⁰ | 2024 | dense | | 137 | NVLM-X 72B (Nvidia, 2024) | \~7.2 × 10¹⁰ | | 2024 | estimate | | 138 | NVLM-H 72B (Nvidia, 2024) | \~7.2 × 10¹⁰ | | 2024 | estimate | | 139 | NVLM-D 72B (Nvidia, 2024) | 7.2 × 10¹⁰ | 7.2 × 10¹⁰ | 2024 | architecture not stated | | 140 | MindLink-72B (Kunlun Inc., 2025) | 7.2 × 10¹⁰ | 7.2 × 10¹⁰ | 2025 | architecture not stated | | 141 | Chinchilla (DeepMind, 2022) | 7 × 10¹⁰ | 7 × 10¹⁰ | 2022 | dense | | 142 | Llama 2-70B (Meta AI, 2023) | 7 × 10¹⁰ | 7 × 10¹⁰ | 2023 | dense | | 143 | PPLX-70B-Online (Perplexity, 2023) | \~7 × 10¹⁰ | | 2023 | estimate | | 144 | Llama 3-70B (Meta AI, 2024) | 7 × 10¹⁰ | 7 × 10¹⁰ | 2024 | dense | | 145 | ALLaM adapted 70B (Saudi Data and Artificial Intelligence Authority, 2024) | 7 × 10¹⁰ | 7 × 10¹⁰ | 2024 | architecture not stated | | 146 | Llama 3.3 70B (Meta AI, 2024) | 7 × 10¹⁰ | 7 × 10¹⁰ | 2024 | dense | | 147 | Reka Core (Reka AI, 2024) | \~6.7 × 10¹⁰ | | 2024 | estimate | | 148 | LLaMA-65B (Meta AI, 2023) | 6.5 × 10¹⁰ | 6.5 × 10¹⁰ | 2023 | dense | | 149 | SNM-skip (Google, 2014) | \~6.2 × 10¹⁰ | | 2014 | estimate | | 150 | PaLI-X (Google Research, 2023) | \~5.5 × 10¹⁰ | | 2023 | estimate | | 151 | RT-2 (Google DeepMind, 2023) | 5.5 × 10¹⁰ | 5.5 × 10¹⁰ | 2023 | architecture not stated | | 152 | RT-2-X (Google DeepMind, 2023) | 5.5 × 10¹⁰ | 5.5 × 10¹⁰ | 2023 | architecture not stated | | 153 | NLLB (Meta AI, 2022) | 5.5 × 10¹⁰ | 5.5 × 10¹⁰ | 2022 | dense | | 154 | BloombergGPT (Bloomberg, 2023) | 5.1 × 10¹⁰ | 5.1 × 10¹⁰ | 2023 | dense | | 155 | M4-50B (Google, 2019) | 5 × 10¹⁰ | 5 × 10¹⁰ | 2019 | mixture of experts (active count unpublished) | | 156 | Mixtral 8x7B (Mistral AI, 2023) | \~4.7 × 10¹⁰ | | 2023 | estimate | | 157 | AlphaCode (DeepMind, 2022) | 4.1 × 10¹⁰ | 4.1 × 10¹⁰ | 2022 | architecture not stated | | 158 | Falcon-40B (Technology Innovation Institute, 2023) | 4 × 10¹⁰ | 4 × 10¹⁰ | 2023 | dense | | 159 | Qwen3-Omni-30B-A3B (Alibaba, 2025) | 3.5 × 10¹⁰ | 3 × 10⁹ | 2025 | mixture of experts | | 160 | Yi-34B (01.AI, 2023) | 3.4 × 10¹⁰ | 3.4 × 10¹⁰ | 2023 | dense | | 161 | Cambrian-1-34B (New York University (NYU), 2024) | 3.4 × 10¹⁰ | 3.4 × 10¹⁰ | 2024 | architecture not stated | | 162 | Oryx 34B (Tsinghua University, 2024) | 3.4 × 10¹⁰ | 3.4 × 10¹⁰ | 2024 | architecture not stated | | 163 | Kaiju Medium (Character.ai, 2025) | \~3.4 × 10¹⁰ | | 2025 | estimate | | 164 | EXAONE 4.5 (LG AI Research, 2026) | 3.3 × 10¹⁰ | 3.3 × 10¹⁰ | 2026 | architecture not stated | | 165 | Qwen2.5-32B (Alibaba, 2024) | 3.3 × 10¹⁰ | 3.3 × 10¹⁰ | 2024 | dense | | 166 | QwQ-32B (Alibaba, 2025) | \~3.3 × 10¹⁰ | | 2025 | estimate | | 167 | EXAONE 3.5 32B (LG AI Research, 2024) | 3.2 × 10¹⁰ | 3.2 × 10¹⁰ | 2024 | architecture not stated | | 168 | EXAONE Deep 32B (LG AI Research, 2025) | 3.2 × 10¹⁰ | 3.2 × 10¹⁰ | 2025 | architecture not stated | | 169 | EXAONE 4.0 (LG AI Research, 2025) | 3.2 × 10¹⁰ | 3.2 × 10¹⁰ | 2025 | architecture not stated | | 170 | Olmo 3 (Allen Institute for AI, 2025) | 3.2 × 10¹⁰ | 3.2 × 10¹⁰ | 2025 | architecture not stated | | 171 | HyperCLOVA X SEED 32B Think (NAVER, 2025) | 3.2 × 10¹⁰ | 3.2 × 10¹⁰ | 2025 | architecture not stated | | 172 | Nemotron 3-Nano-30B-A3B (Nvidia, 2025) | \~3.2 × 10¹⁰ | | 2025 | estimate | | 173 | Tongyi DeepResearch (Alibaba, 2025) | 3 × 10¹⁰ | 3 × 10¹⁰ | 2025 | architecture not stated | | 174 | MM1-30B (Apple, 2024) | \~3 × 10¹⁰ | | 2024 | estimate | | 175 | Movie Gen Video (Meta AI, 2024) | 3 × 10¹⁰ | 3 × 10¹⁰ | 2024 | architecture not stated | | 176 | AgentFounder-30B (Alibaba, 2025) | 3 × 10¹⁰ | 3 × 10¹⁰ | 2025 | architecture not stated | | 177 | PLUG (Alibaba, 2021) | 2.7 × 10¹⁰ | 2.7 × 10¹⁰ | 2021 | architecture not stated | | 178 | Qwen Image (Alibaba, 2025) | 2.7 × 10¹⁰ | 2.7 × 10¹⁰ | 2025 | architecture not stated | | 179 | GenSLM (University of Chicago, 2022) | 2.5 × 10¹⁰ | 2.5 × 10¹⁰ | 2022 | architecture not stated | | 180 | ViT-22B (Google, 2023) | 2.2 × 10¹⁰ | 2.2 × 10¹⁰ | 2023 | architecture not stated | | 181 | KN-LM (Google, 2007) | \~2.1 × 10¹⁰ | | 2007 | estimate | | 182 | gpt-oss-20b (OpenAI, 2025) | 2.1 × 10¹⁰ | 2.1 × 10¹⁰ | 2025 | mixture of experts (active count unpublished) | | 183 | RNN for 1B words (Google, 2013) | \~2 × 10¹⁰ | | 2013 | estimate | | 184 | GPT-NeoX-20B (EleutherAI, 2022) | 2 × 10¹⁰ | 2 × 10¹⁰ | 2022 | dense | | 185 | UL2 (Google Research, 2022) | 2 × 10¹⁰ | 2 × 10¹⁰ | 2022 | architecture not stated | | 186 | Parti (Google Research, 2022) | 2 × 10¹⁰ | 2 × 10¹⁰ | 2022 | architecture not stated | | 187 | GPT-3.5 Turbo (OpenAI, 2023) | \~2 × 10¹⁰ | | 2023 | estimate | | 188 | GPT-3.5 Turbo Instruct (OpenAI, 2023) | \~2 × 10¹⁰ | | 2023 | estimate | | 189 | SPHINX (Shanghai AI Lab, 2023) | \~2 × 10¹⁰ | | 2023 | estimate | | 190 | AlexaTM 20B (Amazon, 2022) | 2 × 10¹⁰ | 2 × 10¹⁰ | 2022 | architecture not stated | | 191 | CogAgent (Tsinghua University, 2023) | \~1.8 × 10¹⁰ | | 2023 | estimate | | 192 | Turing-NLG (Microsoft, 2020) | \~1.7 × 10¹⁰ | | 2020 | estimate | | 193 | CogVLM-17B (Tsinghua University, 2023) | 1.7 × 10¹⁰ | 1.7 × 10¹⁰ | 2023 | architecture not stated | | 194 | PaLI (Google, 2022) | \~1.7 × 10¹⁰ | | 2022 | estimate | | 195 | CodeT5+ (Salesforce, 2023) | 1.6 × 10¹⁰ | 1.6 × 10¹⁰ | 2023 | architecture not stated | | 196 | StarCoder (Hugging Face, 2023) | 1.6 × 10¹⁰ | 1.6 × 10¹⁰ | 2023 | dense | | 197 | ESM2-15B (Meta AI, 2022) | 1.5 × 10¹⁰ | 1.5 × 10¹⁰ | 2022 | architecture not stated | | 198 | FunSearch (Google DeepMind, 2023) | \~1.5 × 10¹⁰ | | 2023 | estimate | | 199 | NVILA 15B (Nvidia, 2024) | 1.5 × 10¹⁰ | 1.5 × 10¹⁰ | 2024 | architecture not stated | | 200 | nekomata-14b (rinna, 2023) | 1.4 × 10¹⁰ | 1.4 × 10¹⁰ | 2023 | architecture not stated | | 201 | VILA1.5-13B (Nvidia, 2024) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2024 | architecture not stated | | 202 | VILA-13B (Nvidia, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | architecture not stated | | 203 | mT5-XXL (Google, 2020) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2020 | dense | | 204 | mT0-13B (Hugging Face, 2022) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2022 | architecture not stated | | 205 | LLaVA (University of Wisconsin Madison, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | dense | | 206 | InstructBLIP (Salesforce Research, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | architecture not stated | | 207 | Jais (Cerebras Systems, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | architecture not stated | | 208 | FinGPT-13B (University of California Los Angeles (UCLA), 2023) | \~1.3 × 10¹⁰ | | 2023 | estimate | | 209 | Ferret (Columbia University, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | architecture not stated | | 210 | Skywork-13B (Kunlun Inc., 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | architecture not stated | | 211 | LLaVA 1.5 (University of Wisconsin Madison, 2023) | 1.3 × 10¹⁰ | 1.3 × 10¹⁰ | 2023 | dense | | 212 | Volcano 13B (Korea University, 2023) | \~1.3 × 10¹⁰ | | 2023 | estimate | | 213 | Aya (Cohere Labs (formerly Cohere for AI), 2024) | \~1.3 × 10¹⁰ | | 2024 | estimate | | 214 | Kaiju Small (Character.ai, 2025) | \~1.3 × 10¹⁰ | | 2025 | estimate | | 215 | ByT5-XXL (Google, 2021) | \~1.3 × 10¹⁰ | | 2021 | estimate | | 216 | CoRe (Tsinghua University, 2023) | \~1.2 × 10¹⁰ | | 2023 | estimate | | 217 | DALL-E (OpenAI, 2021) | \~1.2 × 10¹⁰ | | 2021 | estimate | | 218 | Codex (OpenAI, 2021) | \~1.2 × 10¹⁰ | | 2021 | estimate | | 219 | T5-11B (Google, 2019) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2019 | dense | | 220 | UnifiedQA (Allen Institute for AI, 2020) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2020 | dense | | 221 | Unicorn (Allen Institute for AI, 2021) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2021 | architecture not stated | | 222 | PLATO-XL (Baidu, 2021) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2021 | architecture not stated | | 223 | CoEdiT-xxl (University of Minnesota, 2023) | \~1.1 × 10¹⁰ | | 2023 | estimate | | 224 | GQA-8-XXL (Google Research, 2023) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2023 | architecture not stated | | 225 | XLMR-XXL (Facebook AI Research, 2021) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2021 | architecture not stated | | 226 | Llama 3.2 11B (Meta AI, 2024) | 1.1 × 10¹⁰ | 1.1 × 10¹⁰ | 2024 | dense | | 227 | ERNIE 3.0 (Baidu, 2021) | 1 × 10¹⁰ | 1 × 10¹⁰ | 2021 | dense | | 228 | ERNIE-ViLG (Baidu, 2021) | \~1 × 10¹⁰ | | 2021 | estimate | | 229 | Qwen-VL (Alibaba, 2023) | \~9.6 × 10⁹ | | 2023 | estimate | | 230 | Generative BST (Facebook AI Research, 2021) | 9.4 × 10⁹ | 9.4 × 10⁹ | 2021 | architecture not stated | | 231 | Sparse all-MLP (Meta AI, 2022) | 9.4 × 10⁹ | 9.4 × 10⁹ | 2022 | mixture of experts (active count unpublished) | | 232 | CogVideo (Tsinghua University, 2022) | \~9.4 × 10⁹ | | 2022 | estimate | | 233 | eDiff-I (Nvidia, 2022) | \~9.1 × 10⁹ | | 2022 | estimate | | 234 | Eagle 2 (Nvidia, 2025) | 8.9 × 10⁹ | 8.9 × 10⁹ | 2025 | architecture not stated | | 235 | MoE-Multi (Jagiellonian University, 2017) | 8.7 × 10⁹ | 8.7 × 10⁹ | 2017 | mixture of experts (active count unpublished) | | 236 | Qwen-Audio-Chat (Alibaba, 2023) | \~8.5 × 10⁹ | | 2023 | estimate | | 237 | Megatron-LM (Nvidia, 2019) | \~8.3 × 10⁹ | | 2019 | estimate | | 238 | BigSSL (Google, 2021) | \~8 × 10⁹ | | 2021 | estimate | | 239 | Nemotron-3-8B (Nvidia, 2023) | 8 × 10⁹ | 8 × 10⁹ | 2023 | architecture not stated | | 240 | Stable Diffusion 3 (Stability AI, 2024) | 8 × 10⁹ | 8 × 10⁹ | 2024 | dense | | 241 | Qwen3 Embedding (Alibaba, 2025) | 8 × 10⁹ | 8 × 10⁹ | 2025 | mixture of experts (active count unpublished) | | 242 | Imagen (Google Brain, 2022) | \~7.8 × 10⁹ | | 2022 | estimate | | 243 | XGLM-7.5B (Meta AI, 2021) | 7.5 × 10⁹ | 7.5 × 10⁹ | 2021 | architecture not stated | | 244 | RETRO-7B (DeepMind, 2022) | 7.5 × 10⁹ | 7.5 × 10⁹ | 2022 | architecture not stated | | 245 | OpenVLA (Stanford University, 2024) | 7.2 × 10⁹ | 7.2 × 10⁹ | 2024 | architecture not stated | | 246 | mPLUG-Owl2 (Alibaba, 2023) | \~7.1 × 10⁹ | | 2023 | estimate | | 247 | Goat-7B (National University of Singapore, 2023) | \~7 × 10⁹ | | 2023 | estimate | | 248 | Llama 2-7B (Meta AI, 2023) | 7 × 10⁹ | 7 × 10⁹ | 2023 | dense | | 249 | Llama Guard (Meta AI, 2023) | 7 × 10⁹ | 7 × 10⁹ | 2023 | dense | | 250 | Qwen-VL-Max (Alibaba, 2024) | 7 × 10⁹ | 7 × 10⁹ | 2024 | dense | | 251 | Mathstral (Mistral AI, 2024) | 7 × 10⁹ | 7 × 10⁹ | 2024 | architecture not stated | | 252 | Apollo 7B (Meta AI, 2024) | 7 × 10⁹ | 7 × 10⁹ | 2024 | architecture not stated | | 253 | Eurus-2-7B-PRIME (Tsinghua University, 2025) | \~7 × 10⁹ | | 2025 | estimate | | 254 | INTELLECT-MATH (Prime Intellect, 2025) | 7 × 10⁹ | 7 × 10⁹ | 2025 | architecture not stated | | 255 | Incoder-6.7B (Facebook AI Research, 2023) | 6.7 × 10⁹ | 6.7 × 10⁹ | 2023 | architecture not stated | | 256 | ProGen2-xlarge (Salesforce Research, 2022) | 6.4 × 10⁹ | 6.4 × 10⁹ | 2022 | architecture not stated | | 257 | GPipe (Google, 2018) | \~6 × 10⁹ | | 2018 | estimate | | 258 | InstructGPT 6B (OpenAI, 2022) | 6 × 10⁹ | 6 × 10⁹ | 2022 | dense | | 259 | Vega v2 (Wuhan University, 2022) | 6 × 10⁹ | 6 × 10⁹ | 2022 | architecture not stated | | 260 | ChatGLM3-6B (Z.ai (Zhipu AI), 2023) | \~6 × 10⁹ | | 2023 | estimate | | 261 | MolmoAct 2 (Allen Institute for AI, 2026) | \~5.5 × 10⁹ | | 2026 | estimate | | 262 | T-NLRv5 XXL (Microsoft, 2021) | 5.4 × 10⁹ | 5.4 × 10⁹ | 2021 | architecture not stated | | 263 | π0.6 (Physical Intelligence, 2025) | 5.3 × 10⁹ | 5.3 × 10⁹ | 2025 | mixture of experts (active count unpublished) | | 264 | PaLI-3 (Google DeepMind, 2023) | 5 × 10⁹ | 5 × 10⁹ | 2023 | architecture not stated | | 265 | Mesh-TensorFlow Transformer 4.9B (Google Brain, 2018) | 4.9 × 10⁹ | 4.9 × 10⁹ | 2018 | dense | | 266 | W.A.L.T (Stanford University, 2023) | 4.7 × 10⁹ | 4.7 × 10⁹ | 2023 | architecture not stated | | 267 | CogView (Tsinghua University, 2021) | \~4 × 10⁹ | | 2021 | estimate | | 268 | Make-A-Scene (Meta AI, 2022) | \~4 × 10⁹ | | 2022 | estimate | | 269 | ONE-PEACE (Alibaba, 2023) | \~4 × 10⁹ | | 2023 | estimate | | 270 | Megatron-BERT (Nvidia, 2019) | 3.9 × 10⁹ | 3.9 × 10⁹ | 2019 | dense | | 271 | DALL·E 2 (OpenAI, 2022) | \~3.5 × 10⁹ | | 2022 | estimate | | 272 | Stable Diffusion XL (Stability AI, 2023) | \~3.4 × 10⁹ | | 2023 | estimate | | 273 | MusicGen (Meta AI, 2023) | \~3.4 × 10⁹ | | 2023 | estimate | | 274 | Gemini Nano-2 (Google DeepMind, 2023) | 3.3 × 10⁹ | 3.3 × 10⁹ | 2023 | architecture not stated | | 275 | Zidong Taichu (Chinese Academy of Sciences, 2021) | 3.2 × 10⁹ | 3.2 × 10⁹ | 2021 | architecture not stated | | 276 | DeepNet (Microsoft Research, 2022) | 3.2 × 10⁹ | 3.2 × 10⁹ | 2022 | architecture not stated | | 277 | MS-ensemble-speech-recognition (Microsoft, 2016) | \~3.2 × 10⁹ | | 2016 | estimate | | 278 | BASIC-L (Google, 2021) | \~3.1 × 10⁹ | | 2021 | estimate | | 279 | BASIC-L + Lion (Google, 2023) | 3.1 × 10⁹ | 3.1 × 10⁹ | 2023 | architecture not stated | | 280 | LEP-AD (King Abdullah University of Science and Technology (KAUST), 2023) | 3 × 10⁹ | 3 × 10⁹ | 2023 | architecture not stated | | 281 | ViT-G/14 (Google Research, 2021) | 3 × 10⁹ | 3 × 10⁹ | 2021 | architecture not stated | | 282 | ProtT5-XL-U50 (Technical University of Munich, 2021) | 3 × 10⁹ | 3 × 10⁹ | 2021 | architecture not stated | | 283 | Swin Transformer V2 (Microsoft Research Asia, 2021) | 3 × 10⁹ | 3 × 10⁹ | 2021 | architecture not stated | | 284 | LongT5 (Google Research, 2021) | 3 × 10⁹ | 3 × 10⁹ | 2021 | architecture not stated | | 285 | ReALM (Apple, 2024) | 3 × 10⁹ | 3 × 10⁹ | 2024 | architecture not stated | | 286 | Mesh-TensorFlow Transformer 2.9B (Google Brain, 2018) | \~2.9 × 10⁹ | | 2018 | estimate | | 287 | T5-3B (Google, 2019) | 2.8 × 10⁹ | 2.8 × 10⁹ | 2019 | dense | | 288 | DPO on Pythia-2.8B (Stanford University, 2023) | 2.8 × 10⁹ | 2.8 × 10⁹ | 2023 | dense | | 289 | AFM-on-device (Apple, 2024) | 2.7 × 10⁹ | 2.7 × 10⁹ | 2024 | architecture not stated | | 290 | PolyCoder (Carnegie Mellon University (CMU), 2022) | \~2.7 × 10⁹ | | 2022 | estimate | | 291 | Hybrid H3-2.7B (Stanford University, 2022) | \~2.7 × 10⁹ | | 2022 | estimate | | 292 | GPT3-2.7B (Stanford University, 2023) | 2.7 × 10⁹ | 2.7 × 10⁹ | 2023 | architecture not stated | | 293 | Meena (Google Brain, 2020) | 2.6 × 10⁹ | 2.6 × 10⁹ | 2020 | dense | | 294 | CPM-Large (Tsinghua University, 2020) | 2.6 × 10⁹ | 2.6 × 10⁹ | 2020 | dense | | 295 | Nucleotide Transformer (Nvidia, 2023) | \~2.5 × 10⁹ | | 2023 | estimate | | 296 | Fugatto 1 (Nvidia, 2024) | 2.5 × 10⁹ | 2.5 × 10⁹ | 2024 | architecture not stated | | 297 | CoAtNet (Google, 2021) | 2.4 × 10⁹ | 2.4 × 10⁹ | 2021 | architecture not stated | | 298 | GShard (Google, 2020) | 2.3 × 10⁹ | 2.3 × 10⁹ | 2020 | dense | | 299 | SeamlessM4T (Facebook, 2023) | 2.3 × 10⁹ | 2.3 × 10⁹ | 2023 | architecture not stated | | 300 | Turing ULRv5 (Microsoft, 2021) | 2.2 × 10⁹ | 2.2 × 10⁹ | 2021 | architecture not stated | | 301 | CoCa (Google Research, 2022) | 2.1 × 10⁹ | 2.1 × 10⁹ | 2022 | architecture not stated | | 302 | MuseNet (OpenAI, 2019) | \~2 × 10⁹ | | 2019 | estimate | | 303 | Infinity (ByteDance, 2024) | 2 × 10⁹ | 2 × 10⁹ | 2024 | architecture not stated | | 304 | Seq2Seq LSTM (Google, 2014) | 1.9 × 10⁹ | 1.9 × 10⁹ | 2014 | dense | | 305 | BEIT-3 (Microsoft, 2022) | \~1.9 × 10⁹ | | 2022 | estimate | | 306 | Ankh\_large (Technical University of Munich, 2023) | 1.9 × 10⁹ | 1.9 × 10⁹ | 2023 | architecture not stated | | 307 | ViT-G/14 (Google Brain, 2021) | 1.8 × 10⁹ | 1.8 × 10⁹ | 2021 | architecture not stated | | 308 | ViT-G (University of Washington, 2022) | 1.8 × 10⁹ | 1.8 × 10⁹ | 2022 | architecture not stated | | 309 | Phenaki (University College London (UCL), 2022) | \~1.8 × 10⁹ | | 2022 | estimate | | 310 | Gemini Nano-1 (Google DeepMind, 2023) | 1.8 × 10⁹ | 1.8 × 10⁹ | 2023 | architecture not stated | | 311 | DistBelief Vision (Google, 2012) | \~1.7 × 10⁹ | | 2012 | estimate | | 312 | Whisper (OpenAI, 2022) | \~1.6 × 10⁹ | | 2022 | estimate | | 313 | GPT-2 (OpenAI, 2019) | \~1.5 × 10⁹ | | 2019 | estimate | | 314 | DeBERTa (Microsoft, 2021) | 1.5 × 10⁹ | 1.5 × 10⁹ | 2021 | architecture not stated | | 315 | AR-LDM (Alibaba, 2022) | 1.5 × 10⁹ | 1.5 × 10⁹ | 2022 | architecture not stated | | 316 | AudioLM (Google Research, 2023) | \~1.5 × 10⁹ | | 2023 | estimate | | 317 | BLIP-2 (Salesforce Research, 2023) | 1.5 × 10⁹ | 1.5 × 10⁹ | 2023 | architecture not stated | | 318 | LDM-1.45B (Heidelberg University, 2021) | 1.4 × 10⁹ | 1.4 × 10⁹ | 2021 | architecture not stated | | 319 | Stable Diffusion (Runway, 2022) | 1.4 × 10⁹ | 1.4 × 10⁹ | 2022 | dense | | 320 | SEER (Facebook AI Research, 2021) | 1.3 × 10⁹ | 1.3 × 10⁹ | 2021 | architecture not stated | | 321 | InstructGPT 1.3B (OpenAI, 2022) | 1.3 × 10⁹ | 1.3 × 10⁹ | 2022 | dense | | 322 | Megatron-LM (Nvidia, 2019) | 1.2 × 10⁹ | 1.2 × 10⁹ | 2019 | dense | | 323 | RDT-1B (Tsinghua University, 2024) | \~1.2 × 10⁹ | | 2024 | estimate | | 324 | Gato (DeepMind, 2022) | 1.2 × 10⁹ | 1.2 × 10⁹ | 2022 | architecture not stated | | 325 | DINOv2 (Facebook AI Research, 2023) | 1.1 × 10⁹ | 1.1 × 10⁹ | 2023 | architecture not stated | | 326 | Diffusion Renderer (Nvidia, 2025) | 1.1 × 10⁹ | 1.1 × 10⁹ | 2025 | architecture not stated | | 327 | InternImage (Shanghai AI Lab, 2022) | 1.1 × 10⁹ | 1.1 × 10⁹ | 2022 | architecture not stated | | 328 | EVA-01 (Beijing Academy of Artificial Intelligence / BAAI, 2022) | 1 × 10⁹ | 1 × 10⁹ | 2022 | architecture not stated | | 329 | Unsupervised High-level Feature Learner (Google, 2012) | \~1 × 10⁹ | | 2012 | estimate | | 330 | Conformer + Wav2vec 2.0 + Noisy Student (Google, 2020) | 1 × 10⁹ | 1 × 10⁹ | 2020 | dense | | 331 | HuBERT (Facebook AI Research, 2021) | \~1 × 10⁹ | | 2021 | estimate | | 332 | W2v-BERT (Google Brain, 2021) | 1 × 10⁹ | 1 × 10⁹ | 2021 | dense | | 333 | AudioGen (Meta AI, 2023) | \~1 × 10⁹ | | 2023 | estimate | | 334 | VideoMAE V2 (Nanjing University, 2023) | 1 × 10⁹ | 1 × 10⁹ | 2023 | architecture not stated | | 335 | TransE (Universite de Technologie de Compiègne – CNRS, 2013) | \~9.4 × 10⁸ | | 2013 | estimate | | 336 | ImageBind (Meta AI, 2023) | \~9.3 × 10⁸ | | 2023 | estimate | | 337 | Big Transfer (Google Brain, 2019) | \~9.3 × 10⁸ | | 2019 | estimate | | 338 | Florence (Microsoft, 2021) | 8.9 × 10⁸ | 8.9 × 10⁸ | 2021 | architecture not stated | | 339 | NÜWA (Microsoft Research, 2021) | 8.7 × 10⁸ | 8.7 × 10⁸ | 2021 | architecture not stated | | 340 | MusicLM (Google, 2023) | 8.6 × 10⁸ | 8.6 × 10⁸ | 2023 | architecture not stated | | 341 | ResNeXt-101 32x48d (Facebook, 2018) | 8.3 × 10⁸ | 8.3 × 10⁸ | 2018 | dense | | 342 | FixRes ResNeXt-101 WSL (Facebook AI, 2019) | \~8.3 × 10⁸ | | 2019 | estimate | | 343 | ALIGN (Google Research, 2021) | 8.2 × 10⁸ | 8.2 × 10⁸ | 2021 | architecture not stated | | 344 | Statement Curriculum Learning (OpenAI, 2022) | \~7.7 × 10⁸ | | 2022 | estimate | | 345 | CodeT5-large (Salesforce, 2022) | \~7.7 × 10⁸ | | 2022 | estimate | | 346 | DITTO (Tsinghua University, 2022) | 7.5 × 10⁸ | 7.5 × 10⁸ | 2022 | architecture not stated | | 347 | FGN (Google DeepMind, 2025) | 7.2 × 10⁸ | 7.2 × 10⁸ | 2025 | architecture not stated | | 348 | data2vec (Meta AI, 2022) | \~7.1 × 10⁸ | | 2022 | estimate | | 349 | Tranception (University of Oxford, 2022) | 7 × 10⁸ | 7 × 10⁸ | 2022 | architecture not stated | | 350 | Word2Vec (Google, 2013) | \~6.9 × 10⁸ | | 2013 | estimate | | 351 | DiT-XL/2 (New York University (NYU), 2023) | 6.8 × 10⁸ | 6.8 × 10⁸ | 2023 | architecture not stated | | 352 | DiT-XL/2 + CADS (ETH Zurich, 2023) | \~6.8 × 10⁸ | | 2023 | estimate | | 353 | OmegaPLM (Massachusetts Institute of Technology (MIT), 2022) | 6.7 × 10⁸ | 6.7 × 10⁸ | 2022 | architecture not stated | | 354 | XLM (Facebook, 2019) | \~6.7 × 10⁸ | | 2019 | estimate | | 355 | ESM1b (Facebook AI Research, 2020) | 6.5 × 10⁸ | 6.5 × 10⁸ | 2020 | dense | | 356 | Segment Anything Model (Meta AI, 2023) | 6.4 × 10⁸ | 6.4 × 10⁸ | 2023 | architecture not stated | | 357 | ViT-Huge/14 (Google Brain, 2020) | 6.3 × 10⁸ | 6.3 × 10⁸ | 2020 | dense | | 358 | Masked Autoencoders ViT-H (Facebook AI Research, 2021) | \~6.3 × 10⁸ | | 2021 | estimate | | 359 | Retrieval-Augmented Generator (Facebook, 2020) | 6.3 × 10⁸ | 6.3 × 10⁸ | 2020 | dense | | 360 | DLDL (University of Oxford, 2016) | \~5.6 × 10⁸ | | 2016 | estimate | | 361 | ADM (OpenAI, 2021) | 5.6 × 10⁸ | 5.6 × 10⁸ | 2021 | architecture not stated | | 362 | TrOCR (Beihang University, 2021) | 5.6 × 10⁸ | 5.6 × 10⁸ | 2021 | architecture not stated | | 363 | XLM-RoBERTa (Facebook AI, 2019) | 5.5 × 10⁸ | 5.5 × 10⁸ | 2019 | dense | | 364 | LUKE (University of Washington, 2020) | \~4.8 × 10⁸ | | 2020 | estimate | | 365 | EfficientNet-L2 (Google, 2019) | \~4.8 × 10⁸ | | 2019 | estimate | | 366 | Noisy Student (Carnegie Mellon University (CMU), 2019) | 4.8 × 10⁸ | 4.8 × 10⁸ | 2019 | dense | | 367 | Meta Pseudo Labels (Google Brain, 2021) | \~4.8 × 10⁸ | | 2021 | estimate | | 368 | EMDR (Mila - Quebec AI (originally Montreal Institute for Learning Algorithms), 2021) | 4.4 × 10⁸ | 4.4 × 10⁸ | 2021 | architecture not stated | | 369 | NMT Transformer 437M (Google, 2019) | 4.4 × 10⁸ | 4.4 × 10⁸ | 2019 | dense | | 370 | Adaptive Inputs + LayerDrop (Facebook AI Research, 2019) | 4.2 × 10⁸ | 4.2 × 10⁸ | 2019 | dense | | 371 | ProtBERT-BFD (Technical University of Munich, 2021) | 4.2 × 10⁸ | 4.2 × 10⁸ | 2021 | architecture not stated | | 372 | OntoProtein (Zhejiang University (ZJU), 2022) | \~4.2 × 10⁸ | | 2022 | estimate | | 373 | DeBERTaV3large + KEAR (Microsoft, 2022) | 4.2 × 10⁸ | 4.2 × 10⁸ | 2022 | architecture not stated | | 374 | BART-large (Facebook AI, 2019) | \~4.1 × 10⁸ | | 2019 | estimate | | 375 | SigLIP 400M (Google DeepMind, 2023) | 4 × 10⁸ | 4 × 10⁸ | 2023 | architecture not stated | | 376 | BERT-Large-CAS (Amazon, 2019) | \~4 × 10⁸ | | 2019 | estimate | | 377 | MoCo (Facebook AI, 2019) | \~3.8 × 10⁸ | | 2019 | estimate | | 378 | SimCLR (Google Brain, 2020) | \~3.8 × 10⁸ | | 2020 | estimate | | 379 | CLIP (OpenAI, 2021) | 3.7 × 10⁸ | 3.7 × 10⁸ | 2021 | architecture not stated | | 380 | RoBERTa Large (Facebook, 2019) | 3.5 × 10⁸ | 3.5 × 10⁸ | 2019 | dense | | 381 | AbLang (University of Oxford, 2022) | 3.5 × 10⁸ | 3.5 × 10⁸ | 2022 | architecture not stated | | 382 | GPT-2 Medium (Stanford University, 2022) | 3.5 × 10⁸ | 3.5 × 10⁸ | 2022 | dense | | 383 | VALL-E (Microsoft, 2023) | \~3.5 × 10⁸ | | 2023 | estimate | | 384 | BERT-Large (Google, 2018) | 3.4 × 10⁸ | 3.4 × 10⁸ | 2018 | dense | | 385 | XLNet (Carnegie Mellon University (CMU), 2019) | 3.4 × 10⁸ | 3.4 × 10⁸ | 2019 | dense | | 386 | ERNIE-GEN (Baidu, 2020) | \~3.4 × 10⁸ | | 2020 | estimate | | 387 | CamemBERT (Facebook, 2019) | 3.4 × 10⁸ | 3.4 × 10⁸ | 2019 | dense | | 388 | ELECTRA (Stanford University, 2020) | \~3.4 × 10⁸ | | 2020 | estimate | | 389 | German ELECTRA Large (deepset, 2020) | 3.4 × 10⁸ | 3.4 × 10⁸ | 2020 | dense | | 390 | ALM 1.0 (Beijing Academy of Artificial Intelligence / BAAI, 2022) | \~3.4 × 10⁸ | | 2022 | estimate | | 391 | MT-DNN (Microsoft, 2019) | 3.3 × 10⁸ | 3.3 × 10⁸ | 2019 | dense | | 392 | Fusion in Encoder (Samsung, 2022) | \~3.3 × 10⁸ | | 2022 | estimate | | 393 | wave2vec 2.0 LARGE (Facebook, 2020) | 3.2 × 10⁸ | 3.2 × 10⁸ | 2020 | dense | | 394 | CPC v2 (DeepMind, 2019) | \~3 × 10⁸ | | 2019 | estimate | | 395 | Transformer - LibriVox + Decoding/Rescoring (Facebook, 2019) | 3 × 10⁸ | 3 × 10⁸ | 2019 | dense | | 396 | DDPM-IP (Utrecht University, 2023) | \~3 × 10⁸ | | 2023 | estimate | | 397 | GNMT (Google, 2016) | \~2.8 × 10⁸ | | 2016 | estimate | | 398 | base LM+GNN+kNN (Shannon.AI, 2021) | 2.7 × 10⁸ | 2.7 × 10⁸ | 2021 | architecture not stated | | 399 | YOLO (University of Washington, 2015) | \~2.7 × 10⁸ | | 2015 | estimate | | 400 | Transformer-XL (Carnegie Mellon University (CMU), 2019) | \~2.6 × 10⁸ | | 2019 | estimate | | 401 | Transformer-XL + RMS dynamic eval (University of Edinburgh, 2019) | 2.6 × 10⁸ | 2.6 × 10⁸ | 2019 | dense | | 402 | Transformer-XL Large + Phrase Induction (Massachusetts Institute of Technology (MIT), 2019) | \~2.6 × 10⁸ | | 2019 | estimate | | 403 | Segatron-XL large, M=384 + HCP (Microsoft Research, 2022) | 2.6 × 10⁸ | 2.6 × 10⁸ | 2022 | architecture not stated | | 404 | Denoising Diffusion Probabilistic Models (University of California (UC) Berkeley, 2021) | 2.6 × 10⁸ | 2.6 × 10⁸ | 2021 | architecture not stated | | 405 | Pangu-Weather (Huawei, 2023) | 2.6 × 10⁸ | 2.6 × 10⁸ | 2023 | architecture not stated | | 406 | SPN (Google Brain, 2018) | 2.5 × 10⁸ | 2.5 × 10⁸ | 2018 | dense | | 407 | S4 (Stanford University, 2021) | \~2.5 × 10⁸ | | 2021 | estimate | | 408 | Base LM + kNN LM + Continuous Cache (Stanford University, 2019) | \~2.5 × 10⁸ | | 2019 | estimate | | 409 | ERNIE-Doc (Baidu, 2020) | 2.5 × 10⁸ | 2.5 × 10⁸ | 2020 | dense | | 410 | Adaptive Input Transformer + RD (Microsoft Research Asia, 2021) | \~2.5 × 10⁸ | | 2021 | estimate | | 411 | Transformer (Adaptive Input Embeddings) WT103 (Facebook AI Research, 2018) | 2.5 × 10⁸ | 2.5 × 10⁸ | 2018 | dense | | 412 | TaLK Convolution (Carleton University, 2020) | \~2.4 × 10⁸ | | 2020 | estimate | | 413 | ALBERT-xxlarge (Toyota Technological Institute at Chicago, 2020) | \~2.4 × 10⁸ | | 2020 | estimate | | 414 | SRU++ Large (ASAPP, 2021) | 2.3 × 10⁸ | 2.3 × 10⁸ | 2021 | architecture not stated | | 415 | GR-2 (ByteDance, 2024) | 2.3 × 10⁸ | 2.3 × 10⁸ | 2024 | architecture not stated | | 416 | MaskGIT (Google Research, 2022) | 2.3 × 10⁸ | 2.3 × 10⁸ | 2022 | architecture not stated | | 417 | MetNet (Google, 2020) | \~2.3 × 10⁸ | | 2020 | estimate | | 418 | FFN SwiGLU (Google, 2020) | 2.2 × 10⁸ | 2.2 × 10⁸ | 2020 | dense | | 419 | CodeT5-base (Salesforce, 2021) | \~2.2 × 10⁸ | | 2021 | estimate | | 420 | Transformer (Google Research, 2017) | 2.1 × 10⁸ | 2.1 × 10⁸ | 2017 | dense | | 421 | Sandwich Transformer (Allen Institute for AI, 2019) | \~2.1 × 10⁸ | | 2019 | estimate | | 422 | EfficientNetV2-XL (Google, 2021) | 2.1 × 10⁸ | 2.1 × 10⁸ | 2021 | architecture not stated | | 423 | Word2Vec (Google, 2013) | \~2.1 × 10⁸ | | 2013 | estimate | | 424 | Multilingual DNN (Google, 2013) | 2.1 × 10⁸ | 2.1 × 10⁸ | 2013 | dense | | 425 | DreamerV3 (DeepMind, 2023) | \~2 × 10⁸ | | 2023 | estimate | | 426 | DL scaling speech (Baidu, 2017) | \~1.9 × 10⁸ | | 2017 | estimate | | 427 | ResNeXt-101 Billion-scale (Facebook AI, 2019) | \~1.9 × 10⁸ | | 2019 | estimate | | 428 | (NTT Communication Science Laboratories, 2018) | 1.9 × 10⁸ | 1.9 × 10⁸ | 2018 | dense | | 429 | TrellisNet (Carnegie Mellon University (CMU), 2018) | 1.8 × 10⁸ | 1.8 × 10⁸ | 2018 | dense | | 430 | DL scaling LM (Baidu, 2017) | \~1.8 × 10⁸ | | 2017 | estimate | | 431 | EXAONE Path 2.0 (LG AI Research, 2025) | 1.8 × 10⁸ | 1.8 × 10⁸ | 2025 | architecture not stated | | 432 | OpenAI Five Rerun (OpenAI, 2019) | 1.6 × 10⁸ | 1.6 × 10⁸ | 2019 | dense | | 433 | OpenAI Five (OpenAI, 2019) | 1.6 × 10⁸ | 1.6 × 10⁸ | 2019 | dense | | 434 | 4 layer QRNN (Salesforce Research, 2018) | \~1.5 × 10⁸ | | 2018 | estimate | | 435 | TransformerXL + spectrum control (University of California Los Angeles (UCLA), 2020) | \~1.5 × 10⁸ | | 2020 | estimate | | 436 | AlphaGeometry (Google DeepMind, 2024) | 1.5 × 10⁸ | 1.5 × 10⁸ | 2024 | architecture not stated | | 437 | PermuteFormer (Peking University, 2021) | \~1.5 × 10⁸ | | 2021 | estimate | | 438 | Fragment embedding (Stanford University, 2014) | \~1.4 × 10⁸ | | 2014 | estimate | | 439 | OverFeat (New York University (NYU), 2013) | 1.4 × 10⁸ | 1.4 × 10⁸ | 2013 | dense | | 440 | VGG19 (University of Oxford, 2014) | \~1.4 × 10⁸ | | 2014 | estimate | | 441 | LRCN (UT Austin, 2014) | \~1.4 × 10⁸ | | 2014 | estimate | | 442 | Transformer-XL DeFINE (University of Washington, 2019) | \~1.4 × 10⁸ | | 2019 | estimate | | 443 | Deep Autoencoders (University of Toronto, 2011) | 1.4 × 10⁸ | 1.4 × 10⁸ | 2011 | dense | | 444 | AlphaStar (DeepMind, 2019) | 1.4 × 10⁸ | 1.4 × 10⁸ | 2019 | dense | | 445 | VGG16 (University of Oxford, 2014) | 1.4 × 10⁸ | 1.4 × 10⁸ | 2014 | dense | | 446 | VGG-Face (University of Oxford, 2015) | 1.4 × 10⁸ | 1.4 × 10⁸ | 2015 | dense | | 447 | SAF R-CNN (Beijing Institute of Technology, 2015) | \~1.4 × 10⁸ | | 2015 | estimate | | 448 | Template Adaptation (University of Oxford, 2016) | \~1.4 × 10⁸ | | 2016 | estimate | | 449 | LRR-4X (UC Irvine, 2016) | \~1.4 × 10⁸ | | 2016 | estimate | | 450 | CMS-RCNN (IEEE, 2016) | \~1.4 × 10⁸ | | 2016 | estimate | | 451 | QRNN (Salesforce Research, 2018) | \~1.4 × 10⁸ | | 2018 | estimate | | 452 | Multiresolution CNN (Google, 2014) | \~1.3 × 10⁸ | | 2014 | estimate | | 453 | FTW (DeepMind, 2018) | \~1.3 × 10⁸ | | 2018 | estimate | | 454 | Feedback Transformer (LORIA, 2020) | \~1.3 × 10⁸ | | 2020 | estimate | | 455 | KEPLER (Tsinghua University, 2020) | 1.3 × 10⁸ | 1.3 × 10⁸ | 2020 | dense | | 456 | DL scaling Image (Baidu, 2017) | 1.2 × 10⁸ | 1.2 × 10⁸ | 2017 | dense | | 457 | GloVe (Stanford University, 2014) | \~1.2 × 10⁸ | | 2014 | estimate | | 458 | Conformer (Google, 2020) | 1.2 × 10⁸ | 1.2 × 10⁸ | 2020 | dense | | 459 | GPT-1 (OpenAI, 2018) | \~1.2 × 10⁸ | | 2018 | estimate | | 460 | ContextNet (Google, 2020) | \~1.1 × 10⁸ | | 2020 | estimate | | 461 | SciBERT (Allen Institute for AI, 2019) | 1.1 × 10⁸ | 1.1 × 10⁸ | 2019 | dense | | 462 | DNABERT (Northeastern University, 2021) | 1.1 × 10⁸ | 1.1 × 10⁸ | 2021 | architecture not stated | | 463 | Contriever (Meta AI, 2021) | \~1.1 × 10⁸ | | 2021 | estimate | | 464 | BERT-RBP (Waseda University, 2022) | 1.1 × 10⁸ | 1.1 × 10⁸ | 2022 | dense | | 465 | RoFormer (Zhuiyi Technology, 2023) | 1.1 × 10⁸ | 1.1 × 10⁸ | 2023 | architecture not stated | | 466 | LSTM LM (RWTH Aachen University, 2012) | \~1 × 10⁸ | | 2012 | estimate | | 467 | ReLU-Speech (Google, 2013) | \~1 × 10⁸ | | 2013 | estimate | | 468 | STORM-B/8 (University of Southern California, 2024) | 1 × 10⁸ | 1 × 10⁸ | 2024 | architecture not stated | | 469 | Support Vector Machines (AT&T, 1995) | \~1 × 10⁸ | | 1995 | estimate | | 470 | GPU DBNs (Stanford University, 2009) | 1 × 10⁸ | 1 × 10⁸ | 2009 | dense | | 471 | MSA Transformer (Facebook AI Research, 2021) | \~1 × 10⁸ | | 2021 | estimate | | 472 | YOLOX-X (Megvii Inc, 2021) | \~9.9 × 10⁷ | | 2021 | estimate | | 473 | DeLighT (University of Washington, 2020) | \~9.9 × 10⁷ | | 2020 | estimate | | 474 | ELMo (University of Washington, 2018) | \~9.4 × 10⁷ | | 2018 | estimate | | 475 | AlphaFold 2 (DeepMind, 2020) | \~9.3 × 10⁷ | | 2020 | estimate | | 476 | AlphaMissense (Google DeepMind, 2023) | \~9.3 × 10⁷ | | 2023 | estimate | | 477 | Octo-Base (University of California (UC) Berkeley, 2024) | 9.3 × 10⁷ | 9.3 × 10⁷ | 2024 | architecture not stated | | 478 | PolyNet (Chinese University of Hong Kong (CUHK), 2016) | \~9.2 × 10⁷ | | 2016 | estimate | | 479 | Transformer local-attention (Google Cloud, 2021) | 9 × 10⁷ | 9 × 10⁷ | 2021 | architecture not stated | | 480 | Transformer + Simple Recurrent Unit (ASAPP, 2018) | 9 × 10⁷ | 9 × 10⁷ | 2018 | dense | | 481 | NASNet-A (Google Brain, 2017) | \~8.9 × 10⁷ | | 2017 | estimate | | 482 | CLIP (OpenAI, 2021) | \~8.9 × 10⁷ | | 2021 | estimate | | 483 | Detic (Meta AI, 2022) | \~8.8 × 10⁷ | | 2022 | estimate | | 484 | MSRA (Microsoft Research, 2015) | 8.7 × 10⁷ | 8.7 × 10⁷ | 2015 | dense | | 485 | BigBiGAN (Google, 2019) | \~8.6 × 10⁷ | | 2019 | estimate | | 486 | ViT-Base/32 (Google Brain, 2020) | \~8.6 × 10⁷ | | 2020 | estimate | | 487 | DeiT-B (Meta AI, 2021) | 8.6 × 10⁷ | 8.6 × 10⁷ | 2021 | architecture not stated | | 488 | CaLM (University of Oxford, 2022) | \~8.6 × 10⁷ | | 2022 | estimate | | 489 | Tensor-Transformer (University of California (UC) Berkeley, 2020) | 8.5 × 10⁷ | 8.5 × 10⁷ | 2020 | dense | | 490 | ResNeXt-101 (University of California San Diego, 2016) | 8.3 × 10⁷ | 8.3 × 10⁷ | 2016 | dense | | 491 | RBM Image Classifier (University of Toronto, 2009) | \~8 × 10⁷ | | 2009 | estimate | | 492 | Routing Transformer (Google Research, 2020) | 8 × 10⁷ | 8 × 10⁷ | 2020 | dense | | 493 | Big-Little Net (IBM, 2018) | \~7.7 × 10⁷ | | 2018 | estimate | | 494 | EfficientDet (Google Brain, 2020) | \~7.7 × 10⁷ | | 2020 | estimate | | 495 | CODEFUSION (Microsoft, 2023) | 7.5 × 10⁷ | 7.5 × 10⁷ | 2023 | architecture not stated | | 496 | RNN LM (Johns Hopkins University, 2010) | \~7 × 10⁷ | | 2010 | estimate | | 497 | R-CNN (University of California (UC) Berkeley, 2013) | \~6.9 × 10⁷ | | 2013 | estimate | | 498 | Variational (University of Cambridge, 2015) | 6.6 × 10⁷ | 6.6 × 10⁷ | 2015 | dense | | 499 | DistilBERT (Hugging Face, 2019) | 6.6 × 10⁷ | 6.6 × 10⁷ | 2019 | dense | | 500 | Theseus 6/768 (University of California San Diego, 2020) | 6.6 × 10⁷ | 6.6 × 10⁷ | 2020 | dense | | 501 | ResNet-152 (Microsoft, 2015) | 6 × 10⁷ | 6 × 10⁷ | 2015 | dense | | 502 | AlexNet (University of Toronto, 2012) | 6 × 10⁷ | 6 × 10⁷ | 2012 | dense | | 503 | DETR (Facebook, 2020) | 6 × 10⁷ | 6 × 10⁷ | 2020 | dense | | 504 | YOLOv3 (University of Washington, 2018) | \~5.7 × 10⁷ | | 2018 | estimate | | 505 | Inception-ResNet-V2 (Google, 2016) | \~5.6 × 10⁷ | | 2016 | estimate | | 506 | Transformer ELMo (Allen Institute for AI, 2019) | 5.6 × 10⁷ | 5.6 × 10⁷ | 2019 | dense | | 507 | Fruit fly brain | 5.5 × 10⁷ | 5.5 × 10⁷ | | synapses | | 508 | NAS with base 8 and shared embeddings (Google Brain, 2016) | 5.4 × 10⁷ | 5.4 × 10⁷ | 2016 | dense | | 509 | RetinaNet-R101 (Facebook AI Research, 2017) | 5.3 × 10⁷ | 5.3 × 10⁷ | 2017 | dense | | 510 | AWD-LSTM+WT+Cache+IOG (NTT Communication Science Laboratories, 2017) | 5.3 × 10⁷ | 5.3 × 10⁷ | 2017 | dense | | 511 | Hierarchical Scene Labeling (New York University (NYU), 2013) | 5.2 × 10⁷ | 5.2 × 10⁷ | 2013 | dense | | 512 | VD-LSTM+REAL Large (Salesforce Research, 2016) | 5.1 × 10⁷ | 5.1 × 10⁷ | 2016 | dense | | 513 | YOLOv2 (University of Washington, 2016) | \~5.1 × 10⁷ | | 2016 | estimate | | 514 | Dropout-LSTM+Noise (Columbia University, 2018) | \~5.1 × 10⁷ | | 2018 | estimate | | 515 | LSTM + dynamic eval (University of Edinburgh, 2017) | \~5 × 10⁷ | | 2017 | estimate | | 516 | Dropout (University of Toronto, 2012) | \~4.9 × 10⁷ | | 2012 | estimate | | 517 | Dropout: SVHN (University of Toronto, 2014) | 4.8 × 10⁷ | 4.8 × 10⁷ | 2014 | dense | | 518 | DistBelief Speech (Google, 2012) | \~4.7 × 10⁷ | | 2012 | estimate | | 519 | AlphaGo Zero (DeepMind, 2017) | 4.6 × 10⁷ | 4.6 × 10⁷ | 2017 | dense | | 520 | Fine-tuned-AWD-LSTM-DOC (Samsung R&D Institute Russia, 2018) | 4.6 × 10⁷ | 4.6 × 10⁷ | 2018 | dense | | 521 | CT-MoS (Google, 2020) | 4.5 × 10⁷ | 4.5 × 10⁷ | 2020 | dense | | 522 | JFT (Google Research, 2017) | 4.5 × 10⁷ | 4.5 × 10⁷ | 2017 | dense | | 523 | ResNet-101 (Microsoft, 2015) | 4.5 × 10⁷ | 4.5 × 10⁷ | 2015 | dense | | 524 | HR-ResNet101 (Carnegie Mellon University (CMU), 2016) | 4.5 × 10⁷ | 4.5 × 10⁷ | 2016 | dense | | 525 | 3DMM-CNN (University of Southern California, 2016) | 4.5 × 10⁷ | 4.5 × 10⁷ | 2016 | dense | | 526 | LaNet-L (Brown University, 2019) | 4.4 × 10⁷ | 4.4 × 10⁷ | 2019 | dense | | 527 | ProBERTa (University of Illinois Urbana-Champaign (UIUC), 2020) | 4.4 × 10⁷ | 4.4 × 10⁷ | 2020 | dense | | 528 | PreTrans-3L-250H (University of Toronto, 2013) | \~4.3 × 10⁷ | | 2013 | estimate | | 529 | Inceptionv4 (Google, 2016) | \~4.3 × 10⁷ | | 2016 | estimate | | 530 | GL-LWGC-AWD-MoS-LSTM + dynamic evaluation (Ben-Gurion University of the Negev, 2017) | 3.8 × 10⁷ | 3.8 × 10⁷ | 2017 | dense | | 531 | U-Net (University of Freiburg, 2015) | 3.8 × 10⁷ | 3.8 × 10⁷ | 2015 | dense | | 532 | NASv3 (Google Brain, 2016) | \~3.7 × 10⁷ | | 2016 | estimate | | 533 | MuZero (DeepMind, 2019) | \~3.7 × 10⁷ | | 2019 | estimate | | 534 | AWD-LSTM-MoS + dynamic evaluation (Carnegie Mellon University (CMU), 2017) | \~3.5 × 10⁷ | | 2017 | estimate | | 535 | AWD-LSTM-MoS+PDR + dynamic evaluation (IBM, 2018) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2018 | dense | | 536 | AWD-LSTM-MoS + dynamic evaluation (Peking University, 2018) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2018 | dense | | 537 | AWD-LSTM + MoS + Partial Shuffled (University of Texas at Austin, 2019) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2019 | dense | | 538 | Mogrifier (d2, MoS2, MC) + dynamic eval (DeepMind, 2019) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2019 | dense | | 539 | Mogrifier RLSTM (DeepMind, 2022) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2022 | architecture not stated | | 540 | RT-1 (Google, 2022) | 3.5 × 10⁷ | 3.5 × 10⁷ | 2022 | architecture not stated | | 541 | DenseNet-264 (Tsinghua University, 2016) | 3.4 × 10⁷ | 3.4 × 10⁷ | 2016 | dense | | 542 | RetinaNet-R50 (Facebook AI Research, 2017) | \~3.4 × 10⁷ | | 2017 | estimate | | 543 | Fraternal dropout + AWD-LSTM 3-layer (Jagiellonian University, 2017) | \~3.4 × 10⁷ | | 2017 | estimate | | 544 | AWD-LSTM-DRILL + dynamic evaluation† (IDIAP, 2019) | \~3.4 × 10⁷ | | 2019 | estimate | | 545 | AWD-LSTM - 3-layer LSTM (Salesforce Research, 2017) | 3.3 × 10⁷ | 3.3 × 10⁷ | 2017 | dense | | 546 | TCAN (Nanjing University, 2020) | 3.3 × 10⁷ | 3.3 × 10⁷ | 2020 | dense | | 547 | MMLSTM (Beijing University of Posts and Telecommunications, 2019) | \~3.2 × 10⁷ | | 2019 | estimate | | 548 | Paragraph Vector (Google, 2014) | 3.2 × 10⁷ | 3.2 × 10⁷ | 2014 | dense | | 549 | aLSTM (University of Manchester, 2018) | 3.2 × 10⁷ | 3.2 × 10⁷ | 2018 | dense | | 550 | StyleGAN2 (Nvidia, 2019) | 3 × 10⁷ | 3 × 10⁷ | 2019 | dense | | 551 | UDSMProt (Fraunhofer Heinrich Hertz Institute, 2019) | \~2.8 × 10⁷ | | 2019 | estimate | | 552 | SENet (Chinese Academy of Sciences, 2017) | \~2.8 × 10⁷ | | 2017 | estimate | | 553 | Perceiver IO (DeepMind, 2020) | 2.8 × 10⁷ | 2.8 × 10⁷ | 2020 | dense | | 554 | Fractional Max-Pooling (University of Warwick, 2014) | \~2.7 × 10⁷ | | 2014 | estimate | | 555 | Hierarchical Reasoning Model (Sapient Intelligence, 2025) | 2.7 × 10⁷ | 2.7 × 10⁷ | 2025 | architecture not stated | | 556 | RNN-WER (DeepMind, 2014) | \~2.6 × 10⁷ | | 2014 | estimate | | 557 | StyleGAN (Nvidia, 2018) | 2.6 × 10⁷ | 2.6 × 10⁷ | 2018 | dense | | 558 | PyramidNet (Korea Advanced Institute of Science and Technology (KAIST), 2017) | \~2.6 × 10⁷ | | 2017 | estimate | | 559 | ResNeXt-50 (University of California San Diego, 2016) | \~2.5 × 10⁷ | | 2016 | estimate | | 560 | AWD-LSTM (DeepMind, 2017) | 2.4 × 10⁷ | 2.4 × 10⁷ | 2017 | dense | | 561 | Inception v3 (Google, 2015) | \~2.4 × 10⁷ | | 2015 | estimate | | 562 | Mamba-24M (Carnegie Mellon University (CMU), 2023) | 2.3 × 10⁷ | 2.3 × 10⁷ | 2023 | architecture not stated | | 563 | WeNet (Amazon, 2019) | \~2.3 × 10⁷ | | 2019 | estimate | | 564 | EN^2AS with performance reward (Beijing Institute of Technology, 2019) | \~2.3 × 10⁷ | | 2019 | estimate | | 565 | NAS+ESS (Northeastern University (China), 2020) | 2.3 × 10⁷ | 2.3 × 10⁷ | 2020 | dense | | 566 | Xception (Google, 2016) | 2.3 × 10⁷ | 2.3 × 10⁷ | 2016 | dense | | 567 | MetaMimic (Google, 2018) | \~2.2 × 10⁷ | | 2018 | estimate | | 568 | MMLSTM (Beijing University of Posts and Telecommunications, 2019) | \~2.1 × 10⁷ | | 2019 | estimate | | 569 | Pointer Sentinel-LSTM (MetaMind Inc, 2016) | 2.1 × 10⁷ | 2.1 × 10⁷ | 2016 | dense | | 570 | DiffDock (Massachusetts Institute of Technology (MIT), 2022) | \~2 × 10⁷ | | 2022 | estimate | | 571 | EI-REHN-1000D (Korea Advanced Institute of Science and Technology (KAIST), 2017) | 1.9 × 10⁷ | 1.9 × 10⁷ | 2017 | dense | | 572 | TC-DNN-BLSTM-DNN (Carnegie Mellon University (CMU), 2015) | 1.8 × 10⁷ | 1.8 × 10⁷ | 2015 | dense | | 573 | OR-WideResNet (Duke University, 2017) | 1.8 × 10⁷ | 1.8 × 10⁷ | 2017 | dense | | 574 | BP-DBN (University of Toronto, 2009) | 1.8 × 10⁷ | 1.8 × 10⁷ | 2009 | dense | | 575 | ALBERT (Toyota Technological Institute at Chicago, 2019) | 1.8 × 10⁷ | 1.8 × 10⁷ | 2019 | dense | | 576 | MedBERT (Peng Cheng Laboratory, 2021) | \~1.7 × 10⁷ | | 2021 | estimate | | 577 | LCNP NORB (, 2009) | 1.7 × 10⁷ | 1.7 × 10⁷ | 2009 | dense | | 578 | LF-MMI (Johns Hopkins University, 2016) | 1.7 × 10⁷ | 1.7 × 10⁷ | 2016 | dense | | 579 | AlphaFold (DeepMind, 2020) | \~1.6 × 10⁷ | | 2020 | estimate | | 580 | GNoME for crystal discovery (Google DeepMind, 2023) | \~1.6 × 10⁷ | | 2023 | estimate | | 581 | ReLU (University of Toronto, 2010) | \~1.6 × 10⁷ | | 2010 | estimate | | 582 | ProteinBERT (Hebrew University of Jerusalem, 2022) | 1.6 × 10⁷ | 1.6 × 10⁷ | 2022 | architecture not stated | | 583 | Eve (Harvard Medical School, 2021) | \~1.5 × 10⁷ | | 2021 | estimate | | 584 | LCNP LabelMe (University of Bonn, 2009) | 1.4 × 10⁷ | 1.4 × 10⁷ | 2009 | dense | | 585 | BatchNorm (Google, 2015) | 1.4 × 10⁷ | 1.4 × 10⁷ | 2015 | dense | | 586 | Fold2Seq (IBM, 2021) | \~1.2 × 10⁷ | | 2021 | estimate | | 587 | NPLM (University of Montreal / Université de Montréal, 2003) | 1.2 × 10⁷ | 1.2 × 10⁷ | 2003 | dense | | 588 | LCNP MNIST (, 2009) | 1.2 × 10⁷ | 1.2 × 10⁷ | 2009 | dense | | 589 | ISS (Duke University, 2017) | 1.1 × 10⁷ | 1.1 × 10⁷ | 2017 | dense | | 590 | ResNet-1001 (Microsoft, 2016) | \~1 × 10⁷ | | 2016 | estimate | | 591 | RNN+LDA+KN5+cache (Microsoft, 2012) | \~9 × 10⁶ | | 2012 | estimate | | 592 | Gated HORNN (York University, 2016) | \~9 × 10⁶ | | 2016 | estimate | | 593 | AlphaGo Fan (DeepMind, 2015) | \~8.2 × 10⁶ | | 2015 | estimate | | 594 | genCNN + dyn eval (Chinese Academy of Sciences, 2015) | \~8 × 10⁶ | | 2015 | estimate | | 595 | Once for All (MIT-IBM Watson AI Lab, 2020) | 7.7 × 10⁶ | 7.7 × 10⁶ | 2020 | dense | | 596 | Multi-cell LSTM (University of Hyderabad, 2018) | \~7.2 × 10⁶ | | 2018 | estimate | | 597 | Feedforward NN (University of Montreal / Université de Montréal, 2010) | 7.1 × 10⁶ | 7.1 × 10⁶ | 2010 | dense | | 598 | True-Regularization+Finetune+Dynamic-Eval (Mobvoi, 2019) | 7 × 10⁶ | 7 × 10⁶ | 2019 | dense | | 599 | Neural LM (University of Montreal / Université de Montréal, 2000) | 6.9 × 10⁶ | 6.9 × 10⁶ | 2000 | dense | | 600 | GoogLeNet / InceptionV1 (Google, 2014) | 6.8 × 10⁶ | 6.8 × 10⁶ | 2014 | dense | | 601 | HyenaDNA (Stanford University, 2023) | 6.6 × 10⁶ | 6.6 × 10⁶ | 2023 | architecture not stated | | 602 | Dropout (University of Toronto, 2012) | 5.6 × 10⁶ | 5.6 × 10⁶ | 2012 | dense | | 603 | SimpleNet (Sensifai, 2016) | 5.5 × 10⁶ | 5.5 × 10⁶ | 2016 | dense | | 604 | AlphaX-1 (Facebook AI Research, 2019) | 5.4 × 10⁶ | 5.4 × 10⁶ | 2019 | dense | | 605 | 3DDFA (Chinese Academy of Sciences, 2015) | 5.4 × 10⁶ | 5.4 × 10⁶ | 2015 | dense | | 606 | Deep CNN + COTS (IEEE, 2015) | 5 × 10⁶ | 5 × 10⁶ | 2015 | dense | | 607 | DCNN (University of Maryland, 2015) | 5 × 10⁶ | 5 × 10⁶ | 2015 | dense | | 608 | NLP from scratch (NEC Laboratories, 2011) | \~5 × 10⁶ | | 2011 | estimate | | 609 | SPN-4+KN5 (Singapore University of Technology & Design, 2014) | \~5 × 10⁶ | | 2014 | estimate | | 610 | 6-Act Tether (Facebook AI Research, 2021) | 5 × 10⁶ | 5 × 10⁶ | 2021 | architecture not stated | | 611 | High Performance CNN (IDSIA, 2011) | \~4.9 × 10⁶ | | 2011 | estimate | | 612 | MobileNet (Google, 2017) | \~4.2 × 10⁶ | | 2017 | estimate | | 613 | NPLM (University of Montreal / Université de Montréal, 2003) | 4.1 × 10⁶ | 4.1 × 10⁶ | 2003 | dense | | 614 | LMICA (, 2004) | 4.1 × 10⁶ | 4.1 × 10⁶ | 2004 | dense | | 615 | PoE MNIST (University College London (UCL), 2000) | 3.9 × 10⁶ | 3.9 × 10⁶ | 2000 | dense | | 616 | Dimensionality Reduction (University of Toronto, 2006) | \~3.8 × 10⁶ | | 2006 | estimate | | 617 | GOAT (DeepMind, 2021) | \~3.5 × 10⁶ | | 2021 | estimate | | 618 | MobileNetV2 (Google, 2018) | \~3.4 × 10⁶ | | 2018 | estimate | | 619 | Big-Little Net (IBM, 2018) | \~3.3 × 10⁶ | | 2018 | estimate | | 620 | DLWP (University of Washington, 2021) | 2.7 × 10⁶ | 2.7 × 10⁶ | 2021 | architecture not stated | | 621 | BIDAF (University of Washington, 2016) | 2.6 × 10⁶ | 2.6 × 10⁶ | 2016 | dense | | 622 | DeepStack (University of Alberta, 2017) | \~2.5 × 10⁶ | | 2017 | estimate | | 623 | KataGo (Jane Street, 2019) | \~2.5 × 10⁶ | | 2019 | estimate | | 624 | ShuffleNet v1 (Megvii Inc, 2017) | \~2.4 × 10⁶ | | 2017 | estimate | | 625 | ADAM (University of Amsterdam, 2014) | 2.4 × 10⁶ | 2.4 × 10⁶ | 2014 | dense | | 626 | StyleGAN3-T (Nvidia, 2021) | 2.2 × 10⁶ | 2.2 × 10⁶ | 2021 | architecture not stated | | 627 | LSTM+NeuralCache (KU Leuven, 2018) | \~2.1 × 10⁶ | | 2018 | estimate | | 628 | HLBL (University of Toronto, 2008) | 1.8 × 10⁶ | 1.8 × 10⁶ | 2008 | dense | | 629 | ResNet-110 (Microsoft, 2015) | \~1.7 × 10⁶ | | 2015 | estimate | | 630 | Dueling DQN (Google DeepMind, 2016) | 1.7 × 10⁶ | 1.7 × 10⁶ | 2016 | dense | | 631 | DQN-2015 (Google, 2015) | \~1.7 × 10⁶ | | 2015 | estimate | | 632 | Rational DQN Average (TU Darmstadt, 2021) | \~1.7 × 10⁶ | | 2021 | estimate | | 633 | IBM-5 (IBM, 1993) | \~1.7 × 10⁶ | | 1993 | estimate | | 634 | Deep Belief Nets (University of Toronto, 2006) | \~1.6 × 10⁶ | | 2006 | estimate | | 635 | IMPALA (DeepMind, 2018) | 1.6 × 10⁶ | 1.6 × 10⁶ | 2018 | dense | | 636 | StyleGAN3-R (Nvidia, 2021) | 1.6 × 10⁶ | 1.6 × 10⁶ | 2021 | architecture not stated | | 637 | Deep Multitask NLP Network (NEC Laboratories, 2008) | \~1.5 × 10⁶ | | 2008 | estimate | | 638 | Double DQN (Google DeepMind, 2016) | 1.5 × 10⁶ | 1.5 × 10⁶ | 2016 | dense | | 639 | CNN committee (IDSIA, 2011) | \~1.4 × 10⁶ | | 2011 | estimate | | 640 | SqueezeNet (DeepScale, 2016) | \~1.2 × 10⁶ | | 2016 | estimate | | 641 | Neocognitron (NHK Broadcasting Science Research Laboratories, 1980) | 1.1 × 10⁶ | 1.1 × 10⁶ | 1980 | dense | | 642 | CURL (University of California (UC) Berkeley, 2020) | \~9.1 × 10⁵ | | 2020 | estimate | | 643 | DQN (DeepMind, 2013) | 8.4 × 10⁵ | 8.4 × 10⁵ | 2013 | dense | | 644 | EnhanceNet (Max Planck Institute for Intelligent Systems, 2016) | 8.1 × 10⁵ | 8.1 × 10⁵ | 2016 | dense | | 645 | Image generation (University of Amsterdam, 2013) | 7.8 × 10⁵ | 7.8 × 10⁵ | 2013 | dense | | 646 | Hanabi 4 player (DeepMind, 2019) | 7.6 × 10⁵ | 7.6 × 10⁵ | 2019 | dense | | 647 | TA-CNN (Chinese University of Hong Kong (CUHK), 2014) | \~7.1 × 10⁵ | | 2014 | estimate | | 648 | Robot Parkour (Shanghai Qi Zhi institute, 2023) | 5 × 10⁵ | 5 × 10⁵ | 2023 | architecture not stated | | 649 | LISSOM (University of Texas at Austin, 1995) | \~4.3 × 10⁵ | | 1995 | estimate | | 650 | SPIDER2 (Griffith University, 2016) | \~4.1 × 10⁵ | | 2016 | estimate | | 651 | Mixture of linear models (, 1994) | \~3.8 × 10⁵ | | 1994 | estimate | | 652 | NPD (IEEE, 2014) | 3.1 × 10⁵ | 3.1 × 10⁵ | 2014 | dense | | 653 | Pooling CNN (University of Bonn, 2010) | 2.9 × 10⁵ | 2.9 × 10⁵ | 2010 | dense | | 654 | Pooling CNN (University of Bonn, 2010) | 2.7 × 10⁵ | 2.7 × 10⁵ | 2010 | dense | | 655 | Two Stage Feature Extraction (New York University (NYU), 2009) | 2.6 × 10⁵ | 2.6 × 10⁵ | 2009 | dense | | 656 | Vector Space Model (Stanford University, 2011) | 2.5 × 10⁵ | 2.5 × 10⁵ | 2011 | dense | | 657 | HyperNEAT (University of Texas at Austin, 2014) | \~2.4 × 10⁵ | | 2014 | estimate | | 658 | DNN EM segmentation (IDSIA, 2012) | 2.2 × 10⁵ | 2.2 × 10⁵ | 2012 | dense | | 659 | Predictive Coding NN (Technical University of Munich, 1994) | 2.1 × 10⁵ | 2.1 × 10⁵ | 1994 | dense | | 660 | Table Tennis Agent (Google DeepMind, 2024) | \~1.9 × 10⁵ | | 2024 | estimate | | 661 | CNN Committee (IDSIA, 2011) | \~1.3 × 10⁵ | | 2011 | estimate | | 662 | CNN Committee (IDSIA, 2011) | \~1.2 × 10⁵ | | 2011 | estimate | | 663 | RECONTRA-uncategorized (, 1999) | \~1.1 × 10⁵ | | 1999 | estimate | | 664 | BLSTM for handwriting (University of Bern, 2007) | \~1 × 10⁵ | | 2007 | estimate | | 665 | SVM-CNN (New York University (NYU), 2006) | 9.1 × 10⁴ | 9.1 × 10⁴ | 2006 | dense | | 666 | Invariant CNN (New York University (NYU), 2004) | 9.1 × 10⁴ | 9.1 × 10⁴ | 2004 | dense | | 667 | SexNet compression (, 1990) | 7.3 × 10⁴ | 7.3 × 10⁴ | 1990 | dense | | 668 | NeuroChess (, 1994) | \~7.2 × 10⁴ | | 1994 | estimate | | 669 | RECONTRA-categorized (, 1999) | \~6.7 × 10⁴ | | 1999 | estimate | | 670 | LeNet-5 (AT&T, 1998) | 6 × 10⁴ | 6 × 10⁴ | 1998 | dense | | 671 | Swift (Intel Labs, 2023) | \~5.7 × 10⁴ | | 2023 | estimate | | 672 | TCN (Carnegie Mellon University (CMU), 2018) | 4.2 × 10⁴ | 4.2 × 10⁴ | 2018 | dense | | 673 | TRPO (University of California (UC) Berkeley, 2015) | 3.4 × 10⁴ | 3.4 × 10⁴ | 2015 | dense | | 674 | SOM-CNN (, 1997) | 3.2 × 10⁴ | 3.2 × 10⁴ | 1997 | dense | | 675 | NETtalk reimplementation (Oregon State University, 1990) | 2.7 × 10⁴ | 2.7 × 10⁴ | 1990 | dense | | 676 | TD-Gammon (IBM, 1992) | \~2.5 × 10⁴ | | 1992 | estimate | | 677 | Cognitron (Biological Cybernetics, 1975) | 2.2 × 10⁴ | 2.2 × 10⁴ | 1975 | dense | | 678 | NetTalk (Princeton University, 1987) | 1.9 × 10⁴ | 1.9 × 10⁴ | 1987 | dense | | 679 | CFSS (SenseTime, 2015) | \~1.7 × 10⁴ | | 2015 | estimate | | 680 | MUSIC perceptron (, 1996) | 1.4 × 10⁴ | 1.4 × 10⁴ | 1996 | dense | | 681 | AdaRNN (Beihang University, 2014) | 1.3 × 10⁴ | 1.3 × 10⁴ | 2014 | dense | | 682 | Bidirectional RNN (Advanced Telecommunications Research Institute, 1997) | \~1.3 × 10⁴ | | 1997 | estimate | | 683 | Decision tree (Mitsubishi Electric Research Labs, 2001) | \~1.2 × 10⁴ | | 2001 | estimate | | 684 | LSTM (Technical University of Munich, 1997) | 1.1 × 10⁴ | 1.1 × 10⁴ | 1997 | dense | | 685 | MLN-ASR (McGill University, 1988) | 1 × 10⁴ | 1 × 10⁴ | 1988 | dense | | 686 | Hopfield network (California Institute of Technology, 1982) | \~9.9 × 10³ | | 1982 | estimate | | 687 | Zip CNN (AT&T, 1989) | 9.8 × 10³ | 9.8 × 10³ | 1989 | dense | | 688 | Hierarchical Cognitron (NHK Broadcasting Science Research Laboratories, 1984) | \~9.3 × 10³ | | 1984 | estimate | | 689 | Weight Decay (, 1991) | 8.4 × 10³ | 8.4 × 10³ | 1991 | dense | | 690 | Deep Blue (IBM, 1997) | \~8 × 10³ | | 1997 | estimate | | 691 | Nematode (C. elegans) | 7 × 10³ | 7 × 10³ | | synapses | | 692 | System 11 (Carnegie Mellon University (CMU), 1996) | 6.5 × 10³ | 6.5 × 10³ | 1996 | dense | | 693 | ACF-WIDER (Chinese Academy of Sciences, 2014) | 6.1 × 10³ | 6.1 × 10³ | 2014 | dense | | 694 | RankNet (Microsoft Research, 2005) | 5.7 × 10³ | 5.7 × 10³ | 2005 | dense | | 695 | ANN Eye Tracker (, 1993) | 5.6 × 10³ | 5.6 × 10³ | 1993 | dense | | 696 | JPMAX (, 1994) | \~4.4 × 10³ | | 1994 | estimate | | 697 | Kohonen network (Helsinki University of Technology, 1981) | \~4.1 × 10³ | | 1981 | estimate | | 698 | Speaker-independent vowel classification (University of Washington, 1989) | 3 × 10³ | 3 × 10³ | 1989 | dense | | 699 | Pattern recognition and reading by machine (Sandia Corporation, 1959) | \~2.6 × 10³ | | 1959 | estimate | | 700 | Handwritten digit recognition network (AT&T, 1989) | 2.6 × 10³ | 2.6 × 10³ | 1989 | dense | | 701 | Boosting (Bell Laboratories, 1992) | \~2.6 × 10³ | | 1992 | estimate | | 702 | Decision tree adaline (Tokyo Medical and Dental University, 1969) | 2.5 × 10³ | 2.5 × 10³ | 1969 | dense | | 703 | LTE speaker verification system (IBM, 1966) | \~2.1 × 10³ | | 1966 | estimate | | 704 | Ceramic-MLP (Sapienza Università di Roma, 1994) | \~1.9 × 10³ | | 1994 | estimate | | 705 | SexNet classification (, 1990) | \~1.6 × 10³ | | 1990 | estimate | | 706 | RAAM (, 1990) | 1.5 × 10³ | 1.5 × 10³ | 1990 | dense | | 707 | Super-vector coding (University of Illinois Urbana-Champaign (UIUC), 2010) | \~1 × 10³ | | 2010 | estimate | | 708 | Perceptron Mark I (Cornell Aeronautical Laboratory, 1957) | \~1 × 10³ | | 1957 | estimate | | 709 | Perceptron (Cornell Aeronautical Laboratory, 1960) | \~1 × 10³ | | 1960 | estimate | | 710 | Translation-invariant MLP (Carnegie Mellon University (CMU), 1987) | 8.2 × 10² | 8.2 × 10² | 1987 | mixture of experts (active count unpublished) | | 711 | Truck backer-upper (Stanford University, 1989) | 8.1 × 10² | 8.1 × 10² | 1989 | dense | | 712 | Siamese-TDNN (Bell Laboratories, 1993) | \~7.4 × 10² | | 1993 | estimate | | 713 | MLP with back-propagation (University of California San Diego, 1986) | 7.2 × 10² | 7.2 × 10² | 1986 | dense | | 714 | Cancer drug mechanism prediction (National Cancer Institute, 1992) | \~5.9 × 10² | | 1992 | estimate | | 715 | Distributed representation NN (Carnegie Mellon University (CMU), 1986) | 4.3 × 10² | 4.3 × 10² | 1986 | dense | | 716 | Piecewise linear model (University of Kansas, 1973) | 3.6 × 10² | 3.6 × 10² | 1973 | dense | | 717 | ASE+ACE (University of Massachusetts Amherst, 1983) | \~3.2 × 10² | | 1983 | estimate | | 718 | LSTM with forget gates (IDSIA, 1999) | \~2.8 × 10² | | 1999 | estimate | | 719 | Self Organizing System (Massachusetts Institute of Technology (MIT), 1955) | \~2.3 × 10² | | 1955 | estimate | | 720 | Theseus (Bell Laboratories, 1950) | 4 × 10¹ | 4 × 10¹ | 1950 | dense | | 721 | SNARC (Harvard University, 1952) | \~4 × 10¹ | | 1952 | estimate | | 722 | Bankruptcy-NN (, 1990) | 3.6 × 10¹ | 3.6 × 10¹ | 1990 | dense | | 723 | GNN (University of Siena, 2008) | 3 × 10¹ | 3 × 10¹ | 2008 | dense | | 724 | ADALINE (Stanford University, 1960) | 1.7 × 10¹ | 1.7 × 10¹ | 1960 | dense | | 725 | Samuel Neural Checkers (IBM, 1959) | \~1.6 × 10¹ | | 1959 | estimate | ## Collectives These charts rank animal societies, religions, states, parties and corporations two ways. One is by members. The other is by neuron-equivalents, which weight each member by the share of their waking time the group’s instructions direct. Religious codes, laws, party rules and job descriptions all count the same way. They're all sets of instructions, so we measure them by the same rule. [How directed time is estimated](https://simulation-hypothesis.com/entities/control). ## Animal societies: neurons in coordinated group activity Neurons in the group In group activity Members of a typical group × neurons in each member’s cortex or pallium (whole brain for insects), on a logarithmic scale. Hatched bars use an estimated group size or a related species’ neuron count. 1. Chimpanzee community▲1 7.4 × 10¹¹ 2. Leafcutter ant colony▼1 6.3 × 10¹¹ 3. Bonobo community▲2 4.4 × 10¹¹ 4. Hadza camp (humans, for scale) 4.1 × 10¹¹ 5. Bigg’s orca group▼2 2.6 × 10¹¹ 6. Resident orca matriline 2.4 × 10¹¹ 7. Baboon troop 8.6 × 10¹⁰ 8. Bottlenose dolphin alliance▲1 7.6 × 10¹⁰ 9. Sperm whale social unit▲1 6.4 × 10¹⁰ 10. Honeybee colony▼2 5.8 × 10¹⁰ 11. Elephant family 5.6 × 10¹⁰ 12. Pinyon jay flock 5.3 × 10¹⁰ 13. Spotted hyena clan 2.2 × 10¹⁰ 14. African wild dog pack 7.2 × 10⁹ 15. Wolf pack 4.2 × 10⁹ 16. Meerkat group 1.7 × 10⁹ 17. Naked mole-rat colony 4.1 × 10⁸ 10^8 10^9 10^10 10^11 10^12 neurons Show the numbers | # | Group | Neurons in the group | In group activity | Members | Share directed | Call types | | -- | ------------------------------ | -------------------- | ----------------- | ----------- | -------------- | ---------- | | 1 | Chimpanzee community | 7.4 × 10¹¹ | 2.5 × 10¹¹ | 100 | 34% | — | | 2 | Leafcutter ant colony | 6.3 × 10¹¹ | 5 × 10¹¹ | 2.5 million | 80% | — | | 3 | Bonobo community | 4.4 × 10¹¹ | 1.9 × 10¹¹ | 59 | 43% | — | | 4 | Hadza camp (humans, for scale) | 4.1 × 10¹¹ | 2.1 × 10¹¹ | 25 | 53% | — | | 5 | Bigg’s orca group | 2.6 × 10¹¹ | 2.4 × 10¹¹ | 6 | 91% | — | | 6 | Resident orca matriline | 2.4 × 10¹¹ | 1.7 × 10¹¹ | 6 | 70% | 11 | | 7 | Baboon troop | 8.6 × 10¹⁰ | 5.2 × 10¹⁰ | 30 | 60% | 9 | | 8 | Bottlenose dolphin alliance | 7.6 × 10¹⁰ | 4.2 × 10¹⁰ | 6 | 55% | — | | 9 | Sperm whale social unit | 6.4 × 10¹⁰ | 4.1 × 10¹⁰ | 8 | 65% | — | | 10 | Honeybee colony | 5.8 × 10¹⁰ | 4.9 × 10¹⁰ | 60,000 | 85% | — | | 11 | Elephant family | 5.6 × 10¹⁰ | 3.2 × 10¹⁰ | 10 | 57% | — | | 12 | Pinyon jay flock | 5.3 × 10¹⁰ | 3.2 × 10¹⁰ | 100 | 60% | — | | 13 | Spotted hyena clan | 2.2 × 10¹⁰ | 6.7 × 10⁹ | 45 | 30% | 11 | | 14 | African wild dog pack | 7.2 × 10⁹ | 4.8 × 10⁹ | 14 | 67% | 11 | | 15 | Wolf pack | 4.2 × 10⁹ | 2.6 × 10⁹ | 8 | 63% | — | | 16 | Meerkat group | 1.7 × 10⁹ | 1 × 10⁹ | 15 | 57% | 12 | | 17 | Naked mole-rat colony | 4.1 × 10⁸ | 2.9 × 10⁸ | 78 | 70% | — | [How the groups are scored](https://simulation-hypothesis.com/entities/control). ## Religions: members, and neurons following their instructions Members Following its instructions Whole religions Sects and movements Adherents, on a logarithmic scale. Sects and movements are shown apart from the religions that contain them. Solid bars are counts; hatched bars are estimates. 1. Christianity▲1 2.27 billion 2. Islam▼1 2.02 billion 3. Hinduism 1.18 billion 4. Folk religions 400 million 5. Buddhism 324 million 6. African traditional religions▲1 98.7 million 7. Shinto▲1 87.9 million 8. Sikhism▲1 25 million 9. Judaism▼3 14.8 million 10. Taoism▲1 8 million 11. Baháʼí Faith▲1 8 million 12. Falun Gong▲1 7 million 13. Jainism▼3 4.45 million 14. Spiritism 3.8 million 15. Cao Đài 2.5 million 16. Tenrikyo 1.12 million 17. Brahma Kumaris 1 million 10^5 10^6 10^7 10^8 10^9 10^10 members Show the numbers | # | Religion | Members | Following its instructions | Share directed | Hours a week | | -- | ----------------------------- | ------------ | -------------------------- | -------------- | ------------ | | 1 | Christianity | 2.27 billion | 1.7 × 10¹⁸ | 0.88% | 0.9 h | | 2 | Islam | 2.02 billion | 8.9 × 10¹⁸ | 5.1% | 5.4 h | | 3 | Hinduism | 1.18 billion | 1.6 × 10¹⁸ | 1.6% | 1.6 h | | 4 | Folk religions | 400 million | 2 × 10¹⁷ | 0.59% (proxy) | 0.6 h | | 5 | Buddhism | 324 million | 7.5 × 10¹⁶ | 0.27% | 0.3 h | | 6 | African traditional religions | 98.7 million | 5 × 10¹⁶ | 0.59% (proxy) | 0.6 h | | 7 | Shinto | 87.9 million | 4.5 × 10¹⁶ | 0.59% (proxy) | 0.6 h | | 8 | Sikhism | 25 million | 3.7 × 10¹⁶ | 1.7% | 1.8 h | | 9 | Judaism | 14.8 million | 5.3 × 10¹⁶ | 4.2% | 4.4 h | | 10 | Taoism | 8 million | 4.1 × 10¹⁵ | 0.59% (proxy) | 0.6 h | | 11 | Baháʼí Faith | 8 million | 4.1 × 10¹⁵ | 0.59% (proxy) | 0.6 h | | 12 | Falun Gong | 7 million | 3.6 × 10¹⁵ | 0.59% (proxy) | 0.6 h | | 13 | Jainism | 4.45 million | 1.8 × 10¹⁶ | 4.6% | 4.8 h | | 14 | Spiritism | 3.8 million | 1.9 × 10¹⁵ | 0.59% (proxy) | 0.6 h | | 15 | Cao Đài | 2.5 million | 1.3 × 10¹⁵ | 0.59% (proxy) | 0.6 h | | 16 | Tenrikyo | 1.12 million | 5.7 × 10¹⁴ | 0.59% (proxy) | 0.6 h | | 17 | Brahma Kumaris | 1 million | 5.1 × 10¹⁴ | 0.59% (proxy) | 0.6 h | [Every practice, share and source](https://simulation-hypothesis.com/entities/control). ## States: residents, and neurons following their instructions Residents Following its instructions All East Asia, Pacific Europe, Central Asia Latin America Middle East, N. Africa North America South Asia Sub-Saharan Africa Population, on a logarithmic scale. Solid bars are counts; hatched bars are estimates. 1. India▲1 1.46 billion 2. China▼1 1.41 billion 3. United States 342 million 4. Indonesia 286 million 5. Pakistan▲5 255 million 6. Nigeria▲1 238 million 7. Brazil▼2 213 million 8. Bangladesh▲5 176 million 9. Russia▼3 144 million 10. Ethiopia▲7 135 million 11. Mexico▼2 132 million 12. Japan▲11 123 million 13. Egypt▼2 118 million 14. Philippines 117 million 15. DR Congo▼3 113 million Show all 196 10^4 10^6 10^8 10^10 residents Show the numbers | # | State | Residents | Following its instructions | Share directed | Hours a week | | --- | -------------------------------- | ------------ | -------------------------- | -------------- | ------------ | | 1 | India | 1.46 billion | 2.5 × 10¹⁸ | 2% | 2.1 h | | 2 | China | 1.41 billion | 5 × 10¹⁸ | 4.1% | 4.3 h | | 3 | United States | 342 million | 1.6 × 10¹⁸ | 5.6% | 5.8 h | | 4 | Indonesia | 286 million | 1 × 10¹⁸ | 4.2% | 4.4 h | | 5 | Pakistan | 255 million | 5.7 × 10¹⁷ | 2.6% | 2.7 h | | 6 | Nigeria | 238 million | 6.6 × 10¹⁷ | 3.2% | 3.4 h | | 7 | Brazil | 213 million | 8.7 × 10¹⁷ | 4.8% | 5 h | | 8 | Bangladesh | 176 million | 4.6 × 10¹⁷ | 3% | 3.1 h | | 9 | Russia | 144 million | 7.5 × 10¹⁷ | 6.1% | 6.4 h | | 10 | Ethiopia | 135 million | 3.9 × 10¹⁷ | 3.4% | 3.5 h | | 11 | Mexico | 132 million | 5.9 × 10¹⁷ | 5.2% | 5.5 h | | 12 | Japan | 123 million | 2.8 × 10¹⁷ | 2.7% | 2.8 h | | 13 | Egypt | 118 million | 5.5 × 10¹⁷ | 5.4% | 5.7 h | | 14 | Philippines | 117 million | 4.4 × 10¹⁷ | 4.4% | 4.6 h | | 15 | DR Congo | 113 million | 4.7 × 10¹⁷ | 4.8% | 5.1 h | | 16 | Vietnam | 102 million | 4.2 × 10¹⁷ | 4.8% | 5 h | | 17 | Iran | 92.4 million | 3.5 × 10¹⁷ | 4.3% | 4.6 h | | 18 | Turkey | 85.9 million | 4.3 × 10¹⁷ | 5.8% | 6 h | | 19 | Germany | 83.5 million | 2.9 × 10¹⁷ | 4% | 4.2 h | | 20 | Thailand | 71.6 million | 2.4 × 10¹⁷ | 3.9% | 4.1 h | | 21 | Tanzania | 70.5 million | 2.2 × 10¹⁷ | 3.6% | 3.8 h | | 22 | United Kingdom | 69.5 million | 2.8 × 10¹⁷ | 4.6% | 4.8 h | | 23 | France | 68.7 million | 3.1 × 10¹⁷ | 5.3% | 5.5 h | | 24 | South Africa | 64.7 million | 2.9 × 10¹⁷ | 5.1% | 5.4 h | | 25 | Italy | 58.9 million | 2.1 × 10¹⁷ | 4.2% | 4.4 h | | 26 | Kenya | 57.5 million | 2.3 × 10¹⁷ | 4.7% | 5 h | | 27 | Myanmar | 54.9 million | 1.9 × 10¹⁷ | 4% | 4.2 h | | 28 | Colombia | 53.4 million | 1.7 × 10¹⁷ | 3.7% | 3.9 h | | 29 | South Korea | 51.7 million | 1.4 × 10¹⁷ | 3% | 3.2 h | | 30 | Sudan | 51.7 million | 1.5 × 10¹⁷ | 3.4% | 3.6 h | | 31 | Uganda | 51.4 million | 1.5 × 10¹⁷ | 3.4% | 3.6 h | | 32 | Spain | 49.4 million | 1.8 × 10¹⁷ | 4.2% | 4.3 h | | 33 | Algeria | 47.4 million | 3.2 × 10¹⁷ | 7.9% | 8.3 h | | 34 | Iraq | 47 million | 1.1 × 10¹⁷ | 2.8% | 2.9 h | | 35 | Argentina | 45.9 million | 1.7 × 10¹⁷ | 4.4% | 4.6 h | | 36 | Afghanistan | 43.8 million | 1.8 × 10¹⁷ | 4.8% | 5 h | | 37 | Yemen | 41.8 million | 1.3 × 10¹⁷ | 3.7% | 3.9 h | | 38 | Canada | 41.7 million | 2 × 10¹⁷ | 5.5% | 5.8 h | | 39 | Angola | 39 million | 1.4 × 10¹⁷ | 4.2% | 4.4 h | | 40 | Ukraine | 39 million | 2.1 × 10¹⁷ | 6.2% | 6.5 h | | 41 | Morocco | 38.4 million | 1.5 × 10¹⁷ | 4.5% | 4.7 h | | 42 | Uzbekistan | 37.1 million | 2 × 10¹⁷ | 6.3% | 6.6 h | | 43 | Saudi Arabia | 37 million | 1.4 × 10¹⁷ | 4.3% | 4.6 h | | 44 | Poland | 36.4 million | 2.1 × 10¹⁷ | 6.7% | 7 h | | 45 | Malaysia | 36 million | 1.8 × 10¹⁷ | 5.8% | 6.1 h | | 46 | Mozambique | 35.6 million | 1.5 × 10¹⁷ | 4.8% | 5.1 h | | 47 | Ghana | 35.1 million | 1.2 × 10¹⁷ | 3.9% | 4.1 h | | 48 | Peru | 34.6 million | 1.4 × 10¹⁷ | 4.8% | 5 h | | 49 | Madagascar | 32.7 million | 9.4 × 10¹⁶ | 3.3% | 3.5 h | | 50 | Côte d’Ivoire | 32.7 million | 9.5 × 10¹⁶ | 3.4% | 3.5 h | | 51 | Cameroon | 29.9 million | 9.8 × 10¹⁶ | 3.8% | 4 h | | 52 | Nepal | 29.6 million | 1.1 × 10¹⁷ | 4.2% | 4.4 h | | 53 | Venezuela | 28.5 million | 1.5 × 10¹⁷ | 6.1% | 6.4 h | | 54 | Niger | 27.9 million | 6.4 × 10¹⁶ | 2.6% | 2.8 h | | 55 | Australia | 27.6 million | 1.1 × 10¹⁷ | 4.7% | 5 h | | 56 | North Korea | 26.6 million | 6.6 × 10¹⁷ | 29% | 30.1 h | | 57 | Syria | 25.6 million | 9.8 × 10¹⁶ | 4.4% | 4.6 h | | 58 | Mali | 25.2 million | 4.9 × 10¹⁶ | 2.3% | 2.4 h | | 59 | Burkina Faso | 24.1 million | 5.7 × 10¹⁶ | 2.8% | 2.9 h | | 60 | Taiwan | 23.3 million | 1 × 10¹⁷ | 5% | 5.3 h | | 61 | Malawi | 22.2 million | 1 × 10¹⁷ | 5.4% | 5.6 h | | 62 | Zambia | 21.9 million | 10 × 10¹⁶ | 5.3% | 5.5 h | | 63 | Sri Lanka | 21.8 million | 1.1 × 10¹⁷ | 6% | 6.3 h | | 64 | Chad | 21 million | 4.9 × 10¹⁶ | 2.7% | 2.9 h | | 65 | Kazakhstan | 20.8 million | 1.4 × 10¹⁷ | 7.6% | 7.9 h | | 66 | Chile | 19.9 million | 6.2 × 10¹⁶ | 3.6% | 3.8 h | | 67 | Somalia | 19.7 million | 1.5 × 10¹⁶ | 0.88% | 0.9 h | | 68 | Romania | 19 million | 7.5 × 10¹⁶ | 4.6% | 4.8 h | | 69 | Senegal | 18.9 million | 5.9 × 10¹⁶ | 3.6% | 3.8 h | | 70 | Guatemala | 18.7 million | 6 × 10¹⁶ | 3.7% | 3.9 h | | 71 | Ecuador | 18.3 million | 6.6 × 10¹⁶ | 4.2% | 4.4 h | | 72 | Netherlands | 18.1 million | 7.6 × 10¹⁶ | 4.9% | 5.1 h | | 73 | Cambodia | 17.8 million | 7.4 × 10¹⁶ | 4.8% | 5.1 h | | 74 | Zimbabwe | 17 million | 6.1 × 10¹⁶ | 4.2% | 4.4 h | | 75 | Guinea | 15.1 million | 3.1 × 10¹⁶ | 2.4% | 2.5 h | | 76 | Benin | 14.8 million | 4.4 × 10¹⁶ | 3.4% | 3.6 h | | 77 | Rwanda | 14.6 million | 7 × 10¹⁶ | 5.6% | 5.8 h | | 78 | Burundi | 14.4 million | 5.2 × 10¹⁶ | 4.2% | 4.4 h | | 79 | Bolivia | 12.6 million | 5.8 × 10¹⁶ | 5.4% | 5.6 h | | 80 | Tunisia | 12.3 million | 6.4 × 10¹⁶ | 6% | 6.3 h | | 81 | South Sudan | 12.2 million | 4.4 × 10¹⁶ | 4.2% | 4.4 h | | 82 | Belgium | 11.9 million | 4.5 × 10¹⁶ | 4.3% | 4.5 h | | 83 | Haiti | 11.9 million | 1.9 × 10¹⁶ | 1.8% | 1.9 h | | 84 | Jordan | 11.5 million | 4.9 × 10¹⁶ | 5% | 5.2 h | | 85 | Dominican Republic | 11.5 million | 4.9 × 10¹⁶ | 4.9% | 5.2 h | | 86 | United Arab Emirates | 11.5 million | 3.1 × 10¹⁶ | 3.1% | 3.2 h | | 87 | Honduras | 11 million | 3.2 × 10¹⁶ | 3.3% | 3.5 h | | 88 | Cuba | 10.9 million | 1.6 × 10¹⁷ | 17% | 17.4 h | | 89 | Czechia | 10.9 million | 5.8 × 10¹⁶ | 6.2% | 6.5 h | | 90 | Portugal | 10.8 million | 5.1 × 10¹⁶ | 5.5% | 5.7 h | | 91 | Tajikistan | 10.8 million | 5.3 × 10¹⁶ | 5.7% | 6 h | | 92 | Papua New Guinea | 10.8 million | 4.3 × 10¹⁶ | 4.6% | 4.8 h | | 93 | Sweden | 10.6 million | 6.8 × 10¹⁶ | 7.5% | 7.8 h | | 94 | Greece | 10.4 million | 4.9 × 10¹⁶ | 5.4% | 5.7 h | | 95 | Azerbaijan | 10.2 million | 6.2 × 10¹⁶ | 7% | 7.4 h | | 96 | Israel | 10.1 million | 6.4 × 10¹⁶ | 7.3% | 7.7 h | | 97 | Hungary | 9.51 million | 5.7 × 10¹⁶ | 6.9% | 7.3 h | | 98 | Austria | 9.21 million | 2.5 × 10¹⁶ | 3.2% | 3.4 h | | 99 | Switzerland | 9.09 million | 3.9 × 10¹⁶ | 5% | 5.3 h | | 100 | Belarus | 9.09 million | 7.9 × 10¹⁶ | 10% | 10.6 h | | 101 | Sierra Leone | 8.82 million | 4.9 × 10¹⁶ | 6.5% | 6.8 h | | 102 | Togo | 8.59 million | 3 × 10¹⁶ | 4% | 4.2 h | | 103 | Laos | 7.87 million | 3.2 × 10¹⁶ | 4.8% | 5 h | | 104 | Turkmenistan | 7.62 million | 4.2 × 10¹⁶ | 6.5% | 6.8 h | | 105 | Libya | 7.46 million | 3.9 × 10¹⁶ | 6.1% | 6.4 h | | 106 | Kyrgyzstan | 7.34 million | 4.1 × 10¹⁶ | 6.5% | 6.8 h | | 107 | Paraguay | 7.01 million | 2.9 × 10¹⁶ | 4.8% | 5.1 h | | 108 | Nicaragua | 7.01 million | 2.8 × 10¹⁶ | 4.6% | 4.8 h | | 109 | Serbia | 6.55 million | 4.1 × 10¹⁶ | 7.2% | 7.5 h | | 110 | Republic of the Congo | 6.48 million | 1.7 × 10¹⁶ | 3% | 3.1 h | | 111 | Bulgaria | 6.43 million | 3.3 × 10¹⁶ | 5.9% | 6.2 h | | 112 | El Salvador | 6.37 million | 3.2 × 10¹⁶ | 5.8% | 6.1 h | | 113 | Singapore | 6.11 million | 1.9 × 10¹⁶ | 3.6% | 3.7 h | | 114 | Denmark | 6.01 million | 3.9 × 10¹⁶ | 7.6% | 8 h | | 115 | Lebanon | 5.85 million | 1.5 × 10¹⁶ | 3% | 3.1 h | | 116 | Liberia | 5.73 million | 1.5 × 10¹⁶ | 3.1% | 3.3 h | | 117 | Finland | 5.65 million | 3.2 × 10¹⁶ | 6.6% | 6.9 h | | 118 | Norway | 5.61 million | 3.7 × 10¹⁶ | 7.6% | 8 h | | 119 | Central African Republic | 5.51 million | 1.7 × 10¹⁶ | 3.5% | 3.7 h | | 120 | Oman | 5.49 million | 2.9 × 10¹⁶ | 6.2% | 6.5 h | | 121 | Ireland | 5.48 million | 3.4 × 10¹⁶ | 7.2% | 7.6 h | | 122 | Slovakia | 5.41 million | 3.1 × 10¹⁶ | 6.7% | 7 h | | 123 | Palestine | 5.41 million | 2 × 10¹⁶ | 4.3% | 4.5 h | | 124 | New Zealand | 5.32 million | 2.7 × 10¹⁶ | 5.9% | 6.2 h | | 125 | Mauritania | 5.32 million | 2 × 10¹⁶ | 4.3% | 4.5 h | | 126 | Costa Rica | 5.15 million | 2.6 × 10¹⁶ | 5.9% | 6.2 h | | 127 | Kuwait | 4.87 million | 2.7 × 10¹⁶ | 6.5% | 6.8 h | | 128 | Panama | 4.57 million | 2.3 × 10¹⁶ | 5.9% | 6.2 h | | 129 | Georgia | 3.94 million | 2.1 × 10¹⁶ | 6.1% | 6.4 h | | 130 | Croatia | 3.88 million | 2.2 × 10¹⁶ | 6.7% | 7 h | | 131 | Eritrea | 3.61 million | 1.5 × 10¹⁶ | 5% | 5.2 h | | 132 | Mongolia | 3.57 million | 2.2 × 10¹⁶ | 7% | 7.3 h | | 133 | Uruguay | 3.38 million | 1.7 × 10¹⁶ | 5.9% | 6.2 h | | 134 | Bosnia and Herzegovina | 3.14 million | 1.6 × 10¹⁶ | 5.9% | 6.2 h | | 135 | Namibia | 3.09 million | 1.8 × 10¹⁶ | 6.9% | 7.2 h | | 136 | Armenia | 3.09 million | 1.7 × 10¹⁶ | 6.5% | 6.8 h | | 137 | Qatar | 2.97 million | 9.6 × 10¹⁵ | 3.8% | 3.9 h | | 138 | Lithuania | 2.89 million | 1.8 × 10¹⁶ | 7.4% | 7.7 h | | 139 | Jamaica | 2.84 million | 1.2 × 10¹⁶ | 5% | 5.2 h | | 140 | Gambia | 2.82 million | 1.1 × 10¹⁶ | 4.5% | 4.7 h | | 141 | Gabon | 2.59 million | 9.9 × 10¹⁵ | 4.4% | 4.6 h | | 142 | Botswana | 2.56 million | 1.3 × 10¹⁶ | 5.7% | 6 h | | 143 | Lesotho | 2.36 million | 9.5 × 10¹⁵ | 4.7% | 4.9 h | | 144 | Moldova | 2.36 million | 1.5 × 10¹⁶ | 7.3% | 7.6 h | | 145 | Albania | 2.35 million | 1.2 × 10¹⁶ | 5.7% | 6 h | | 146 | Guinea-Bissau | 2.25 million | 5.7 × 10¹⁵ | 2.9% | 3.1 h | | 147 | Slovenia | 2.13 million | 1.2 × 10¹⁶ | 6.6% | 6.9 h | | 148 | Equatorial Guinea | 1.94 million | 4 × 10¹⁵ | 2.4% | 2.5 h | | 149 | Latvia | 1.85 million | 1.2 × 10¹⁶ | 7.6% | 7.9 h | | 150 | North Macedonia | 1.82 million | 9.2 × 10¹⁵ | 5.9% | 6.2 h | | 151 | Bahrain | 1.6 million | 5.9 × 10¹⁵ | 4.3% | 4.5 h | | 152 | Kosovo | 1.58 million | 8 × 10¹⁵ | 5.9% | 6.2 h | | 153 | Timor-Leste | 1.42 million | 8 × 10¹⁵ | 6.6% | 6.9 h | | 154 | Cyprus | 1.37 million | 5.5 × 10¹⁵ | 4.7% | 4.9 h | | 155 | Trinidad and Tobago | 1.37 million | 9.3 × 10¹⁵ | 7.9% | 8.2 h | | 156 | Estonia | 1.37 million | 8.3 × 10¹⁵ | 7% | 7.4 h | | 157 | Eswatini | 1.26 million | 7.5 × 10¹⁵ | 6.9% | 7.2 h | | 158 | Mauritius | 1.24 million | 5.1 × 10¹⁵ | 4.8% | 5 h | | 159 | Djibouti | 1.18 million | 4.6 × 10¹⁵ | 4.5% | 4.8 h | | 160 | Fiji | 933,154 | 5.6 × 10¹⁵ | 7% | 7.4 h | | 161 | Comoros | 882,847 | 3.5 × 10¹⁵ | 4.6% | 4.8 h | | 162 | Solomon Islands | 838,645 | 3.2 × 10¹⁵ | 4.4% | 4.6 h | | 163 | Guyana | 835,986 | 4.6 × 10¹⁵ | 6.4% | 6.7 h | | 164 | Bhutan | 796,682 | 5.8 × 10¹⁵ | 8.5% | 8.9 h | | 165 | Luxembourg | 686,970 | 2.4 × 10¹⁵ | 4% | 4.2 h | | 166 | Suriname | 639,850 | 3.7 × 10¹⁵ | 6.7% | 7.1 h | | 167 | Montenegro | 623,129 | 4.3 × 10¹⁵ | 8.1% | 8.5 h | | 168 | Malta | 579,704 | 3.1 × 10¹⁵ | 6.2% | 6.5 h | | 169 | Maldives | 529,676 | 4.7 × 10¹⁵ | 10% | 10.8 h | | 170 | Cape Verde | 527,326 | 3.3 × 10¹⁵ | 7.2% | 7.6 h | | 171 | Brunei | 466,330 | 3.6 × 10¹⁵ | 8.9% | 9.3 h | | 172 | Belize | 422,924 | 1.1 × 10¹⁵ | 2.9% | 3.1 h | | 173 | Bahamas | 403,033 | 2.2 × 10¹⁵ | 6.4% | 6.7 h | | 174 | Iceland | 392,404 | 2.5 × 10¹⁵ | 7.4% | 7.7 h | | 175 | Vanuatu | 335,169 | 2 × 10¹⁵ | 6.9% | 7.3 h | | 176 | Barbados | 282,623 | 1.5 × 10¹⁵ | 6% | 6.3 h | | 177 | São Tomé and Príncipe | 240,254 | 1.1 × 10¹⁵ | 5.4% | 5.7 h | | 178 | Samoa | 219,306 | 1.1 × 10¹⁵ | 5.7% | 5.9 h | | 179 | Saint Lucia | 180,149 | 9.3 × 10¹⁴ | 6% | 6.3 h | | 180 | Kiribati | 136,488 | 7.6 × 10¹⁴ | 6.4% | 6.7 h | | 181 | Seychelles | 122,730 | 8.9 × 10¹⁴ | 8.4% | 8.8 h | | 182 | Grenada | 117,303 | 7.3 × 10¹⁴ | 7.2% | 7.5 h | | 183 | Micronesia | 113,683 | 5.7 × 10¹⁴ | 5.8% | 6.1 h | | 184 | Tonga | 103,742 | 5.9 × 10¹⁴ | 6.6% | 6.9 h | | 185 | Saint Vincent and the Grenadines | 99,924 | 4.9 × 10¹⁴ | 5.7% | 5.9 h | | 186 | Antigua and Barbuda | 94,209 | 6.5 × 10¹⁴ | 8% | 8.3 h | | 187 | Andorra | 82,904 | 3.9 × 10¹⁴ | 5.5% | 5.8 h | | 188 | Dominica | 65,871 | 2.3 × 10¹⁴ | 4.1% | 4.3 h | | 189 | Saint Kitts and Nevis | 46,922 | 2.1 × 10¹⁴ | 5.2% | 5.5 h | | 190 | Liechtenstein | 41,024 | 2 × 10¹⁴ | 5.7% | 5.9 h | | 191 | Monaco | 38,341 | 2.3 × 10¹⁴ | 6.9% | 7.3 h | | 192 | Marshall Islands | 36,282 | 3.3 × 10¹⁴ | 10% | 10.9 h | | 193 | San Marino | 34,109 | 1.3 × 10¹⁴ | 4.6% | 4.8 h | | 194 | Palau | 17,663 | 1.6 × 10¹⁴ | 10% | 11 h | | 195 | Nauru | 12,025 | 9.3 × 10¹³ | 9% | 9.4 h | | 196 | Tuvalu | 9,492 | 8 × 10¹³ | 9.8% | 10.2 h | [What’s counted, and what isn’t](https://simulation-hypothesis.com/entities/control). ## Political parties: members, and neurons following their instructions Members Following its instructions Members as the party reports them, on a logarithmic scale. Solid bars are counts; hatched bars are estimates or claims. 1. Bharatiya Janata Party (India)▲1 140 million 2. Chinese Communist Party▼1 101 million 3. Democratic Party (US)▲13 44.9 million 4. Republican Party (US)▲16 38 million 5. Indian National Congress▼2 26 million 6. AIADMK (India)▼2 20 million 7. DMK (India)▼2 20 million 8. Prosperity Party (Ethiopia)▼1 15.7 million 9. TVK (India)▼1 15 million 10. Chama Cha Mapinduzi (Tanzania)▼1 13 million 11. All Progressives Congress (Nigeria)▼1 12.9 million 12. AK Party (Turkey)▼1 11.7 million 13. Morena (Mexico)▼1 11.6 million 14. Telugu Desam Party (India)▼1 10.1 million 15. Cambodian People’s Party▼1 7 million Show all 59 10^4 10^5 10^6 10^7 10^8 10^9 members Show the numbers | # | Party | Members | Following its instructions | Share directed | Hours a week | | -- | ------------------------------------------ | ------------ | -------------------------- | -------------- | ------------ | | 1 | Bharatiya Janata Party (India) | 140 million | 6.3 × 10¹⁶ | 0.52% (proxy) | 0.6 h | | 2 | Chinese Communist Party | 101 million | 8.2 × 10¹⁶ | 0.94% | 1 h | | 3 | Democratic Party (US) | 44.9 million | 2.3 × 10¹⁵ | 0.06% | 0.1 h | | 4 | Republican Party (US) | 38 million | 2 × 10¹⁵ | 0.06% | 0.1 h | | 5 | Indian National Congress | 26 million | 1.2 × 10¹⁶ | 0.52% (proxy) | 0.6 h | | 6 | AIADMK (India) | 20 million | 9 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 7 | DMK (India) | 20 million | 9 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 8 | Prosperity Party (Ethiopia) | 15.7 million | 7 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 9 | TVK (India) | 15 million | 6.7 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 10 | Chama Cha Mapinduzi (Tanzania) | 13 million | 5.8 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 11 | All Progressives Congress (Nigeria) | 12.9 million | 5.8 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 12 | AK Party (Turkey) | 11.7 million | 5.2 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 13 | Morena (Mexico) | 11.6 million | 5.2 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 14 | Telugu Desam Party (India) | 10.1 million | 4.5 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 15 | Cambodian People’s Party | 7 million | 3.1 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 16 | Workers’ Party of Korea | 6.17 million | 7.6 × 10¹⁵ | 1.4% | 1.5 h | | 17 | FRELIMO (Mozambique) | 6 million | 2.7 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 18 | Communist Party of Vietnam | 5.6 million | 2.1 × 10¹⁵ | 0.44% | 0.5 h | | 19 | Democratic Party of Korea | 5 million | 2.2 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 20 | People Power Party (South Korea) | 4.44 million | 2 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 21 | PSUV (Venezuela) | 4.24 million | 1.9 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 22 | ZANU-PF (Zimbabwe) | 4.06 million | 1.8 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 23 | UMNO (Malaysia) | 3.25 million | 1.5 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 24 | Justicialist Party (Argentina) | 3.1 million | 1.4 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 25 | Colorado Party (Paraguay) | 3 million | 1.3 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 26 | United Russia | 2.6 million | 1.2 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 27 | UzLiDeP (Uzbekistan) | 2.31 million | 1 × 10¹⁵ | 0.52% (proxy) | 0.6 h | | 28 | PLD (Dominican Republic) | 2.18 million | 9.7 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 29 | MDB (Brazil) | 2.02 million | 9 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 30 | CHP (Turkey) | 1.88 million | 8.4 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 31 | Radical Civic Union (Argentina) | 1.79 million | 8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 32 | Workers’ Party, PT (Brazil) | 1.67 million | 7.5 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 33 | PRM (Dominican Republic) | 1.55 million | 6.9 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 34 | Authentic Radical Liberal Party (Paraguay) | 1.55 million | 6.9 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 35 | Partido Federal ng Pilipinas | 1.5 million | 6.7 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 36 | PAS (Malaysia) | 1.3 million | 5.8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 37 | PRD (Brazil) | 1.29 million | 5.8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 38 | Progressistas (Brazil) | 1.29 million | 5.8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 39 | PSDB (Brazil) | 1.26 million | 5.6 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 40 | PKR (Malaysia) | 1.15 million | 5.2 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 41 | Economic Freedom Fighters (South Africa) | 1.09 million | 4.9 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 42 | PDT (Brazil) | 1.07 million | 4.8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 43 | União Brasil | 1.07 million | 4.8 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 44 | CPI(M) (India) | 1.02 million | 4.6 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 45 | Liberal Democratic Party (Japan) | 1 million | 4.5 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 46 | FLN (Algeria) | 1 million | 4.5 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 47 | Liberal Party, PL (Brazil) | 952,881 | 4.3 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 48 | Communist Party of Cuba | 700,000 | 2.7 × 10¹⁴ | 0.44% | 0.5 h | | 49 | African National Congress | 688,454 | 3.1 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 50 | Conservative Party of Canada | 678,708 | 2.7 × 10¹⁴ | 0.46% | 0.5 h | | 51 | CDU (Germany) | 364,202 | 1.6 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 52 | SPD (Germany) | 357,116 | 1.6 × 10¹⁴ | 0.52% (proxy) | 0.6 h | | 53 | Labour Party (UK) | 333,235 | 1.6 × 10¹⁴ | 0.55% | 0.6 h | | 54 | Liberal Party of Canada | 163,836 | 6.5 × 10¹³ | 0.46% | 0.5 h | | 55 | Greens (Germany) | 155,296 | 7 × 10¹³ | 0.52% (proxy) | 0.6 h | | 56 | CSU (Germany) | 125,153 | 5.6 × 10¹³ | 0.52% (proxy) | 0.6 h | | 57 | Conservative Party (UK) | 123,000 | 3.7 × 10¹³ | 0.35% | 0.4 h | | 58 | New Democratic Party (Canada) | 100,542 | 4 × 10¹³ | 0.46% | 0.5 h | | 59 | AfD (Germany) | 51,335 | 2.3 × 10¹³ | 0.52% (proxy) | 0.6 h | [Meetings, surveys and sources](https://simulation-hypothesis.com/entities/control). ## Corporations: employees, and neurons following their instructions Employees Following its instructions Employees in the latest annual report or list, on a linear scale. 1. Walmart 2.1 million 2. Amazon▲1 1.58 million 3. State Grid▼1 1.36 million 4. China National Petroleum 1.03 million 5. JD.com 951,420 6. BYD▲1 869,622 7. Accenture▼1 779,000 8. Allied Universal▲3 770,000 9. China Post Group▼1 719,448 10. Russian Railways (RZD)▲2 677,363 11. Volkswagen Group▲6 662,942 12. Foxconn (Hon Hai)▼2 633,167 13. Schwarz Group▲16 604,000 14. Compass Group▲18 590,000 15. Tata Consultancy Services▼6 584,510 Show all 71 0 0.5M 1M 1.5M 2M 2.5M employees Show the numbers | # | Corporation | Employees | Following its instructions | Hours a week | Share directed | | -- | ------------------------------------ | ------------ | -------------------------- | ------------------------ | -------------- | | 1 | Walmart | 2.1 million | 6.3 × 10¹⁶ | 36.3 h (United States) | 35% | | 2 | Amazon | 1.58 million | 4.7 × 10¹⁶ | 36.3 h (United States) | 35% | | 3 | State Grid | 1.36 million | 5.5 × 10¹⁶ | 49 h (China) | 47% | | 4 | China National Petroleum | 1.03 million | 4.1 × 10¹⁶ | 49 h (China) | 47% | | 5 | JD.com | 951,420 | 3.8 × 10¹⁶ | 49 h (China) | 47% | | 6 | BYD | 869,622 | 3.5 × 10¹⁶ | 49 h (China) | 47% | | 7 | Accenture | 779,000 | 3.7 × 10¹⁶ | 57.58 h (India) | 55% | | 8 | Allied Universal | 770,000 | 2.3 × 10¹⁶ | 36.52 h (United States) | 35% | | 9 | China Post Group | 719,448 | 2.9 × 10¹⁶ | 49 h (China) | 47% | | 10 | Russian Railways (RZD) | 677,363 | 2.2 × 10¹⁶ | 39.96 h (Russia) | 38% | | 11 | Volkswagen Group | 662,942 | 2 × 10¹⁶ | 35.95 h (Germany) | 34% | | 12 | Foxconn (Hon Hai) | 633,167 | 2.5 × 10¹⁶ | 49 h (China) | 47% | | 13 | Schwarz Group | 604,000 | 1.6 × 10¹⁶ | 31.49 h (Germany) | 30% | | 14 | Compass Group | 590,000 | 1.5 × 10¹⁶ | 31.7 h (United States) | 30% | | 15 | Tata Consultancy Services | 584,510 | 2.8 × 10¹⁶ | 58.23 h (India) | 56% | | 16 | DHL Group | 583,998 | 1.7 × 10¹⁶ | 35.81 h (Germany) | 34% | | 17 | Sinopec | 513,434 | 2.1 × 10¹⁶ | 49 h (China) | 47% | | 18 | Gazprom | 501,000 | 1.7 × 10¹⁶ | 40.47 h (Russia) | 39% | | 19 | FedEx | 474,200 | 1.6 × 10¹⁶ | 39.98 h (United States) | 38% | | 20 | Home Depot | 470,000 | 1.4 × 10¹⁶ | 36.3 h (United States) | 35% | | 21 | China Mobile | 468,496 | 1.9 × 10¹⁶ | 49 h (China) | 47% | | 22 | UPS | 460,000 | 1.5 × 10¹⁶ | 39.98 h (United States) | 38% | | 23 | Agricultural Bank of China | 457,835 | 1.8 × 10¹⁶ | 49 h (China) | 47% | | 24 | Concentrix | 455,000 | 1.7 × 10¹⁶ | 46.71 h (Philippines) | 45% | | 25 | Teleperformance | 446,716 | 2.2 × 10¹⁶ | 58.89 h (India) | 56% | | 26 | Jardine Matheson | 443,000 | 1.5 × 10¹⁶ | 41.93 h (Indonesia) | 40% | | 27 | Sodexo | 426,464 | 1.1 × 10¹⁶ | 31.7 h (United States) | 30% | | 28 | Capgemini | 423,400 | 2 × 10¹⁶ | 58.23 h (India) | 56% | | 29 | Reliance Industries | 419,911 | 2.1 × 10¹⁶ | 59.57 h (India) | 57% | | 30 | Edeka | 417,500 | 1.1 × 10¹⁶ | 31.49 h (Germany) | 30% | | 31 | Luxshare Precision | 416,197 | 1.7 × 10¹⁶ | 49 h (China) | 47% | | 32 | Target | 415,000 | 1.2 × 10¹⁶ | 36.3 h (United States) | 35% | | 33 | Marriott International | 414,000 | 1.1 × 10¹⁶ | 31.7 h (United States) | 30% | | 34 | Bosch | 412,400 | 1.2 × 10¹⁶ | 35.95 h (Germany) | 34% | | 35 | ICBC | 409,758 | 1.6 × 10¹⁶ | 49 h (China) | 47% | | 36 | Kroger | 403,000 | 1.2 × 10¹⁶ | 36.3 h (United States) | 35% | | 37 | China Resources | 397,398 | 1.6 × 10¹⁶ | 49 h (China) | 47% | | 38 | Magnit | 394,000 | 1.3 × 10¹⁶ | 39.69 h (Russia) | 38% | | 39 | Toyota | 390,927 | 1.3 × 10¹⁶ | 39.6 h (Japan) | 38% | | 40 | UnitedHealth Group | 390,000 | 1.2 × 10¹⁶ | 36.87 h (United States) | 35% | | 41 | X5 Group | 389,000 | 1.3 × 10¹⁶ | 39.69 h (Russia) | 38% | | 42 | Berkshire Hathaway | 387,800 | 1.2 × 10¹⁶ | 37.75 h (United States) | 36% | | 43 | AVIC | 384,000 | 1.5 × 10¹⁶ | 49 h (China) | 47% | | 44 | Ahold Delhaize | 384,000 | 1.1 × 10¹⁶ | 36.3 h (United States) | 35% | | 45 | China Telecom | 381,436 | 1.5 × 10¹⁶ | 49 h (China) | 47% | | 46 | Starbucks | 381,000 | 9.9 × 10¹⁵ | 31.7 h (United States) | 30% | | 47 | Rewe Group | 380,000 | 9.8 × 10¹⁵ | 31.49 h (Germany) | 30% | | 48 | China Construction Bank | 378,344 | 1.5 × 10¹⁶ | 49 h (China) | 47% | | 49 | TJX Companies | 377,000 | 1.1 × 10¹⁶ | 36.3 h (United States) | 35% | | 50 | China State Construction Engineering | 370,272 | 1.5 × 10¹⁶ | 49 h (China) | 47% | | 51 | FEMSA | 368,776 | 1.4 × 10¹⁶ | 47.09 h (Mexico) | 45% | | 52 | Japan Post Holdings | 360,000 | 1.2 × 10¹⁶ | 41.6 h (Japan) | 40% | | 53 | Tesco | 354,744 | 9.3 × 10¹⁵ | 31.81 h (United Kingdom) | 30% | | 54 | Cognizant | 351,600 | 1.7 × 10¹⁶ | 58.23 h (India) | 56% | | 55 | NTT | 344,196 | 1.1 × 10¹⁶ | 40.2 h (Japan) | 38% | | 56 | Costco | 341,000 | 1 × 10¹⁶ | 36.3 h (United States) | 35% | | 57 | Infosys | 328,594 | 1.6 × 10¹⁶ | 58.23 h (India) | 56% | | 58 | ISS | 325,000 | 1.6 × 10¹⁶ | 58.89 h (India) | 56% | | 59 | Securitas | 322,000 | 9.7 × 10¹⁵ | 36.52 h (United States) | 35% | | 60 | HCA Healthcare | 320,000 | 9.7 × 10¹⁵ | 36.87 h (United States) | 35% | | 61 | Rosneft | 320,000 | 1.1 × 10¹⁶ | 40.47 h (Russia) | 39% | | 62 | JPMorgan Chase | 318,512 | 1.1 × 10¹⁶ | 40.14 h (United States) | 38% | | 63 | Siemens | 318,000 | 9.4 × 10¹⁵ | 35.95 h (Germany) | 34% | | 64 | Bank of China | 313,746 | 1.3 × 10¹⁶ | 49 h (China) | 47% | | 65 | Walgreens Boots Alliance | 312,000 | 9.3 × 10¹⁵ | 36.3 h (United States) | 35% | | 66 | PepsiCo | 306,000 | 1 × 10¹⁶ | 40.7 h (United States) | 39% | | 67 | China Railway Construction (CRCC) | 304,927 | 1.2 × 10¹⁶ | 49 h (China) | 47% | | 68 | CHN Energy (China Energy Investment) | 303,418 | 1.2 × 10¹⁶ | 49 h (China) | 47% | | 69 | China Railway Group (CREC) | 302,527 | 1.2 × 10¹⁶ | 49 h (China) | 47% | | 70 | CK Hutchison | 300,000 | 8.6 × 10¹⁵ | 35.08 h (United Kingdom) | 33% | | 71 | CVS Health | 300,000 | 8.9 × 10¹⁵ | 36.3 h (United States) | 35% | [Hours and sources](https://simulation-hypothesis.com/entities/control). ## Animals and other organisms From single cells with no neurons to the human brain. Neuron counts are measured where they exist. ### No neurons * [Escherichia coli](https://simulation-hypothesis.com/entities/ecoli)Escherichia coli 0 measured A single cell with no neurons. It steers toward food and has a chemical memory that lasts a few seconds. * [Slime mould](https://simulation-hypothesis.com/entities/physarum)Physarum polycephalum 0 measured A single giant cell with no neurons. It solves mazes and grows efficient transport networks. * [Sensitive plant](https://simulation-hypothesis.com/entities/mimosa)Mimosa pudica 0 measured A plant whose leaves fold when touched. One study reported that it learns to ignore harmless touches. A later re-analysis disputed that. * [Sponge](https://simulation-hypothesis.com/entities/sponge)Porifera (e.g. Amphimedon queenslandica) 0 measured An animal with no neurons or synapses that still contracts its whole body in a coordinated way. ### Nerve nets, no brain * [Hydra](https://simulation-hypothesis.com/entities/hydra)Hydra vulgaris about 3,000 to 5,000 estimate A small freshwater cnidarian. It's controlled by a diffuse nerve net and has no brain. * [Box jellyfish](https://simulation-hypothesis.com/entities/jellyfish)Tripedalia cystophora No published count A box jellyfish has no central brain, yet it showed associative learning. ### Invertebrates with brains * [Roundworm](https://simulation-hypothesis.com/entities/celegans)Caenorhabditis elegans 302 measured A worm about a millimetre long with exactly 302 neurons. It was the first animal to have its complete wiring diagram mapped. * [Fruit fly](https://simulation-hypothesis.com/entities/drosophila)Drosophila melanogaster 139,255 measured The largest complete brain wiring diagram mapped so far, covering about 139,000 neurons. * [Honeybee](https://simulation-hypothesis.com/entities/honeybee)Apis mellifera about 1 million estimate About a million neurons, and bees can learn abstract concepts such as same and different. * [Ant (Camponotus / Formica)](https://simulation-hypothesis.com/entities/ant)Camponotus spp. No published count A small brain that handles long-distance navigation by counting steps (path integration) and remembering landmarks. * [Portia jumping spider](https://simulation-hypothesis.com/entities/portia)Portia fimbriata / labiata No published count A jumping spider that plans detours. It takes routes that lead away from its prey and out of sight. * [Shore crab / crayfish](https://simulation-hypothesis.com/entities/decapod)Carcinus maenas; Procambarus / Astacus spp. No published count Crabs and crayfish. A 2021 government review found strong evidence that true crabs are sentient. * [Common octopus](https://simulation-hypothesis.com/entities/octopus)Octopus vulgaris 500 million estimate Most of its neurons are in its arms. A 2021 review found very strong evidence that it's sentient. ### Fish and amphibians * [Zebrafish](https://simulation-hypothesis.com/entities/zebrafish)Danio rerio No published count A small fish widely used in neuroscience. Its neurons haven't been fully counted. The adult brain has about 10 million cells. * [Cleaner wrasse](https://simulation-hypothesis.com/entities/wrasse)Labroides dimidiatus No published count A reef fish that passed a version of the mirror mark test. People disagree about what that shows. * [Frog](https://simulation-hypothesis.com/entities/frog)Anura (e.g. Xenopus / Rana) No published count The 2024 New York Declaration says there's a realistic possibility of conscious experience in amphibians. ### Birds * [Rock pigeon](https://simulation-hypothesis.com/entities/pigeon)Columba livia 310 million measured Hundreds of millions of neurons in a small brain. Pigeons can sort complex images into categories. * [Common raven](https://simulation-hypothesis.com/entities/raven)Corvus corax 2.17 billion measured Over two billion neurons, densely packed. Ravens remember individual competitors. * [New Caledonian crow](https://simulation-hypothesis.com/entities/nccrow)Corvus moneduloides No published count It makes hooked tools from twigs and wire. Its neurons haven't been counted. * [African grey parrot](https://simulation-hypothesis.com/entities/greyparrot)Psittacus erithacus 1.57 billion measured About 1.6 billion neurons. Decades of laboratory study of numerosity and categorisation. ### Mammals * [Mouse](https://simulation-hypothesis.com/entities/mouse)Mus musculus 70.9 million measured About 71 million neurons. Mice show facial expressions of pain that can be measured. * [Rat](https://simulation-hypothesis.com/entities/rat)Rattus norvegicus 200 million measured About 200 million neurons. Rats release trapped cagemates. * [Domestic cat](https://simulation-hypothesis.com/entities/cat)Felis catus 1.22 billion measured About 250 million neurons in the cerebral cortex. * [Domestic dog](https://simulation-hypothesis.com/entities/dog)Canis familiaris 1.8 to 2.6 billion, depending on the dog measured Up to about 600 million cortical neurons, depending on the dog. That's more than cats. * [Domestic pig](https://simulation-hypothesis.com/entities/pig)Sus scrofa domesticus 2.22 billion measured Pigs learn what a mirror shows and use it to find food. * [Bottlenose dolphin](https://simulation-hypothesis.com/entities/dolphin)Tursiops truncatus No published count Passes mirror self-recognition tests. There's no measured neuron count for the bottlenose dolphin. * [African elephant](https://simulation-hypothesis.com/entities/elephant)Loxodonta africana 257 billion measured 257 billion neurons, three times as many as a human, almost all in the cerebellum. * [Chimpanzee](https://simulation-hypothesis.com/entities/chimp)Pan troglodytes about 28 billion (predicted from scaling rules, not counted) estimate One of our two closest living relatives (along with the bonobo). It passes the mirror test. * [Human](https://simulation-hypothesis.com/entities/human)Homo sapiens 86.1 billion measured 86 billion neurons, 16 billion of them in the cerebral cortex. We're the only species whose members can give verbal reports of their experience. ## Collective systems Groups that make decisions no single member makes alone. They're studied as collective intelligence, not as minds. * [Ant colonies](https://simulation-hypothesis.com/entities/c-ants)Colonies pick the better nest because individual ants follow a quorum threshold. No ant compares the sites overall. * [Honeybee swarms](https://simulation-hypothesis.com/entities/c-bees)Swarms pick the best cavity through competition between scouts and a quorum. Stop signals provide cross-inhibition, which breaks deadlocks. * [Starling flocks](https://simulation-hypothesis.com/entities/c-starlings)Each bird tracks a fixed number of neighbours (about 6-7), not every bird within a fixed distance. This is called topological, not metric, interaction. * [Fish shoals](https://simulation-hypothesis.com/entities/c-fish)Shoals use quorum rules to decide. Large groups can sense environmental gradients that no single fish can. ## Artificial systems Kinds of machine intelligence, sorted by how they work. No current system is considered a strong candidate for consciousness. * [Rule-based expert systems](https://simulation-hypothesis.com/entities/ai-expert)Programs that encode a domain expert's knowledge as explicit if-then rules. An inference engine applies the rules in sequence to reach conclusions, usually with an explanation of its reasoning. * [Game-tree search engines (chess)](https://simulation-hypothesis.com/entities/ai-chess)Programs that enumerate possible move sequences to a fixed depth and score the resulting positions with a hand-built evaluation function. They prune branches that can't change the choice (minimax with alpha-beta pruning). * [Deep reinforcement learning agents](https://simulation-hypothesis.com/entities/ai-drl)Neural networks trained by trial and error to maximise a reward signal. They learn a policy or value function by interacting with an environment, often a simulated one such as a game. * [Large language models](https://simulation-hypothesis.com/entities/ai-llm)Transformer neural networks trained to predict the next token in very large text corpora, then often tuned on human feedback. * [Embodied robots](https://simulation-hypothesis.com/entities/ai-robots)Machines with sensors and actuators that act in the physical world. They often use layered reactive control instead of a central world model, so behaviour emerges from the loop between body and environment. * [Neuromorphic hardware](https://simulation-hypothesis.com/entities/ai-neuromorphic)Chips whose circuits imitate spiking neurons and synapses. They are event-driven and use little power, unlike a conventional processor-and-memory design. ## Hypothetical minds Minds proposed in the scientific and philosophical literature. Nobody has observed one. * [Whole-brain emulation](https://simulation-hypothesis.com/entities/h-wbe)unobserved Scanning a brain in fine detail and running a software model of it. * [Simulated minds in ancestor simulations](https://simulation-hypothesis.com/entities/h-ancestor)unobserved Bostrom's trilemma: either almost no civilisations reach a posthuman stage, or almost none run ancestor simulations, or we almost certainly live in one. * [Boltzmann brains](https://simulation-hypothesis.com/entities/h-boltzmann)unobserved Brain-like observers that appear out of rare thermal or quantum fluctuations. * [Mind uploading via gradual replacement](https://simulation-hypothesis.com/entities/h-uploading)unobserved Replacing neurons one by one with functionally identical artificial parts. * [Superintelligence](https://simulation-hypothesis.com/entities/h-superintelligence)unobserved A hypothetical intellect greatly exceeding human performance in virtually all domains. Bostrom's book analyses the routes to it (whole-brain emulation, biological cognition, AI), its forms and the control problems. Data version 2.0.0\. [Download (JSON)](https://simulation-hypothesis.com/entities/minds.json). --- title: "Simulations · a taxonomy of the ones we actually run · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations description: "A classification of the simulations people actually run, from lattice QCD and climate models to ant colonies, crowds, ancient villages and video games." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations · a taxonomy of the ones we actually run The simulation hypothesis asks whether we’re being run ourselves. Meanwhile we run simulations of almost everything: quarks, stars, weather, proteins, ant colonies, crowds, markets, ancient villages, and billions of hours of video games. This page sorts them. Each domain has families, and each family has individual simulations. You can also sort the list by floor, method, era or computing needed. The charts show how much simulation the world runs and how big the biggest ones have become. Every series is measured. Each dashed line extends its trend to 2050, with a band for how much its growth rate has varied. The extensions are our own trend lines, not forecasts. ## How much simulation is run ## Simulations running at this moment Machines Machines and minds Games being played Games, projected Roblox alone (measured) Show the numbers | Year | Games being played | Games, projected | Roblox alone (measured) | | ---- | ------------------ | ---------------- | ----------------------- | | 2018 | 92 million | | 1 million | | 2019 | | | 2 million | | 2020 | | | 3 million | | 2021 | 120 million | | 5 million | | 2022 | 126 million | | 6 million | | 2023 | 131 million | | 7 million | | 2024 | 137 million | | 8 million | | 2025 | 143 million | 146 million | 14 million | | 2030 | | 187 million | | | 2035 | | 229 million | | | 2040 | | 268 million | | | 2045 | | 304 million | | | 2050 | | 335 million | | | Running at any moment | 2025 | 2050, projected | | ------------------------------- | ----------- | --------------- | | Games being played | 143 million | 335 million | | Full-flight training simulators | 1,215 | 3,036 | **143 million** running at any moment in 2025, in machines we can count **335 million** projected for 2050 (games 315 million to 355 million) Games make up most of what we can count: 44% of people play, on average 6.33–7.12 hours a week, so about 143 million game simulations run at once; one platform alone averages 14 million. For the projection, the share of people playing follows an adoption curve that gets close to everyone but never passes it (87% by 2050) using the UN’s population projection, with hours held at today’s range. Full-flight simulators: about 1,215 running, growing 3.7% a year. Weather and climate runs, supercomputer jobs, engineering software, digital twins and AI training environments: no published count of how many run at once. Switch to “Machines and minds” to count every human brain’s world model. Sources: Newzoo player counts (2018–2025); Limelight Networks, State of Online Gaming 2019 and 2020 (hours a week); UN World Population Prospects 2024; Roblox annual reports (hours engaged ÷ hours in the year); FlightGlobal (1,270 airline simulators, June 2018); CAE annual reports (network size 2014–2026, utilisation 70–78%); UN World Population Prospects 2024 (medium variant); US time-use survey (9.03 hours in bed); REM 20–25% of sleep. ## Supercomputing: the machines simulation runs on Show the numbers | Year | All 500 largest supercomputers | All 500 largest supercomputers, projected | | ---- | ------------------------------ | ----------------------------------------- | | 1993 | 1.1 × 10¹² FLOPS | | | 1994 | 2.3 × 10¹² FLOPS | | | 1995 | 3.9 × 10¹² FLOPS | | | 1996 | 5.9 × 10¹² FLOPS | | | 1997 | 1.3 × 10¹³ FLOPS | | | 1998 | 2.3 × 10¹³ FLOPS | | | 1999 | 3.9 × 10¹³ FLOPS | | | 2000 | 6.4 × 10¹³ FLOPS | | | 2001 | 1.1 × 10¹⁴ FLOPS | | | 2002 | 2.2 × 10¹⁴ FLOPS | | | 2003 | 3.7 × 10¹⁴ FLOPS | | | 2004 | 8.1 × 10¹⁴ FLOPS | | | 2005 | 1.7 × 10¹⁵ FLOPS | | | 2006 | 2.8 × 10¹⁵ FLOPS | | | 2007 | 5.0 × 10¹⁵ FLOPS | | | 2008 | 1.2 × 10¹⁶ FLOPS | | | 2009 | 2.3 × 10¹⁶ FLOPS | | | 2010 | 3.2 × 10¹⁶ FLOPS | | | 2011 | 5.9 × 10¹⁶ FLOPS | | | 2012 | 1.2 × 10¹⁷ FLOPS | | | 2013 | 2.3 × 10¹⁷ FLOPS | | | 2014 | 2.8 × 10¹⁷ FLOPS | | | 2015 | 3.6 × 10¹⁷ FLOPS | | | 2016 | 5.7 × 10¹⁷ FLOPS | | | 2017 | 7.5 × 10¹⁷ FLOPS | | | 2018 | 1.2 × 10¹⁸ FLOPS | | | 2019 | 1.6 × 10¹⁸ FLOPS | | | 2020 | 2.2 × 10¹⁸ FLOPS | | | 2021 | 2.8 × 10¹⁸ FLOPS | | | 2022 | 4.4 × 10¹⁸ FLOPS | | | 2023 | 5.2 × 10¹⁸ FLOPS | | | 2024 | 8.2 × 10¹⁸ FLOPS | | | 2025 | 1.4 × 10¹⁹ FLOPS | | | 2026 | 1.9 × 10¹⁹ FLOPS | 1.9 × 10¹⁹ FLOPS | | 2030 | | 7.5 × 10¹⁹ FLOPS | | 2035 | | 4.2 × 10²⁰ FLOPS | | 2040 | | 2.4 × 10²¹ FLOPS | | 2045 | | 1.4 × 10²² FLOPS | | 2050 | | 7.7 × 10²² FLOPS | Combined Linpack speed of the world’s 500 largest machines, June lists. Most of their time goes to running simulations: climate, materials, fusion, cosmology, weapons, molecules. Growth slowed from tenfold every 3.8 years before 2013 to tenfold every 6.6 years since; the projection carries on from the latest list at the recent rate. The band covers every rate seen over any ten-year stretch. 2050: 7.7 × 10²² (range 5.6 × 10²² to 9.6 × 10²⁵) operations a second. TOP500, Performance Development (sum of Rmax of all 500 systems, June lists), top500.org/statistics/perfdevel. ## Research that runs simulations Show the numbers | Year | Papers using simulation | Papers using simulation, projected | | ---- | ----------------------- | ---------------------------------- | | 1950 | 47 papers | | | 1951 | 105 papers | | | 1952 | 75 papers | | | 1953 | 121 papers | | | 1954 | 109 papers | | | 1955 | 106 papers | | | 1956 | 108 papers | | | 1957 | 129 papers | | | 1958 | 213 papers | | | 1959 | 244 papers | | | 1960 | 262 papers | | | 1961 | 426 papers | | | 1962 | 517 papers | | | 1963 | 736 papers | | | 1964 | 860 papers | | | 1965 | 983 papers | | | 1966 | 1,259 papers | | | 1967 | 1,461 papers | | | 1968 | 1,740 papers | | | 1969 | 2,120 papers | | | 1970 | 3,501 papers | | | 1971 | 2,825 papers | | | 1972 | 3,389 papers | | | 1973 | 3,808 papers | | | 1974 | 4,239 papers | | | 1975 | 4,726 papers | | | 1976 | 5,229 papers | | | 1977 | 5,880 papers | | | 1978 | 6,257 papers | | | 1979 | 6,875 papers | | | 1980 | 7,549 papers | | | 1981 | 7,864 papers | | | 1982 | 8,515 papers | | | 1983 | 9,517 papers | | | 1984 | 10,872 papers | | | 1985 | 12,367 papers | | | 1986 | 13,544 papers | | | 1987 | 15,437 papers | | | 1988 | 17,773 papers | | | 1989 | 20,152 papers | | | 1990 | 23,161 papers | | | 1991 | 26,109 papers | | | 1992 | 28,868 papers | | | 1993 | 31,209 papers | | | 1994 | 34,057 papers | | | 1995 | 37,476 papers | | | 1996 | 41,190 papers | | | 1997 | 43,698 papers | | | 1998 | 46,776 papers | | | 1999 | 50,962 papers | | | 2000 | 57,344 papers | | | 2001 | 62,246 papers | | | 2002 | 114,667 papers | | | 2003 | 102,545 papers | | | 2004 | 109,496 papers | | | 2005 | 128,784 papers | | | 2006 | 149,005 papers | | | 2007 | 154,542 papers | | | 2008 | 170,916 papers | | | 2009 | 187,596 papers | | | 2010 | 205,418 papers | | | 2011 | 223,917 papers | | | 2012 | 233,914 papers | | | 2013 | 245,876 papers | | | 2014 | 253,642 papers | | | 2015 | 247,138 papers | | | 2016 | 251,770 papers | | | 2017 | 260,018 papers | | | 2018 | 280,800 papers | | | 2019 | 299,533 papers | | | 2020 | 305,034 papers | | | 2021 | 325,897 papers | | | 2022 | 333,370 papers | | | 2023 | 360,122 papers | | | 2024 | 396,783 papers | | | 2025 | 489,071 papers | 489,071 papers | | 2030 | | 684,807 papers | | 2035 | | 958,879 papers | | 2040 | | 1,342,641 papers | | 2045 | | 1,879,991 papers | | 2050 | | 2,632,400 papers | Show the numbers | Year | Share of all papers | | ---- | ------------------- | | 1950 | 0.01% | | 1951 | 0.03% | | 1952 | 0.02% | | 1953 | 0.04% | | 1954 | 0.03% | | 1955 | 0.03% | | 1956 | 0.03% | | 1957 | 0.03% | | 1958 | 0.05% | | 1959 | 0.06% | | 1960 | 0.05% | | 1961 | 0.09% | | 1962 | 0.10% | | 1963 | 0.13% | | 1964 | 0.14% | | 1965 | 0.15% | | 1966 | 0.18% | | 1967 | 0.19% | | 1968 | 0.22% | | 1969 | 0.25% | | 1970 | 0.35% | | 1971 | 0.30% | | 1972 | 0.35% | | 1973 | 0.38% | | 1974 | 0.41% | | 1975 | 0.44% | | 1976 | 0.48% | | 1977 | 0.51% | | 1978 | 0.52% | | 1979 | 0.55% | | 1980 | 0.55% | | 1981 | 0.58% | | 1982 | 0.61% | | 1983 | 0.66% | | 1984 | 0.72% | | 1985 | 0.79% | | 1986 | 0.83% | | 1987 | 0.90% | | 1988 | 0.98% | | 1989 | 1.05% | | 1990 | 1.11% | | 1991 | 1.25% | | 1992 | 1.32% | | 1993 | 1.37% | | 1994 | 1.42% | | 1995 | 1.47% | | 1996 | 1.49% | | 1997 | 1.53% | | 1998 | 1.54% | | 1999 | 1.62% | | 2000 | 1.51% | | 2001 | 1.64% | | 2002 | 2.60% | | 2003 | 2.19% | | 2004 | 2.15% | | 2005 | 2.37% | | 2006 | 2.51% | | 2007 | 2.39% | | 2008 | 2.46% | | 2009 | 2.50% | | 2010 | 2.55% | | 2011 | 2.58% | | 2012 | 2.62% | | 2013 | 2.62% | | 2014 | 2.55% | | 2015 | 2.43% | | 2016 | 2.38% | | 2017 | 2.49% | | 2018 | 2.70% | | 2019 | 2.78% | | 2020 | 2.66% | | 2021 | 3.03% | | 2022 | 3.24% | | 2023 | 3.29% | | 2024 | 3.65% | | 2025 | 3.32% | 489,071 papers in 2025 mention simulation in the title or abstract, 3.3% of all research, up from 0.03% in 1955: simulation has grown faster than science itself. Since 2000 the count has grown at doubling every 10.3 years; 2050: about 2.6 × 10⁶ a year (range 1.3 × 10⁶ to 1.6 × 10⁸). OpenAlex: works whose title or abstract mentions simulation, and all works, by publication year (retrieved 2 October 2026). ## Kinds of simulation in use Show the numbers | Year | Kinds in use | | ---- | ------------ | | 1800 | 15 kinds | | 1805 | 15 kinds | | 1810 | 15 kinds | | 1815 | 16 kinds | | 1820 | 16 kinds | | 1825 | 16 kinds | | 1830 | 17 kinds | | 1835 | 17 kinds | | 1840 | 17 kinds | | 1845 | 17 kinds | | 1850 | 17 kinds | | 1855 | 17 kinds | | 1860 | 17 kinds | | 1865 | 17 kinds | | 1870 | 18 kinds | | 1875 | 23 kinds | | 1880 | 24 kinds | | 1885 | 24 kinds | | 1890 | 24 kinds | | 1895 | 24 kinds | | 1900 | 25 kinds | | 1905 | 26 kinds | | 1910 | 29 kinds | | 1915 | 32 kinds | | 1920 | 35 kinds | | 1925 | 38 kinds | | 1930 | 42 kinds | | 1935 | 45 kinds | | 1940 | 47 kinds | | 1945 | 50 kinds | | 1950 | 58 kinds | | 1955 | 78 kinds | | 1960 | 107 kinds | | 1965 | 145 kinds | | 1970 | 199 kinds | | 1975 | 251 kinds | | 1980 | 315 kinds | | 1985 | 385 kinds | | 1990 | 466 kinds | | 1995 | 539 kinds | | 2000 | 628 kinds | | 2005 | 686 kinds | | 2010 | 749 kinds | | 2015 | 794 kinds | | 2020 | 853 kinds | | 2025 | 896 kinds | | 2026 | 896 kinds | Show the numbers | Year | New kinds in the decade | | ---- | ----------------------- | | 1805 | 0 new kinds | | 1815 | 1 new kinds | | 1825 | 1 new kinds | | 1835 | 0 new kinds | | 1845 | 0 new kinds | | 1855 | 0 new kinds | | 1865 | 1 new kinds | | 1875 | 6 new kinds | | 1885 | 0 new kinds | | 1895 | 1 new kinds | | 1905 | 3 new kinds | | 1915 | 6 new kinds | | 1925 | 8 new kinds | | 1935 | 5 new kinds | | 1945 | 9 new kinds | | 1955 | 47 new kinds | | 1965 | 82 new kinds | | 1975 | 111 new kinds | | 1985 | 148 new kinds | | 1995 | 163 new kinds | | 2005 | 130 new kinds | | 2015 | 103 new kinds | | 2025 | 56 new kinds | The 896 kinds of simulation catalogued in this section, counted from the year each was first run (15 predate 1800, from the Antikythera mechanism to the orrery and the obstetric phantom). Most began after the electronic computer. The latest decades are still under-counted: a kind usually gets catalogued years after it first runs. The census behind this chart added the most to the newest decades (the 2010s rose from 21 to 103 kinds, the 2020s from 1 to 56), which suggests they're still the least complete. The 2020s point covers only 2020 to 2026\. The research chart above, which counts activity rather than kinds, shows no slowdown. There's no projection, for the same reason. Gaming alone puts a simulation in front of 3.58 billion people (2025, Newzoo, Global Games Market Report 2024 (2022–2024) and 2025 forecast via PocketGamer.biz). ## How large simulations have become ## The largest simulations: how many things they track Cosmology: particles Cosmology: particles, projected Brain, spiking neurons Brain, spiking neurons, projected Brain, detailed neurons Molecular dynamics: atoms Machine-learned molecular dynamics: atoms Show the numbers | Year | Cosmology: particles | Cosmology: particles, projected | Brain, spiking neurons | Brain, spiking neurons, projected | Brain, detailed neurons | Molecular dynamics: atoms | Machine-learned molecular dynamics: atoms | | ---- | -------------------- | ------------------------------- | ---------------------- | --------------------------------- | ----------------------- | ------------------------- | ----------------------------------------- | | 1964 | | | | | | 8.6 × 10² | | | 2001 | 10⁹ | | | | | | | | 2005 | 10¹⁰ | | | | | | | | 2008 | 7.0 × 10¹⁰ | | 10⁶ | | | 10¹² | | | 2012 | 3.0 × 10¹¹ | | | | | | | | 2013 | | | 1.7 × 10⁹ | | | | | | 2014 | 1.1 × 10¹² | | | | | | | | 2015 | | | | | 3.1 × 10⁴ | | | | 2016 | 2.0 × 10¹² | | | | | | | | 2019 | | | 6.0 × 10⁹ | | | | | | 2020 | 2.1 × 10¹² | | 6.8 × 10¹⁰ | | | | 1.1 × 10⁸ | | 2021 | | | | | | 6.5 × 10¹¹ | | | 2024 | 4.0 × 10¹² | 4.0 × 10¹² | 8.6 × 10¹⁰ | 8.6 × 10¹⁰ | | 4.7 × 10¹¹ | | | 2025 | | 5.8 × 10¹² | | 1.7 × 10¹¹ | 9.0 × 10⁶ | | 2.9 × 10¹⁰ | | 2026 | | 8.3 × 10¹² | | 3.4 × 10¹¹ | | | 1.6 × 10¹² | | 2030 | | 3.6 × 10¹³ | | 5.1 × 10¹² | | | | | 2040 | | 1.4 × 10¹⁵ | | 4.7 × 10¹⁵ | | | | | 2050 | | 5.4 × 10¹⁶ | | 4.3 × 10¹⁸ | | | | Each dot is a published record: particles in cosmology, neurons in brain simulations, atoms in molecular dynamics. Counts measure size, not detail or speed: a spiking neuron is a few equations, a detailed one thousands, and none of the brain runs went at real-time speed. Projected lines carry each record forward (cosmology tenfold every 6.3 years, spiking-neuron brains tenfold every 3.4 years); each starts from the latest record. They're this site's own trend lines, not forecasts. The band is a fitted range from a handful of records, not a calibrated probability. Classical molecular dynamics hasn't passed its 2008 record of a trillion atoms; machine-learned potentials are closing in at near-quantum accuracy. ## Milestones on the trends | Milestone | Count | Trend | Year | | ------------------------------------------------------------------------- | ---------- | ------------------- | ----------------------------- | | every person aliveUN World Population Prospects 2024 | 8.2 × 10⁹ | spiking neurons | reached 2020 | | neurons in one human brainAzevedo et al. 2009 | 8.6 × 10¹⁰ | spiking neurons | reached 2024 | | stars in the Milky WayNASA: 100 to 400 billion | 2.0 × 10¹¹ | cosmology particles | reached 2012 | | cells in one human bodyBianconi et al. 2013 | 3.7 × 10¹³ | cosmology particles | about 2031range: 2025 to 2044 | | neurons in every human brain alive8.2 billion people × 86 billion neurons | 7.0 × 10²⁰ | spiking neurons | about 2058range: 2045 to 2099 | A projected year assumes the record keeps growing at its fitted rate. It says nothing about how detailed the simulation is. The last row is the scale of an ancestor simulation of everyone now alive, at the level of single spiking neurons; it still leaves out the chemistry of every synapse, every body and the world around them. Data retrieved 2026-10-02\. Projections: least-squares fits to the logarithm of each series, extended to 2050\. [Download (JSON)](https://simulation-hypothesis.com/simulations/growth.json). ## Reading the taxonomy * Domain. What’s being simulated. 18 domains, from fundamental physics to video games, each split into families. * Method. How it’s computed. 19 methods, from Monte Carlo to agent-based to real time. Most simulations combine two or three methods. * Computing and age. Each entry gives roughly how much computing a serious run uses today, in operations per second (the Sandbox’s unit). It has a confidence tag and the date of the first such simulation. * Floor. The smallest thing the simulation tracks. It matches the Sandbox’s matter-floor dial: subatomic, atoms, molecules, cells, bodies, fields, populations, rules. 848 scientific, engineering and training simulations · 93 video game genres · 18 domains [14 interactive models](https://simulation-hypothesis.com/simulations/run) Expand all Collapse all domain Fundamental physics 45 types Quarks, nuclei, plasmas and quantum matter: the smallest systems simulated, and among the most computationally expensive. [Fundamental physics page ▸](https://simulation-hypothesis.com/simulations/fundamental-physics) family Particles and fields 8 Lattice QCD Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Collider event generation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collider-events) Detector response Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#detector-response) Cosmic-ray air showers Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#air-showers) Accelerator beam dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Neutrino detector simulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neutrino-detectors) Generative calorimeter shower models Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#calorimeter-shower-generators) Flow-based sampling for lattice field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) family Nuclei and radiation 9 Nuclear structure Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Reactor core physics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Radiation transport Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#radiation-transport) Nuclear criticality safety Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#criticality-safety) Radioactivation and decay chains Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Fusion breeding blanket neutronics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-blanket) Nuclear lattice effective field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Time-dependent nuclear mean-field dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Neutron-star crust pasta dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) family Plasma 14 Fusion plasma turbulence Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Particle-in-cell plasma Bodies [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) Plasma equilibrium and stability Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Inertial confinement implosion Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#inertial-confinement-fusion) Magnetic reconnection Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Industrial plasma processing Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Laser wakefield acceleration Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Stellarator configuration optimisation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Tokamak edge pedestal and ELM modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Tokamak whole-device modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Collisionless shock simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) Dusty plasma and Yukawa-system simulation Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) One-component plasma simulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) Learned plasma control in simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) family Quantum matter and computers 14 Quantum many-body systems Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Quantum computer emulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-circuit-emulation) Analogue quantum simulation Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#analogue-quantum) Quantum error correction Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Topological quantum matter Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Ultracold atomic gas dynamics Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#cold-atom-bec) Digital quantum simulation on hardware Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#digital-quantum-simulation) Lattice gauge theory on quantum hardware Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) Neural-network quantum states Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) Superconducting vortex dynamics Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) Path-integral Monte Carlo of quantum fluids Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) Stabilizer circuit simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Learned error-correction decoders Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) Quantum network simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) domain Astronomy and cosmology 61 types The universe from its first minutes to the cosmic web, and the stars, planets and black holes within it. [Astronomy and cosmology page ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology) family The universe as a whole 22 Cosmological N-body Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-n-body) Galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Big Bang nucleosynthesis Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#nucleosynthesis) Cosmic microwave background Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Cosmic reionization Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Intergalactic medium and the Lyman-alpha forest Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Wave dark matter simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Constrained simulations of the local universe Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Cosmological emulators Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Stellar population synthesis Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Galactic chemical evolution Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Semi-analytic galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Self-interacting dark matter simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#self-interacting-dark-matter) Massive-neutrino cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Weak-lensing ray tracing through simulated universes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Cosmic string network evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Early-universe lattice field dynamics Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) Galactic cosmic-ray propagation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Differentiable cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Synthetic sky survey catalogues and images Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Galaxy collision and merger simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) family Stars 13 Stellar evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-evolution) Core-collapse supernovae Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Star formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Stellar oscillations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-interiors-seismology) Binary star evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-star-evolution) Stellar atmospheres and spectra Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Supernova neutrino flavour evolution Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) Stellar surface convection simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Common-envelope evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Binary population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Collapsar and gamma-ray burst jets Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Astrochemical reaction networks Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) Interstellar magnetised turbulence Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) family Planets and orbits 12 Planet formation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Orbital dynamics Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Planetary and exoplanet atmospheres Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-atmospheres) Planetary interiors and dynamos Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-interiors) Impact cratering Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Exoplanet detection and characterisation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) Giant-impact simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Planet population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Exoplanet atmosphere retrieval Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) Habitable-zone climate modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Planetesimal formation by streaming instability Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Planet-disk interaction and migration Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) family Extreme gravity and space plasma 14 Black hole mergers Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#numerical-relativity) Accretion discs and jets Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#accretion) Space weather Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Neutron star mergers Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#neutron-star-mergers) Pulsar magnetospheres Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Solar interior and dynamo Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#solar-dynamo) Gravitational-wave template banks from numerical relativity Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Gravitational-wave mock data challenges Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) Magnetar magnetosphere and flare simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Black-hole shadow and image rendering Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Tidal disruption of stars by black holes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) Kilonova radiative transfer Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) Radiation belt modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) Neural inference for gravitational waves Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) domain Earth and climate 61 types Weather, climate, oceans, ice, earthquakes, floods and fire: the planet as a set of coupled equations. [Earth and climate page ▸](https://simulation-hypothesis.com/simulations/earth-climate) family Climate 20 Earth system models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system) Palaeoclimate Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Ice sheets and sea level Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ice-sheets) Integrated assessment models Populations [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) Regional climate downscaling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#regional-climate-downscaling) Solar geoengineering Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geoengineering-modelling) World-Earth models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Global cloud-resolving models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Superparameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Extreme-event attribution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Volunteer-computed perturbed-physics ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Initial-condition large ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Learned climate emulators Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-climate-emulators) Earth-system digital twins Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Radiative-convective climate model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Energy-balance climate model Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Dynamic global vegetation and carbon-cycle modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Coupled carbon-cycle and climate simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Ocean ecosystem and biogeochemistry modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Learned subgrid parameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) family Weather and air 14 Numerical weather prediction Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Machine-learned weather Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-weather) Tropical cyclones Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tropical-cyclones) Air quality and dispersion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Seasonal forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Severe convective storms Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#severe-storms) Generative ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) Ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Atmospheric reanalysis Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Atmospheric boundary-layer large-eddy simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Global storm-resolving simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Mineral dust emission and transport Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Urban surface energy-balance modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Thermosphere and ionosphere modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) family Water 13 Ocean circulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-circulation) Tsunamis and storm surge Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tsunami-surge) Rivers and floods Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) Groundwater Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#groundwater) Sea ice Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#sea-ice-dynamics) Ocean wave forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-wave-forecasting) Flood inundation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Coastal and estuarine circulation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Marine debris and Lagrangian drift modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Petroleum and gas reservoir simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Glacial isostatic adjustment and sea-level fingerprints Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Geological carbon-dioxide storage simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Reactive transport in the subsurface Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) family Solid Earth and landscape 14 Mantle convection and plate tectonics Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mantle-convection) Earthquakes and seismic waves Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquakes) Volcanic eruptions and lava flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landscape evolution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Wildfire spread Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) Landslides and debris flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) Physics-based seismic hazard Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Geodynamo simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Full-waveform seismic inversion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Spectral-element seismic wave propagation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Earthquake-cycle simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Stochastic earthquake-catalogue models Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) Land-surface model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Coupled fire and atmosphere models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) domain Chemistry and materials 56 types Electrons, bonds, liquids, crystals and fracture: the behaviour of matter before it is synthesised. [Chemistry and materials page ▸](https://simulation-hypothesis.com/simulations/chemistry-materials) family Electrons and bonds 18 Electronic structure Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#electronic-structure) Reaction dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Computational materials screening Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Excited states and photochemistry Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#excited-states-photochemistry) Spectroscopy prediction Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#spectroscopy-prediction) Solvation free energy Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#solvation-free-energy) Machine-learned interatomic potentials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Universal interatomic potentials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#universal-interatomic-potentials) Quantum chemistry on quantum computers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-chemistry-on-quantum-computers) Ab initio molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Path-integral molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Real-time electron dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Quantum wavepacket dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Transition-state and reaction-path search Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Automated reaction-mechanism generation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) Quantum Monte Carlo for electrons Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Learned density functionals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Neural-network wavefunctions for molecules Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) family Molecules in motion 16 Liquids and solutions Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#liquids-solutions) Polymers and soft matter Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Combustion Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#combustion) Colloids and nanoparticle assembly Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Glass formation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#glass-formation) Molten salts and ionic liquids Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ionic-liquids-electrolytes) Reactive force-field dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reactive-force-field-dynamics) Metadynamics and enhanced sampling Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Learned equilibrium samplers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Kinetic Monte Carlo Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Coarse-grained molecular dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Dissipative particle dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Enhanced-sampling free-energy methods Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Adsorption in porous materials Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#grand-canonical-adsorption) Polymer self-consistent field theory Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Chain-growth Monte Carlo for polymers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chain-growth-monte-carlo) family Solids 14 Magnetism and phase transitions Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) Fracture and defects Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fracture) Microstructure Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Granular materials Bodies [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#granular) Dislocation dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Thin film growth Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#thin-film-growth) Radiation-damage cascades in materials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) Alloy cluster expansion Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Crystal plasticity finite-element modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Micromagnetic simulation Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Organic semiconductor charge transport Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Lattice thermal-conductivity calculation Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Diffusion-limited aggregation Rules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) Generative models of crystals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) family Reactions, catalysis and electrochemistry 8 Catalysis Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#catalysis) Battery and electrochemical cell modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Corrosion Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Crystallisation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) Chemical reactor engineering Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chemical-reactor-engineering) Polymerisation kinetics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) Fuel-cell membrane and transport modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) Pore-network modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) domain Life and medicine 83 types Proteins, cells, organs, patients and epidemics: biology from the molecular scale to the population. [Life and medicine page ▸](https://simulation-hypothesis.com/simulations/life-medicine) family Molecules of life 10 Protein folding and dynamics Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#protein-dynamics) Molecular docking and drug binding Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) Membranes and ion channels Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#membranes) Whole virus particles Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virus-particles) RNA folding and structure Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) Enzyme catalysis Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) Coarse-grained DNA and RNA models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coarse-grained-nucleic-acids) Learned protein structure prediction Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#learned-structure-prediction) Generative protein ensembles Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#generative-protein-ensembles) Volunteer-computed molecular dynamics Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#volunteer-computing-molecular-dynamics) family Cells 15 Stochastic biochemistry Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#stochastic-biochemistry) Gene regulatory networks Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Metabolic networks Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#metabolism) Whole-cell models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Pattern formation Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Tissue and tumour growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Cell perturbation-response models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#perturbation-response-models) Tumour evolution agent-based models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Microbial community metabolic models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Tumour growth and therapy response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Tumour microenvironment evolution Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Tumour-induced blood vessel growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Cancer drug response and resistance dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Blood cell production dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#haematopoiesis-dynamics) Bacterial colony growth and biofilms Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) family Bodies 28 The heart Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Blood flow Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#blood-flow) Breathing and airways Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#lungs) Musculoskeletal biomechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#biomechanics) Immune response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Pharmacokinetics Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacokinetics) In silico clinical trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Cardiac digital twins Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Neural predictive models of sensory brain areas Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#neural-predictive-digital-twins) Brain-stimulation field models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Virtual-population drug exposure models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Gut microbiome community models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Surgical planning with patient-specific models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Heart valve fluid-structure interaction Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Bone adaptation and implant remodelling Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Musculoskeletal models for surgery Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#musculoskeletal-surgery-models) Radiotherapy dose calculation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Virtual anatomical phantoms for imaging Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Magnetic resonance image simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Fracture healing simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Within-host virus dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#within-host-viral-dynamics) Coronary flow reserve from scans Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Cochlear mechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Whole-body integrative physiology Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Bioheat transfer and hyperthermia Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Kidney nephron transport models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Vocal fold and voice production models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Circadian clock models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) family Public health 23 Compartment epidemic models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#compartment-epidemics) Agent-based epidemics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Pathogen evolution Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) Disease burden and health economic modelling Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Outbreak genomic epidemiology Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Environmental and chemical exposure risk assessment Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Mobility-network epidemic models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Individual-based malaria models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Scenario modelling hubs Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Digital contact-tracing models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Antimicrobial resistance spread Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Malaria transmission and intervention models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Indoor airborne transmission simulation Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) Tobacco-control policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Vaccine allocation optimisation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-allocation-optimisation) Virtual imaging trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Epidemics on contact networks Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Mosquito population dynamics Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Cancer screening microsimulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Obesity and diet agent-based models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) Organ allocation policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Ambulance and fire station deployment models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) Synthetic patient record generation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) family Drug discovery and pharmacology 7 Predictive toxicology Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) Pharmacodynamic modelling Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacodynamics) Clinical trial design simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#trial-design-simulation) Drug repurposing network models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-repurposing-networks) Drug formulation and delivery modelling Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) Vaccine antigen design Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) Closed-loop diabetes control in silico Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) domain Ecology, evolution and animal behaviour 51 types Ant colonies, flocks, food webs, forests and genes across generations. [Ecology, evolution and animal behaviour page ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour) family Collective behaviour 7 Ant colony foraging Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) Honeybee colonies Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Flocking and schooling Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) Termite mound building Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Slime mould aggregation Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Bacterial swarming and quorum sensing Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) Locust marching bands Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) family Individual animals 6 Movement and foraging Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) Migration and navigation Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#migration) Animal locomotion Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) Evolution of behaviour Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Birdsong and vocal learning models Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) Dynamic energy budget modelling Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#dynamic-energy-budget) family Populations and ecosystems 22 Predator–prey dynamics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) Food webs Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Forest dynamics Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forest-dynamics) Fisheries and wildlife management Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Species ranges Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) Wildlife disease Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) General ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Metapopulation dynamics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Individual-based ecological models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Coral reef resilience models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Spatial host-parasitoid and pest lattices Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) Fisheries management strategy evaluation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Trophic mass-balance ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Plankton ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Lake eutrophication models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Marine larval dispersal and connectivity Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Honeybee colony and landscape models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Pollination service across landscapes Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) Wind seed and pollen dispersal models Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) Near-term ecological forecasting Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Size-spectrum ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) Neutral community models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) family Evolution 10 Population genetics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Coalescent and phylogenetic simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coalescent) Origin of life Molecules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) Host-parasite coevolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Speciation and macroevolution models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Sexual selection and mate choice evolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Adaptive dynamics of coevolution Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Gene drive population models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Forward-time genome simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Animal contest strategies Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) family Conservation and reserve design 6 Population viability analysis Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Reserve and corridor design Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) Reintroduction and translocation planning Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) Invasive species spread Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) Poaching and anti-poaching patrol games Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#poaching-patrol-games) Rewilding and trophic cascade modelling Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) domain Agriculture and food 35 types Fields, herds, ponds and supply chains, run forward to estimate whether supply will meet demand. [Agriculture and food page ▸](https://simulation-hypothesis.com/simulations/agriculture-food) family Crops and soil 19 Crop growth and yield models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Soil water and nutrient transport Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Pest and plant disease spread Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Irrigation scheduling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Soil erosion and land degradation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Crop breeding simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Precision agriculture optimisation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Multi-model crop ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Soil organic carbon turnover Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Agricultural catchment pollution models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Global gridded crop model ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Farm agent-based models of land use and adoption Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#farm-agent-based-adoption) Pesticide resistance management models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Agrivoltaic light-sharing models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Plant architecture growth models Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Degree-day pest phenology models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Sterile insect release models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Land-use change agent models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) Greenhouse climate models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) family Livestock and aquaculture 7 Livestock herd and feed models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Grazing and pasture management Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Aquaculture and fish farming Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Livestock disease outbreak models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Livestock breeding and genetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) Precision livestock monitoring Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Aquaculture pond bioenergetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) family Food systems and processing 9 Food supply chain simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) Famine early warning models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) Fermentation process modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Baking and thermal food processing Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) Cold chain and spoilage modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Food safety and traceability simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) Predictive food microbiology Cells [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) Quantitative microbial risk assessment Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) Digestion and gastric flow simulation Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) domain Human behaviour and society 73 types Decisions, crowds, opinions, markets, past societies and whole populations. [Human behaviour and society page ▸](https://simulation-hypothesis.com/simulations/human-society) family Minds and decisions 8 Cognitive architectures Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cognitive-architectures) Models of decision-making Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#decision-models) Models of learning Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Social cognition and theory-of-mind models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Emotion and affect modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Choice under risk and uncertainty modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Language-model survey respondents Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-survey-respondents) Language-model behavioural experiments Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-behavioural-experiments) family Social dynamics 16 Residential sorting Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) Opinion dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Cooperation and norms Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Diffusion of ideas Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Social network formation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#network-formation) Language evolution Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#language-evolution) Cultural evolution Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Language-model agent societies Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) Populated social-system prototypes Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Language-model social platform simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Recommender feedback-loop simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Language-model user simulation for recommenders Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) Misinformation and rumour spread Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Migration under climate stress Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#climate-migration-abm) Human mobility and migration models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Synthetic population generation Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) family Crowds 6 Pedestrian and crowd dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) Crowd emotion and behavioural contagion Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Collective action and tipping-point models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Collective estimation and crowd wisdom Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) Protest mobilisation network models Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Mass gathering disease risk modelling Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) family Economies and markets 19 Macroeconomic models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Agent-based economies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#agent-economies) Financial markets Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Financial risk Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#risk) Market and auction design Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) Artificial societies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#artificial-societies) AI-designed economic policy simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Agent-based exchange simulators Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Housing market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#housing-market-abm) Dynamic stochastic general equilibrium models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Insurance catastrophe models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Financial contagion in interbank networks Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Kinetic wealth exchange models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) Disaster economic ripple models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Electricity market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Coupled epidemic and economy models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#epidemic-economy-coupled) Flash-crash market models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Algorithmic pricing collusion Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Language-model macroeconomic agents Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) family Anthropology and archaeology 6 Reconstructed ancient societies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#archaeological-abm) Human dispersal Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) Hunter-gatherer economies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#hunter-gatherers) Ancient trade and exchange Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Demographic microsimulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#demographic-microsimulation) Monument construction and engineering reconstruction Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) family Policy and organisations 11 Tax and benefit microsimulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) World models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#world-models) Organisations and teams Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#organisations) Computable general equilibrium modelling Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#computable-general-equilibrium) Institutional corruption and integrity modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Policy diffusion network models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) Language-model agent organisations Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Language-grounded negotiation agents Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Opioid epidemic system dynamics Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opioid-system-dynamics) Exploratory modelling under deep uncertainty Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Supply-chain dynamics and the bullwhip effect Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) family Law, justice and elections 7 Electoral and voting system simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Court and case-flow simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Sentencing and recidivism risk modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) Policing and patrol deployment simulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) Legislative bargaining and coalition simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) Jury decision-making simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) Crime hotspot dynamics Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) domain Engineering and technology 69 types Airflow over wings, structures under load, chips before fabrication, robots before they are built. [Engineering and technology page ▸](https://simulation-hypothesis.com/simulations/engineering) family Flow 16 Aerodynamics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#aerodynamics) Turbulence Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#turbulence) Physical scale models Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#scale-models) Cavitation simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#cavitation) Multiphase and pipeline flow Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multiphase-flow) Ice accretion simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#icing) Physics-informed neural networks Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Neural operators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Graph-network learned simulators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Learned fluid solvers Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Lattice-gas automata for fluid flow Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) Lattice Boltzmann flow simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) Rarefied-gas direct simulation Molecules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) Wind-farm large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Fluid-structure interaction Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Fire dynamics large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) family Structures and machines 10 Structural analysis Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#structural-analysis) Crash simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#crash) Multibody dynamics Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multibody) Acoustics and vibration Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#acoustics) Fatigue and crack growth Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#durability-fatigue) Tribology and contact mechanics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tribology-contact) Topology optimisation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Peridynamic fracture modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Orbital-debris and satellite-collision modelling Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Co-simulation of linked models Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) family Electronics and computers 12 Circuit simulation Populations [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#circuit-simulation) Chip logic simulation Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Electromagnetics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#electromagnetics) Computer network simulation Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-simulation) Emulation and virtual machines Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#emulation) Semiconductor device simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Network digital twins Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) Optical lithography simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Semiconductor process simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) Processor thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Photonic-crystal band-structure calculation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Stacked chip thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) family Robotics and autonomy 17 Robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Autonomous vehicle testing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) Swarm robotics Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#swarm-robotics) Digital twins Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) Planetary rover mobility Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Exoskeleton and prosthetic control Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) GPU-parallel robot learning environments Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Domain-randomised sim-to-real training Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Differentiable physics simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Adversarial driving-scenario generation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) Open driving simulators with sensor models Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) Learned legged locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned humanoid locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Drone flight simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Learned drone racing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Soft robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Tactile sensor simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) family Spaceflight and energy 8 Spacecraft trajectories Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#trajectory-design) Atmospheric entry Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#reentry) Batteries and fuel cells Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) Rocket engine simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rocket-propulsion) Spacecraft thermal and power simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#spacecraft-thermal) Solar and wind farm yield simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Mega-constellation collision risk Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) Conjunction collision probability Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) family Manufacturing and materials processing 6 Metal casting and solidification Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-casting) Welding simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#welding-simulation) Additive manufacturing simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#additive-manufacturing) Metal forming and stamping Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-forming) Machining simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#machining-simulation) Injection moulding simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#injection-moulding) domain Cities, infrastructure and operations 42 types Traffic, queues, supply chains, water, power and the built environment. [Cities, infrastructure and operations page ▸](https://simulation-hypothesis.com/simulations/cities-operations) family Movement 11 Traffic flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Transport and land use Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Urban growth Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#urban-growth) Evacuation and emergency response Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#evacuation) Public transit network simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Ride-hailing and dispatch simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Aircraft boarding simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Airport airside simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Elevator traffic simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Shared autonomous vehicle fleets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Airspace fast-time simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) family Queues and logistics 11 Supply chains Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Manufacturing lines Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#manufacturing) Queues and service systems Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#service-queues) Hospital patient flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Warehouse and distribution centre simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Last-mile delivery routing Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Project schedule risk simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Warehouse robot fleet coordination Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Supply chain digital twins Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Container terminal simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Construction process simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) family Infrastructure 12 Power grids Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Water and drainage networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Building energy and daylight Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) Infrastructure interdependence Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Waste collection and treatment simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) District heating and cooling networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Power-system electromagnetic transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Energy-system capacity-planning models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) Agent-based electricity markets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) Cascading-blackout models Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Smart-grid co-simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Gas pipeline network transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) family Telecommunications and the internet 8 Mobile network planning Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Internet backbone and cable resilience Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Data centre facility simulation Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) Satellite broadband constellation simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) Telecom traffic engineering Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) Smart-city sensor network simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Internet worm propagation models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) Vehicular network simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) domain Minds, brains and artificial worlds 42 types Neurons, brains, artificial life, and the simulated worlds in which machines learn. [Minds, brains and artificial worlds page ▸](https://simulation-hypothesis.com/simulations/minds-computation) family Brains 11 Detailed neuron models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#detailed-neurons) Large-scale brain circuits Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Whole-brain network models Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Simulated small organisms Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Neuromorphic hardware simulation Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Brain disease and seizure spread Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Connectome-constrained whole-brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Neural mass and field models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Functional spiking brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Attractor memory networks Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Connectome-based insect brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) family Artificial life and complexity 14 Cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) Digital evolution Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#digital-evolution) Evolved virtual creatures Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Self-organised criticality Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) Swarm intelligence algorithms Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Random Boolean networks Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Continuous cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-cellular-automata) Neural cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Self-replicating program soups Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Artificial chemistry Molecules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Evolutionary robotics Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Continuous artificial life Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) Artificial immune models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) Core War battles Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) family Worlds for artificial minds 17 Reinforcement learning environments Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Multi-agent AI societies Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) Synthetic training data Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#synthetic-data) Learned world models Fields [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learned-world-models) Self-play strategy training Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) AI safety red-teaming environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Embodied household simulators Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) Open-ended environment generation Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) Simulated web environments for agents Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Recommender-system simulators Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) Neural game engines Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Interactive generative worlds Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#interactive-generative-worlds) Learned real-world interactive simulators Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#real-world-interactive-simulators) Generative driving world models Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#driving-world-models) Simulated robot soccer Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) Software engineering agent sandboxes Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) domain Mathematics and computation 46 types Numbers, proofs, graphs and machines, investigated by computation as well as by deduction. [Mathematics and computation page ▸](https://simulation-hypothesis.com/simulations/mathematics-computation) family Pure mathematics by computer 15 Random matrix experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-matrix-experiments) Random graph experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Percolation simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Experimental mathematics searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Monte Carlo estimation of constants Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) Computational number theory searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Chaotic-attractor numerics Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#chaotic-attractor-numerics) Nonlinear lattice experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) Soliton numerical experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) Fractal-set rendering Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fractal-set-rendering) Sandpile self-organised criticality Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) Riemann zeta zero computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Digits of pi by computer Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) AI-guided conjecture discovery Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#ai-guided-conjecture-discovery) Learned algorithm and construction search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) family Proof, logic and security 16 Model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#model-checking) Automated theorem proving search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) SAT and constraint solving Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Cryptographic attack modelling Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Side-channel leakage simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Security protocol verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Computer-assisted proof by exhaustive case checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Validated numerics Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#validated-numerics) Turing-machine enumeration Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) Statistical model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Fuzz testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Symbolic execution Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Abstract interpretation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Bounded model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Property-based random testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Neural network verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) family Systems and machines 15 Computer architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Distributed systems and consensus simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Storage systems simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Operating system scheduler simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#os-scheduler-simulation) Compiler and program optimisation search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Empirical algorithm performance testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) Language-model program execution Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#llm-program-execution) Blockchain consensus simulation Populations [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) Parallel discrete-event simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#parallel-discrete-event-simulation) Graphics processor architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) FPGA-accelerated system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Full-system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Lightweight network emulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) Simulated annealing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Approximate Bayesian computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) domain Minds as simulators 45 types The simulations that brains run: dreaming, imagining, modelling other minds, play, and building models of the body and the world. [Minds as simulators page ▸](https://simulation-hypothesis.com/simulations/mind-simulations) family Sleep and dreaming 7 REM dreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#rem-dreaming) Lucid dreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#lucid-dreaming) Hippocampal replay in rats Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-replay) Threat-simulation theory of dreams Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#threat-simulation-theory) Sleep-dependent memory consolidation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#memory-consolidation-sleep) Hypnagogic imagery Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hypnagogic-imagery) Hippocampal preplay Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-preplay) family Imagination and planning 13 Mental rehearsal in athletes Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rehearsal-athletes) Episodic future thinking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#episodic-future-thinking) Counterfactual thinking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#counterfactual-thinking) Mental rotation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rotation) Mental navigation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-navigation) Mind-wandering and daydreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mind-wandering) Constructive episodic simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#constructive-episodic-simulation) Motor imagery Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-imagery) Visual mental imagery Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#visual-mental-imagery) Affective forecasting Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#affective-forecasting) Mental models of reasoning Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Vicarious trial and error Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#vicarious-trial-and-error) Future planning in animals Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-future-planning) family Other minds 7 Theory of mind Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#theory-of-mind) Empathy as simulation theory Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#empathy-simulation-theory) Mirror systems Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mirror-systems) Audience design Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#audience-design) Visual perspective-taking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#perspective-taking) Joint attention Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#joint-attention) Fiction as social simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#fiction-as-social-simulation) family Play and pretence 6 Children's pretend play Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#pretend-play-children) Animal play as practice Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-play-practice) Imaginary companions Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#imaginary-companions) Sociodramatic play Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) Paracosms Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#paracosms) Object play in primates Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#primate-object-play) family The brain's world model 12 Predictive processing Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#predictive-processing) Motor forward models Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-forward-models) The body schema Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-schema) Hallucination as uncontrolled prediction Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hallucination-uncontrolled-prediction) Blind-spot filling-in Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#blind-spot-filling-in) Interoception Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#interoception) Thought as simulated action Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) Grounded cognition Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#grounded-cognition) The phenomenal self-model Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#phenomenal-self-model) Body ownership illusions Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-ownership-illusions) Embodied language simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#embodied-language-simulation) The intuitive physics engine Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) domain Training simulators 29 types Simulations with a person in the loop: cockpits, operating theatres, control rooms and bridges. [Training simulators page ▸](https://simulation-hypothesis.com/simulations/training) family Vehicles 6 Full-flight simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#flight-simulators) Driving and rail simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#driving-simulators) Ship bridge simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ship-bridge) Spaceflight and mission control Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) Heavy equipment simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#heavy-equipment-simulators) Diving and submersible simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) family Medicine 15 Surgical simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) Patient simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Dental simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) Childbirth simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) Anaesthesia simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Paramedic and mass-casualty triage training Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Virtual human patients Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Agent hospitals Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Catheter and endovascular simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Structured clinical examinations Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#clinical-examination-standardised-patients) Ultrasound training simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Robotic surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Endoscopy simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Language-model simulated students Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) family Control and crisis 8 Control-room simulators Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) Emergency exercises Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#tabletop-exercises) Business simulations Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) Air traffic control simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) Negotiation and diplomacy training simulations Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) Emergency incident command simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) Language-model conflict rehearsal Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-conflict-rehearsal) Mass-casualty exercises Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) domain Before computers 41 types Simulation before the transistor: gears, water, sand and rehearsal as stand-ins for the real system. [Before computers page ▸](https://simulation-hypothesis.com/simulations/before-computers) family Models of the heavens 8 Orrery Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#orrery) Astrolabe Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astrolabe) The Antikythera mechanism Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#antikythera-mechanism) Optical planetarium Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#planetarium) Armillary sphere Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#armillary-sphere) Equatorium Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#equatorium) Terrestrial globe Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#terrestrial-globe) Astronomical clock Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astronomical-clock) family Scale models and tanks 9 Ship-model towing tank Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#towing-tank) Physical river basin model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#river-basin-model) Harbour and estuary model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harbour-model) Dam and spillway model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#spillway-model) Structural scale model Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#structural-scale-model) Architectural acoustic scale model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#acoustic-scale-model) Hele-Shaw cell Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) Hanging-chain arch model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Soap film minimal-surface models Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) family Analogue computers 10 Mechanical differential analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#differential-analyser) Tide-predicting machine Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#tide-predicting-machine) Hydraulic economy model Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hydraulic-economy-model) Electrical network analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#electrical-network-analyser) Mechanical harmonic analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harmonic-analyser) Analogue fire-control computer Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#analogue-fire-control-computer) Galton board Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Buffon's needle Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) Iron wire nerve model Cells [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) Cybernetic tortoises Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) family Tables, boards and rehearsals 6 Sand table Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#sand-table) Staff ride Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#staff-ride) Dress rehearsal Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#dress-rehearsal) Fire and evacuation drills Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#fire-drills) Mock trial Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) Military field exercises Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#field-exercises) family Bodies and manikins 8 Anatomical models Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#anatomical-models) Obstetric phantom Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#obstetric-phantom) Early resuscitation manikins Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#resuscitation-manikins) Crash-test dummies Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#crash-test-dummies) Moulage Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#moulage) Ballistic gelatin blocks Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#ballistic-gelatin) Automata Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) Motion platforms Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) domain Defence and conflict 35 types War games, combat models, military trainers and weapons physics: the origin of many of the methods in this taxonomy. [Defence and conflict page ▸](https://simulation-hypothesis.com/simulations/defence-conflict) family War games and analysis 14 Professional war games Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#professional-wargames) Political–military crisis games Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Historical war games Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Combat and campaign models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Agent-based combat models Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#agent-combat) Military logistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) Deterrence and arms races Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) Models of civil conflict Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Language-model wargame agents Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) Swarm combat simulation Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Computer virus and malware epidemics Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Search and rescue drift planning Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) Naval salvo exchange models Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#naval-salvo-models) Anti-submarine search theory Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) family Military training 7 Military flight and mission simulators Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Vehicle and crew trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crew-trainers) Networked training exercises Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Marksmanship and use-of-force trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) Cyber ranges Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) Combat medic trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) Autonomous cyber-defence gyms Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) family Weapons physics and protection 7 Nuclear stockpile simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) Ballistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Blast and impact protection Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#blast-protection) Radar and sensor performance Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Directed energy weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Torpedo and underwater weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) Chemical, biological and radiological hazard plumes Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) family Consequences of war 7 Climate effects of nuclear war Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#nuclear-winter) Displacement and refugee flows Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Casualty and humanitarian response Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) Landmine and unexploded ordnance clearance planning Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) War economic and reconstruction modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Sanctions and economic warfare modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) Biological attack response models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) domain Film, media and art 34 types Cloth, smoke, crowds and light, generated from physical models rather than animated by hand. [Film, media and art page ▸](https://simulation-hypothesis.com/simulations/media-art) family Simulated physical media 10 Cloth simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Hair and fur simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Fluid and smoke simulation for effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Destruction and debris simulation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Muscle and skin deformation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Rigid body dynamics for animation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Position-based dynamics Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Ocean surface synthesis Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Particle system effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Snow and granular material simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) family Populated and built worlds 15 Digital crowd simulation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-crowds) Digital humans and faces Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Procedural cities and landscapes Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Virtual production sets Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Digital ecosystems and vegetation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Atmospheric and sky simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Neural avatars Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-avatars) Virtual idols and influencers Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Virtual concerts Populations [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) Digital de-ageing Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Performance-captured digital characters Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) L-system plant modelling Cells [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) Machinima Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Animatronic figures Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) Physics-based character control Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) family Light and sound 9 Physically based light transport Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) Sound propagation and acoustics Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) Physical modelling synthesis of instruments Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) Generative art systems Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) Procedural and generative music Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Procedural texture and material generation Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) Physically based sound effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Live-coded music and visuals Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) Neural scene rendering Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) domain Video games 93 types Every video game simulates something. The genres here are sorted by what they model and what they leave out. [Video games page ▸](https://simulation-hypothesis.com/simulations/video-games) family Vehicles and machines 11 Flight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Spaceflight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) Racing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Arcade racing Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arcade-racing) Driving and transport simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Naval and submarine simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) Job and machinery simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Open-city driving Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Flight simulation over streamed Earth Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Soft-body vehicle crash simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Mech combat simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) family Life and people 8 Life simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Virtual pets Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#virtual-pets) Farming and village life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Relationship simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#relationship-sims) Social hangout worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) Dating simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Parenting and family life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) Surgery and medical games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) family Systems and societies 9 City building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Colony simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) Management and tycoon Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) God games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) Ecosystem and evolution games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) Automation and factory building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Idle and incremental Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#idle-games) Social deduction games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Station systems simulation Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) family Strategy 7 Grand strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) 4X strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#four-x) Real-time strategy Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Hex-and-counter war games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Tactics Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Tower defence Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tower-defence) Auto-battlers Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) family Worlds and sandboxes 9 Block and voxel sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Survival and crafting Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) Physics sandboxes and building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Falling-sand games Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) Space exploration and trading Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) Level and world creation tools Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) Terrarium and habitat sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Agent-based game playtesting Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) User-generated game platforms Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) family Role-playing and story 10 Role-playing games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Massively multiplayer worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) Immersive simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Open-world adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Roguelikes Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Interactive fiction Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#interactive-fiction) Visual novels and narrative games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#visual-novels) Exploration and walking Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#exploration) Adventure and point-and-click Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#puzzle-adventure) Alternate reality games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) family Action and skill 10 Platformers Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#platformers) Action adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#shooters) Fighting games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Tactical military simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Stealth Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Team arena games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) Rhythm games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rhythm) Battle royale Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Extraction shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) family Sports 9 Sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Sports management Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) Fitness and motion games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fitness-games) Extreme and action sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Golf simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Combat sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) Racket and ball sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) Fishing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Hunting simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) family Puzzle and abstract 10 Physics puzzles Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) Logic and falling-block puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#logic-puzzles) Board and card game adaptations Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Word and letter puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#word-puzzles) Match-three and tile-swap puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) Hidden-object and spot-the-difference Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hidden-object) Number and grid logic puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#number-logic-puzzles) Escape-room puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#escape-room-games) Programming battle games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Hacking simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) family Immersive hardware 10 Virtual reality Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr) Augmented and location-based Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#augmented-reality) Motion-controller games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#motion-controller-games) Haptic and force-feedback games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#haptic-feedback-games) Location-based and arcade VR Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#large-scale-vr) Cockpit and rig simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cockpit-sim-rigs) Biometric-adaptive games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Virtual reality social worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) Augmented reality pets Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) Cloud-streamed games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) --- title: "Tools · small instruments for the simulation hypothesis · Simulation Hypothesis" url: https://simulation-hypothesis.com/tools description: "Work out the computing for a single day, check any system against published criteria for mind, and run interactive models in your browser." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Tools · instruments for the simulation question Each tool answers one question. The calculators keep their state in the link, so you can share a result. They also tag each estimate with how sure we are. [When could our computers run each simulation? The countdown Humanity’s computing, measured since 1946 and projected in three scenarios that level off at physical ceilings, against the computing every sandbox scenario needs. It includes the hardware, energy, AI, brain-mapping and interest data behind the curve.](https://simulation-hypothesis.com/countdown)[Given a computer, what world can it run? What a computer can run The totals run backwards. Pick a machine, from a phone to every kilogram of the observable universe computing at the physical limit. See the largest world and finest matter floor it can run, or how many minds it can run with no world at all.](https://simulation-hypothesis.com/budget)[How deep can a stack of simulations go? Simulations within simulations Build a stack of worlds, each running the next. A simulated computer can never out-compute the world it runs in, so every layer has less than the one above. See where the stack stops and what the base reality has to supply.](https://simulation-hypothesis.com/nesting)[How much computing would one day of a life take? The computing in one day An ordinary day, itemised: the computing it takes to simulate one person’s day, rendering only what that person perceives.](https://simulation-hypothesis.com/bill)[Check a system against the evidence Mind assessment Mark the properties of an animal or an AI system against the published criteria for sentience (Birch et al. 2021) and consciousness (Butlin et al. 2023).](https://simulation-hypothesis.com/score)[Browser simulations Interactive models Conway’s Game of Life, Monte Carlo estimation of π, flocking, an epidemic, falling sand, traffic flow, ant trails, Turing patterns, a sandpile, residential sorting, the three-body problem, forest fires, an Ising magnet, and predator and prey. Each one is small enough to run in your browser. We compare it with the computing a full-scale run of the same kind would need.](https://simulation-hypothesis.com/simulations/run) --- title: "Everything on this site · Simulation Hypothesis" url: https://simulation-hypothesis.com/map description: "The full site map: the sandbox and its scenarios, the tools, the interactive models, the Entities and Simulations field guides, and the library." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Everything on this site · the map This site works out what it would take to simulate a world. It doesn’t argue that we’re in one. The pages below are grouped by what they do. ## Trees * [Trees](https://simulation-hypothesis.com/trees) · explorable histories * [Technology tree](https://simulation-hypothesis.com/trees/technology) · 82 nodes: how virtual worlds became possible * [Simulations tree](https://simulation-hypothesis.com/trees/simulations) · 107 nodes: what we have learned to simulate * [Ethics tree](https://simulation-hypothesis.com/trees/ethics) · 91 nodes: where our rules came from, and where they go * [Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic) · 100 nodes: from biological to synthetic life ## Sandbox and tools * [Sandbox](https://simulation-hypothesis.com/sandbox) · nine parameters, one total: the computing a simulated universe takes * [Scenarios](https://simulation-hypothesis.com/builds) · 9 preset universes, each worked out * [Featured scenario](https://simulation-hypothesis.com/today) · one scenario a day, the same for everyone * [The countdown](https://simulation-hypothesis.com/countdown) · when could our computers run each simulation * [What a computer can run](https://simulation-hypothesis.com/budget) · given a computer, what world can it run * [Simulations within simulations](https://simulation-hypothesis.com/nesting) · how deep can a stack of simulations go * [The computing in one day](https://simulation-hypothesis.com/bill) · how much computing would one day of a life take * [Mind assessment](https://simulation-hypothesis.com/score) · check a system against the evidence * [Interactive models](https://simulation-hypothesis.com/simulations/run) · cellular automata, flocking, epidemics, traffic, ant colonies and more, running in your browser ## Field guides * [Entities](https://simulation-hypothesis.com/entities) · 44 minds and possible minds, in order of evidence * [Sentience criteria for animals](https://simulation-hypothesis.com/entities/sentience) · the eight criteria from the 2021 review that led UK law to recognise octopuses and crabs as sentient, and what the review found * [How directed time is estimated](https://simulation-hypothesis.com/entities/control) · how the Entities charts weigh religions, states, parties and corporations by how much of their members’ waking time they direct. Every practice, survey share and source is listed * [Consciousness indicators for AI](https://simulation-hypothesis.com/entities/indicators) · the fourteen indicators from Butlin, Long and colleagues (2023), taken from six scientific theories of consciousness * [Simulations](https://simulation-hypothesis.com/simulations) · 18 domains of the simulations people actually run * [Simulations by floor](https://simulation-hypothesis.com/simulations/floors) · every simulation sorted by the smallest entity it tracks, from quarks up to pure rules * [Simulations by method](https://simulation-hypothesis.com/simulations/methods) · the same taxonomy sorted by computational method, from Monte Carlo to agent-based to real-time * [Simulations by era](https://simulation-hypothesis.com/simulations/eras) · when the first simulation of each kind ran, from orreries and war games to the present * [Simulations by cost](https://simulation-hypothesis.com/simulations/costs) · how much computing each kind of simulation uses, from no computer at all to the largest machines on Earth ## Reference * [Library](https://simulation-hypothesis.com/library) · 55 terms, each with a definition and what it does in the model * [Thinkers](https://simulation-hypothesis.com/thinkers) · 14 thinkers, each with its matching sandbox dial * [Guided routes](https://simulation-hypothesis.com/guide) · five minutes, an hour, or for research * [Objections](https://simulation-hypothesis.com/objections) · the standard objections, and where the computing model stops * [Tests](https://simulation-hypothesis.com/tests) · proposed experiments and physical bounds, and what each one found * [Reading](https://simulation-hypothesis.com/reading) · annotated further reading, with difficulty tags * [Method](https://simulation-hypothesis.com/method) · how each total is worked out, with sources ## About the site * [What runs here](https://simulation-hypothesis.com/licences) · no cookies, no accounts, one page counter * [Home](https://simulation-hypothesis.com/) · what this is, and three ways in --- title: "The countdown · When could our computers run each simulation? · Simulation Hypothesis" url: https://simulation-hypothesis.com/countdown description: "Humanity’s computing, measured since 1946 and projected in three scenarios that level off at physical ceilings, against the computing every sandbox scenario needs." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # The countdown · when our computers could run each simulation Each scenario in the [sandbox](https://simulation-hypothesis.com/sandbox) needs a certain number of operations per second. Humanity’s computers add up to a total. This page puts the two on one chart. We measure up to now, then project three scenarios that level off as they hit physical limits. It’s an illustration built on measured data, not a forecast. The three scenarios are ours, and every year below means “if growth stayed at this rate”. Humanity computes about 10^21 operations a second, all hardware on Earth rough Next finish line \~2050 The 2050 Server, 1.8 × 10^24, if growth stayed steady wild guess Earth, atom by atom 1.3 × 10^47 × beyond all existing computation rough Chips vs the floor 4.7 × 10^9 × today’s best hardware, above the Landauer limit textbook ## The crossing Solid lines are measured. Dashed lines are three scenarios. Each one grows at a steady rate while it’s far from its ceiling, then levels off as it gets close, like logistic growth. Each band shows the same scenario with growth a fifth lower and a fifth higher. That spread is arbitrary. It isn’t a probability. Where a dashed line crosses a finish line, that’s the year our computers could run it, if a civilisation threw its full capacity at the job. The scenarios that go past today’s grid also assume energy per operation keeps falling towards the thermodynamic floor. The best chips have barely improved since 2022, so that’s the shakiest assumption on the page. Growth: 35% a year UntilEarth’s whole grid, today’s chips1% of Earth’s sunlight, perfect chipsThe whole Sun, perfect chipsEarth’s mass as the ultimate computer Fastest single machine All of humanity’s computers Fast Steady Stalled Show the numbers | Year | Fastest single machine | All of humanity’s computers | Fast | Steady | Stalled | | ---- | ---------------------- | --------------------------- | ---------------- | ---------------- | ---------------- | | 1946 | 5.0 × 10² FLOPS | | | | | | 1964 | 3.0 × 10⁶ FLOPS | | | | | | 1976 | 1.6 × 10⁸ FLOPS | | | | | | 1986 | | 3.0 × 10¹⁴ FLOPS | | | | | 1993 | 6.0 × 10¹⁰ FLOPS | 4.4 × 10¹⁵ FLOPS | | | | | 1997 | 1.3 × 10¹² FLOPS | | | | | | 2000 | | 2.9 × 10¹⁷ FLOPS | | | | | 2002 | 3.6 × 10¹³ FLOPS | | | | | | 2007 | | 6.4 × 10¹⁸ FLOPS | | | | | 2008 | 1.1 × 10¹⁵ FLOPS | | | | | | 2011 | 1.1 × 10¹⁶ FLOPS | | | | | | 2013 | 3.4 × 10¹⁶ FLOPS | | | | | | 2016 | 9.3 × 10¹⁶ FLOPS | | | | | | 2018 | 1.4 × 10¹⁷ FLOPS | | | | | | 2020 | 4.4 × 10¹⁷ FLOPS | | | | | | 2022 | 1.1 × 10¹⁸ FLOPS | | | | | | 2024 | 1.7 × 10¹⁸ FLOPS | | | | | | 2025 | | 10²¹ FLOPS | 10²¹ FLOPS | 10²¹ FLOPS | 10²¹ FLOPS | | 2026 | 2.2 × 10¹⁸ FLOPS | | | | | | 2050 | | | 1.3 × 10²⁶ FLOPS | 1.8 × 10²⁴ FLOPS | 7.0 × 10²² FLOPS | | 2075 | | | 1.6 × 10³¹ FLOPS | 3.3 × 10²⁷ FLOPS | 2.5 × 10²³ FLOPS | | 2100 | | | 2.0 × 10³⁶ FLOPS | 6.0 × 10³⁰ FLOPS | 2.6 × 10²³ FLOPS | | 2125 | | | 2.6 × 10⁴¹ FLOPS | 1.1 × 10³⁴ FLOPS | 2.6 × 10²³ FLOPS | | 2150 | | | 2.6 × 10⁴⁶ FLOPS | 5.8 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2175 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2200 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2225 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2250 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2275 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | | 2300 | | | 1.3 × 10⁴⁷ FLOPS | 6.0 × 10³⁵ FLOPS | 2.6 × 10²³ FLOPS | * **Fast.** 60% more computing every year, the pace of the 1990s, until a civilisation beyond Earth has used up the Sun’s output. wild guess * **Steady.** 35% a year, about the last twenty years, until hardware hits the thermodynamic floor and a slice of Earth’s sunlight goes to computing. wild guess * **Stalled.** 20% a year with no new energy supply. Computing grows until it uses the whole electricity grid at today’s efficiency. wild guess | Finish line | Computing needed | Fast | Steady | Stalled | | ------------------------------------------------------------------------------------------------------------------------------------ | ---------------- | --------- | --------- | ------- | | [Brain in a Vat](https://simulation-hypothesis.com/builds/vat)A real brain in base reality. Only its world is computed, and everyone else is scripted. | 8.2 × 10^15 | already | already | already | | [Solipsism](https://simulation-hypothesis.com/builds/solipsism)One real mind. The world is only as detailed as that mind can test. | 10^18 | already | already | already | | [The Afterlife](https://simulation-hypothesis.com/builds/afterlife)A world with no suffering, computed only when someone’s there. | 10^18 | already | already | already | | [The 2050 Server](https://simulation-hypothesis.com/builds/server-2050)Everyone on Earth, with only as many real minds as 2050’s computers can run. | 1.8 × 10^24 | 2039–2044 | 2046–2055 | never | | Everyone alive, as mindsEight billion minds, working at the functional level, and no simulated environment. | 8.2 × 10^27 | 2054–2066 | 2070–2089 | never | | [The Matrix](https://simulation-hypothesis.com/builds/sleepers)Present-day Earth with billions of fully computed minds, drawn in only where someone is looking. | 8.2 × 10^31 | 2071–2089 | 2097–2127 | never | | [Earth, atom by atom, since 1900](https://simulation-hypothesis.com/builds/custom)Earth atom by atom since 1900, as a starting point for changing one dial at a time. | 1.3 × 10^68 | never | never | never | | [Local Universe](https://simulation-hypothesis.com/builds/local)The Milky Way at atomic resolution, from the Big Bang. | 7.0 × 10^85 | never | never | never | | [Universe Lite](https://simulation-hypothesis.com/builds/lite)The observable universe at molecular resolution, with half of it left out. | 5.8 × 10^91 | never | never | never | On one star’s power, with ordinary logic that erases a bit per operation at room temperature, we never get enough computing to run a full world. Reversible computing and a colder heat sink would lower that floor. We don’t count them here. Past the Sun’s line, the only way to get enough is to turn matter itself into a computer near Lloyd’s bound. That bound is a ceiling for matter as hot as a plasma, not for anything like rock. For the operations alone, Earth atom by atom needs at least 2.5 × 10^17 kg. That’s 24 million times less than the Earth. Storing its state takes at least 5 × 10^52 bits, and that needs far more matter (over 10^18 kg even at the black-hole limit). Bostrom’s argument assumes posthuman civilisations that can build computers like that. That’s why it’s about them and not us. ## Drivers of growth ## Machines Fastest single machine All computers on Earth Show the numbers | Year | Fastest single machine | All computers on Earth | | ---- | ---------------------- | ---------------------- | | 1946 | 5.0 × 10² FLOPS | | | 1964 | 3.0 × 10⁶ FLOPS | | | 1976 | 1.6 × 10⁸ FLOPS | | | 1986 | | 3.0 × 10¹⁴ FLOPS | | 1993 | 6.0 × 10¹⁰ FLOPS | 4.4 × 10¹⁵ FLOPS | | 1997 | 1.3 × 10¹² FLOPS | | | 2000 | | 2.9 × 10¹⁷ FLOPS | | 2002 | 3.6 × 10¹³ FLOPS | | | 2007 | | 6.4 × 10¹⁸ FLOPS | | 2008 | 1.1 × 10¹⁵ FLOPS | | | 2011 | 1.1 × 10¹⁶ FLOPS | | | 2013 | 3.4 × 10¹⁶ FLOPS | | | 2016 | 9.3 × 10¹⁶ FLOPS | | | 2018 | 1.4 × 10¹⁷ FLOPS | | | 2020 | 4.4 × 10¹⁷ FLOPS | | | 2022 | 1.1 × 10¹⁸ FLOPS | | | 2024 | 1.7 × 10¹⁸ FLOPS | | | 2025 | | 10²¹ FLOPS | | 2026 | 2.2 × 10¹⁸ FLOPS | | Seventy-nine years, fifteen orders of magnitude: about a thousandfold every fifteen years. measured Source: the twice-yearly TOP500 list (measured on the Linpack benchmark) from 1993, latest June 2026; peak figures from machine histories before that, and the 1946 one is approximate. Every processor, summed. The 2011 census has not been repeated, so the last stretch is a straight line to a rough anchor. It counts general-purpose instructions, as the census did. AI chips alone reached about 4 × 10^21 low-precision operations a second by late 2024; those are a cheaper unit, and adding them would raise the total about fivefold and bring each steady-growth crossing forward by about five years. rough Source: Hilbert & López, “The World’s Technological Capacity to Store, Communicate, and Compute Information”, Science 332 (2011), counting one instruction as one operation; the 2025 point is the site’s own order-of-magnitude anchor. ## Energy per operation Show the numbers | Year | Energy per operation, best machine | | ---- | ---------------------------------- | | 1946 | 3.0 × 10² J | | 1964 | 10⁻² J | | 1976 | 7.0 × 10⁻⁴ J | | 2008 | 1.9 × 10⁻⁹ J | | 2012 | 4.0 × 10⁻¹⁰ J | | 2016 | 1.1 × 10⁻¹⁰ J | | 2020 | 3.8 × 10⁻¹¹ J | | 2022 | 1.5 × 10⁻¹¹ J | | 2024 | 1.4 × 10⁻¹¹ J | | 2025 | 1.4 × 10⁻¹¹ J | Joules spent per operation fell by a factor of twenty trillion. The red line is the floor physics allows at room temperature; the best chips are still about five billion times above it. measured Source: the Green500 list of the most energy-efficient supercomputers from 2008 (November lists, to 73.3 billion operations per watt in 2025); approximate power and speed from machine histories before that. Koomey et al. (2011) measured a doubling every 1.57 years from 1946 to 2009. ## Transistors on one chip Show the numbers | Year | Transistors on one chip | | ---- | ----------------------- | | 1971 | 2.3 × 10³ | | 1978 | 2.9 × 10⁴ | | 1985 | 2.8 × 10⁵ | | 1989 | 1.2 × 10⁶ | | 1993 | 3.1 × 10⁶ | | 2000 | 4.2 × 10⁷ | | 2010 | 3.0 × 10⁹ | | 2016 | 1.5 × 10¹⁰ | | 2020 | 5.4 × 10¹⁰ | | 2022 | 8.0 × 10¹⁰ | | 2024 | 2.1 × 10¹¹ | Moore’s 1965 doubling, still roughly on schedule, now by joining two dies in one package. Chips made from a whole wafer reached four trillion in 2024; they are left off because they are not like for like. measured Source: manufacturers’ published counts for the largest chip or package of each year. ## The largest AI training run Show the numbers | Year | Largest AI training run | | ---- | ----------------------- | | 2012 | 6.0 × 10¹⁷ operations | | 2015 | 4.0 × 10²⁰ operations | | 2017 | 8.0 × 10²⁰ operations | | 2020 | 3.0 × 10²³ operations | | 2022 | 3.0 × 10²⁴ operations | | 2023 | 2.0 × 10²⁵ operations | | 2024 | 4.0 × 10²⁵ operations | | 2025 | 4.0 × 10²⁶ operations | | 2026 | 10²⁷ operations | Total operations spent on the biggest training run of each year, growing four to five times a year since 2010\. The grey lines are the same total counted in years of one human brain at the functional rate: the 2025 record is about a dozen brain-years. rough Source: Epoch AI’s data on frontier AI models (estimates, rounded to one figure; 2026 is preliminary); growth rate from Sevilla and Roldán (2024). ## Algorithms Image recognition 44 × less compute for the same result, 2012 to 2019 measured Language models ½ the compute for the same result, about every 8 months rough Hardware is only part of the trend. Better algorithms cut the operations a task needs every year, so the scenarios above may be conservative. Source: Hernandez & Brown (2020); Ho et al. (2024). ## Electricity for data centres Show the numbers | Year | Data-centre electricity | Data-centre electricity, projected | | ---- | ----------------------- | ---------------------------------- | | 2010 | 194 TWh | | | 2015 | 200 TWh | | | 2018 | 205 TWh | | | 2020 | 270 TWh | | | 2024 | 415 TWh | | | 2025 | 485 TWh | 485 TWh | | 2030 | | 945 TWh | Terawatt-hours a year. Flat for a decade while chips got more efficient, then bent upward by AI; the dashed stretch is the agency’s base case. The whole world used about 29,000 terawatt-hours in 2024\. rough Source: Masanet et al., Science 367 (2020), for 2010 to 2018; the International Energy Agency, “Energy and AI” (2025), for 2020 onward and the 2030 projection. ## Brains, mapped and run Mapped, every synapse Simulated, simplified Show the numbers | Year | Mapped, every synapse | Simulated, simplified | | ---- | --------------------- | --------------------- | | 1986 | 3.0 × 10² neurons | | | 2013 | | 1.7 × 10⁹ neurons | | 2023 | 3.0 × 10³ neurons | | | 2024 | 1.4 × 10⁵ neurons | 8.6 × 10¹⁰ neurons | Mapped means every neuron and synapse traced from real tissue: a worm, a larva, a fly. Simulation is a separate measure: 1.7 billion model neurons in 2013, and in 2024 a run with as many units as a human brain, each one simplified to a point with guessed wiring. The top line is one human brain. Human and mouse cubic millimetres (2024, 2025) are mapped too, but they are fragments, not whole brains. measured Source: White et al. (1986), the worm; Winding et al. (2023), the fly larva; Dorkenwald et al. (2024), the adult fly. RIKEN and Jülich (2013) for the K computer run; Fudan University (2024) for the human-scale run. ## Machine-generated content ## Machine-made share of new items Nobody has measured this for the world as a whole. There’s one real time series, from a single music service counting its own uploads. There are also a few single counts, each for one kind of item in one place. Treat them as samples. Show the numbers | Year | Fully machine-made share of new music uploads | | -------- | --------------------------------------------- | | Jan 2025 | 10% | | Jun 2025 | 18% | | Sep 2025 | 28% | | Nov 2025 | 34% | | Jan 2026 | 39% | | Apr 2026 | 44% | | Jul 2026 | 50% | Percent of each day’s new tracks. It passed half in July 2026\. The often-quoted “90% of online content will be synthetic by 2026” has no traceable source and is not used here. rough Source: a major music-streaming service’s own detector, from its announcements (January 2025 to July 2026). 50% **New English web articles that are mostly machine-written** · 2025 rough An SEO firm’s classifier run on a sample of the open web crawl; flat since early 2025. 17% **Top-20 search results flagged as machine-written** · 2025 rough A detection vendor’s own tool, 500 searches on the biggest search engine; it was 7% in March 2024. 15% **Posts on a large discussion site that are likely machine-written** · 2025 rough The same vendor; 13% the year before. 3% **Plays of fully machine-made songs on the streaming service above** · 2026 rough The service itself: uploads are flooding in, listening is not following. ## Interest We use two stand-ins for interest. One is visits to the encyclopedia article for each idea (English, human traffic only). The other is new scholarly papers that use the phrase. Each chart has its own scale. Hollow dots mark years that aren’t finished. The paper index itself grew fast in 2025 and 2026, so part of the late rise is an artefact of counting, not growth in the field. ## Simulation hypothesis · visits Show the numbers | Year | Simulation hypothesis · visits | | ---- | ------------------------------ | | 2016 | 338,998 | | 2017 | 300,904 | | 2018 | 362,320 | | 2019 | 453,578 | | 2020 | 449,018 | | 2021 | 479,322 | | 2022 | 318,153 | | 2023 | 338,869 | | 2024 | 360,061 | | 2025 | 347,213 | | 2026 | 165,640 | Encyclopedia visits a year. 2026 runs to 2026-08. ## Generative AI · visits Show the numbers | Year | Generative AI · visits | | ---- | ---------------------- | | 2023 | 561,844 | | 2024 | 949,100 | | 2025 | 939,238 | | 2026 | 294,748 | Encyclopedia visits a year. 2026 runs to 2026-08. ## Digital twins · visits Show the numbers | Year | Digital twins · visits | | ---- | ---------------------- | | 2017 | 51,601 | | 2018 | 163,210 | | 2019 | 224,792 | | 2020 | 241,048 | | 2021 | 270,726 | | 2022 | 257,797 | | 2023 | 204,803 | | 2024 | 276,219 | | 2025 | 176,899 | | 2026 | 83,070 | Encyclopedia visits a year. 2026 runs to 2026-08. ## Simulation hypothesis · papers Show the numbers | Year | Simulation hypothesis · papers | | ---- | ------------------------------ | | 2003 | 2 | | 2004 | 2 | | 2005 | 3 | | 2006 | 6 | | 2007 | 8 | | 2008 | 4 | | 2009 | 5 | | 2010 | 5 | | 2011 | 10 | | 2012 | 6 | | 2013 | 11 | | 2014 | 7 | | 2015 | 9 | | 2016 | 12 | | 2017 | 12 | | 2018 | 14 | | 2019 | 22 | | 2020 | 19 | | 2021 | 27 | | 2022 | 17 | | 2023 | 29 | | 2024 | 35 | | 2025 | 92 | | 2026 | 291 | Papers a year using “simulation hypothesis” in the title or abstract. ## Digital twins · papers Show the numbers | Year | Digital twins · papers | | ---- | ---------------------- | | 2010 | 4 | | 2011 | 3 | | 2012 | 10 | | 2013 | 5 | | 2014 | 11 | | 2015 | 13 | | 2016 | 43 | | 2017 | 129 | | 2018 | 493 | | 2019 | 1,301 | | 2020 | 2,371 | | 2021 | 4,228 | | 2022 | 6,334 | | 2023 | 9,513 | | 2024 | 13,036 | | 2025 | 22,180 | | 2026 | 32,175 | Papers a year using “digital twin” in the title or abstract. ## World models · papers Show the numbers | Year | World models · papers | | ---- | --------------------- | | 2000 | 98 | | 2001 | 157 | | 2002 | 288 | | 2003 | 214 | | 2004 | 186 | | 2005 | 227 | | 2006 | 219 | | 2007 | 204 | | 2008 | 206 | | 2009 | 246 | | 2010 | 266 | | 2011 | 264 | | 2012 | 268 | | 2013 | 257 | | 2014 | 265 | | 2015 | 283 | | 2016 | 233 | | 2017 | 266 | | 2018 | 286 | | 2019 | 299 | | 2020 | 357 | | 2021 | 357 | | 2022 | 374 | | 2023 | 533 | | 2024 | 803 | | 2025 | 1,744 | | 2026 | 5,352 | Papers a year using “world model” in the title or abstract. ## AI-generated · papers Show the numbers | Year | AI-generated · papers | | ---- | --------------------- | | 2010 | 1 | | 2011 | 3 | | 2012 | 1 | | 2013 | 2 | | 2014 | 1 | | 2015 | 6 | | 2016 | 8 | | 2017 | 6 | | 2018 | 24 | | 2019 | 75 | | 2020 | 140 | | 2021 | 208 | | 2022 | 295 | | 2023 | 1,752 | | 2024 | 4,867 | | 2025 | 13,032 | | 2026 | 22,260 | Papers a year using “AI-generated” in the title or abstract. ## Synthetic data · papers Show the numbers | Year | Synthetic data · papers | | ---- | ----------------------- | | 2000 | 250 | | 2001 | 283 | | 2002 | 537 | | 2003 | 524 | | 2004 | 573 | | 2005 | 637 | | 2006 | 850 | | 2007 | 875 | | 2008 | 945 | | 2009 | 1,028 | | 2010 | 1,111 | | 2011 | 1,253 | | 2012 | 1,300 | | 2013 | 1,422 | | 2014 | 1,558 | | 2015 | 1,620 | | 2016 | 1,818 | | 2017 | 2,001 | | 2018 | 2,272 | | 2019 | 2,772 | | 2020 | 3,214 | | 2021 | 3,913 | | 2022 | 4,379 | | 2023 | 5,402 | | 2024 | 7,243 | | 2025 | 10,796 | | 2026 | 12,775 | Papers a year using “synthetic data” in the title or abstract. ## Whole brain emulation · papers Show the numbers | Year | Whole brain emulation · papers | | ---- | ------------------------------ | | 2008 | 1 | | 2010 | 1 | | 2011 | 1 | | 2012 | 7 | | 2013 | 5 | | 2014 | 3 | | 2015 | 6 | | 2016 | 2 | | 2017 | 7 | | 2018 | 6 | | 2019 | 4 | | 2020 | 3 | | 2021 | 3 | | 2022 | 7 | | 2023 | 2 | | 2024 | 7 | | 2025 | 13 | | 2026 | 47 | Papers a year using “whole brain emulation” in the title or abstract. ## Belief ## Belief in the simulation hypothesis **No repeated measurement.** There is no survey of the public, or of any profession, that has asked whether we live in a simulation in two different years. So there is no trend to draw, and this page does not draw one. measured **Philosophers, 2020.** The largest survey of professional philosophers had no question about simulation. The nearest is about the outside world: 79.5% chose non-sceptical realism, that it exists and we can know it. A well-made simulation would get the same answer. measured **Unsourced figures.** A “22% of adults” figure and older claims about a television network’s poll are widely repeated; neither could be traced to a real poll, so neither is used here. The interest charts above stand in as proxies: public lookups of the idea and scholarly publication on it. wild guess ## How this page is counted * A scenario is the logistic curve written in log10: growth _r_ a year, levelling off towards a ceiling _C_. From 10^21 in 2025, the level in year _t_ is _C_ − log\_10(1 + (10_C_−21 − 1) · (1 + _r_)−(_t_−2025)). * Each ceiling is a power supply times an efficiency: Earth’s grid (about 3.5 × 10^12 W) at today’s best 7 × 10^10 FLOPS per watt; 1% of the sunlight reaching Earth, or the Sun’s whole output, at Landauer’s limit (1 / 2.87 × 10^−21 operations per joule); Earth’s mass at Lloyd’s bound. * Finish lines are the sandbox presets, measured by the same engine as the rest of the site. [The method](https://simulation-hypothesis.com/method) lists every constant. * An operation, a FLOP and an erased bit are counted as one unit, as elsewhere on this site. This overstates the ceilings by a factor of about 10^3 to 10^4. Sources * TOP500 and Green500 lists (top500.org), June 1993 to June 2026. * Hilbert & López, Science 332 (2011): the world’s general-purpose computing, 1986 to 2007. * Koomey, Berard, Sanchez & Wong, IEEE Annals of the History of Computing (2011): computations per kilowatt-hour. * Epoch AI, data on frontier AI models; Sevilla et al. (2022), “Compute Trends Across Three Eras of Machine Learning”; Sevilla & Roldán (2024) on 4 to 5 times a year. * Hernandez & Brown (2020): 44 times less compute for the same image-recognition result, 2012 to 2019\. Ho et al. (2024): language models need half the compute for the same result about every 8 months. * Masanet et al., Science 367 (2020); International Energy Agency, “Energy and AI” (2025). * White et al. (1986); Winding et al. (2023); Dorkenwald et al. (2024); Shapson-Coe et al. (2024); the MICrONS consortium (2025). * Bourget & Chalmers, the 2020 PhilPapers survey. * Interest data fetched 2026-09-28 from Wikimedia pageviews (English Wikipedia, human traffic) and OpenAlex (title and abstract phrase search). Copy the link Save the card Link format The whole state of this page lives in its link, so a link can be written by hand, by a script or by an agent. Parameters for `/countdown`: * `g`: annual growth in computing, in percent. integer `5` to `100` * `c`: physical ceiling the growth levels off at. `grid`, `sunlight`, `sun`, `earth-mass` Example: [https://simulation-hypothesis.com/countdown?g=35&c=sunlight](https://simulation-hypothesis.com/countdown?g=35&c=sunlight). The same for every tool, and the site’s open data, at . --- title: "What a computer can run · Given a computer, what world can it run? · Simulation Hypothesis" url: https://simulation-hypothesis.com/budget description: "The totals run backwards. Pick a machine, from a phone to every kilogram of the observable universe computing at the physical limit." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # What a computer can run · the computing totals, run backwards Pick a computer and this page lists the richest world it can run. For every extent, it shows the finest matter floor the computer can handle. The other dials stay at the [Sandbox](https://simulation-hypothesis.com/sandbox) baseline: everyone alive is a fully computed mind at functional detail, and time runs forward from 1900\. Every cell opens in the Sandbox with that setup. ## The computer phone laptop AI accelerator biggest supercomputer every computer on Earth Dyson-swarm data centre Sun of Landauer-limit chips Earth-mass ultimate computer Jupiter brain Sun-mass ultimate computer galaxy-mass ultimate computer universe-computer Or any amount of computing **10^21 FLOPS** · every computer on Earth rough Everything computed, always Only what some mind observes ## The richest world it runs The largest world it can run is **one room**, down to **tissue**. Atom by atom, it runs nothing, not even one brain. * Observable universe can’t run at any floor * Milky Way can’t run at any floor * Solar system can’t run at any floor * Earth can’t run at any floor * One room [down to tissue · 10^18 FLOPS](https://simulation-hypothesis.com/sandbox?sc=room&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion) * One brain [down to cell · 1.1 × 10^18 FLOPS](https://simulation-hypothesis.com/sandbox?sc=brain&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion) ## Every extent at every floor Each cell is the computing that world needs. Filled cells are ones this computer can run. The finest one it can run on each row is outlined. | Extent | Painted set | Organ | Tissue | Cell | Organelle | Protein | Molecule | Atom | Particle | Quark | Quantum, mean field | Quantum, fully entangled | | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | One brain | [18](https://simulation-hypothesis.com/sandbox?sc=brain&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Painted set: 10^18 FLOPS") | [18](https://simulation-hypothesis.com/sandbox?sc=brain&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Organ: 10^18 FLOPS") | [18](https://simulation-hypothesis.com/sandbox?sc=brain&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Tissue: 10^18 FLOPS") | [18](https://simulation-hypothesis.com/sandbox?sc=brain&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Cell: 1.1 × 10^18 FLOPS") | [24](https://simulation-hypothesis.com/sandbox?sc=brain&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Organelle: 1.4 × 10^24 FLOPS") | [34](https://simulation-hypothesis.com/sandbox?sc=brain&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Protein: 1.4 × 10^34 FLOPS") | [43](https://simulation-hypothesis.com/sandbox?sc=brain&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Molecule: 6.0 × 10^42 FLOPS") | [44](https://simulation-hypothesis.com/sandbox?sc=brain&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Atom: 1.2 × 10^44 FLOPS") | [47](https://simulation-hypothesis.com/sandbox?sc=brain&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Particle: 1.3 × 10^47 FLOPS") | [54](https://simulation-hypothesis.com/sandbox?sc=brain&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Quark: 3.0 × 10^54 FLOPS") | [55](https://simulation-hypothesis.com/sandbox?sc=brain&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Quantum, mean field: 1.3 × 10^55 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=brain&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One brain, Quantum, fully entangled: off the scale") | | One room | [18](https://simulation-hypothesis.com/sandbox?sc=room&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Painted set: 10^18 FLOPS") | [18](https://simulation-hypothesis.com/sandbox?sc=room&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Organ: 10^18 FLOPS") | [18](https://simulation-hypothesis.com/sandbox?sc=room&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Tissue: 10^18 FLOPS") | [21](https://simulation-hypothesis.com/sandbox?sc=room&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Cell: 10^21 FLOPS") | [28](https://simulation-hypothesis.com/sandbox?sc=room&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Organelle: 10^28 FLOPS") | [38](https://simulation-hypothesis.com/sandbox?sc=room&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Protein: 10^38 FLOPS") | [46](https://simulation-hypothesis.com/sandbox?sc=room&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Molecule: 1.5 × 10^46 FLOPS") | [47](https://simulation-hypothesis.com/sandbox?sc=room&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Atom: 3.0 × 10^47 FLOPS") | [51](https://simulation-hypothesis.com/sandbox?sc=room&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Particle: 9.0 × 10^50 FLOPS") | [58](https://simulation-hypothesis.com/sandbox?sc=room&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Quark: 2.1 × 10^58 FLOPS") | [59](https://simulation-hypothesis.com/sandbox?sc=room&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Quantum, mean field: 9.0 × 10^58 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=room&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "One room, Quantum, fully entangled: off the scale") | | Earth | [28](https://simulation-hypothesis.com/sandbox?sc=earth&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Painted set: 8.2 × 10^27 FLOPS") | [29](https://simulation-hypothesis.com/sandbox?sc=earth&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Organ: 1.3 × 10^29 FLOPS") | [32](https://simulation-hypothesis.com/sandbox?sc=earth&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Tissue: 3.0 × 10^32 FLOPS") | [42](https://simulation-hypothesis.com/sandbox?sc=earth&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Cell: 6.0 × 10^41 FLOPS") | [49](https://simulation-hypothesis.com/sandbox?sc=earth&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Organelle: 6.0 × 10^48 FLOPS") | [59](https://simulation-hypothesis.com/sandbox?sc=earth&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Protein: 6.0 × 10^58 FLOPS") | [67](https://simulation-hypothesis.com/sandbox?sc=earth&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Molecule: 6.6 × 10^66 FLOPS") | [68](https://simulation-hypothesis.com/sandbox?sc=earth&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Atom: 1.3 × 10^68 FLOPS") | [72](https://simulation-hypothesis.com/sandbox?sc=earth&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Particle: 5.4 × 10^71 FLOPS") | [79](https://simulation-hypothesis.com/sandbox?sc=earth&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Quark: 1.2 × 10^79 FLOPS") | [80](https://simulation-hypothesis.com/sandbox?sc=earth&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Quantum, mean field: 5.4 × 10^79 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=earth&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Earth, Quantum, fully entangled: off the scale") | | Solar system | [28](https://simulation-hypothesis.com/sandbox?sc=solar&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Painted set: 8.2 × 10^27 FLOPS") | [35](https://simulation-hypothesis.com/sandbox?sc=solar&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Organ: 4.0 × 10^34 FLOPS") | [38](https://simulation-hypothesis.com/sandbox?sc=solar&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Tissue: 10^38 FLOPS") | [47](https://simulation-hypothesis.com/sandbox?sc=solar&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Cell: 2.0 × 10^47 FLOPS") | [54](https://simulation-hypothesis.com/sandbox?sc=solar&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Organelle: 2.0 × 10^54 FLOPS") | [64](https://simulation-hypothesis.com/sandbox?sc=solar&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Protein: 2.0 × 10^64 FLOPS") | [74](https://simulation-hypothesis.com/sandbox?sc=solar&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Molecule: 6.0 × 10^73 FLOPS") | [75](https://simulation-hypothesis.com/sandbox?sc=solar&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Atom: 1.2 × 10^75 FLOPS") | [77](https://simulation-hypothesis.com/sandbox?sc=solar&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Particle: 2.2 × 10^77 FLOPS") | [85](https://simulation-hypothesis.com/sandbox?sc=solar&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Quark: 4.6 × 10^84 FLOPS") | [85](https://simulation-hypothesis.com/sandbox?sc=solar&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Quantum, mean field: 2.2 × 10^85 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=solar&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Solar system, Quantum, fully entangled: off the scale") | | Milky Way | [34](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Painted set: 8.2 × 10^33 FLOPS") | [45](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Organ: 2.4 × 10^45 FLOPS") | [49](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Tissue: 6.0 × 10^48 FLOPS") | [58](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Cell: 1.2 × 10^58 FLOPS") | [65](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Organelle: 1.2 × 10^65 FLOPS") | [75](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Protein: 1.2 × 10^75 FLOPS") | [85](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Molecule: 3.5 × 10^84 FLOPS") | [86](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Atom: 7.0 × 10^85 FLOPS") | [88](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Particle: 1.3 × 10^88 FLOPS") | [95](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Quark: 2.8 × 10^95 FLOPS") | [96](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Quantum, mean field: 1.3 × 10^96 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=galaxy&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Milky Way, Quantum, fully entangled: off the scale") | | Observable universe | [45](https://simulation-hypothesis.com/sandbox?sc=universe&fi=0&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Painted set: 1.6 × 10^45 FLOPS") | [57](https://simulation-hypothesis.com/sandbox?sc=universe&fi=1&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Organ: 3.0 × 10^57 FLOPS") | [61](https://simulation-hypothesis.com/sandbox?sc=universe&fi=2&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Tissue: 7.5 × 10^60 FLOPS") | [70](https://simulation-hypothesis.com/sandbox?sc=universe&fi=3&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Cell: 1.5 × 10^70 FLOPS") | [77](https://simulation-hypothesis.com/sandbox?sc=universe&fi=4&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Organelle: 1.5 × 10^77 FLOPS") | [87](https://simulation-hypothesis.com/sandbox?sc=universe&fi=5&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Protein: 1.5 × 10^87 FLOPS") | [97](https://simulation-hypothesis.com/sandbox?sc=universe&fi=6&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Molecule: 5.0 × 10^96 FLOPS") | [98](https://simulation-hypothesis.com/sandbox?sc=universe&fi=7&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Atom: 10^98 FLOPS") | [100](https://simulation-hypothesis.com/sandbox?sc=universe&fi=8&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Particle: 1.7 × 10^100 FLOPS") | [108](https://simulation-hypothesis.com/sandbox?sc=universe&fi=9&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Quark: 3.5 × 10^107 FLOPS") | [108](https://simulation-hypothesis.com/sandbox?sc=universe&fi=10&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Quantum, mean field: 1.7 × 10^108 FLOPS") | [∞](https://simulation-hypothesis.com/sandbox?sc=universe&fi=11&lb=multi&co=10&mm=functional&ob=100&tm=linear&sy=1900&su=natural&fw=illusion "Observable universe, Quantum, fully entangled: off the scale") | Numbers are powers of ten: 68 means 10^68 FLOPS. At molecule and finer floors the brains are already computed as matter, so minds add nothing. ## Or minds alone Human brains with no world around them. This is how many the computer can run in real time, at each level of detail. | Scripted | 10^15 | | ----------- | ------- | | Functional | 1,000 | | Biophysical | not one | | Molecular | not one | | Quantum | not one | For scale, about 8.2 billion people are alive. --- title: "Simulations within simulations · How deep can a stack of simulations go? · Simulation Hypothesis" url: https://simulation-hypothesis.com/nesting description: "Build a stack of worlds, each running the next. A simulated computer can never out-compute the world it runs in, so every layer has less than the one above." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations within simulations · where the stack stops Everything a simulated computer does is computed by the machine running its world. So a nested simulation can use at most a share of its parent’s computing, and never more than its world’s matter could compute at Lloyd’s bound. Every layer has less computing than the world that runs it. If the parent world is resolved atom by atom, nesting adds nothing to the base reality’s total. A computer built inside it is ordinary matter, and that’s already counted. If the parent is coarser, nothing inside it can compute. Then the operator has to run the inner simulation separately, on its own computing. Other dials stay at the [Sandbox](https://simulation-hypothesis.com/sandbox) baseline. ## The share each world uses Share of a world’s computing used to run the simulation inside it: **1%** wild guess At 100%, a world does nothing but run the next one down. Our own civilisation uses a tiny fraction of its matter for computing. ## The stack 1. Base reality Physics like ours: 1% of every kilogram in the observable universe at Lloyd’s bound, 8.1 × 10^101 FLOPS. 2. Layer 1 One brainOne roomEarthSolar systemMilky WayObservable universePainted setOrganTissueCellOrganelleProteinMoleculeAtomParticleQuarkQuantum, mean fieldQuantum, fully entangled needs 1.3 × 10^68 FLOPS; the base reality allows 8.1 × 10^101 FLOPS. **Runs.** 3. Layer 2 One brainOne roomEarthSolar systemMilky WayObservable universePainted setOrganTissueCellOrganelleProteinMoleculeAtomParticleQuarkQuantum, mean fieldQuantum, fully entangled needs 6.0 × 10^41 FLOPS; its parent allows 1.3 × 10^66 FLOPS (its share of the parent’s computing). **Runs.** 4. Layer 3 One brainOne roomEarthSolar systemMilky WayObservable universePainted setOrganTissueCellOrganelleProteinMoleculeAtomParticleQuarkQuantum, mean fieldQuantum, fully entangled needs 10^21 FLOPS; the base reality allows 8.1 × 10^101 FLOPS. **Runs.** Its parent is coarser than atoms and can’t contain a computer, so the base reality runs this layer directly. Add a layer Remove the last ## What the base reality runs The stack runs **3 layers** deep. The base reality has to supply **1.3 × 10^68 FLOPS**, for 2 layers computed separately. A layer resolved at atom detail or finer can contain working computers. These numbers come from the Sandbox engine, with everyone alive computed as a functional mind and time running from 1900\. The share is a wild guess. The ceilings are textbook physics. --- title: "The computing in one day · How much computing would one day of a life take? · Simulation Hypothesis" url: https://simulation-hypothesis.com/bill description: "An ordinary day, itemised: the computing it takes to simulate one person’s day, rendering only what that person perceives." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # The computing in one day · how much computing it takes to simulate one day of one life Describe a day and the receipt lists the computing it takes to simulate it for one observer. We only render what that observer perceives. The constants are the same as in the [Sandbox](https://simulation-hypothesis.com/sandbox). ## Your day Awake 16 h Outside 1 h On screens 5 h Talked to 6 people Looked at the night sky Matter near you is computed as Painted setTissueCellAtomParticleQuark Every atom tracked on its own, using classical physics. Your mind is computed as ScriptedFunctionalBiophysicalMolecularQuantumReal brain, outside SIMULATION HYPOTHESIS computing needed · one observer · one day * Your mind 8.6 × 10^22 Functional model, all day. Sleep counts at the same rate, since the brain stays active. rough * Your body 1.8 × 10^50 At the atom floor, since you perceive the whole body. rough * Everything within reach 1.7 × 10^55 About a building’s worth of matter near the observer, at the atom floor, while awake. wild guess * Everything seen but not touched 5.8 × 10^17 Painted: just a surface, with nothing inside until an observer gets close. rough * 6 conversations 7.2 × 10^16 Faces and voices, twenty minutes each. Their minds aren’t counted here. They’d be counted in their own days. wild guess * Screens 1.8 × 10^17 A render inside the render. Whatever shows on a screen has to be rendered too. rough * Sky and weather 3.6 × 10^18 The air out to the horizon, run as a regional weather model, while you’re outside. rough Not rendered today * While you slept −8.6 × 10^54 None of the matter outside the observer’s head needed rendering. * The inside of the Earth −1.5 × 10^73 The rest of the planet. Nobody observed any of it. * The far side of the Moon −9.5 × 10^70 Nobody observed it, so it isn’t rendered. * Everything past the Moon −3.9 × 10^101 Shown as a painted backdrop. TOTAL 1.7 × 10^55 operations * Biggest line: everything within reach. * Peak: 3.0 × 10^50 FLOPS, about 2,200 × a Sun of Landauer-limit chips. textbook * That’s 2.0 × 10^29 days of every computer on Earth running flat out. rough * At the thermodynamic floor: 5.0 × 10^34 joules, 1.3 × 10^8 seconds of the Sun’s entire output. textbook * On today’s hardware: 2.4 × 10^44 joules, 6.1 × 10^17 seconds of the Sun’s entire output. rough Counts are in operations. All estimates are on a log scale. Copy the link Save the card Start again Link format The whole state of this page lives in its link, so a link can be written by hand, by a script or by an agent. Parameters for `/bill`: * `aw`: hours awake. `0` to `24`, in steps of `0.5` * `ou`: hours outside. `0` to `24`, in steps of `0.5` * `sc`: hours on screens. `0` to `24`, in steps of `0.5` * `pe`: people talked to. integer `0` to `200` * `fl`: matter floor near the observer. `painted`, `tissue`, `cell`, `atom`, `particle`, `quark` * `mm`: how the observer’s mind is computed. `scripted`, `functional`, `biophysical`, `molecular`, `quantum`, `outside` * `sk`: optional: looked at the night sky. `1` Example: [https://simulation-hypothesis.com/bill?aw=16&ou=1&sc=5&pe=6&fl=atom&mm=functional](https://simulation-hypothesis.com/bill?aw=16&ou=1&sc=5&pe=6&fl=atom&mm=functional). The same for every tool, and the site’s open data, at . ## How it’s counted * One observer, one day, and only what that observer perceives. Everything else is rendered as scenery, the cheapest option the Sandbox has. * The mind runs all day at the rate of the model you pick. The rates come from the whole-brain emulation roadmap of Sandberg and Bostrom (2008). * We assume the matter within reach is 10^7 kg (a wild guess), computed at the floor you pick. The body is always computed at that floor. While you sleep, the matter around you isn’t rendered. * Other people’s minds aren’t counted here. If they’re simulated, their computing belongs to their own days. * The savings are the computing we skip for matter nobody perceived, at the same floor. That’s what rendering on demand saves. --- title: "Mind assessment · Check a system against the evidence · Simulation Hypothesis" url: https://simulation-hypothesis.com/score description: "Mark the properties of an animal or an AI system against the published criteria for sentience (Birch et al. 2021) and consciousness (Butlin et al. 2023)." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Mind assessment · a system assessed against published criteria No test can show that a system is conscious. What we have are checklists of properties that the evidence, or the leading theories, link to experience. Pick a checklist, mark the properties the system has, and read the result the way the source would. An animal: sentience criteria An AI system: consciousness indicators The eight criteria from [Birch and colleagues (2021)](https://simulation-hypothesis.com/entities/sentience), the review behind the UK’s decision to recognise decapod crustaceans and cephalopod molluscs as sentient. Start from one of its published findings, or mark your own. Published finding: none (mark your own)OctopodsCuttlefishOther coleoids (squid)NautiloidsTrue crabs (Brachyura)Anomuran crabsAstacid lobsters/crayfishSpiny lobstersCaridean shrimpsPenaeid shrimps Criteria met * 1 The animal possesses receptors sensitive to noxious stimuli (nociceptors) * 2 The animal possesses integrative brain regions capable of integrating information from different sensory sources * 3 The animal possesses neural pathways connecting the nociceptors to the integrative brain regions * 4 The animal's behavioural response to a noxious stimulus is modulated by chemical compounds affecting the nervous system (e.g. local anaesthetics, analgesics, opioid-type systems) * 5 The animal shows motivational trade-offs, in which the disvalue of a noxious or threatening stimulus is weighed against the value of an opportunity for reward, leading to flexible decision-making * 6 The animal shows flexible self-protective behaviour (e.g. wound-tending, guarding, grooming, rubbing) of a type likely to involve representing the bodily location of an injury or noxious stimulus * 7 The animal shows associative learning in which noxious stimuli become associated with neutral stimuli, and/or novel ways of avoiding noxious stimuli are learned through reinforcement (habituation and sensitisation do not count) * 8 The animal shows that it values a putative analgesic or anaesthetic when injured (e.g. self-administers it, or learns to prefer a location where it is available) ## Result **0 of 8** criteria met The review’s grading would call this **sentience unknown or unlikely**. A checklist describes evidence. It doesn’t settle whether anything is felt. Copy the link Save the card Link format The whole state of this page lives in its link, so a link can be written by hand, by a script or by an agent. Parameters for `/score`: * `m`: mode. `n` animal (sentience criteria), `a` AI system (consciousness indicators) * `b`: one digit per criterion, in order, \`1\` met and \`0\` not met. 8 digits in animal mode, 14 in AI mode. Animal criteria, in order: (1) The animal possesses receptors sensitive to noxious stimuli (nociceptors) (2) The animal possesses integrative brain regions capable of integrating information from different sensory sources (3) The animal possesses neural pathways connecting the nociceptors to the integrative brain regions (4) The animal's behavioural response to a noxious stimulus is modulated by chemical compounds affecting the nervous system (e.g. local anaesthetics, analgesics, opioid-type systems) (5) The animal shows motivational trade-offs, in which the disvalue of a noxious or threatening stimulus is weighed against the value of an opportunity for reward, leading to flexible decision-making (6) The animal shows flexible self-protective behaviour (e.g. wound-tending, guarding, grooming, rubbing) of a type likely to involve representing the bodily location of an injury or noxious stimulus (7) The animal shows associative learning in which noxious stimuli become associated with neutral stimuli, and/or novel ways of avoiding noxious stimuli are learned through reinforcement (habituation and sensitisation do not count) (8) The animal shows that it values a putative analgesic or anaesthetic when injured (e.g. self-administers it, or learns to prefer a location where it is available) AI indicators, in order: RPT-1, RPT-2, GWT-1, GWT-2, GWT-3, GWT-4, HOT-1, HOT-2, HOT-3, HOT-4, AST-1, PP-1, AE-1, AE-2 * `p`: optional: a published row of the 2021 review, animal mode only. `0` Octopods, `1` Cuttlefish, `2` Other coleoids (squid), `3` Nautiloids, `4` True crabs (Brachyura), `5` Anomuran crabs, `6` Astacid lobsters/crayfish, `7` Spiny lobsters, `8` Caridean shrimps, `9` Penaeid shrimps Example: [https://simulation-hypothesis.com/score?m=a&b=11110000000000](https://simulation-hypothesis.com/score?m=a&b=11110000000000). The same for every tool, and the site’s open data, at . --- title: "The Matrix · a universe that takes 8.2 × 10³¹ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/sleepers description: "Present-day Earth with billions of fully computed minds, drawn in only where someone is looking." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)1/9 # The Matrix · Present-day Earth with billions of fully computed minds, drawn in only where someone is looking. Open in the sandbox ▸ The world of the film The Matrix, with one change: the sleepers’ minds are computed too, not real brains in pods. A present-day Earth that’s drawn in consistently wherever anyone looks. Billions of people live in it without knowing it’s a simulation, and a few suspect it. Suffering is higher than what we see, and it helps keep things stable. Choices are fixed by earlier causes, but they feel free. Required computing power rough 8.2 × 10^31 FLOPS Our computers could run this between 2097 and 2127, if steady growth runs a fifth faster or slower (2109 at the central rate). [The countdown ▸](https://simulation-hypothesis.com/countdown) More than every computer on Earth put together, by a factor of about 10^11. Computer sizerough 10¹¹ × every computer on Earth Servers, personal computers, phones and consoles added together. Feasibility Beyond all existing hardware More than every computer on Earth combined. Universe-computerstextbook 10^-72 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 240 GW The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. A fraction of a national power grid, at the thermodynamic minimum for erasing bits. On every computer on Earthrough 2,598 years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 2,598 years of all Earth’s computing for every simulated second. World actually computedwild guess 0.071637% 1.4 × 10^-6% of the mass is watched by 8.2 billion observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * If you can’t tell the difference, does it matter? * Does knowing you’re simulated change what you owe anyone? * Is suffering justified if it keeps the illusion stable? * Should the ones who suspect tell everyone else, or let them be? “Worked out a world with more suffering than ours: 8.2 × 10^31 FLOPS. Suffering isn’t what takes the computing.” ## Report card Instance report PAINTED SURFACES, FULL MINDS Settings Scale Earth Matter floor Painted set Lobby Real and scripted minds Inner lives 8.2 billion · biophysical Computed 0.071637% Time Linear, live from 1996 Slot A scripted character that detects the seams Computing needed 8.2 × 10^31 FLOPS Computer size 10¹¹ × every computer on Earth Universe-computers 10^-72 Feasibility Beyond all existing hardware Judged, not measured The author’s reading. None of these changes the computing total. Suffering Raised Free will Feels free Utilitarian leans against Deontological leans against Virtue ethics leans against Existentialist leans against “Worked out a world with more suffering than ours: 8.2 × 10^31 FLOPS. Suffering isn’t what takes the computing.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 8.2 × 10^22 FLOPS Only surfaces are computed, and only where someone is looking. Anything unobserved is just a stored value. Mind computingrough 8.2 × 10^31 FLOPS Sandberg & Bostrom 2008, level 5 8.2 billion minds, each computed as a biophysical model. Next to the matter, they’re a small part of the total. Inner liveswild guess 8.2 billion 8.2 billion real minds. 4.5 × 10^20 organisms left as scenery. Operations so farrough 7.8 × 10^40 30 years on the clock, at 8.2 × 10^31 per second. History that is only storedrough 99.9999998% Computing begins in 1996\. 5.77 billion humans are present at the start, with preinstalled memories. [◂ The Afterlife](https://simulation-hypothesis.com/builds/afterlife)Open in the sandbox ▸ [Brain in a Vat ▸](https://simulation-hypothesis.com/builds/vat) --- title: "Brain in a Vat · a universe that takes 8.2 × 10¹⁵ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/vat description: "A real brain in base reality. Only its world is computed, and everyone else is scripted." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)2/9 # Brain in a Vat · A real brain in base reality. Only its world is computed, and everyone else is scripted. Open in the sandbox ▸ A real brain, kept alive in a vat in base reality and wired to a computer. The brain isn’t simulated. Its own neurons do the thinking. The computer supplies everything it senses and responds to everything it does. That means a present-day Earth, drawn in only where the brain looks, with every other person scripted. Only the world counts toward the total, which makes this the cheapest build in the sandbox. Required computing power rough 8.2 × 10^15 FLOPS Our computers could run this today. [The countdown ▸](https://simulation-hypothesis.com/countdown) Data-centre scale. Our computers already run this. Computer sizerough 8 × one AI accelerator One of today’s data-centre accelerators at low precision. Training a large language model takes thousands of them. Feasibility Possible today Data-centre territory: a rented GPU cluster would do. Universe-computerstextbook 10^-88 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 0.000024 W The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. At the thermodynamic minimum, a wall socket would do. On every computer on Earthrough faster than real time How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. Real time, on computers we have today. World actually computedwild guess 1.7 × 10^-16% 1.7 × 10^-16% of the mass is watched by one observer. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * If only one mind really exists, does ethics still apply? * How could you know that other people are real? * Can meaning be built from input alone? * If a memory is of something that never happened, is it still yours? “Worked out a brain in a vat: a real brain in base reality, with only its world computed. 8.2 × 10^15 FLOPS, or 8 × one AI accelerator.” ## Report card Instance report A BRAIN IN A VAT Settings Scale Earth Matter floor Painted set Lobby Single player Inner lives 8.2 billion · real brain, outside Computed 1.7 × 10^-16% Time Linear, live from 1996 Slot A player Computing needed 8.2 × 10^15 FLOPS Computer size 8 × one AI accelerator Universe-computers 10^-88 Feasibility Possible today Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Feels free Utilitarian divided Deontological divided Virtue ethics divided Existentialist leans against “Worked out a brain in a vat: a real brain in base reality, with only its world computed. 8.2 × 10^15 FLOPS, or 8 × one AI accelerator.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 10^13 FLOPS Only surfaces are computed, and only where someone is looking. Anything unobserved is just a stored value. Mind computingwild guess 8.2 × 10^15 FLOPS none, by definition: the brain runs on its own neurons, outside the simulation One real brain in base reality, which does its own thinking, and 8.2 billion scripted characters. Inner liveswild guess 8.2 billion 1 real mind, 8.2 billion scripted, 4.5 × 10^20 animals as scenery. Operations so farrough 7.8 × 10^24 30 years on the clock, at 8.2 × 10^15 per second. History that is only storedrough 99.9999998% Computing begins in 1996\. 5.77 billion humans are present at the start, with preinstalled memories. [◂ The Matrix](https://simulation-hypothesis.com/builds/sleepers)Open in the sandbox ▸ [Solipsism ▸](https://simulation-hypothesis.com/builds/solipsism) --- title: "Solipsism · a universe that takes 10¹⁸ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/solipsism description: "One real mind. The world is only as detailed as that mind can test. Only one mind is real." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)3/9 # Solipsism · One real mind. The world is only as detailed as that mind can test. Open in the sandbox ▸ Only one mind is real. The world is drawn in around wherever it’s paying attention, and goes back to stored values everywhere else. The detail only goes as deep as that mind’s instruments can test. Open a drawer and there’s an inside. Use a microscope and there are cells. Every other person is scripted. Required computing power rough 10^18 FLOPS Our computers could run this today. [The countdown ▸](https://simulation-hypothesis.com/countdown) Supercomputer scale. Big, expensive, and already built. Computer sizemeasured the biggest supercomputer Exascale class. It fills a building. Feasibility Possible at national scale Supercomputer territory: large, but it exists. Universe-computerstextbook 1.2 × 10^-86 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 0.0029 W The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. At the thermodynamic minimum, a wall socket would do. On every computer on Earthrough faster than real time How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. Real time, on computers we have today. World actually computedwild guess 1.7 × 10^-16% 1.7 × 10^-16% of the mass is watched by one observer. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * Are other people real, or just convincing? * If nobody else is conscious, is anything allowed? * Does looking at something actually bring it into existence? * If you’re the only real mind, are you alone? “Worked out a world that’s only drawn in where one mind looks: 10^18 FLOPS.” ## Report card Instance report ONE MIND, DRAWN-IN SURROUNDINGS Settings Scale Earth Matter floor Painted set Lobby Single player Inner lives 8.2 billion · functional Computed 1.7 × 10^-16% Time Linear, live from 1996 Slot A player Computing needed 10^18 FLOPS Computer size the biggest supercomputer Universe-computers 1.2 × 10^-86 Feasibility Possible at national scale Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Genuinely free Utilitarian divided Deontological divided Virtue ethics leans for Existentialist leans for “Worked out a world that’s only drawn in where one mind looks: 10^18 FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 10^13 FLOPS Only surfaces are computed, and only where someone is looking. Anything unobserved is just a stored value. Mind computingrough 10^18 FLOPS Sandberg & Bostrom 2008, level 4 One fully computed functional mind and 8.2 billion scripted ones. Inner liveswild guess 8.2 billion 1 real mind, 8.2 billion scripted, 4.5 × 10^20 animals as scenery. Operations so farrough 9.5 × 10^26 30 years on the clock, at 10^18 per second. History that is only storedrough 99.9999998% Computing begins in 1996\. 5.77 billion humans are present at the start, with preinstalled memories. [◂ Brain in a Vat](https://simulation-hypothesis.com/builds/vat)Open in the sandbox ▸ [The 2050 Server ▸](https://simulation-hypothesis.com/builds/server-2050) --- title: "The 2050 Server · a universe that takes 1.8 × 10²⁴ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/server-2050 description: "Everyone on Earth, with only as many real minds as 2050’s computers can run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)4/9 # The 2050 Server · Everyone on Earth, with only as many real minds as 2050’s computers can run. Open in the sandbox ▸ A present-day Earth running on every computer humanity is on track to have in 2050, pooled into one machine. That’s enough for about 1.8 million real minds. The other 8.2 billion people are scripted, and you can’t tell which you are from the inside. Your odds of being one of the real minds are about 1 in 4,523. Required computing power rough 1.8 × 10^24 FLOPS Our computers could run this between 2046 and 2055, if steady growth runs a fifth faster or slower (2050 at the central rate). [The countdown ▸](https://simulation-hypothesis.com/countdown) All the chips humanity has ever made would be a small fraction of this. Computer sizerough 1,800 × every computer on Earth Servers, personal computers, phones and consoles added together. Feasibility Beyond all existing hardware More than every computer on Earth combined. Universe-computerstextbook 2.2 × 10^-80 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 5.2 kW The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. At the thermodynamic minimum, a wall socket would do. On every computer on Earthrough under a year per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. A few months of all Earth’s computing for every simulated second. World actually computedwild guess 3.0 × 10^-10% 3.0 × 10^-10% of the mass is watched by 1.8 million observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * If you met a real mind, how would you know? * Do we owe a scripted character the same care as a real mind? * Who decides which few million minds are real? * If you’re scripted, whose thoughts are these? “Worked out a world of full minds among painted surfaces: 1.8 × 10^24 FLOPS.” ## Report card Instance report PAINTED SURFACES, FULL MINDS Settings Scale Earth Matter floor Painted set Lobby Real and scripted minds Inner lives 8.2 billion · functional Computed 3.0 × 10^-10% Time Linear, live from 1996 Computing needed 1.8 × 10^24 FLOPS Computer size 1,800 × every computer on Earth Universe-computers 2.2 × 10^-80 Feasibility Beyond all existing hardware Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Genuinely free Utilitarian divided Deontological divided Virtue ethics leans for Existentialist leans for “Worked out a world of full minds among painted surfaces: 1.8 × 10^24 FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 1.8 × 10^19 FLOPS Only surfaces are computed, and only where someone is looking. Anything unobserved is just a stored value. Mind computingrough 1.8 × 10^24 FLOPS Sandberg & Bostrom 2008, level 4 1.8 million fully computed functional minds and 8.2 billion scripted ones. Your odds of being fully computed are about 1 in 4,523. Inner liveswild guess 8.2 billion 1.8 million real minds, 8.2 billion scripted, 4.5 × 10^20 animals as scenery. Operations so farrough 1.7 × 10^33 30 years on the clock, at 1.8 × 10^24 per second. History that is only storedrough 99.9999998% Computing begins in 1996\. 5.77 billion humans are present at the start, with preinstalled memories. [◂ Solipsism](https://simulation-hypothesis.com/builds/solipsism)Open in the sandbox ▸ [Local Universe ▸](https://simulation-hypothesis.com/builds/local) --- title: "Local Universe · a universe that takes 7.0 × 10⁸⁵ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/local description: "The Milky Way at atomic resolution, from the Big Bang. Everything we could plausibly reach, computed atom by atom from the starting state." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)5/9 # Local Universe · The Milky Way at atomic resolution, from the Big Bang. Open in the sandbox ▸ Everything we could plausibly reach, computed atom by atom from the starting state. Past the edge of the galaxy nothing is computed. It’s kept only as a probability distribution. Required computing power rough 7.0 × 10^85 FLOPS Never on one star’s power with ordinary logic, even at the thermodynamic floor. [The countdown ▸](https://simulation-hypothesis.com/countdown) That’s 8.6 × 10^-19 of one universe-computer, which is the whole observable universe running at its physical limit. Computer sizetextbook 65,000 × a Sun-mass ultimate computer A star turned into a computer. At Lloyd’s bound this takes 65,000 Suns of matter, all of it computing. Feasibility Beyond an Earth-mass computer More than a planet’s worth of matter could compute at the physical limit. Universe-computerstextbook 8.6 × 10^-19 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 5.2 × 10^38 Suns The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. 5.2 × 10^38 Suns of power at the Landauer floor, assuming perfect chips. The best real chips use about five billion times more energy than that. On every computer on Earthrough 2.2 × 10^57 years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 1.6 × 10^47 ages of the universe, on all of Earth’s computing, for every simulated second. World actually computedwild guess 100% 6.9 × 10^-17% of the mass is watched by 8.3 × 10^15 observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * Why does the simulation stop at the edge of the galaxy? * What does running something this big say about whoever runs it? * Are we important enough for atomic detail? * Is what we can’t observe a different kind of thing, or just not drawn in? “Worked out galaxy at atom resolution: 7.0 × 10^85 FLOPS, or 65,000 × a Sun-mass ultimate computer.” ## Report card Instance report ONE SIMULATED WORLD Settings Scale Milky Way Matter floor Atom Lobby Multiplayer Inner lives 8.3 × 10^15 · functional Computed 100% Time Linear, live from 1.4 × 10^10 yrs ago Computing needed 7.0 × 10^85 FLOPS Computer size 65,000 × a Sun-mass ultimate computer Universe-computers 8.6 × 10^-19 Feasibility Beyond an Earth-mass computer Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Dice Utilitarian leans for Deontological leans for Virtue ethics leans for Existentialist divided “Worked out galaxy at atom resolution: 7.0 × 10^85 FLOPS, or 65,000 × a Sun-mass ultimate computer.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 7.0 × 10^85 FLOPS 7.0 × 10^67 atom-sized units across galaxy, each updated every 1 fs. Mind computingrough rides along free At the atom floor, brains are already computed as matter. On their own they’d take 8.2 × 10^33. At this matter floor the brains are already computed as matter, so minds add nothing to the total. Inner liveswild guess 8.3 × 10^15 8.3 × 10^15 real minds. 4.5 × 10^26 organisms left as scenery. Operations so farrough 3.0 × 10^103 13.8 billion years on the clock, at 7.0 × 10^85 per second. History that is only storedrough 0% Computing begins 13.8 billion years ago. No humans are present at the start. [◂ The 2050 Server](https://simulation-hypothesis.com/builds/server-2050)Open in the sandbox ▸ [Universe Lite ▸](https://simulation-hypothesis.com/builds/lite) --- title: "Universe Lite · a universe that takes 5.8 × 10⁹¹ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/lite description: "The observable universe at molecular resolution, with half of it left out." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)6/9 # Universe Lite · The observable universe at molecular resolution, with half of it left out. Open in the sandbox ▸ The whole observable universe, simplified down to molecules, with half of it left out and every nervous system counted. Reality, but with detail thrown away. Required computing power rough 5.8 × 10^91 FLOPS Never on one star’s power with ordinary logic, even at the thermodynamic floor. [The countdown ▸](https://simulation-hypothesis.com/countdown) More than a computer with the mass of the Earth could do at the physical limit. Computer sizetextbook a galaxy-mass ultimate computer The Milky Way as a single computer. At Lloyd’s bound this takes 0.89 Milky Ways of matter, all of it computing. Feasibility Beyond an Earth-mass computer More than a planet’s worth of matter could compute at the physical limit. Universe-computerstextbook 7.1 × 10^-13 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 4.3 × 10^44 Suns The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. 4.3 × 10^44 Suns of power at the Landauer floor, assuming perfect chips. The best real chips use about five billion times more energy than that. On every computer on Earthrough 1.8 × 10^63 years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 1.3 × 10^53 ages of the universe, on all of Earth’s computing, for every simulated second. World actually computedwild guess 0.001155% 1.3 × 10^-8% of the mass is watched by 2.0 × 10^36 observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * What gets lost between atoms and molecules? * If mind is everywhere but thin, is it still mind? * Does leaving half of it out change what’s real? * Is choosing not to compute suffering a kindness, or a dodge? “Gave every nervous system an inner life. The minds barely change the total. The matter dominates: 5.8 × 10^91 FLOPS.” ## Report card Instance report EVERY NERVOUS SYSTEM COUNTED Settings Scale Observable universe Matter floor Molecule Lobby Multiplayer Inner lives 2.0 × 10^36 · functional Computed 0.001155% Time Linear, live from 1.4 × 10^10 yrs ago Computing needed 5.8 × 10^91 FLOPS Computer size a galaxy-mass ultimate computer Universe-computers 7.1 × 10^-13 Feasibility Beyond an Earth-mass computer Judged, not measured The author’s reading. None of these changes the computing total. Suffering Background hum Free will Dice Utilitarian leans for Deontological leans for Virtue ethics divided Existentialist divided “Gave every nervous system an inner life. The minds barely change the total. The matter dominates: 5.8 × 10^91 FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 5.8 × 10^91 FLOPS 5.0 × 10^79 molecule-sized units across universe, each updated every 10 fs. Mind computingrough rides along free At the molecule floor, brains are already computed as matter. On their own they’d take 5.3 × 10^48. At this matter floor the brains are already computed as matter, so minds add nothing to the total. Inner liveswild guess 2.0 × 10^36 2.0 × 10^36 real minds. 8.8 × 10^37 organisms left as scenery. Operations so farrough 2.5 × 10^109 13.8 billion years on the clock, at 5.8 × 10^91 per second. History that is only storedrough 0% Computing begins 13.8 billion years ago. No humans are present at the start. [◂ Local Universe](https://simulation-hypothesis.com/builds/local)Open in the sandbox ▸ [Full Quantum ▸](https://simulation-hypothesis.com/builds/full-quantum) --- title: "Full Quantum · a universe that takes a total that leaves the number line · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/full-quantum description: "The observable universe as one wavefunction. The upper limit. The observable universe as a single wavefunction, with every mind a quantum process." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)7/9 # Full Quantum · The observable universe as one wavefunction. The upper limit. Open in the sandbox ▸ The observable universe as a single wavefunction, with every mind a quantum process. Perfect detail, and more than any possible computer could run. Required computing power rough 1010^79.7 FLOPS Never, within a single universe. [The countdown ▸](https://simulation-hypothesis.com/countdown) Even the exponent needs an exponent. No physical computer comes anywhere near this scale. Computer sizerough one universe-computer Every kilogram of ordinary matter in the observable universe computing at Lloyd’s bound. That’s the ceiling for ordinary matter. Counting dark matter would raise it about sixfold, but we couldn’t actually use any of it. Nothing bigger is physically possible. Feasibility Too large to write as a number The exponent itself needs an exponent. Universe-computerstextbook 1010^79.7 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook not a number The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. The power needed can’t be written as a physical quantity. On every computer on Earthrough unbounded How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. No amount of time is enough. World actually computedwild guess 100% 1.3 × 10^-8% of the mass is watched by 2.0 × 10^36 observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * Does perfect detail even make sense as a goal? * Would quantum consciousness change what experience means? * Does computing suffering in perfect detail make the moral debt bigger? * What can something impossible tell us about the things that are possible? “Worked out a simulation whose total has an exponent on its exponent: 10^(10^79.7) FLOPS.” ## Report card Instance report BEYOND ANY COMPUTER Settings Scale Observable universe Matter floor Quantum, fully entangled Lobby Multiplayer Inner lives 9.0 × 10^79 · quantum Computed 100% Time Linear, live from 1.4 × 10^10 yrs ago Computing needed 1010^79.7 FLOPS Computer size one universe-computer Universe-computers 1010^79.7 Feasibility Too large to write as a number Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Genuinely free Utilitarian divided Deontological leans for Virtue ethics leans for Existentialist leans for “Worked out a simulation whose total has an exponent on its exponent: 10^(10^79.7) FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 1010^79.7 FLOPS Every particle is held in one shared quantum state. That state grows exponentially with the number of particles. Mind computingwild guess rides along free At the quantum, fully entangled floor, brains are already computed as matter. On their own they’d take 1.4 × 10^80. At this matter floor the brains are already computed as matter, so minds add nothing to the total. Inner liveswild guess 9.0 × 10^79 9.0 × 10^79 real minds. 8.8 × 10^37 organisms left as scenery. Operations so farrough 1010^79.7 13.8 billion years on the clock, at 1010^79.7 per second. History that is only storedrough 0% Computing begins 13.8 billion years ago. No humans are present at the start. [◂ Universe Lite](https://simulation-hypothesis.com/builds/lite)Open in the sandbox ▸ [Baseline ▸](https://simulation-hypothesis.com/builds/custom) --- title: "Baseline · a universe that takes 1.3 × 10⁶⁸ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/custom description: "Earth atom by atom since 1900, as a starting point for changing one dial at a time." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)8/9 # Baseline · Earth atom by atom since 1900, as a starting point for changing one dial at a time. Open in the sandbox ▸ Earth, atom by atom, everyone a real player, functional minds, one timeline since 1900\. Far more than today’s computers can run, but within physical limits. Change one dial and you see how much it adds to the total. Required computing power rough 1.3 × 10^68 FLOPS Never on one star’s power with ordinary logic, even at the thermodynamic floor. [The countdown ▸](https://simulation-hypothesis.com/countdown) More power than the Sun puts out, even on ordinary chips at the thermodynamic limit (one bit erased per operation, at room temperature). Computer sizetextbook 10²¹ × a Sun of Landauer-limit chips The Sun’s whole output, at the thermodynamic floor of one bit erased per operation, at room temperature. At Lloyd’s bound this takes 246.3 trillion tonnes of matter, all of it computing. Feasibility Beyond the Sun’s whole output More power than the Sun emits, even with conventional logic at the thermodynamic floor. Universe-computerstextbook 1.6 × 10^-36 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 10^21 Suns The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. 10^21 Suns of power at the Landauer floor, assuming perfect chips. The best real chips use about five billion times more energy than that. On every computer on Earthrough 4.2 × 10^39 years per second How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. 3.1 × 10^29 ages of the universe, on all of Earth’s computing, for every simulated second. World actually computedwild guess 100% 1.4 × 10^-6% of the mass is watched by 8.2 billion observers. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * Which dial changes the total most? * Which assumptions matter, and which barely register? “Worked out Earth at atom resolution: 1.3 × 10^68 FLOPS, or 10²¹ × a Sun of Landauer-limit chips.” ## Report card Instance report A RECENTLY STARTED WORLD Settings Scale Earth Matter floor Atom Lobby Multiplayer Inner lives 8.2 billion · functional Computed 100% Time Linear, live from 1900 Computing needed 1.3 × 10^68 FLOPS Computer size 10²¹ × a Sun of Landauer-limit chips Universe-computers 1.6 × 10^-36 Feasibility Beyond the Sun’s whole output Judged, not measured The author’s reading. None of these changes the computing total. Suffering As found Free will Feels free Utilitarian divided Deontological leans for Virtue ethics leans for Existentialist divided “Worked out Earth at atom resolution: 1.3 × 10^68 FLOPS, or 10²¹ × a Sun of Landauer-limit chips.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 1.3 × 10^68 FLOPS 1.3 × 10^50 atom-sized units across Earth, each updated every 1 fs. Mind computingrough rides along free At the atom floor, brains are already computed as matter. On their own they’d take 8.2 × 10^27. At this matter floor the brains are already computed as matter, so minds add nothing to the total. Inner liveswild guess 8.2 billion 8.2 billion real minds. 4.5 × 10^20 organisms left as scenery. Operations so farrough 5.3 × 10^77 126 years on the clock, at 1.3 × 10^68 per second. History that is only storedrough 99.9999991% Computing begins in 1900\. 1.6 billion humans are present at the start, with preinstalled memories. [◂ Full Quantum](https://simulation-hypothesis.com/builds/full-quantum)Open in the sandbox ▸ [The Afterlife ▸](https://simulation-hypothesis.com/builds/afterlife) --- title: "The Afterlife · a universe that takes 10¹⁸ FLOPS · Simulation Hypothesis" url: https://simulation-hypothesis.com/builds/afterlife description: "A world with no suffering, computed only when someone’s there. A painted world that exists only where the person in it is paying attention." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Scenarios](https://simulation-hypothesis.com/builds)9/9 # The Afterlife · A world with no suffering, computed only when someone’s there. Open in the sandbox ▸ A painted world that exists only where the person in it is paying attention. It repeats in a cycle and has no suffering. It fits on one of today’s largest supercomputers. Required computing power rough 10^18 FLOPS Our computers could run this today. [The countdown ▸](https://simulation-hypothesis.com/countdown) About one of today’s largest supercomputers. Computer sizemeasured the biggest supercomputer Exascale class. It fills a building. Feasibility Possible at national scale Supercomputer territory: large, but it exists. Universe-computerstextbook 1.2 × 10^-86 One universe-computer is every kilogram in the observable universe computing at Lloyd’s bound. Power draw, Landauer floortextbook 0.0029 W The thermodynamic minimum for flipping bits at room temperature. The best real hardware uses about five billion times more energy than that. At the thermodynamic minimum, a wall socket would do. On every computer on Earthrough faster than real time How long it takes, on a clock, to compute one second of simulation on all of humanity’s computers, \~10^21 FLOPS. Real time, on computers we have today. World actually computedwild guess 1.7 × 10^-16% 1.7 × 10^-16% of the mass is watched by one observer. The observation dial sets how much of the remainder is computed at the full floor. ## Questions this scenario asks * Would you go in, knowing what it is? * If you remove suffering, do you remove meaning too? * Can happiness be real with nothing at stake? * Is it okay to keep the people inside from knowing? “Worked out a world that’s only drawn in where one mind looks: 10^18 FLOPS.” ## Report card Instance report ONE MIND, DRAWN-IN SURROUNDINGS Settings Scale Earth Matter floor Painted set Lobby Single player Inner lives 8.2 billion · functional Computed 1.7 × 10^-16% Time Cyclic, live from 2026 Slot A player Computing needed 10^18 FLOPS Computer size the biggest supercomputer Universe-computers 1.2 × 10^-86 Feasibility Possible at national scale Judged, not measured The author’s reading. None of these changes the computing total. Suffering Off Free will Feels free Utilitarian leans for Deontological divided Virtue ethics leans against Existentialist leans against “Worked out a world that’s only drawn in where one mind looks: 10^18 FLOPS.” Two of these are rough and three are wild guesses, and each is tagged that way. Change any one dial and you get a different universe. Matter computingrough 10^13 FLOPS Only surfaces are computed, and only where someone is looking. Anything unobserved is just a stored value. Mind computingrough 10^18 FLOPS Sandberg & Bostrom 2008, level 4 One fully computed functional mind and 8.2 billion scripted ones. Inner liveswild guess 8.2 billion 1 real mind, 8.2 billion scripted, 4.5 × 10^20 animals as scenery. Operations so farrough 3.2 × 10^25 less than a year on the clock, at 10^18 per second. History that is only storedrough 100% Computing begins in 2026\. 8.2 billion humans are present at the start, with preinstalled memories. [◂ Baseline](https://simulation-hypothesis.com/builds/custom)Open in the sandbox ▸ [The Matrix ▸](https://simulation-hypothesis.com/builds/sleepers) --- title: "Plato’s cave · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/plato description: "Prisoners, a fire and shadows on a wall: an early picture of a projection mistaken for the world. Plato, Republic, book VII · around 375 BC" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)1/14 # Plato’s cave Plato, Republic, book VII · around 375 BC Prisoners, a fire and shadows on a wall: an early picture of a projection mistaken for the world. The prisoners have been chained since childhood, facing a wall. Behind them a fire burns, and between the fire and their backs people carry objects along a walkway. The prisoners see only the shadows the objects cast, and hear only the echoes. So the shadows are their whole world. They name them, argue about them, get good at predicting which shadow comes next, and give out honours for it. One prisoner is freed and dragged into daylight. It hurts. At first he can’t see anything. Then he sees reflections, then the objects themselves, and finally the sun. When he goes back to tell the others, his eyes haven’t readjusted to the dark. He’s worse at the shadow game, and they decide the trip has harmed him. Plato adds that if they could get their hands on him, they’d kill him. Plato meant it as a story about education, and about the difference between opinion and knowledge. Read today, it sounds like a rendering pipeline. There’s a light source behind the viewer, and projected images that get mistaken for the objects. The people have never seen anything else, so they build a full science of the projection. Two things carry over to a computed world. First, the prisoners aren’t irrational. Their science works, because it predicts shadows. A simulated physics would work in exactly that way. Second, the freed prisoner is worse off in the cave afterwards. Knowing what’s behind the projection gives you no edge inside it. The cave is an early and influential version of the question this site asks, but not the earliest. The Bṛhadāraṇyaka Upaniṣad (4.3) was composed in India before the Buddha. It already describes the dreaming self making chariots, horses and roads where none exist. The cave is also honest about what an answer costs. The one who has seen the sun can’t prove it to the others. They’re the majority, and they’re hostile. In the sandbox · ObservationThe shadows are a painted set: matter that behaves as if it’s there when it isn’t. At zero on the Observation dial, the sandbox renders only what’s being observed. Everything behind the prisoners is just a stored number. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Good because God says so? · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-euthyphro)[The Ring of Gyges · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-gyges) ## Sources Republic, book VII (514a–520a) Plato, c. 375 BC. Any translation; the allegory runs to about ten pages. [Plato’s Republic](https://plato.stanford.edu/entries/plato-ethics-politics/) Stanford Encyclopedia of Philosophy In the Library [Epistemology](https://simulation-hypothesis.com/library/epistemology)[Skepticism](https://simulation-hypothesis.com/library/skepticism)[Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail) [◂ Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers)[Zhuangzi’s butterfly ▸](https://simulation-hypothesis.com/thinkers/zhuangzi) --- title: "Zhuangzi’s butterfly · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/zhuangzi description: "Zhuangzi dreams he’s a butterfly, then wakes up and can’t say which of the two is dreaming. Zhuangzi, chapter 2, “On the Equality of Things” · around 300 BC" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)2/14 # Zhuangzi’s butterfly Zhuangzi, chapter 2, “On the Equality of Things” · around 300 BC Zhuangzi dreams he’s a butterfly, then wakes up and can’t say which of the two is dreaming. Zhuang Zhou dreamed he was a butterfly. He flitted about, happy, completely a butterfly, with no idea he’d ever been Zhou. Then he woke up, and he was clearly Zhou. He didn’t know if he was Zhou who had dreamed he was a butterfly, or a butterfly now dreaming it was Zhou. The passage is four sentences long, and it’s been open for twenty-three centuries. Zhuangzi doesn’t settle it. He says there must be some difference between Zhou and the butterfly, calls it “the transformation of things”, and moves on. Not answering is the point. Western versions of the worry, from Descartes on, look for a way out. They want a certainty that survives the doubt, or a proof that the sceptical story makes no sense. Zhuangzi doesn’t look for an exit. Dreaming and waking are both fully real while they last. You can’t tell from the inside which one you’re in, and that isn’t a problem to solve. It’s part of being something that changes. For the simulation hypothesis, this is the calmest position on offer. If you can’t check from the inside, then “is this rendered?” is in the same boat as “is this the dream?” You can leave it open. In the same chapter Zhuangzi does name an exit, a great awakening after which we’d know this life was a great dream. But he adds that the people who think they’re already awake are the fools. The passage also gives an early answer to whether a simulated life would matter less. The butterfly isn’t a lesser Zhou. While it’s a butterfly, it’s completely one. In the sandbox · SlotThe Slot dial records who you take yourself to be in the scenario: a player, a non-player character who has noticed the seams, or the operator on a break. On Zhuangzi’s view, the label doesn’t change anything about the butterfly. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources Zhuangzi, chapter 2 (Qiwulun), closing passage c. 300 BC. Burton Watson’s translation is standard; Brook Ziporyn’s has the fuller notes. [Zhuangzi](https://plato.stanford.edu/entries/zhuangzi/) Stanford Encyclopedia of Philosophy In the Library [Skepticism](https://simulation-hypothesis.com/library/skepticism)[Ontology](https://simulation-hypothesis.com/library/ontology)[The problem of other minds](https://simulation-hypothesis.com/library/other-minds) [◂ Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Vasubandhu’s dream ▸](https://simulation-hypothesis.com/thinkers/vasubandhu) --- title: "Vasubandhu’s dream · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/vasubandhu description: "A shared, orderly world that affects us can appear without outside objects. Vasubandhu argues it with a dream, hungry ghosts and a nightmare of hell." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)3/14 # Vasubandhu’s dream Vasubandhu, Viṃśatikā (Twenty Verses on Appearance Only) · 4th–5th century AD A shared, orderly world that affects us can appear without outside objects. Vasubandhu argues it with a dream, hungry ghosts and a nightmare of hell. Vasubandhu, an Indian Buddhist philosopher of the Yogācāra school, opens the Twenty Verses with a thesis. Everything in the three realms is representation only (vijñaptimātra), because objects can appear that aren’t there. A person with an eye disease sees hairs and a second moon. The Stanford Encyclopedia dates him to the fourth to fifth century AD, and ties him to the reign of Chandragupta II (380–415) through Paramārtha’s biography. His aim is liberation from suffering. The question he asks is whether the world needs outside objects to look the way it does. He states the strongest objection himself. A dream is a poor model, says the opponent, because waking life differs in four ways. What you see is tied to a place. It’s tied to a time. Many beings share it. And it has effects. A dreamer’s lover can’t be touched, and a dreamed meal doesn’t feed anyone. Those four features are what make a world look independent of the mind. They’re also what a simulation would have to supply to be convincing. He answers them one at a time. In dreams, too, certain things show up at certain places and times, so a regular order doesn’t need a physical object. For sharing, he points to the hungry ghosts (pretas). They all see a river as pus, because their past actions ripen in similar ways. He also points to the guardians of hell, whom all its inhabitants see. A shared appearance has a shared cause in the minds that have it, not in an object. For effects, he points to the nocturnal emission, a bodily effect from a dream encounter with no partner. He also takes up other minds. Minds, he says, influence one another. So other beings are no less real for lacking outside bodies in the sense the objector means. And what you know of another’s mind isn’t knowledge of it as it really is (verses 18–21 on his numbering, and translations differ). He adds that until awakening, you don’t see that what appears isn’t as it seems (verse 17). That’s close to Zhuangzi’s great awakening. For the sandbox, this is the cleanest ancient statement that observers agreeing doesn’t prove there’s a world outside the representation. One computed state, sent to many players, would produce exactly the shared, ordered, effective appearances he lists. The difference from Berkeley is that Vasubandhu needs no divine perceiver. The consistency comes from the causal history of the streams of minds. In the sandbox · LobbyMultiplayer is Vasubandhu’s third objection: how can many beings share one world if there’s no outside object? In the Lobby control, multiplayer and players-plus-NPCs both send one consistent state to many minds. At single player, the same appearances are produced for one. On his view, the setting changes the computing needed but not what anyone sees. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources [Vasubandhu](https://plato.stanford.edu/entries/vasubandhu/) Stanford Encyclopedia of Philosophy, sec. on the Twenty Verses (the dream, the four objections and replies) [Yogācāra](https://plato.stanford.edu/entries/yogacara/) Stanford Encyclopedia of Philosophy Viṃśatikā-kārikā with Vṛtti (Twenty Verses) Vasubandhu, 4th–5th c. AD. Translations: Kapstein, in Reason’s Traces (Wisdom, 2001); Anacker, Seven Works of Vasubandhu (Motilal, 1984); Tola and Dragonetti (2004). Verse numbers vary between translations. In the Library [Ontology](https://simulation-hypothesis.com/library/ontology)[The problem of other minds](https://simulation-hypothesis.com/library/other-minds)[Epistemology](https://simulation-hypothesis.com/library/epistemology)[Skepticism](https://simulation-hypothesis.com/library/skepticism) [◂ Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Shankara’s māyā ▸](https://simulation-hypothesis.com/thinkers/shankara) --- title: "Shankara’s māyā · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/shankara description: "The world is real enough to live in and not real in the last analysis. Advaita Vedānta keeps both claims at once." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)4/14 # Shankara’s māyā Śaṅkara, commentary on the Brahmasūtra; the Yoga Vāsiṣṭha · 8th century AD The world is real enough to live in and not real in the last analysis. Advaita Vedānta keeps both claims at once. Śaṅkara was an Indian philosopher of the Advaita (“non-dual”) Vedānta school. The Stanford Encyclopedia puts him in the eighth century AD. His thesis is short. Only Brahman, pure consciousness, is ultimately real. The many things of the world, you and me included, are māyā: an appearance laid over Brahman. His favourite picture is a rope in poor light. You see a snake, you jump, your heart races. When a lamp comes, the snake is gone, but it never was anything except the rope. You might expect him to say the world is just a dream. He doesn’t. In his commentary on the Brahmasūtra (2.2.28–29) he argues against the Buddhist Yogācāra school, Vasubandhu’s school, that waking life isn’t like a dream. A dream is cancelled when you wake up. The waking world isn’t cancelled by anything you can reach from inside it. So he gives reality levels. The everyday world is real for every practical purpose: you can eat the food and the fire burns. It just isn’t the last word. The Yoga Vāsiṣṭha, a long Sanskrit poem whose date scholars still argue about, tells the idea as stories. In one, a magician waves a fan of peacock feathers in front of King Lavaṇa. For a moment the king sits frozen. In that moment he lives a whole life far away as an outcast. He marries, raises children, survives a famine and is about to throw himself into a fire when he wakes on his throne. Later he travels to the hills and finds the village, and people there who remember the famine. For the simulation hypothesis, Advaita gives a ready answer to the worry that a simulated world would be fake. It would be real at its own level, the way the waking world is for Śaṅkara, and not the deepest level. The Lavaṇa story adds something the sandbox can count. A lifetime can fit in a moment of outside time, and what was lived still leaves marks other people can find. In the sandbox · TimeKing Lavaṇa remembers a whole life he lived in a moment. The Time dial sets when the computing begins. Everything before that point is stored history, and the people present at the start arrive with their memories already installed. From inside, stored years and lived years feel the same. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources [Śaṅkara](https://plato.stanford.edu/entries/shankara/) Stanford Encyclopedia of Philosophy (dates, levels of reality, the argument against Yogācāra at Brahmasūtra commentary 2.2.28) [Vedanta, Advaita](https://iep.utm.edu/advaita-vedanta/) Internet Encyclopedia of Philosophy Brahmasūtrabhāṣya, 2.2.28–32 Śaṅkara. Translations: Thibaut, The Vedānta-Sūtras with the Commentary by Śaṅkarācārya (Sacred Books of the East 34, 1890); Gambhirananda (Advaita Ashrama, 1965). Yoga Vāsiṣṭha, book 3, the story of Lavaṇa Date disputed. Abridged translation: Swami Venkatesananda, The Concise Yoga Vāsiṣṭha (SUNY Press, 1984). In the Library [Ontology](https://simulation-hypothesis.com/library/ontology)[Consciousness](https://simulation-hypothesis.com/library/consciousness)[Epistemology](https://simulation-hypothesis.com/library/epistemology) [◂ Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[al-Ghazali’s doubt ▸](https://simulation-hypothesis.com/thinkers/ghazali) --- title: "al-Ghazali’s doubt · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/ghazali description: "Five centuries before Descartes, a Persian scholar asked what would make waking life look like a dream." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)5/14 # al-Ghazali’s doubt Abū Ḥāmid al-Ghazālī, Deliverance from Error (al-Munqidh min al-ḍalāl) · early 12th century Five centuries before Descartes, a Persian scholar asked what would make waking life look like a dream. Al-Ghazālī (1058–1111), born in Tus in Persia, became one of the most famous scholars of his age. Late in his life he wrote Deliverance from Error, the story of how he lost his certainty and got it back. He wanted knowledge so sure that nothing could shake it. So he tested the two things he trusted most, the senses and reason. The senses failed first. You look at a shadow and it seems to stand still, but an hour later it has moved. You look at a star and it seems the size of a coin, but geometry shows it is bigger than the earth. If the senses can be corrected by reason, maybe reason can be corrected by something above it. Then he lets the senses answer back. Don’t you see, they say, that in sleep you believe things and see whole situations, and you’re sure they’re solid and lasting? Then you wake up and know none of it had any basis. What makes you sure that waking life isn’t the same, compared with some state beyond it? From there your waking certainties would look the way dreams look from here. He notes that the Sufis claim to reach such states, and he quotes the saying “People are asleep, and when they die they wake up.” He couldn’t argue his way out, because any proof would have to use the reason that was in question. For about two months, he says, he was a sceptic in fact, if not in speech. What ended it wasn’t an argument. It was, in his words, a light God cast into his breast, which gave him back his trust in the basic truths of reason. That’s why the passage matters for the simulation hypothesis. It’s the cleanest early statement of the problem: from inside one level, you can’t prove there is no level above it. Al-Ghazālī accepts that, and gets out by grace, not by logic. Descartes, five centuries later, would try to get out by logic. In the sandbox · Slot · A scripted character that detects the seamsThe shadow that moves and the star that is bigger than it looks are seams: places where the appearance and the measurement disagree. The Slot dial’s scripted character who detects the seams is al-Ghazālī’s doubter. Noticing them doesn’t tell you what is outside. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources al-Munqidh min al-ḍalāl (Deliverance from Error) al-Ghazālī, early 12th century. Translations: W. Montgomery Watt, The Faith and Practice of al-Ghazālī (1953); R. J. McCarthy, Al-Ghazālī’s Path to Sufism: His Deliverance from Error (Fons Vitae, 2000). [al-Ghazali](https://plato.stanford.edu/entries/al-ghazali/) Stanford Encyclopedia of Philosophy [Al-Ghazālī](https://iep.utm.edu/al-ghazali/) Internet Encyclopedia of Philosophy In the Library [Skepticism](https://simulation-hypothesis.com/library/skepticism)[Epistemology](https://simulation-hypothesis.com/library/epistemology)[Base reality](https://simulation-hypothesis.com/library/base-reality) [◂ Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[Ibn Arabi’s imagination ▸](https://simulation-hypothesis.com/thinkers/ibn-arabi) --- title: "Ibn Arabi’s imagination · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/ibn-arabi description: "The whole world is imagination, made new at every instant. For Ibn Arabi that makes it more meaningful, not less." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)6/14 # Ibn Arabi’s imagination Ibn ʿArabī, The Bezels of Wisdom (Fuṣūṣ al-ḥikam) · 1229 The whole world is imagination, made new at every instant. For Ibn Arabi that makes it more meaningful, not less. Ibn ʿArabī (1165–1240) was born in Murcia in al-Andalus and died in Damascus. He’s one of the most influential thinkers in Sufism. Near the end of his life he wrote The Bezels of Wisdom, twenty-seven chapters, each on the wisdom of one prophet. The chapter on Joseph, the prophet who read dreams, makes a startling claim. Everything we call “other than God” is imagination (khayāl), and the cosmos is a dream that has to be interpreted. He builds on the saying al-Ghazālī quoted: “People are asleep, and when they die they wake up.” But he reads it differently. For al-Ghazālī the dream was a threat to certainty. For Ibn ʿArabī it’s a way to read. A dream is made of images that point beyond themselves, and Joseph’s skill was knowing what they meant. The world works the same way. Its things are signs, and the work is to see through them to what they show. He also doesn’t treat imagination as a lack of reality. He calls it a barzakh, an isthmus: something between pure spirit and dense matter, which shares in both. On his view an image isn’t nothing. It’s real as an image. And the world isn’t built once and left standing. Reading the Qur’an’s phrase about “a new creation” (50:15), he holds that the cosmos is recreated at every instant. It only looks continuous, like a flame or a river. Put next to the simulation hypothesis, this is close to a rendering engine described from a believer’s side. The world is redrawn at every instant. Its solidity is an appearance. And its meaning lies in what it points to, not in the stuff it’s made of. Like Chalmers eight centuries later, Ibn ʿArabī doesn’t conclude that the world is fake. He concludes that we have to read it properly. In the sandbox · Matter floorThe Matter floor sets how fine the world is built, from a painted set up to every quantum. On Ibn ʿArabī’s view the floor doesn’t decide what is real. Even the coarsest image is real as an image. What it costs to redraw it at every instant is what the sandbox counts. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources Fuṣūṣ al-ḥikam (The Bezels of Wisdom), the chapter on Joseph Ibn ʿArabī, Damascus, 1229\. Translation: R. W. J. Austin, The Bezels of Wisdom (Paulist Press, 1980). [Ibn ʿArabī](https://plato.stanford.edu/entries/ibn-arabi/) Stanford Encyclopedia of Philosophy (imagination, the barzakh) Imaginal Worlds: Ibn al-ʿArabī and the Problem of Religious Diversity William C. Chittick, SUNY Press, 1994. In the Library [Ontology](https://simulation-hypothesis.com/library/ontology)[Consciousness](https://simulation-hypothesis.com/library/consciousness)[Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail) [◂ al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Calderón’s life is a dream ▸](https://simulation-hypothesis.com/thinkers/calderon) --- title: "Calderón’s life is a dream · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/calderon description: "A prince is told his best day was a dream. He decides to act well anyway, in case he wakes." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)7/14 # Calderón’s life is a dream Pedro Calderón de la Barca, Life Is a Dream (La vida es sueño) · 1635 A prince is told his best day was a dream. He decides to act well anyway, in case he wakes. In Calderón’s play the king of Poland, Basilio, is an astrologer. The stars tell him his son Segismundo will be a tyrant, so he raises the boy chained in a tower in the mountains. Years later he tests the prophecy. Segismundo is drugged, carried to the palace and wakes up as a prince. He’s violent. He throws a servant off a balcony and threatens his own father. So they drug him again and put him back in the tower, and his jailer tells him it was all a dream. Segismundo’s speech at the end of the second act is one of the most quoted in Spanish: “What is life? A frenzy. What is life? An illusion, a shadow, a fiction, and the greatest good is small; for all of life is a dream, and dreams are only dreams.” He can no longer tell the palace from the tower. Both felt completely real while he was in them. The third act is where the play turns into philosophy. Soldiers free him and offer him the throne. Segismundo isn’t sure he isn’t dreaming again, and he decides it doesn’t matter. He’ll act well either way. If it’s real, it’s right for its own sake. If it’s a dream, then doing good, as his jailer told him, isn’t lost even in dreams. He spares his father and wins the kingdom. For the simulation hypothesis, this is the most practical answer on the list. You may never know if your world is base reality. The play says you don’t need to know in order to act. A good act done in a simulation is still a good act, and if there’s waking up, you take your character with you. The play makes a second point too. Basilio’s prediction comes true only because he locked his son away in fear of it. In the sandbox · Free willBasilio believed the stars fixed his son’s character. Segismundo proves that they only inclined it. The Free will dial is a moral setting: it changes the ethics meters, not the FLOPS. Calderón’s point is that it should change how you act either way. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources La vida es sueño Calderón, first published 1636 (written about 1635). Segismundo’s speech closes the second act. Translations include Gregary Racz (Yale, 2006) and Michael Kidd (Colorado, 2004). In the Library [Free will](https://simulation-hypothesis.com/library/free-will)[Determinism](https://simulation-hypothesis.com/library/determinism)[Virtue ethics](https://simulation-hypothesis.com/library/virtue-ethics) [◂ Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Descartes’ demon ▸](https://simulation-hypothesis.com/thinkers/descartes) --- title: "Descartes’ demon · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/descartes description: "Suppose a being of great power has put all its effort into deceiving you. What’s left? René Descartes, Meditations on First Philosophy · 1641" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)8/14 # Descartes’ demon René Descartes, Meditations on First Philosophy · 1641 Suppose a being of great power has put all its effort into deceiving you. What’s left? Descartes wanted something he couldn’t doubt, so he started by doubting everything on purpose. First the senses, which have fooled him before and might be fooling him now. Then the whole of waking life, since nothing marks it off for sure from a dream. Finally he imagines a deceiver. It isn’t God, who wouldn’t lie. It’s a malicious demon of enormous power and cunning. The demon has made the sky, the air, the earth, colours, shapes, sounds and every outside thing into illusions, set up to trap his judgement. The demon is a thought experiment about the limits of evidence. It’s also the first simulation hypothesis in the modern sense: a complete, coherent, deliberately made world that’s false all the way through. The key word is complete. The demon makes no mistakes, so there’s no glitch to find. Whatever test you run, the result has already been rendered. One thing survives. If he’s being deceived, he exists, because there has to be something for the demon to deceive. The act of doubting can’t itself be doubted away. This is the cogito, and it’s a much smaller foothold than people remember. It gives you a thinking thing, right now, and nothing more. Everything else Descartes builds on it, including the outside world, he rebuilds by arguing that a good God wouldn’t allow such a demon. Most readers find the demolition more convincing than the rebuilding. Swap the demon for a data centre and the argument doesn’t change. Every era states the worry with the most vivid image of deception it has, and in 1641 that image was a demon. The demon also gives the site its idea of an operator: someone or something is running the scenario. The operator on a break in the Slot dial is a watered-down version of Descartes’ deceiver. It’s still all-powerful inside the world and still not answering questions, but it’s barely paying attention. In the sandbox · Slot · The operator on a breakThe demon is the operator. Every scenario has one. The Honesty axis of the ethics meters asks the demon’s question from the inhabitants’ side: could they find out, even in principle? [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Suppose you are the only one · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-alone) ## Sources Meditations on First Philosophy, First and Second Meditations Descartes, 1641\. The demon appears at the end of the First Meditation. [Descartes’ Epistemology](https://plato.stanford.edu/entries/descartes-epistemology/) Stanford Encyclopedia of Philosophy In the Library [Descartes’ demon](https://simulation-hypothesis.com/library/evil-demon)[Skepticism](https://simulation-hypothesis.com/library/skepticism)[Epistemology](https://simulation-hypothesis.com/library/epistemology) [◂ Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Berkeley’s perceiver ▸](https://simulation-hypothesis.com/thinkers/berkeley) --- title: "Berkeley’s perceiver · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/berkeley description: "To be is to be perceived, and things nobody is looking at still exist because God is." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)9/14 # Berkeley’s perceiver George Berkeley, Principles of Human Knowledge; Three Dialogues between Hylas and Philonous · 1710–1713 To be is to be perceived, and things nobody is looking at still exist because God is. Berkeley argued that the things we perceive are collections of ideas, and that nothing perceived exists apart from a mind. His formula is esse est percipi, to be is to be perceived (Principles, §3, along with the spirit that perceives it). In §6 he says the whole furniture of the world has no existence outside a mind. He meant this as a defence of common sense against the philosophers’ unperceivable matter. A table is real because I see and feel it. The obvious objection is the table in the empty room. Berkeley first replies that if he left the room, the table would still exist in this sense: he, or some other spirit, would perceive it if he were there (§3). The harder question is whether things stop existing whenever nobody perceives them. That’s where the argument got famous. In the Three Dialogues he says ideas of sense exist in an infinite mind. So things carry on when no finite mind perceives them, because God does. Commentators don’t agree that this is secure. The SEP notes that sensory ideas can’t be copies of God’s non-sensory ideas, and that God’s ideas would cover objects we wouldn’t call real. One proposed fix ties continued existence to God’s decrees to produce the ideas. Then the world exists as a lawful pattern of what would be perceived. In sandbox terms, this is a rendering policy. With Observation set low, only what’s being perceived gets computed. Berkeley’s world is the policy where nothing is ever unobserved, because a standing observer keeps every state. His theology does the job that unlimited computing power would do. The comparison cuts both ways. A computed world doesn’t need a divine perceiver. It needs a store of state and a rule for producing a view of it. A developer who stores state has a fact about the unobserved table. Berkeley wanted the opposite. For him, there’s no fact beyond ideas and what would be perceived. In the sandbox · ObservationAt high Observation, everything is computed whether or not anyone’s looking. That’s Berkeley’s standing divine observer. At low Observation, only what’s observed is rendered, and the rest is a stored number. That’s the picture Berkeley’s objector worries about, and the one he answers by adding God. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) ## Sources [George Berkeley](https://plato.stanford.edu/entries/berkeley/) Stanford Encyclopedia of Philosophy (esse est percipi; unperceived objects; God’s ideas versus decrees) A Treatise Concerning the Principles of Human Knowledge, Part I, §§3, 6, 45–48 Berkeley, 1710\. Any edition; Works ed. Jessop and Luce, vol. 2. Three Dialogues between Hylas and Philonous, esp. the Third Dialogue Berkeley, 1713\. Works ed. Jessop and Luce, vol. 2, pp. 212–215 and 253 as cited by SEP. In the Library [Epistemology](https://simulation-hypothesis.com/library/epistemology)[Ontology](https://simulation-hypothesis.com/library/ontology)[Observer effect](https://simulation-hypothesis.com/library/observer-effect)[Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail) [◂ Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Borges’ circular ruins ▸](https://simulation-hypothesis.com/thinkers/borges) --- title: "Borges’ circular ruins · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/borges description: "A man dreams a son into being, then learns that someone is dreaming him. Jorge Luis Borges, “The Circular Ruins” (“Las ruinas circulares”), in Ficciones · 1940" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)10/14 # Borges’ circular ruins Jorge Luis Borges, “The Circular Ruins” (“Las ruinas circulares”), in Ficciones · 1940 A man dreams a son into being, then learns that someone is dreaming him. A grey, silent man comes by canoe from the south and climbs to a ruined circular temple, burned long ago. He has one purpose. He wants to dream a man, with full detail, and put him into reality. His first try fails: he dreams a whole lecture hall of students and can’t make any of them solid. So he starts again with less. He dreams a beating heart, night after night, then the organs one at a time, then the whole body. The god of the temple is Fire. Fire agrees to bring the dreamed man to life, so that everyone except Fire and the dreamer will think he’s a real person. The man trains his son, then wipes the son’s memory of the training, so he’ll never know he was dreamed. He sends him downriver to another ruined temple. Later he hears of a man there who can walk on fire without being burned, and he’s afraid. If his son ever thinks about that, he’ll work out that he is only an image. Then fire comes to the circular ruins. The man walks into it to die, and it doesn’t burn him. The story ends: “With relief, with humiliation, with terror, he understood that he too was an appearance, that another was dreaming him.” Borges published the story in 1940\. It’s the simulation argument as a short story, more than sixty years before Bostrom. If minds can be made, then whoever makes one has to ask whether he was made too. The detail that gives it away is small. A made mind is fine until it meets the one thing that treats it differently, here a fire that won’t burn. In the sandbox that’s what a test from inside would look for. In the sandbox · The Infinite regress windowThe dreamer is a level above his son and a level below someone else. The Infinite regress window shows what each level of nesting costs the one above it. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Dreams · Simulations](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) ## Sources Las ruinas circulares Borges, Sur, December 1940; collected in El jardín de senderos que se bifurcan (1941) and Ficciones (1944). English: Andrew Hurley, Collected Fictions (Viking, 1998). In the Library [Infinite regress](https://simulation-hypothesis.com/library/infinite-regress)[Base reality](https://simulation-hypothesis.com/library/base-reality)[Simulation hypothesis](https://simulation-hypothesis.com/library/simulation-hypothesis) [◂ Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Nozick’s experience machine ▸](https://simulation-hypothesis.com/thinkers/nozick) --- title: "Nozick’s experience machine · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/nozick description: "A machine that gives you any life you choose, one you can’t tell from the real thing. Would you plug in?" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)11/14 # Nozick’s experience machine Robert Nozick, Anarchy, State, and Utopia, chapter 3 · 1974 A machine that gives you any life you choose, one you can’t tell from the real thing. Would you plug in? Suppose a machine could give you any experience you wanted. Neuropsychologists could stimulate your brain so you’d think and feel you were writing a great novel, making a friend, or reading an interesting book. All the while you’d be floating in a tank with electrodes attached to your brain. You can program your experiences for the next two years, then come up for ten minutes to pick the next two. Should you plug in for life? Nozick thought most people would say no. Surveys since find the answers shift with how the case is framed, especially with whether you’re already plugged in (De Brigard, 2010). He drew three conclusions. We want to actually do certain things, not just have the experience of doing them. We want to be a certain kind of person, and a body floating in a tank is no kind of person. And we want contact with a reality deeper than anything we could construct. If experience were all that mattered, none of that would count. So experience isn’t all that matters. The argument was aimed at hedonism and the simplest forms of utilitarianism, and it still has force. It also works as a design brief for a simulation: what would a world look like if it were built to be plugged into? The Afterlife preset answers that. It has a painted set, single player, nothing rendered unless you want it, suffering off, and time in a loop. The sandbox works out how much computing that paradise takes, and the answer is telling. It’s among the cheapest builds available. No suffering means no stakes, no stakes means little to compute, and the total collapses. Three of the four schools in the ethics window object. The fourth endorses it, because a painless world of maximum bliss is what its arithmetic recommends. There’s a second reading. Nozick asks whether you’d choose the machine. The simulation hypothesis asks whether you’re already in one and nobody asked you. His three reasons for refusing are the same three reasons a simulated person might feel wronged. None of them is about how good the rendering is. In the sandbox · Suffering · OffThe Afterlife preset is the experience machine, built and measured. Setting Suffering to Off in any scenario pushes the Stakes axis of the ethics radar toward zero. That’s on purpose. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [The experience machine · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-machine)[Choosing a virtual life · Ethics](https://simulation-hypothesis.com/trees/ethics?n=q-choose-being) ## Sources Anarchy, State, and Utopia, chapter 3, “The Experience Machine” Nozick, Basic Books, 1974\. The passage is about three pages. [Hedonism](https://plato.stanford.edu/entries/hedonism/) Stanford Encyclopedia of Philosophy [If you like it, does it matter if it’s real?](https://scholars.duke.edu/publication/1695344) De Brigard, Philosophical Psychology 23 (2010), 43–57 In the Library [The experience machine](https://simulation-hypothesis.com/library/experience-machine)[Utilitarianism](https://simulation-hypothesis.com/library/utilitarianism)[Virtue ethics](https://simulation-hypothesis.com/library/virtue-ethics) [◂ Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Putnam’s brain in a vat ▸](https://simulation-hypothesis.com/thinkers/putnam) --- title: "Putnam’s brain in a vat · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/putnam description: "The demon becomes hardware. Then Putnam argues that a brain in a vat couldn’t truly say it’s in a vat." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)12/14 # Putnam’s brain in a vat Hilary Putnam, Reason, Truth and History, chapter 1 · 1981 The demon becomes hardware. Then Putnam argues that a brain in a vat couldn’t truly say it’s in a vat. A brain floats in a vat of nutrients. Every nerve ending is wired to a computer that supplies a complete world: the warmth of the sun, the weight of a cup, the voice of an acquaintance. From the inside, nothing tells this apart from being a person in a room. By 1981 the case was a standard example in philosophy classes, and Putnam used it in a surprising way. He argued that the scenario refutes itself, and his reason is about reference. The word “vat” gets its meaning from causal contact with vats. A brain that has only ever experienced the computer’s world has never touched a real vat. So its word “vat” refers to vats in the simulation, not to the vat it’s floating in. When the brain thinks “I am a brain in a vat”, the thought is about simulated vats, and it’s false. On this account, nobody in a vat can truly think they are. The argument is clever, and it hasn’t comforted many people. It’s about reference, and the wiring doesn’t care what the words refer to. Putnam shows that the brain in the vat can’t state its situation. He doesn’t show that it isn’t in that situation. The vat gives this site a figure. The Brain in a Vat preset builds exactly this: a real brain in base reality, with a world fed in through its nerves. The brain does its own thinking, so only the world has to be computed. It’s the cheapest simulation the sandbox can produce, and it fits in a few racks of GPUs that already exist. It also marks a shift. Before the vat, the deceiver was a demon or a dream, nothing anyone could build. After it, the deceiver is equipment. The question stopped being about theology and became a question about resources, which we can investigate. In the sandbox · Mind model · Real brain, outsideThe Brain in a Vat preset: mind model set to a real brain outside, single player, and a painted Earth rendered only where the brain looks. It’s the smallest build in the sandbox. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Full-immersion VR · Technology](https://simulation-hypothesis.com/trees/technology?n=fulldive) ## Sources Brains in a Vat Putnam, Reason, Truth and History, chapter 1\. Cambridge University Press, 1981. [Skepticism and Content Externalism](https://plato.stanford.edu/entries/skepticism-content-externalism/) Stanford Encyclopedia of Philosophy In the Library [Brain in a vat](https://simulation-hypothesis.com/library/brain-in-a-vat)[Skepticism](https://simulation-hypothesis.com/library/skepticism)[Solipsism](https://simulation-hypothesis.com/library/solipsism) [◂ Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Bostrom’s trilemma ▸](https://simulation-hypothesis.com/thinkers/bostrom) --- title: "Bostrom’s trilemma · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/bostrom description: "Not an argument that we’re simulated, but an argument that one of three propositions must hold." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)13/14 # Bostrom’s trilemma Nick Bostrom, “Are You Living in a Computer Simulation?”, Philosophical Quarterly · 2003 Not an argument that we’re simulated, but an argument that one of three propositions must hold. Picture a civilisation that gets advanced enough to run detailed simulations of its own past, with people in them who think and feel. Bostrom’s paper argues that at least one of these is then true. Almost no civilisations reach that stage, because something stops them first. Or almost none that reach it choose to run such simulations. Or we’re almost certainly living in one. If ancestor simulations get run at all, simulated minds vastly outnumber original ones, and a mind picked at random is probably one of the many. The argument is short, and it’s careful about what “almost” means. It doesn’t say which of the three holds. That sets it apart from earlier versions of the question. Plato, Zhuangzi, Descartes and Putnam ask whether you can know. Bostrom asks about probabilities, and shows you can’t make all three possibilities small at once. People often try to find a fourth option. The qualifications are real: how many minds a simulation holds, whether simulated civilisations run simulations of their own, what counts as maturity. They change how much weight each of the three carries. The argument itself rests on two premises, substrate independence and an indifference principle. Denying either one is the main route to a fourth possibility. The paper also explains why this site looks the way it does. Bostrom’s argument contains a number, the simulated minds per original mind. That number depends on how much computing a simulation takes. The sandbox makes that explicit. The Trilemma window treats the scenario you chose as the thing being simulated. It works out how many copies one universe-scale computer could run, and lets you set the other two probabilities. The third bar is just arithmetic. Bostrom has said he spreads his credence across all three. Informed people have settled on each one. The trilemma doesn’t tell you where to stand. It only says that at least one of three uncomfortable propositions is true. In the sandbox · The Trilemma windowThe scenario you chose is the thing being simulated. One universe-scale computer can run some number of copies of it, set by the computing it needs. You set the extinction and abstention probabilities, and the third bar is whatever’s left. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Ancestor simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-ancestor)[Shadow-people · Simulations](https://simulation-hypothesis.com/trees/simulations?n=min-shadow)[Sharing with digital minds · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-shulman)[Sharing the world with digital minds · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=shulman-2021) ## Sources [Are You Living in a Computer Simulation?](https://simulation-argument.com/) Bostrom, Philosophical Quarterly 53 (2003), 243–255. [The Simulation Argument FAQ](https://simulation-argument.com/faq) Bostrom’s follow-ups and replies In the Library [Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma)[Ancestor simulation](https://simulation-hypothesis.com/library/ancestor-simulation)[Posthuman civilisation](https://simulation-hypothesis.com/library/posthuman) [◂ Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Chalmers: virtual worlds are real ▸](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Chalmers: virtual worlds are real · Simulation Hypothesis" url: https://simulation-hypothesis.com/thinkers/chalmers description: "The strongest recent case that a simulated world wouldn’t be a fake one. David Chalmers, Reality+ · 2022" license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Thinkers](https://simulation-hypothesis.com/thinkers)14/14 # Chalmers: virtual worlds are real David Chalmers, Reality+ · 2022 The strongest recent case that a simulated world wouldn’t be a fake one. Most versions of the simulation hypothesis sound sceptical. If this is a simulation, nothing is real, and the cup in your hand isn’t a cup. Chalmers’ book argues at length that this doesn’t follow. A simulated cup is a real cup, made of bits instead of atoms. A simulated world is a real world with a different physics underneath. Being in a simulation wouldn’t show that the things around you don’t exist. It would show you were wrong about what they’re made of. He calls the position simulation realism, and it rests on a distinction that’s easy to miss. “Real” can mean that it exists, that it has causal powers, that it isn’t an illusion, that it’s independent of minds, or that it’s genuine rather than fake. A simulated tree meets all of these except possibly the last. Chalmers argues it meets that one too: a virtual tree is a real virtual tree, the way a digital photograph is a real photograph. The book also takes the computing question seriously, which is unusual in philosophy. Chalmers accepts that a perfect simulation of everything may be impossible. He argues it doesn’t need to be perfect. It only has to render what its inhabitants can observe, at the detail they can observe it. That’s the idea behind the Observation dial and the Matter floor, put as a philosophical claim instead of a number. Any disagreement between this site and the book is about emphasis. Chalmers argues that the hypothesis shouldn’t trouble us. The sandbox shows how much computing the hypothesis takes, so you can judge how worried to be. In the sandbox · Observation and Matter floorA simulation only needs to be as fine as its inhabitants can observe. Chalmers puts this as philosophy. The sandbox puts it as fifty orders of magnitude between Painted set and Quantum, fully entangled. [Open the sandbox ▸](https://simulation-hypothesis.com/sandbox) In the trees [Do virtual lives count · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-chalmers)[Choosing a virtual life · Ethics](https://simulation-hypothesis.com/trees/ethics?n=q-choose-being) ## Sources Reality+: Virtual Worlds and the Problems of Philosophy Chalmers, W. W. Norton, 2022. [The Virtual and the Real](https://philpapers.org/rec/CHATVA-2) Chalmers, Disputatio 9 (2017), the paper from which the book developed. In the Library [Simulation hypothesis](https://simulation-hypothesis.com/library/simulation-hypothesis)[Ontology](https://simulation-hypothesis.com/library/ontology)[Substrate independence](https://simulation-hypothesis.com/library/substrate-independence) [◂ Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Plato’s cave ▸](https://simulation-hypothesis.com/thinkers/plato) --- title: "Simulation hypothesis · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/simulation-hypothesis description: "The simulation hypothesis is the idea that our reality is a computer simulation run by some other reality." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Simulation hypothesis Definition The simulation hypothesis is the idea that our reality is a computer simulation run by some other reality. The people in it, and what they experience, would be made of computation. On this site This is the premise of the site. We don’t claim it’s true. The sandbox shows what it would take. Role in the model Every other page on the site comes out of this idea. The site doesn’t ask whether the hypothesis is true. It asks what it would take to run one. You can argue about a number. You can’t really argue about a belief. Related [Base reality](https://simulation-hypothesis.com/library/base-reality)[Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma)[Ancestor simulation](https://simulation-hypothesis.com/library/ancestor-simulation) In the trees [Ancestor simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-ancestor) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Base reality · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/base-reality description: "Base reality is the supposed non-simulated reality that runs simulations, if the simulation hypothesis is true." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Base reality Definition Base reality is the supposed non-simulated reality that runs simulations, if the simulation hypothesis is true. We assume it exists but can’t show it does, and the chain of simulations might never end. On this site The Infinite Regress window counts how many nested layers a given amount of computing can hold before the innermost is no bigger than a laptop. Role in the model Every world in the sandbox is run by a world one level up. If that world is simulated too, it has less computing power than the world above it. The Infinite Regress window turns this into a depth: how many nested worlds a given build can run before the innermost one is no bigger than a laptop. Related [Simulation hypothesis](https://simulation-hypothesis.com/library/simulation-hypothesis)[Infinite regress](https://simulation-hypothesis.com/library/infinite-regress) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Bostrom’s trilemma · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/bostrom-trilemma description: "Bostrom’s trilemma is Nick Bostrom’s 2003 argument that at least one of three propositions is true." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Bostrom’s trilemma Definition Bostrom’s trilemma is Nick Bostrom’s 2003 argument that at least one of three propositions is true. This follows if minds can run on any substrate and we have no reason to think we’re special. Either almost all civilisations die out before they can run ancestor simulations, or almost none of the mature ones ever do, or we almost certainly live in one. On this site The Trilemma window takes the first two probabilities as inputs and gives you the third. It’s just arithmetic on what you put in. It isn’t a verdict. Role in the model This is why the site treats your credence as a bet and not a verdict. We don’t ask you to accept a conclusion. We ask which of three options you find least unlikely. The Trilemma window fixes two of the probabilities and works out the third. Related [Ancestor simulation](https://simulation-hypothesis.com/library/ancestor-simulation)[Posthuman civilisation](https://simulation-hypothesis.com/library/posthuman)[Simulation hypothesis](https://simulation-hypothesis.com/library/simulation-hypothesis) In the trees [Ancestor simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-ancestor) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Ancestor simulation · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/ancestor-simulation description: "An ancestor simulation is a detailed recreation of a civilisation’s own past, including conscious inhabitants, run by its technologically mature descendants." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Ancestor simulation Definition An ancestor simulation is a detailed recreation of a civilisation’s own past, including conscious inhabitants, run by its technologically mature descendants. On this site The Render start slider. If the tape starts in 1900, everything earlier is unrendered backstory. Role in the model This is the kind of simulation Bostrom’s argument is about: descendants running their own past. It matters for the computing needed because a simulation of history can start late. The Render start slider shows this directly. Everything before switch-on is backstory, and nobody has to compute it. Related [Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma)[Posthuman civilisation](https://simulation-hypothesis.com/library/posthuman) In the trees [Ancestor simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-ancestor) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Posthuman civilisation · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/posthuman description: "A posthuman civilisation is one whose technology is far beyond ours today." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Posthuman civilisation Definition A posthuman civilisation is one whose technology is far beyond ours today. In particular, it can turn astronomical amounts of matter into computing. On this site The machine ladder ends in a universe-scale computer. That’s what “posthuman” has to mean for the biggest scenarios. Role in the model The machine ladder climbs from a phone to a computer the size of the universe. Every rung past “every computer on Earth” belongs to a civilisation that doesn’t exist yet. When a scenario lands on a Jupiter brain, this term names who would own it. Related [Bostrom’s trilemma](https://simulation-hypothesis.com/library/bostrom-trilemma)[Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound) In the trees [Superintelligence · Technology](https://simulation-hypothesis.com/trees/technology?n=asi)[Star-scale computer · Technology](https://simulation-hypothesis.com/trees/technology?n=matrioshka)[Post-biological civilisation · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=f-postbio) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Substrate independence · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/substrate-independence description: "Substrate independence is the idea that a mind depends only on how a system is organised and what it does, not on what it’s made of." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Substrate independence Definition Substrate independence is the idea that a mind depends only on how a system is organised and what it does, not on what it’s made of. Carbon, silicon or pure computation would all work. On this site Every mind in the sandbox is substrate-independent by design. Whether that even makes sense is a question for the hard problem. Role in the model The Mind model dial only makes sense if a mind can run on something other than a brain. If substrate independence is false, the computing a mind needs isn’t just large. It’s undefined, and every simulated person in every scenario is not really a someone. The sandbox assumes it’s true and says so. Related [Functionalism](https://simulation-hypothesis.com/library/functionalism)[Computationalism](https://simulation-hypothesis.com/library/computationalism)[The hard problem](https://simulation-hypothesis.com/library/hard-problem) In the trees [Mind uploading · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-upload)[Crossing by degrees · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=p-gradual)[A defence of AI rights · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-schwitz-garza) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Computationalism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/computationalism description: "Computationalism is the view that cognition is a form of computation, and that a mind is, in the relevant sense, a computing system." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Computationalism Definition Computationalism is the view that cognition is a form of computation, and that a mind is, in the relevant sense, a computing system. On this site The Mind model dial measures, in FLOPS, the computing that would run a mind. That only means something if computationalism is at least a reasonable working assumption. Role in the model Measuring a mind in floating-point operations is a computationalist commitment. If cognition isn’t computation, the Mind total measures the wrong thing. The site states the assumption out loud. The other choice is to leave minds out of the total, and that’s a bigger assumption dressed up as caution. Related [Substrate independence](https://simulation-hypothesis.com/library/substrate-independence)[Functionalism](https://simulation-hypothesis.com/library/functionalism)[Whole-brain emulation](https://simulation-hypothesis.com/library/whole-brain-emulation) In the trees [Universal machine · Technology](https://simulation-hypothesis.com/trees/technology?n=turing) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Infinite regress · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/infinite-regress description: "Infinite regress is the problem that if our reality is simulated, the reality running it might be too, with no natural place to stop." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Simulation hypothesis # Infinite regress Definition Infinite regress is the problem that if our reality is simulated, the reality running it might be too, with no natural place to stop. On this site The Regress window. Each layer has to run the one nested inside it, so the computing available sets a maximum depth. Role in the model A simulation inside a simulation isn’t free. Each layer has to run the one inside it. The Regress window does the division. For most builds the stack is shallow. For the biggest ones it has depth zero, because the outer universe can’t run even one copy. Related [Base reality](https://simulation-hypothesis.com/library/base-reality)[Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "FLOPS · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/flops description: "FLOPS means floating-point operations per second." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # FLOPS Definition FLOPS means floating-point operations per second. It measures how much arithmetic a machine can do. A modern laptop does around 10^13, and the largest supercomputers around 10^18. On this site The main figure on every tile. Everything else on the site is worked out from it. Role in the model FLOPS is the unit for the whole site. Every tile and bar shows a rate of operations per second, scaled differently. If you know what a laptop’s ten trillion FLOPS can and can’t do, you can read every other figure by counting orders of magnitude. Related [Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound)[Landauer limit](https://simulation-hypothesis.com/library/landauer-limit) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Lloyd’s bound · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/lloyd-bound description: "Lloyd’s bound is the physical limit on computing found by Seth Lloyd (2000)." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Lloyd’s bound Definition Lloyd’s bound is the physical limit on computing found by Seth Lloyd (2000). He worked out from quantum mechanics that one kilogram of matter can do at most about 5 × 10^50 elementary operations per second. For the observable universe that comes to roughly 10^104 operations per second, and 10^120 over cosmic history. On this site The universe-computer rung: all matter working at the physical maximum. It’s the top of the machine ladder. Role in the model Lloyd’s bound is the ceiling on the machine ladder. It makes a universe-scale computer a real physical object and not just a figure of speech. All the mass in the observable universe, computing at the physical limit, gives about 10^104 operations per second. Several sandbox scenarios need more than that. That’s what “physics says no” means here. Related [FLOPS](https://simulation-hypothesis.com/library/flops)[Landauer limit](https://simulation-hypothesis.com/library/landauer-limit)[Bekenstein bound](https://simulation-hypothesis.com/library/bekenstein-bound) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Landauer limit · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/landauer-limit description: "The Landauer limit is the least energy it takes to erase one bit of information." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Landauer limit Definition The Landauer limit is the least energy it takes to erase one bit of information. Rolf Landauer (1961) showed it’s at least kT ln 2, about 3 × 10^-21 joules at room temperature. On this site The Power tile multiplies the computing needed by this figure to get watts, then shows the result in solar luminosities. The most efficient hardware measured gives off about five billion times the limit per operation. Role in the model The Power tile multiplies the computing needed by the Landauer limit to get heat output, then shows it in Suns. Even with perfect hardware, a simulation this size has to give off at least this much heat somewhere. The most efficient hardware measured gives off about five billion times more per operation. Related [Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound)[FLOPS](https://simulation-hypothesis.com/library/flops) In the trees [Reversible computing · Technology](https://simulation-hypothesis.com/trees/technology?n=reversible)[The cost of forgetting · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=landauer-1961) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Bekenstein bound · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/bekenstein-bound description: "The Bekenstein bound is an upper limit on how much information a region of space can hold, given its energy." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Bekenstein bound Definition The Bekenstein bound is an upper limit on how much information a region of space can hold, given its energy. It grows with the region’s radius times its energy. On this site It means a simulation can’t store more state than the universe that contains it. So each nested layer has to be smaller than the one above, and the regress can’t go on forever. Role in the model Lloyd’s bound limits how fast a given mass can compute. Bekenstein’s limits how much it can store. Together they limit the regress. A simulated universe can’t hold more state than the region of the outer universe that runs it. So each layer has to be smaller than the one around it, and the nesting can’t go on forever. Related [Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound)[Infinite regress](https://simulation-hypothesis.com/library/infinite-regress) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Matter fidelity · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/matter-fidelity description: "Matter fidelity is how finely a simulation represents physical matter." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Matter fidelity Definition Matter fidelity is how finely a simulation represents physical matter. It runs from coarse statistical summaries, to individual particles, to full quantum states. On this site The Matter floor ladder, from Painted set to Quantum, fully entangled. It’s the dial that matters most for the total. Role in the model The Matter floor is the dial that matters most for the total. Other dials move it by a factor of ten or so. This one moves it by fifty orders of magnitude, from Painted set to Quantum, fully entangled. Related [Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail)[Molecular dynamics](https://simulation-hypothesis.com/library/molecular-dynamics)[Timestep](https://simulation-hypothesis.com/library/timestep) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Level of detail (LOD) · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/level-of-detail description: "Level of detail is a graphics technique where an object is drawn in more or less detail depending on how much the viewer needs it, usually how far it is from the camera." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Level of detail (LOD) Definition Level of detail is a graphics technique where an object is drawn in more or less detail depending on how much the viewer needs it, usually how far it is from the camera. On this site The Observation dial. At lower settings, only observed matter gets the full floor. Role in the model Video games have long saved effort by drawing what the player is looking at and roughly sketching the rest. The Observation dial applies the same idea to a universe. It’s the biggest single saving available to whoever runs the simulation. Related [Matter fidelity](https://simulation-hypothesis.com/library/matter-fidelity)[Observer effect](https://simulation-hypothesis.com/library/observer-effect)[Solipsism](https://simulation-hypothesis.com/library/solipsism) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Molecular dynamics · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/molecular-dynamics description: "Molecular dynamics is a way of simulating atoms and molecules on a computer." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Molecular dynamics Definition Molecular dynamics is a way of simulating atoms and molecules on a computer. It steps Newton’s equations forward with empirical force fields, usually in femtosecond timesteps. It’s the workhorse of computational chemistry. On this site The Atom rung uses the standard all-atom figure of about a thousand operations per atom per femtosecond step. Role in the model The Atom rung uses the operations per atom per femtosecond that chemists really use when they simulate a protein. The difference is scale. They simulate millions of atoms for microseconds. The sandbox asks for a whole planet over a century. Related [Matter fidelity](https://simulation-hypothesis.com/library/matter-fidelity)[Timestep](https://simulation-hypothesis.com/library/timestep) In the trees [Molecular dynamics · Simulations](https://simulation-hypothesis.com/trees/simulations?n=m-md)[Hard-sphere fluids · Simulations](https://simulation-hypothesis.com/trees/simulations?n=mat-hard) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Lattice QCD · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/lattice-qcd description: "Lattice QCD is a way of studying quantum chromodynamics, the theory of quarks and gluons, on a grid of discrete points in spacetime." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Lattice QCD Definition Lattice QCD is a way of studying quantum chromodynamics, the theory of quarks and gluons, on a grid of discrete points in spacetime. It’s among the most demanding computations in science. On this site The Quark rung. The computing it needs is too big to read on any normal scale. Role in the model When the Matter floor reaches Quark, the total stops being readable, and lattice QCD is why. Simulating the inside of a single proton carefully keeps a supercomputer busy for a long time. The sandbox multiplies that by every proton in the scenario. Related [Matter fidelity](https://simulation-hypothesis.com/library/matter-fidelity)[Quantum computing](https://simulation-hypothesis.com/library/quantum-computing) In the trees [Lattice gauge Monte Carlo · Simulations](https://simulation-hypothesis.com/trees/simulations?n=mat-lqcd) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Quantum computing · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/quantum-computing description: "Quantum computing uses superposition and entanglement." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Quantum computing Definition Quantum computing uses superposition and entanglement. Richard Feynman (1982) pointed out that ordinary computers can’t efficiently simulate typical quantum systems, and proposed quantum computers as the fix. On this site The Quantum, fully entangled rung is worked out for an ordinary classical machine, which has to store 2^(particles) amplitudes. This is the obstacle Feynman described. Role in the model Feynman’s point was that a classical computer needs 2^N numbers to describe N entangled particles. The Quantum, fully entangled rung is that number for a whole universe. It’s the one setting that pushes the total off the scale, because the exponent itself needs an exponent. Related [Superposition](https://simulation-hypothesis.com/library/superposition)[Entanglement](https://simulation-hypothesis.com/library/entanglement)[Lattice QCD](https://simulation-hypothesis.com/library/lattice-qcd) In the trees [Feynman’s quantum simulator · Simulations](https://simulation-hypothesis.com/trees/simulations?n=mat-feynman)[Quantum chemistry simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-quantum) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Whole-brain emulation · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/whole-brain-emulation description: "Whole-brain emulation is the proposal to simulate one particular brain in enough detail to reproduce its behaviour." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Whole-brain emulation Definition Whole-brain emulation is the proposal to simulate one particular brain in enough detail to reproduce its behaviour. Sandberg and Bostrom (2008) estimated the computing needed at anywhere from 10^15 FLOPS for population models to 10^43 for molecular detail. On this site The Mind model dial uses the roadmap’s levels: functional, biophysical and molecular. The quantum level is a placeholder with no empirical basis. Role in the model The Mind model dial comes from the whole-brain-emulation roadmap: functional, biophysical and molecular levels, each with a published computing figure per brain. It’s the only part of the model taken from a document and not from a physical constant. The Method page says so. Related [Computationalism](https://simulation-hypothesis.com/library/computationalism)[Substrate independence](https://simulation-hypothesis.com/library/substrate-independence)[Consciousness](https://simulation-hypothesis.com/library/consciousness) In the trees [Whole-brain emulation · Technology](https://simulation-hypothesis.com/trees/technology?n=wbe)[Whole-brain emulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-wbe)[Whole-brain emulation · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=s-wbe) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Timestep · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/timestep description: "A timestep is the slice of simulated time between one update of a simulation and the next." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Physics & computation # Timestep Definition A timestep is the slice of simulated time between one update of a simulation and the next. Faster physics needs smaller timesteps: femtoseconds for atoms, attoseconds for electrons. On this site It’s why the Atom rung needs 10^15 updates per second for each atom. Role in the model Detail adds up twice: in how many things you track, and in how often you update them. Atoms need a new position every femtosecond, so an atom-level world runs at a quadrillion updates per second. That’s why finer matter floors take far more computing than the number of things alone would suggest. Related [Matter fidelity](https://simulation-hypothesis.com/library/matter-fidelity)[Molecular dynamics](https://simulation-hypothesis.com/library/molecular-dynamics)[Planck time](https://simulation-hypothesis.com/library/planck-time) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Consciousness · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/consciousness description: "Consciousness is subjective experience: there being something it’s like to be a given system." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Consciousness Definition Consciousness is subjective experience: there being something it’s like to be a given system. It’s very hard to define and very hard to explain in physical terms. On this site The inner-lives cutoff and the Mind model together decide which entities get credited with experience, and how much. Role in the model The sandbox has one dial for how many things have an inside and another for how much inside each one has. Both rest on one working premise, stated here once for the whole site: computational functionalism. That’s the view that running the right computation is enough for a mind. On that premise, the model measures the computing that would run a mind. It doesn’t measure experience itself, and the tiles carry a “wild guess” tag where that matters. Related [The hard problem](https://simulation-hypothesis.com/library/hard-problem)[Qualia](https://simulation-hypothesis.com/library/qualia)[Sentience](https://simulation-hypothesis.com/library/sentience)[Panpsychism](https://simulation-hypothesis.com/library/panpsychism) In the trees [Cambridge Declaration · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-cambridge)[New York Declaration · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-ny-declaration) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "The hard problem · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/hard-problem description: "The hard problem is the question of why and how physical processes give rise to experience at all." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # The hard problem Definition The hard problem is the question of why and how physical processes give rise to experience at all. David Chalmers coined the name, to set it apart from the “easy” problems of explaining behaviour and function. On this site The Mind model dial measures the easy problems. The hard problem isn’t in the total, because nobody knows what it would take. Role in the model The Mind total covers the easy problems: perception, memory and behaviour. All of those can be computed in principle. The hard problem isn’t in the total, because nobody knows what it would take, if it takes anything. When the sandbox says a scenario “thinks”, it isn’t claiming the scenario feels. Related [Consciousness](https://simulation-hypothesis.com/library/consciousness)[Qualia](https://simulation-hypothesis.com/library/qualia)[Philosophical zombie](https://simulation-hypothesis.com/library/philosophical-zombie) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Qualia · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/qualia description: "Qualia are the felt qualities of experience that you can notice in yourself: the redness of red, the painfulness of pain." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Qualia Definition Qualia are the felt qualities of experience that you can notice in yourself: the redness of red, the painfulness of pain. On this site The Suffering dial assumes simulated pain might really feel like pain. The sandbox can’t settle that. It only measures the computing for the behaviour that goes with it. Role in the model The Suffering dial changes the ethics meters and not a single FLOP, and qualia are the reason. Simulating the body’s side of pain is cheap. Whether that comes with the felt quality of pain is something the computing figure can’t show. The sandbox doesn’t pretend it can. Related [Consciousness](https://simulation-hypothesis.com/library/consciousness)[The hard problem](https://simulation-hypothesis.com/library/hard-problem)[Sentience](https://simulation-hypothesis.com/library/sentience) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Philosophical zombie · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/philosophical-zombie description: "A philosophical zombie is an imagined being that’s physically and behaviourally identical to a conscious person but has no inner experience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Philosophical zombie Definition A philosophical zombie is an imagined being that’s physically and behaviourally identical to a conscious person but has no inner experience. People use it to argue that consciousness doesn’t follow from the physical facts alone. On this site The Scripted mind model, or the whole world with the inner-lives switch off. Role in the model Setting the Mind model to Scripted fills a scenario with mimics. They say the right words and react the right way from a script, with no experience behind it. They aren’t zombies in the strict sense. A strict zombie is a physical and functional copy of a person, and a script is far simpler. It’s by far the cheapest way to fill a world with people. The Four schools window shows how each school of ethics judges it. Related [The hard problem](https://simulation-hypothesis.com/library/hard-problem)[Functionalism](https://simulation-hypothesis.com/library/functionalism)[The problem of other minds](https://simulation-hypothesis.com/library/other-minds) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Functionalism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/functionalism description: "Functionalism is the view that a mental state is defined by what it does: how it connects to inputs, outputs and other mental states." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Functionalism Definition Functionalism is the view that a mental state is defined by what it does: how it connects to inputs, outputs and other mental states. What it’s physically made of doesn’t matter. On this site The Functional mind model. Each neuron is a node and each synapse is a weight, and nothing else is represented. Role in the model The Functional mind model is functionalism with a number on it: each neuron is a node, each synapse is a weight, and nothing else is represented. If only the rough functional organisation matters, this rung is enough for a mind. If finer physical detail matters, you need a higher rung, all the way up to the quantum one. If no digital version can be conscious, as Searle and integrated information theory say, no rung works. Related [Computationalism](https://simulation-hypothesis.com/library/computationalism)[Substrate independence](https://simulation-hypothesis.com/library/substrate-independence)[Philosophical zombie](https://simulation-hypothesis.com/library/philosophical-zombie) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Sentience · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/sentience description: "Sentience is the ability to have experiences that feel good or bad." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Sentience Definition Sentience is the ability to have experiences that feel good or bad. It means being able to feel, and especially to suffer. On this site The inner-lives ladder from fruit fly to human is ordered by how likely sentience is. It isn’t a list of confirmed cases. Role in the model The inner-lives ladder runs from fruit fly to human, ordered by how likely it is that the entity can suffer. Where you set the cutoff decides how many billions of inhabitants the ethics meters have to weigh. It’s a gradient, not a roster. Related [Consciousness](https://simulation-hypothesis.com/library/consciousness)[Qualia](https://simulation-hypothesis.com/library/qualia)[Moral status](https://simulation-hypothesis.com/library/moral-status) In the trees [Can they suffer · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-bentham)[Crabs and octopuses review · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-birch)[The UK’s Animal Welfare (Sentience) Act 2022 · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-sentience-act) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Panpsychism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/panpsychism description: "Panpsychism is the view that mind is basic and everywhere, so even elementary physical things have some tiny form of experience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Panpsychism Definition Panpsychism is the view that mind is basic and everywhere, so even elementary physical things have some tiny form of experience. On this site The top of the inner-lives ladder, Everything, gives every particle a micro-experience at one operation per second. Role in the model The top of the inner-lives ladder is labelled Everything. At that setting every particle gets a tiny experience at one operation per second. The total barely changes. That’s the panpsychist’s point: experience may be cheap, free, or already included. Related [Consciousness](https://simulation-hypothesis.com/library/consciousness)[The hard problem](https://simulation-hypothesis.com/library/hard-problem) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Integrated information theory · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/integrated-information description: "Integrated information theory is Giulio Tononi’s proposal that consciousness matches the amount of integrated information (Φ) a system produces, over and above what its parts produce alone." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # Integrated information theory Definition Integrated information theory is Giulio Tononi’s proposal that consciousness matches the amount of integrated information (Φ) a system produces, over and above what its parts produce alone. On this site It’s one of the few frameworks that could in principle tell us whether a given simulation contains minds. The sandbox doesn’t try the calculation. Role in the model IIT puts consciousness in the physical cause-and-effect structure of a system, not in the computation it runs. So on IIT, a brain simulated on ordinary digital hardware would have almost none, whatever it simulates. It’s the best-known theory on which the model’s working premise fails. The sandbox assumes the premise and says so. Related [Consciousness](https://simulation-hypothesis.com/library/consciousness)[Functionalism](https://simulation-hypothesis.com/library/functionalism) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "The problem of other minds · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/other-minds description: "The problem of other minds is the question of how you can justify believing that anyone else has a mind, when you only ever have direct access to your own experience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Philosophy of mind # The problem of other minds Definition The problem of other minds is the question of how you can justify believing that anyone else has a mind, when you only ever have direct access to your own experience. On this site The Lobby dial: a single player, everyone, or players and non-player characters you can’t tell apart from the inside. Role in the model The Lobby dial is this problem turned into a setting. You can have a single player, everyone as a real player, or real players mixed with non-player characters. From the inside, you can’t tell which. Related [Solipsism](https://simulation-hypothesis.com/library/solipsism)[Philosophical zombie](https://simulation-hypothesis.com/library/philosophical-zombie)[Skepticism](https://simulation-hypothesis.com/library/skepticism) In the trees [Suppose you are the only one · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-alone)[Simulating other minds · Simulations](https://simulation-hypothesis.com/trees/simulations?n=soc-gordon) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Epistemology · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/epistemology description: "Epistemology is the part of philosophy about what knowledge is, where it comes from, and where it runs out." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Epistemology Definition Epistemology is the part of philosophy about what knowledge is, where it comes from, and where it runs out. It also covers what makes a belief justified. On this site The Honesty axis: whether the inhabitants could, in principle, find out how their world works. Role in the model The Honesty axis in the ethics radar measures one thing: whether the inhabitants of a scenario could, in principle, work out how their world runs. A world that hides how it’s rendered sets a trap for what its people can know. The meters score it down for that. Related [Skepticism](https://simulation-hypothesis.com/library/skepticism)[Solipsism](https://simulation-hypothesis.com/library/solipsism)[Brain in a vat](https://simulation-hypothesis.com/library/brain-in-a-vat) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Skepticism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/skepticism description: "Skepticism is any philosophical position that denies we can know things, or certain kinds of things." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Skepticism Definition Skepticism is any philosophical position that denies we can know things, or certain kinds of things. Radical skepticism doubts that the outside world exists. On this site The opening question of the site. Neither answer is graded. Role in the model Your Reality is a skeptic’s tool. Ten answers describe a reality, and none of them is marked right or wrong. The human-cost scores beside each answer are the author’s judgement, not a grade. Related [Descartes’ demon](https://simulation-hypothesis.com/library/evil-demon)[Brain in a vat](https://simulation-hypothesis.com/library/brain-in-a-vat)[Epistemology](https://simulation-hypothesis.com/library/epistemology) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Solipsism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/solipsism description: "Solipsism is the view that only your own mind is certain to exist, and that the outside world and other minds might be made up by it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Solipsism Definition Solipsism is the view that only your own mind is certain to exist, and that the outside world and other minds might be made up by it. On this site The Solipsism preset: a single player, with only observed matter rendered. It’s among the cheapest scenarios. Role in the model The Solipsism preset is a single player with only observed matter rendered. It’s among the cheapest scenarios. So the universe that fits “only I exist” best is also the cheapest one to run. Related [The problem of other minds](https://simulation-hypothesis.com/library/other-minds)[Skepticism](https://simulation-hypothesis.com/library/skepticism)[Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail) In the trees [Suppose you are the only one · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-alone) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Brain in a vat · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/brain-in-a-vat description: "A brain in a vat is a thought experiment about a brain with no body, fed simulated sensory input." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Brain in a vat Definition A brain in a vat is a thought experiment about a brain with no body, fed simulated sensory input. It tests whether we can know we’re not in that situation. Hilary Putnam argued the scenario defeats itself, because of what our words can refer to. On this site The Brain in a Vat preset. The brain itself doesn’t count toward the total, and the world it senses fits in a few racks of GPUs. Role in the model The Brain in a Vat preset is the smallest simulation the sandbox can build: a real brain in base reality, with the world fed to it as sensory input. The brain does its own thinking, so only the world needs computing, and it fits in a few racks of GPUs. Related [Descartes’ demon](https://simulation-hypothesis.com/library/evil-demon)[Skepticism](https://simulation-hypothesis.com/library/skepticism)[Solipsism](https://simulation-hypothesis.com/library/solipsism) In the trees [Full-immersion VR · Technology](https://simulation-hypothesis.com/trees/technology?n=fulldive) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Descartes’ demon · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/evil-demon description: "Descartes’ demon is the all-powerful deceiver Descartes imagined in 1641, who systematically fakes all your experience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Descartes’ demon Definition Descartes’ demon is the all-powerful deceiver Descartes imagined in 1641, who systematically fakes all your experience. He used it to find out what, if anything, survives radical doubt. On this site The operator on a break, in the Slot dial, is a weaker version of the demon on purpose. Role in the model Descartes’ deceiver is an early simulation hypothesis, four centuries before the hardware. The operator on a break in the Slot dial is a weaker version of the same figure. The thinker page lays out the argument. Related [Skepticism](https://simulation-hypothesis.com/library/skepticism)[Brain in a vat](https://simulation-hypothesis.com/library/brain-in-a-vat) In the trees [Suppose you are the only one · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-alone) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Ontology · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/ontology description: "Ontology is the part of metaphysics about what exists and what kinds of things there are." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Epistemology & reality # Ontology Definition Ontology is the part of metaphysics about what exists and what kinds of things there are. On this site Whether the beings in a scenario exist is an ontological question. The computing figure takes no side on it. Role in the model The computing figure takes no side on whether the inhabitants of a scenario exist. It measures the computation and stops there. Whether a perfectly simulated person is a person is an ontological question. The sandbox only helps by showing what the simulation takes. Related [Base reality](https://simulation-hypothesis.com/library/base-reality)[Consciousness](https://simulation-hypothesis.com/library/consciousness) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Moral status · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/moral-status description: "Moral status is what an entity has when its interests matter in themselves, and have to be counted when we decide what’s right." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Moral status Definition Moral status is what an entity has when its interests matter in themselves, and have to be counted when we decide what’s right. On this site The Moral weight window shows how much consideration each kind of entity gets under the current dial settings. Role in the model The Moral weight window splits consideration among players, non-player characters, animals with experience, scenery and the operator. The split follows from the dial settings. It’s a sketch, labelled as one, and it makes one point: the settings decide who counts before anyone asks the question. Related [Sentience](https://simulation-hypothesis.com/library/sentience)[Utilitarianism](https://simulation-hypothesis.com/library/utilitarianism)[Deontology](https://simulation-hypothesis.com/library/deontology) In the trees [Can they suffer · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-bentham)[Taking AI welfare seriously · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-long) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Utilitarianism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/utilitarianism description: "Utilitarianism is the theory that the right action is the one that does the most good overall." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Utilitarianism Definition Utilitarianism is the theory that the right action is the one that does the most good overall. Classically, that means the most pleasure over pain. On this site The Util. column. It scores the Dialed-up setting poorly and the Experience machine highly. Role in the model The Util. column adds up the suffering in a scenario, weighted by how much each being can experience it. It scores Dialed up poorly and the Afterlife preset highly, because a painless world of maximum bliss is what hedonic arithmetic recommends. That’s the hedonic version of utilitarianism. The preference and objective-list versions wouldn’t endorse the Afterlife preset. Related [Moral status](https://simulation-hypothesis.com/library/moral-status)[The experience machine](https://simulation-hypothesis.com/library/experience-machine) In the trees [Count the consequences · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-util) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Deontology · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/deontology description: "Deontology is a family of ethical theories that say some acts are right or wrong in themselves, because of duties and rights, whatever their results." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Deontology Definition Deontology is a family of ethical theories that say some acts are right or wrong in themselves, because of duties and rights, whatever their results. Kant is the classic example. On this site The Deont. column. It marks down deceiving the inhabitants and using pain as a tool. Role in the model The Deont. column holds two objections no matter what it costs: deceiving the inhabitants about what their world is, and using pain to control them. Both are cheap in FLOPS. On this view neither is allowed, whatever the numbers say. Related [Moral status](https://simulation-hypothesis.com/library/moral-status)[Free will](https://simulation-hypothesis.com/library/free-will) In the trees [Give yourself the law · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-kant) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Virtue ethics · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/virtue-ethics description: "Virtue ethics is the tradition, going back to Aristotle, that judges actions by what they say about a person’s character and whether they help a person flourish." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Virtue ethics Definition Virtue ethics is the tradition, going back to Aristotle, that judges actions by what they say about a person’s character and whether they help a person flourish. It cares less about rules or outcomes. On this site The Virtue column peaks at As found, on the view that character needs something to push against. Role in the model The Virtue column peaks at As found suffering and real freedom, and drops off in both directions. A world with no hardship gives people no chance to build character. A world with nothing but hardship doesn’t either. Related [The experience machine](https://simulation-hypothesis.com/library/experience-machine)[Free will](https://simulation-hypothesis.com/library/free-will) In the trees [Virtue is a habit · Ethics](https://simulation-hypothesis.com/trees/ethics?n=a-aristotle)[Choose who you are · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-virtue-back) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Existentialism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/existentialism description: "Existentialism is a tradition about freedom, responsibility and making your own meaning in a world with no given purpose." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Existentialism Definition Existentialism is a tradition about freedom, responsibility and making your own meaning in a world with no given purpose. Kierkegaard, Nietzsche, Sartre and de Beauvoir are tied to it. On this site The Exist. column. It favours Genuinely free will and real stakes, and treats engineered bliss as bad faith. Role in the model The Exist. column favours real freedom and real stakes, and treats engineered bliss as bad faith. It’s the one school whose approval goes up as the scenario gets less comfortable. Related [Free will](https://simulation-hypothesis.com/library/free-will)[Eternal return](https://simulation-hypothesis.com/library/eternal-return) In the trees [Existence before essence · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-sartre)[Live without a given meaning · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-camus) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Free will · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/free-will description: "Free will is the ability of agents to choose between alternatives in a way that makes them morally responsible." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Free will Definition Free will is the ability of agents to choose between alternatives in a way that makes them morally responsible. Libertarians say this needs indeterminism. Compatibilists say it fits with determinism. Hard determinists deny it exists. On this site The Free will dial. Genuinely free adds no computing, because nobody knows how to compute it. Role in the model The Free will dial adds no computing, and that’s the finding. Determined, random and compatibilist choices are all cheap to render. For Genuinely free, nobody knows how to compute it. So whoever runs the world has to leave a gap and accept whatever shows up in it. The Tensions window flags this. Related [Determinism](https://simulation-hypothesis.com/library/determinism)[Compatibilism](https://simulation-hypothesis.com/library/compatibilism)[Existentialism](https://simulation-hypothesis.com/library/existentialism) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Determinism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/determinism description: "Determinism is the thesis that every event is made necessary by earlier events together with the laws of nature." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Determinism Definition Determinism is the thesis that every event is made necessary by earlier events together with the laws of nature. On this site The Determined setting: seeded, replayable and identical on every run. Role in the model The Determined setting is a seeded universe. You can replay it, and it comes out the same on every run, with each choice fixed by what came before. It’s also the cheapest time model, because a deterministic world can be stored as a seed and a rule. Related [Free will](https://simulation-hypothesis.com/library/free-will)[Compatibilism](https://simulation-hypothesis.com/library/compatibilism)[Causality](https://simulation-hypothesis.com/library/causality) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Compatibilism · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/compatibilism description: "Compatibilism is the view that free will and determinism can both be true." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # Compatibilism Definition Compatibilism is the view that free will and determinism can both be true. An action is free if it comes from the agent’s own reasons and desires, even if those were themselves determined. On this site The Feels free setting. The experience of choosing is rendered in full, and the mechanism stays hidden. Role in the model The Feels free setting is the default because it matches what most people mean by free will when they think about it. The experience of choosing is rendered in full. The inhabitant never sees the mechanism underneath. Related [Free will](https://simulation-hypothesis.com/library/free-will)[Determinism](https://simulation-hypothesis.com/library/determinism) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "The experience machine · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/experience-machine description: "The experience machine is Robert Nozick’s 1974 thought experiment about a machine that gives you any experiences you pick, indistinguishable from reality." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Ethics & metaphysics # The experience machine Definition The experience machine is Robert Nozick’s 1974 thought experiment about a machine that gives you any experiences you pick, indistinguishable from reality. Most people say they wouldn’t plug in. That suggests we value more than just experience. On this site The Afterlife preset, which is cheaper to run than an ordinary day. Role in the model The Afterlife preset is Nozick’s machine, built and measured. Paradise turns out cheaper than an ordinary day. No suffering means no stakes, and no stakes means little to compute. Three of the four schools object. One doesn’t. Related [Utilitarianism](https://simulation-hypothesis.com/library/utilitarianism)[Virtue ethics](https://simulation-hypothesis.com/library/virtue-ethics)[Qualia](https://simulation-hypothesis.com/library/qualia) In the trees [The experience machine · Ethics](https://simulation-hypothesis.com/trees/ethics?n=x-machine) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Superposition · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/superposition description: "Superposition is the principle that a quantum system can be in a blend of different states at once, and only gives a definite result when it’s measured." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Superposition Definition Superposition is the principle that a quantum system can be in a blend of different states at once, and only gives a definite result when it’s measured. On this site In the sandbox, it’s the state of unobserved regions under Level of detail. Role in the model The unobserved parts of a low-observation world aren’t rendered as matter. They’re stored as a placeholder and filled in when someone looks. The sandbox borrows the word from quantum mechanics because the idea has a similar shape. The mechanism isn’t the same. Related [Wave function](https://simulation-hypothesis.com/library/wave-function)[The measurement problem](https://simulation-hypothesis.com/library/measurement-problem)[Observer effect](https://simulation-hypothesis.com/library/observer-effect) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Wave function · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/wave-function description: "The wave function is the mathematical object that holds the complete quantum state of a system." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Wave function Definition The wave function is the mathematical object that holds the complete quantum state of a system. For N two-state particles it has 2^N complex components. On this site The Quantum, fully entangled rung stores one of these for the whole build. That’s why the total goes off the scale. Role in the model The Quantum, fully entangled rung stores one wave function for the whole build. For a universe, that’s 2^(10^80) numbers. The total doesn’t just grow. It leaves the number line, and the site has to adopt a new notation to write it down. Related [Superposition](https://simulation-hypothesis.com/library/superposition)[Entanglement](https://simulation-hypothesis.com/library/entanglement)[Quantum computing](https://simulation-hypothesis.com/library/quantum-computing) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Entanglement · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/entanglement description: "Entanglement is a quantum link between systems, so that the state of the whole can’t be written as separate states of the parts." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Entanglement Definition Entanglement is a quantum link between systems, so that the state of the whole can’t be written as separate states of the parts. On this site The difference between the Mean-field rung, which treats particles as separate, and the Fully entangled rung, which doesn’t. Role in the model Entanglement is the gap between the Mean-field and Fully entangled rungs. Mean-field treats each particle as separate, and the total stays finite. Fully entangled admits they aren’t separate, and the exponent gets an exponent. Related [Wave function](https://simulation-hypothesis.com/library/wave-function)[Quantum computing](https://simulation-hypothesis.com/library/quantum-computing)[Decoherence](https://simulation-hypothesis.com/library/decoherence) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "The measurement problem · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/measurement-problem description: "The measurement problem is the open question of how, why and whether the wave function collapses to one definite result when we measure it, and what counts as a measurement." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # The measurement problem Definition The measurement problem is the open question of how, why and whether the wave function collapses to one definite result when we measure it, and what counts as a measurement. On this site The Observation dial takes a render-on-observation view: being watched is what costs computing. Role in the model The Observation dial takes the renderer’s side in a dispute that’s still open: being watched is what costs computing. Physicists don’t agree on what observing does to a system. The sandbox doesn’t need them to agree. It only needs a dial. Related [Superposition](https://simulation-hypothesis.com/library/superposition)[Observer effect](https://simulation-hypothesis.com/library/observer-effect)[Many-worlds interpretation](https://simulation-hypothesis.com/library/many-worlds) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Many-worlds interpretation · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/many-worlds description: "The many-worlds interpretation is Hugh Everett’s idea that the wave function never collapses." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Many-worlds interpretation Definition The many-worlds interpretation is Hugh Everett’s idea that the wave function never collapses. Every possible measurement result happens, in a branching multiverse. On this site The Many worlds time model. The computing needed doubles with each quantum event, and there are a great many events. Role in the model The Many worlds time model doubles the computing needed at every quantum event, and there are a great many. Apart from full entanglement, it’s the only setting that can push a scenario off the scale. Related [The measurement problem](https://simulation-hypothesis.com/library/measurement-problem)[Wave function](https://simulation-hypothesis.com/library/wave-function)[Superposition](https://simulation-hypothesis.com/library/superposition) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Decoherence · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/decoherence description: "Decoherence is the process where a quantum system’s contact with its surroundings wipes out the interference between the parts of its superposition." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Decoherence Definition Decoherence is the process where a quantum system’s contact with its surroundings wipes out the interference between the parts of its superposition. After that, it behaves classically. On this site The physical reason the Atom rung can use classical mechanics for most of the universe most of the time. Role in the model Decoherence is why the Atom rung can use classical physics for most of the universe most of the time. Macroscopic objects stop acting quantum-mechanically because their surroundings keep interacting with them. It’s the physics that makes a cheap simulation defensible. Related [Superposition](https://simulation-hypothesis.com/library/superposition)[Entanglement](https://simulation-hypothesis.com/library/entanglement) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Observer effect · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/observer-effect description: "In quantum mechanics, the observer effect is the way measuring a system disturbs it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Observer effect Definition In quantum mechanics, the observer effect is the way measuring a system disturbs it. People often mix it up with consciousness causing collapse, which few physicists accept. On this site The Observation dial is about how much attention a renderer spends, not about minds collapsing wave functions. Role in the model The Observation dial is about how much attention the renderer spends, not about consciousness collapsing the wave function. The sandbox keeps the two apart on purpose, because most physicists reject the popular version of the observer effect. Related [The measurement problem](https://simulation-hypothesis.com/library/measurement-problem)[Level of detail (LOD)](https://simulation-hypothesis.com/library/level-of-detail) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Planck time · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/planck-time description: "Planck time is about 5.4 × 10^-44 seconds." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Quantum mechanics # Planck time Definition Planck time is about 5.4 × 10^-44 seconds. It’s the timescale where quantum gravity is expected to matter, and below it the idea of time may not apply. On this site The finest timestep a simulation could need. The sandbox stops at yoctoseconds, but the physics might not. Role in the model This is the finest timestep a simulation could need. The sandbox stops at yoctoseconds for the quark rung. A universe simulated at the Planck scale would need roughly another twenty orders of magnitude. Nothing on the machine ladder comes close. Related [Timestep](https://simulation-hypothesis.com/library/timestep)[Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Causality · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/causality description: "Causality is the link between causes and their effects." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Time & causality # Causality Definition Causality is the link between causes and their effects. In physics, it’s the rule that an effect never comes before its cause in any reference frame. On this site The Time model dial: linear, looped, forked or simultaneous. Role in the model The Time model dial sets the cause-and-effect structure: one timeline, a loop, a pruned tree, or every branch at once. Each one takes a different amount of computing. Each gives a different answer to whether yesterday had to happen the way it did. Related [Determinism](https://simulation-hypothesis.com/library/determinism)[Block universe](https://simulation-hypothesis.com/library/block-universe)[Arrow of time](https://simulation-hypothesis.com/library/arrow-of-time) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Eternal return · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/eternal-return description: "Eternal return is Nietzsche’s thought experiment of a universe that repeats exactly, over and over without end." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Time & causality # Eternal return Definition Eternal return is Nietzsche’s thought experiment of a universe that repeats exactly, over and over without end. He posed it as a test of whether you’d say yes to your own life. On this site The Cyclic time model, which stores one cycle and replays it. Role in the model The Cyclic time model stores one cycle of the universe and replays it. It takes no more than linear time plus a very long tape. It also puts Nietzsche’s question to every inhabitant: would you say yes to living this exact life again, forever? Related [Existentialism](https://simulation-hypothesis.com/library/existentialism)[Causality](https://simulation-hypothesis.com/library/causality) In the trees [The death of God · Ethics](https://simulation-hypothesis.com/trees/ethics?n=g-nietzsche) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Block universe · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/block-universe description: "The block universe is the view, encouraged by relativity, that past, present and future are all equally real, and that time passing isn’t a basic feature of the world." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Time & causality # Block universe Definition The block universe is the view, encouraged by relativity, that past, present and future are all equally real, and that time passing isn’t a basic feature of the world. On this site The Render start slider treats everything before the start as backstory. In a block universe, all of it is equally present. Role in the model If all of time already exists, the Render start slider measures the wrong thing. There’s no “before switch-on”, only earlier pages of a book that’s already printed. The sandbox uses the other view, where time unfolds, because it’s the one you can attach a number to. Related [Causality](https://simulation-hypothesis.com/library/causality)[Arrow of time](https://simulation-hypothesis.com/library/arrow-of-time)[Determinism](https://simulation-hypothesis.com/library/determinism) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Arrow of time · Library · Simulation Hypothesis" url: https://simulation-hypothesis.com/library/arrow-of-time description: "The arrow of time is the difference between past and future." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- ## Time & causality # Arrow of time Definition The arrow of time is the difference between past and future. At bottom it comes from the second law of thermodynamics: entropy goes up. On this site It’s behind the energy a simulation needs. Landauer’s limit ties the irreversibility of erasure to an energy cost. Role in the model Landauer’s limit is the arrow of time with an energy cost attached. Each irreversible step the simulation takes erases information. Erasing costs heat, and that heat is entropy going up. The Power tile is the second law, shown in Suns. Related [Landauer limit](https://simulation-hypothesis.com/library/landauer-limit)[Causality](https://simulation-hypothesis.com/library/causality)[Block universe](https://simulation-hypothesis.com/library/block-universe) ## The people behind the terms 14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading). [Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers) --- title: "Sentience criteria for animals · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/sentience description: "The eight criteria from the 2021 review that led UK law to recognise octopuses and crabs as sentient, and what the review found." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Sentience criteria # Sentience criteria for animals In 2021 a team led by Jonathan Birch reviewed the evidence that octopuses, crabs and related animals are sentient, using eight criteria. The report led the UK to recognise them as sentient in law. 1. The animal possesses receptors sensitive to noxious stimuli (nociceptors) 2. The animal possesses integrative brain regions capable of integrating information from different sensory sources 3. The animal possesses neural pathways connecting the nociceptors to the integrative brain regions 4. The animal's behavioural response to a noxious stimulus is modulated by chemical compounds affecting the nervous system (e.g. local anaesthetics, analgesics, opioid-type systems) 5. The animal shows motivational trade-offs, in which the disvalue of a noxious or threatening stimulus is weighed against the value of an opportunity for reward, leading to flexible decision-making 6. The animal shows flexible self-protective behaviour (e.g. wound-tending, guarding, grooming, rubbing) of a type likely to involve representing the bodily location of an injury or noxious stimulus 7. The animal shows associative learning in which noxious stimuli become associated with neutral stimuli, and/or novel ways of avoiding noxious stimuli are learned through reinforcement (habituation and sensitisation do not count) 8. The animal shows that it values a putative analgesic or anaesthetic when injured (e.g. self-administers it, or learns to prefer a location where it is available) ## How the review graded evidence * **2**: some evidence * **7-8 criteria at high/very high**: very strong evidence * **5-6**: strong evidence * **3-4**: substantial evidence * **0-1**: sentience unknown or unlikely ## What it found Very strong evidence of sentience in octopods. Substantial evidence in other coleoids (high confidence for criteria 1, 2, 3 and 7). Strong evidence in true crabs (high or very high for 1, 2, 4, 6 and 7). Substantial evidence in anomuran crabs (high for 1, 2 and 6, medium for 5) and in astacid lobsters and crayfish (high or very high for 1, 2 and 4). Low confidence means the evidence is thin, not that the trait is absent. No group had high confidence of failing a criterion. | Group | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | | ------------------------- | -- | -- | - | -- | - | -- | -- | -- | | Octopods | VH | VH | H | H | M | VH | VH | H | | Cuttlefish | H | VH | H | L | M | M | VH | L | | Other coleoids (squid) | H | VH | H | L | M | L | H | L | | Nautiloids | H | L | L | L | L | L | M | VL | | True crabs (Brachyura) | H | VH | L | VH | L | VH | H | VL | | Anomuran crabs | H | VH | L | L | M | H | L | VL | | Astacid lobsters/crayfish | H | VH | L | VH | L | L | M | VL | | Spiny lobsters | H | VH | L | L | L | L | M | VL | | Caridean shrimps | H | VH | L | M | L | M | L | VL | | Penaeid shrimps | H | L | L | M | L | L | L | VL | VH very high, H high, M medium, L low, VL very low. ## What changed The UK Animal Welfare (Sentience) Act 2022 (Royal Assent 28 April 2022) recognises animals as sentient and sets up an Animal Sentience Committee. The committee reports on whether government policy pays due regard to animal welfare. After the Birch report, the Lords amended the Bill so that 'animal' includes decapod crustaceans and cephalopod molluscs as well as vertebrates. That covers all cephalopods and decapods, not just octopods and true crabs. https://www.legislation.gov.uk/ukpga/2022/22 Birch J, Burn C, Schnell A, Browning H, Crump A (2021). Review of the Evidence of Sentience in Cephalopod Molluscs and Decapod Crustaceans. LSE Consulting, 19 Nov 2021\. https://www.lse.ac.uk/business/consulting/assets/documents/Sentience-in-Cephalopod-Molluscs-and-Decapod-Crustaceans-Final-Report-November-2021.pdf (read directly) --- title: "How directed time is estimated · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/control description: "How the Entities charts weigh religions, states, parties and corporations by how much of their members’ waking time they direct." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › How directed time is estimated # How directed time is estimated Religious codes, laws, party rules and job descriptions are treated alike here: as instructions that direct some of their members’ waking time. The charts estimate that share and express it in neuron-equivalents. It's a share of time scaled by brain size, not a count of neurons in use. A brain that's following an instruction is still doing plenty else. ## The estimate **Neuron-equivalents = members × 8.61 × 10¹⁰ × c.** The neuron count is the measured human average. The share directed, _c_, is the fraction of a member’s waking hours that the organisation’s instructions decide. Each hour is weighted by how fully they decide it: * **Directed (1.0):** the organisation sets the action. A shift at work, a prayer, a service, a lesson. * **Restricted (0.5):** it rules out most options for a stretch of time. Examples are the Sabbath, and dietary laws that settle most of a meal. * **Ruled (0.25):** it rules out one kind of option. Examples are a rule against one kind of food, or a community code on dress, media and technology. _c_ \= Σ (share of members who keep the practice × hours a week × weight) ÷ 104.79 waking hours. The week has 104.79 waking hours because adults spend 9.03 hours a day in bed; meals take 8.68 hours a week; the waking part of a 25-hour Sabbath is 15.59 hours. US Bureau of Labor Statistics, American Time Use Survey (2024 eating; 2025 sleep). The weights are judgement calls, not measurements. A rule that removes one kind of option governs less of an hour than one that removes most of them, and less than an instruction that fills the hour. Shares come from surveys of what members say they do, not from what doctrine requires. A code over “all other hours” covers only what the listed practices leave, so no hour is counted twice. ## What it leaves out * Influence without instruction: belief, identity, and the choices a member makes in the organisation’s spirit. We only count behaviour that takes a measurable amount of time. * Children. Survey shares are for adults and are applied to all members. * Overlap. Someone who belongs to a religion and works for a company is counted in both. The charts are separate, so nothing is added up. * Shareholders and customers. They're influenced, not directed. ## Religions ### Islam: 5.1%, 8.9 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 2.02 billion members (Pew Research Center (2025), How the Global Religious Landscape Changed From 2010 to 2020). The diet share is measured in India only. Dress and modesty codes vary by country and are not counted. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Sunni Islam: 5.1%, 7.9 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 1.79 billion members (Pew Research Center: the 2025 Muslim total × the 2009 sect shares (87–90% Sunni, 10–13% Shia)). Surveys find practice differs by country, not by sect (Ramadan fasting: 88% median in both, five countries), so the Islam figures are used. Following a senior cleric (taqlid) and the khums tax are Shia obligations no survey has measured. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Christianity: 0.88%, 1.7 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 2.27 billion members (Pew Research Center (2025), How the Global Religious Landscape Changed From 2010 to 2020). Lent and other fasts are not measured worldwide and are left out. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Hinduism: 1.6%, 1.6 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer or puja \* | 59% | 1.17 | 1 (directed) | 0.69 | | Vegetarian diet at meals | 44% | 8.68 | 0.25 (ruled) | 0.95 | | **Total** | | | | **1.64** | 1.18 billion members (Pew Research Center (2025), How the Global Religious Landscape Changed From 2010 to 2020). Measured in India, home to about 94% of Hindus. Fasts and temple visits are not counted. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Protestantism: 1.9%, 1.3 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 800 million members (Pew Research Center (2011), Global Christianity). Shares are Latin American medians; Protestants elsewhere, especially in Europe, attend less. Membership is from 2010\. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Catholicism: 1.1%, 1.3 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | --------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 64% | 1.17 | 1 (directed) | 0.75 | | Weekly Mass \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **1.14** | 1.41 billion members (Vatican, Annuarium Statisticum Ecclesiae (2023)). Shares are Latin American medians, where about two in five Catholics live. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Shia Islam: 5.1%, 1 × 10¹⁸ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 233 million members (Pew Research Center: the 2025 Muslim total × the 2009 sect shares (87–90% Sunni, 10–13% Shia)). Surveys find practice differs by country, not by sect (Ramadan fasting: 88% median in both, five countries), so the Islam figures are used. Following a senior cleric (taqlid) and the khums tax are Shia obligations no survey has measured. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Twelver Shia: 5.1%, 7.5 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 170 million members ('about 170-220 million Twelvers' (2020)). No survey of this branch’s practice was found, so the figures for Shia Islam are used. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Vaishnavism: 1.6%, 5.4 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer or puja \* | 59% | 1.17 | 1 (directed) | 0.69 | | Vegetarian diet at meals | 44% | 8.68 | 0.25 (ruled) | 0.95 | | **Total** | | | | **1.64** | 400 million members (World Religion Database 2020 via (2020)). No survey of this branch’s practice was found, so the figures for Hinduism are used. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Shaivism: 1.6%, 5.2 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer or puja \* | 59% | 1.17 | 1 (directed) | 0.69 | | Vegetarian diet at meals | 44% | 8.68 | 0.25 (ruled) | 0.95 | | **Total** | | | | **1.64** | 385 million members (World Religion Database 2020 via (2020)). No survey of this branch’s practice was found, so the figures for Hinduism are used. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Evangelicals: 1.9%, 4.7 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 285 million members (Pew 2011 Global Christianity (2011)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Pentecostals: 1.9%, 4.6 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 279 million members (Pew 2011 Global Christianity (2011)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Shaktism: 1.6%, 4.1 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer or puja \* | 59% | 1.17 | 1 (directed) | 0.69 | | Vegetarian diet at meals | 44% | 8.68 | 0.25 (ruled) | 0.95 | | **Total** | | | | **1.64** | 306 million members (World Religion Database 2020 via (2020)). No survey of this branch’s practice was found, so the figures for Hinduism are used. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Charismatics: 0.88%, 2.3 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 305 million members (Pew 2011 Global Christianity (2011)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Folk religions: 0.59%, 2 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 400 million members (Pew 2012 Global Religious Landscape: 'more than 400 million people (6%) practice various folk or traditional religions' (2010)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Eastern Orthodoxy: 0.86%, 1.9 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | --------------------------------------- | ------------------- | ------------ | ---------------- | ------------- | | Daily prayer \* | 31% | 1.17 | 1 (directed) | 0.36 | | Weekly liturgy \* | 20% | 1.5 | 1 (directed) | 0.30 | | Lent fast: no meat or dairy for 48 days | 42% | 1.14 | 0.5 (restricted) | 0.24 | | **Total** | | | | **0.90** | 260 million members (Pew Research Center (2017), Orthodox Christianity in the 21st Century (weighted by Orthodox population)). Weekly attendance ranges from 6% (Russia) to 78% (Ethiopia). The year’s other fast days are not counted. Sources: Pew Research Center (2017), Orthodox Christianity in the 21st Century (weighted by Orthodox population). ### Reformed and Presbyterian: 1.9%, 1.7 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 100 million members (Wikipedia, WCRC: 227 member denominations, 108 countries, \~100M adherents claimed (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Assemblies of God: 1.9%, 1.5 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 88.9 million members (Wikipedia: 88.9M members and adherents worldwide (2025); 69M (2022); 67M (WCD 2020) (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Anglicanism: 1.9%, 1.4 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 85 million members (Wikipedia, Anglican Communion, states 85-110 million members (WCD research) (2023)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Methodists: 1.9%, 1.3 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 80 million members (WMC self-claim since 2018 per Wikipedia (2018)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Lutherans: 1.9%, 1.3 × 10¹⁷ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 78.4 million members (Wikipedia, LWF: 78,431,111 members, 150 churches (2023) (2023)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Baptists: 1.9%, 8.9 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 53.9 million members (Wikipedia, Baptist World Alliance: 53.87M members, 283 member bodies, 138 countries (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Buddhism: 0.27%, 7.5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer or devotion (Theravada 30%, Mahayana 21%, weighted) \* | 25% | 1.17 | 1 (directed) | 0.29 | | **Total** | | | | **0.29** | 324 million members (Pew Research Center (2025), How the Global Religious Landscape Changed From 2010 to 2020). China was not surveyed. Temple visits are reported monthly, not weekly, and meditation time is not measured, so neither is counted. Sources: Pew Research Center (2023), Buddhism, Islam and Religious Pluralism in South and Southeast Asia. Pew Research Center (2024), Religion and Spirituality in East Asian Societies. ### Jehovah’s Witnesses: 7.6%, 6.1 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 90% | 1.17 | 1 (directed) | 1.05 | | Two congregation meetings a week \* | 85% | 3.5 | 1 (directed) | 2.98 | | Preaching (average per publisher) | 100% | 3.99 | 1 (directed) | 3.99 | | **Total** | | | | **8.02** | 9.21 million members (Jehovah’s Witnesses, 2025 Service Year Report (peak publishers)). Members are active publishers, so the shares fit. Study at home is not counted. Sources: Pew Research Center (2015), 2014 Religious Landscape Study: Religious Practices and Experiences (US); Jehovah’s Witnesses, 2023 Service Year Report (field hours ÷ average publishers). ### Oriental Orthodoxy: 0.88%, 5.5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 72 million members (Wikipedia, Oriental Orthodox Churches: \~72M members in 2020, \~87M self-reported (2020)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Judaism: 4.2%, 5.3 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | --------------------------------------- | ------------------- | ------------ | ---------------- | ------------- | | Weekly service \* | 12% | 2.5 | 1 (directed) | 0.30 | | Sabbath kept (no money, travel or work) | 30% | 15.59 | 0.5 (restricted) | 2.34 | | Kosher diet at meals | 40% | 8.68 | 0.5 (restricted) | 1.74 | | **Total** | | | | **4.38** | 14.8 million members (Pew Research Center (2025), How the Global Religious Landscape Changed From 2010 to 2020). Shares weight Israel (45% keep the Sabbath, 63% kosher) and the US (15%, 17%) about equally, as their Jewish populations are about equal. Sources: Pew Research Center (2021), Jewish Americans in 2020; Pew Research Center (2016), Israel’s Religiously Divided Society. ### Ismaili Shia: 5.1%, 5.3 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 12 million members ('12-15 million' (infobox, source not stated) (2020)). No survey of this branch’s practice was found, so the figures for Shia Islam are used. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### African traditional religions: 0.59%, 5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 98.7 million members (Encyclopaedia Britannica mid-2002 figure for traditional religions in Africa, quoted at (2002)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Haredi Judaism (Israel): 39%, 4.8 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------------------------- | ------------------- | ------------ | ---------------- | ------------- | | Three daily services (men \~1¼ h, women less) \* | 76% | 5.25 | 1 (directed) | 3.99 | | Sabbath services \* | 85% | 2.5 | 1 (directed) | 2.13 | | Full-time Torah study (169,366 students) | 12% | 42.5 | 1 (directed) | 4.96 | | Sabbath | 100% | 15.59 | 0.5 (restricted) | 7.80 | | Kosher diet at meals | 100% | 8.68 | 0.5 (restricted) | 4.34 | | Community code on dress, media and contact, other hours \* | 100% | 69.45 | 0.25 (ruled) | 17.36 | | **Total** | | | | **40.57** | 1.45 million members (Israel Democracy Institute (2024), Statistical Report on Ultra-Orthodox Society in Israel). Israel only (about half of Haredim worldwide). Sources: Pew Research Center (2016), Israel’s Religiously Divided Society; Israel Democracy Institute (2024), Statistical Report on Ultra-Orthodox Society in Israel. ### Shinto: 0.59%, 4.5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 87.9 million members (Japan Agency for Cultural Affairs Religious Yearbook (Reiwa 3 ed., data to 31 Dec 2020): Shinto 87,924,087, as reported at (2020)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Shinto affiliation is counted by shrine registration and overlaps with Buddhism; few of those counted pray daily, so this overstates. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Ahmadiyya: 5.1%, 4.4 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 10 million members ('Independent sources give estimates between 10 and 20 million'; community says 'tens of millions' (2020)). No survey of this branch’s practice was found, so the figures for Islam are used. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Seventh-day Adventists: 1.9%, 4 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 24.1 million members (Wikipedia infobox 24,051,322 (2025), from General Conference statistics (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Sikhism: 1.7%, 3.7 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 45% | 1.17 | 1 (directed) | 0.53 | | Vegetarian diet at meals | 59% | 8.68 | 0.25 (ruled) | 1.28 | | **Total** | | | | **1.81** | 25 million members (World Religion Database via Pew Research Center (2012), The Global Religious Landscape). Measured in India. The full daily prayers (Nitnem) take longer than the 10 minutes assumed. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Mahayana Buddhism: 0.23%, 3.6 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (median of East Asian societies) \* | 21% | 1.17 | 1 (directed) | 0.24 | | **Total** | | | | **0.24** | 182 million members (Branch shares (56% Mahayana, 38% Theravada) via BuddhaNet, applied to the Pew 2025 total). China was not surveyed, and the Pew count leaves out most Chinese Buddhists, so the membership is understated. Sources: Pew Research Center (2024), Religion and Spirituality in East Asian Societies. ### Theravada Buddhism: 0.33%, 3.5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (Sri Lanka 76%, Thailand 30%, Cambodia 23%: median) \* | 30% | 1.17 | 1 (directed) | 0.35 | | **Total** | | | | **0.35** | 123 million members (Branch shares (56% Mahayana, 38% Theravada) via BuddhaNet, applied to the Pew 2025 total). Shares are for all adults in each country. Alms-giving and holy-day precepts are not measured. Sources: Pew Research Center (2023), Buddhism, Islam and Religious Pluralism in South and Southeast Asia. ### Latter-day Saints: 2.1%, 3.3 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 73% | 1.17 | 1 (directed) | 0.85 | | Sunday worship (two-hour block) | 69% | 2 | 1 (directed) | 1.38 | | **Total** | | | | **2.23** | 17.9 million members (Church of Jesus Christ of Latter-day Saints, 2025 statistical report (via Deseret News)). Shares are for US members; the church counts all members on record, active or not, so this overstates. Sources: Pew Research Center (2026), Latter-day Saints are highly religious, though not uniformly so (US). ### Ethiopian Orthodox Tewahedo: 0.88%, 2.7 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 36 million members (Wikipedia, Oriental Orthodox Churches table: 36M members, 60M self-reported (2021)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Southern Baptist Convention: 1.9%, 2 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 12.3 million members (Wikipedia, SBC: 12,331,954 members, 46,608 congregations (2025) (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Jainism: 4.6%, 1.8 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------------------- | ------------------- | ------------ | ---------------- | ------------- | | Daily prayer \* | 73% | 1.17 | 1 (directed) | 0.85 | | Jain diet at meals (most also avoid root vegetables) | 92% | 8.68 | 0.5 (restricted) | 3.99 | | **Total** | | | | **4.84** | 4.45 million members (Census of India (2011), religion tables). India census, 2011\. Sources: Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Redeemed Christian Church of God: 1.9%, 1.6 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 9.94 million members (Wikipedia: 9,938,617 members, 51,580 congregations (2021) (2021)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Kimbanguists: 0.88%, 1.5 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 20 million members (Wikipedia infobox 20M citing a 2024 handbook; other estimates 6M and 32M (2024)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Ibadi Islam: 5.1%, 1.3 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | All five daily prayers \* | 63% | 4.1 | 1 (directed) | 2.58 | | Some daily prayer, not all five \* | 13% | 1.17 | 1 (directed) | 0.15 | | Friday sermon (beyond the noon prayer) \* | 58% | 0.5 | 1 (directed) | 0.29 | | Ramadan fast: meals set by the fast, one month a year | 93% | 0.71 | 1 (directed) | 0.66 | | Halal diet at meals | 77% | 8.68 | 0.25 (ruled) | 1.67 | | **Total** | | | | **5.36** | 3 million members ('roughly 3 million Ibadis worldwide, \~250,000 outside Oman' (cites Britannica; year not stated) (2020)). No survey of this branch’s practice was found, so the figures for Islam are used. Sources: Pew Research Center (2012), The World’s Muslims: Unity and Diversity (median of 39 countries); Pew Research Center (2018), The Age Gap in Religion Around the World (country averages); Pew Research Center (2013), Global median of 93% of Muslims say they fast during Ramadan; Pew Research Center (2021), Religion in India: Tolerance and Segregation. ### Amish: 26%, 9.2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Church service, every other Sunday (3 h) \* | 100% | 1.5 | 1 (directed) | 1.50 | | The Ordnung: dress, transport and technology, all other hours \* | 100% | 103.29 | 0.25 (ruled) | 25.82 | | **Total** | | | | **27.32** | 410,660 members (Young Center for Anabaptist and Pietist Studies (2025), Amish Population). Farm and family work is not directed by the church and is not counted. Sources: Young Center for Anabaptist and Pietist Studies (2025), Amish Population. ### Coptic Orthodox: 0.88%, 6.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 9 million members (Wikipedia, Oriental Orthodox Churches table: 9M members, 12M self-reported (2021)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### New Apostolic Church: 0.88%, 6.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 8.92 million members (Wikipedia infobox citing NAC International: 8,923,420 members (1 Jan 2016) (2016)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Universal Church of the Kingdom of God: 1.9%, 5 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 3 million members (Wikipedia infobox: 3-8.2M worldwide, 1.8-7M in Brazil (year not given)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Taoism: 0.59%, 4.1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 8 million members (Pew 2012 (quoting World Religion Database): 'more than 8 million Taoists' (2010)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Baháʼí Faith: 0.59%, 4.1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 8 million members ( (2020)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Zion Christian Church: 0.88%, 3.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 4.97 million members (Wikipedia: South African census 2001 \~4.97M (1996: 3.87M) (2001)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Falun Gong: 0.59%, 3.6 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 7 million members (Freedom House 2017: 7 to 20 million practitioners in China (lower bound used); Chinese government pre-1999 estimate 70M; via (2017)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Mennonites: 1.9%, 2.4 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 80% | 1.17 | 1 (directed) | 0.93 | | Weekly service \* | 72% | 1.5 | 1 (directed) | 1.08 | | **Total** | | | | **2.01** | 1.45 million members (Wikipedia, MWC: 1.45M baptized members, 111 denominations, 61 countries (2025)). No survey of this branch’s practice was found, so the figures for Protestantism are used. Sources: Pew Research Center (2014), Religion in Latin America (medians of 18 countries and Puerto Rico). ### Soka Gakkai: 0.23%, 2.4 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (median of East Asian societies) \* | 21% | 1.17 | 1 (directed) | 0.24 | | **Total** | | | | **0.24** | 12 million members (Soka Gakkai International claims 'over 12 million' adherents worldwide; 8.27M households in Japan (own count), via (2025)). No survey of this branch’s practice was found, so the figures for Mahayana Buddhism are used. Sources: Pew Research Center (2024), Religion and Spirituality in East Asian Societies. ### Iglesia ni Cristo: 0.88%, 2.1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer \* | 47% | 1.17 | 1 (directed) | 0.54 | | Weekly service \* | 39% | 1 | 1 (directed) | 0.39 | | **Total** | | | | **0.93** | 2.8 million members (Wikipedia: 2.8M in Philippines per 2020 Philippine census; \~3M worldwide estimate (2020)). No survey of this branch’s practice was found, so the figures for Christianity are used. Sources: Pew Research Center (2018), The Age Gap in Religion Around the World (country averages). ### Spiritism: 0.59%, 1.9 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 3.8 million members (Brazil IBGE 2010 census \~3.8M, via (2010)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Cao Đài: 0.59%, 1.3 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 2.5 million members (UN finding Jan 2015 \~2.5M, government/body claim 4.4M Tay Ninh adherents (6M with other branches), via (2015)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Tenrikyo: 0.59%, 5.7 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 1.12 million members (Agency for Cultural Affairs count 1,121,541 in Japan (2025), peak 2,298,420 in 1974, via (2025)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Brahma Kumaris: 0.59%, 5.1 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Daily prayer (proxy: median of surveyed religions) \* | 53% | 1.17 | 1 (directed) | 0.61 | | **Total** | | | | **0.61** | 1 million members (Organisation's own count '1,000,000+ students' (2021) via (2021)). No survey of this religion’s practice was found, so daily prayer at the median share of the surveyed religions (53%) is used. Sources: Median daily-prayer share of the surveyed whole religions on this chart. ### Reform Judaism (US): 0.21%, 3.9 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | -------------------- | ------------------- | ------------ | ---------------- | ------------- | | Kosher diet at meals | 5% | 8.68 | 0.5 (restricted) | 0.22 | | **Total** | | | | **0.22** | 2.15 million members (Computed: Pew 2021 Reform 37% of \~5.8M US Jewish adults (2020)). Only the practices measured for this branch are counted, so its share is a floor. Sources: . \* The time a practice takes is our estimate; the share of members who keep it is from the survey. The chart covers every religion and branch counted at a million adherents or more in a standard reference (Pew Research Center, the World Religion Database, the bodies’ own counts, national censuses). Where no survey of a branch’s practice exists, it takes the figures of the tradition it belongs to; where none exists for a whole religion, it takes daily prayer at the median share of the surveyed religions. Both are marked in the chart. Branches and movements overlap (a Pentecostal may also be a Baptist and an Evangelical), so they are ranked apart from whole religions and never summed. Counts before 2015 are marked as weak data. ## States A state is counted by the time it directs that we can measure in every country. That's its employees at work, its soldiers off duty under military law, its pupils in class, and its prisoners, since it directs all of their waking time. Government employment is assumed to include the armed forces, so soldiers’ duty hours (48.1 a week, US active duty) aren't counted twice. Where a country doesn't publish its instruction time, we use the average of the countries that do (898 hours a year). General law isn't counted. Most of it forbids things people wouldn't do anyway. Where it does bind an activity, such as traffic law at the wheel, nobody measures that time across countries. Taxation takes the proceeds of work rather than directing it. So each state’s share is a minimum. Where a country publishes no hours for public administration, we use its average for all employees. If that's missing too, we use the average of the other countries (41.6 hours). Every state is included: the 193 members of the United Nations, Palestine, Kosovo and Taiwan. We researched thirty-three one by one. The rest use international data series. Public employment is the median public share of employment across a country’s ILOSTAT surveys since 2010, applied to ILO modelled employment for 2025; armed forces are the World Bank’s series from the IISS (2020); pupils are UNESCO enrolment less the private share. Where a figure is missing, we estimate it from the median of the country’s region and mark it \*. India’s public employment is the latest official count (2012) and excludes public companies; North Korea’s is all employment, since nearly all work is in state units. Left out: Vatican City, whose few hundred residents are almost all its own staff, so the measure does not apply. | State | Residents | Employees | Soldiers | Pupils | Hours a week | c | Neuron-equivalents | | -------------------------------- | ------------ | --------- | -------- | ------- | ------------ | ----- | ------------------ | | China | 1.41 billion | 4% | 0.14% | 13% | 4.30 | 4.1% | 5 × 10¹⁸ | | India | 1.46 billion | 0.81% \* | 0.21% | 9.1% | 2.10 | 2% | 2.5 × 10¹⁸ | | United States | 342 million | 6.9% | 0.39% | 13% | 5.83 | 5.6% | 1.6 × 10¹⁸ | | Indonesia | 286 million | 4.3% | 0.15% | 15% | 4.43 | 4.2% | 1 × 10¹⁸ | | Brazil | 213 million | 6% | 0.18% | 14% | 4.99 | 4.8% | 8.7 × 10¹⁷ | | Russia | 144 million | 9.8% | 0.88% | 13% | 6.39 | 6.1% | 7.5 × 10¹⁷ | | Nigeria | 238 million | 1.4% | 0.06% | 16% | 3.37 | 3.2% | 6.6 × 10¹⁷ | | North Korea | 26.6 million | 65% \* | 5.5% | 12% \* | 30.06 | 29% | 6.6 × 10¹⁷ | | Mexico | 132 million | 4.2% | 0.23% | 18% | 5.47 | 5.2% | 5.9 × 10¹⁷ | | Pakistan | 255 million | 2.1% | 0.26% | 9.4% | 2.72 | 2.6% | 5.7 × 10¹⁷ | | Egypt | 118 million | 4.4% | 0.37% | 20% | 5.66 | 5.4% | 5.5 × 10¹⁷ | | DR Congo | 113 million | 3.1% | 0.12% | 22% | 5.07 | 4.8% | 4.7 × 10¹⁷ | | Bangladesh | 176 million | 1.4% | 0.097% | 14% | 3.15 | 3% | 4.6 × 10¹⁷ | | Philippines | 117 million | 3.7% | 0.14% | 18% | 4.61 | 4.4% | 4.4 × 10¹⁷ | | Turkey | 85.9 million | 6% | 0.41% | 19% | 6.04 | 5.8% | 4.3 × 10¹⁷ | | Vietnam | 102 million | 4.2% | 0.44% | 18% | 5.01 | 4.8% | 4.2 × 10¹⁷ | | Ethiopia | 135 million | 1.8% | 0.37% | 15% | 3.51 | 3.4% | 3.9 × 10¹⁷ | | Iran | 92.4 million | 3.8% | 0.66% | 15% | 4.56 | 4.3% | 3.5 × 10¹⁷ | | Algeria | 47.4 million | 9.5% | 0.69% | 24% | 8.31 | 7.9% | 3.2 × 10¹⁷ | | France | 68.7 million | 9.3% | 0.3% | 12% | 5.55 | 5.3% | 3.1 × 10¹⁷ | | Germany | 83.5 million | 6.6% | 0.22% | 11% | 4.21 | 4% | 2.9 × 10¹⁷ | | South Africa | 64.7 million | 4.3% | 0.11% | 19% | 5.40 | 5.1% | 2.9 × 10¹⁷ | | Japan | 123 million | 2.7% | 0.2% | 10% | 2.79 | 2.7% | 2.8 × 10¹⁷ | | United Kingdom | 69.5 million | 8.2% | 0.2% | 10% | 4.84 | 4.6% | 2.8 × 10¹⁷ | | Thailand | 71.6 million | 5.1% | 0.5% | 10% | 4.11 | 3.9% | 2.4 × 10¹⁷ | | Kenya | 57.5 million | 2.3% | 0.042% | 22% | 4.95 | 4.7% | 2.3 × 10¹⁷ | | Tanzania | 70.5 million | 0.89% | 0.038% | 19% | 3.81 | 3.6% | 2.2 × 10¹⁷ | | Italy | 58.9 million | 6.1% | 0.27% | 11% | 4.40 | 4.2% | 2.1 × 10¹⁷ | | Poland | 36.4 million | 12% | 0.52% | 12% | 7.02 | 6.7% | 2.1 × 10¹⁷ | | Ukraine | 39 million | 11% | 0.76% | 10% | 6.50 | 6.2% | 2.1 × 10¹⁷ | | Uzbekistan | 37.1 million | 7% | 0.18% | 21% | 6.61 | 6.3% | 2 × 10¹⁷ | | Canada | 41.7 million | 11% | 0.15% | 11% | 5.79 | 5.5% | 2 × 10¹⁷ | | Myanmar | 54.9 million | 2.4% | 0.84% | 16% | 4.16 | 4% | 1.9 × 10¹⁷ | | Afghanistan | 43.8 million | 2% | 0.38% | 23% | 5.00 | 4.8% | 1.8 × 10¹⁷ | | Malaysia | 36 million | 8% | 0.38% | 14% | 6.08 | 5.8% | 1.8 × 10¹⁷ | | Spain | 49.4 million | 7.3% | 0.4% | 9.1% | 4.35 | 4.2% | 1.8 × 10¹⁷ | | Argentina | 45.9 million | 4.6% | 0.18% | 15% | 4.63 | 4.4% | 1.7 × 10¹⁷ | | Colombia | 53.4 million | 1.6% | 0.53% | 13% | 3.90 | 3.7% | 1.7 × 10¹⁷ | | Cuba | 10.9 million | 35% | 0.69% | 11% \* | 17.41 | 17% | 1.6 × 10¹⁷ | | Sudan | 51.7 million | 2.8% | 0.28% | 13% | 3.61 | 3.4% | 1.5 × 10¹⁷ | | Uganda | 51.4 million | 1.6% | 0.09% | 15% | 3.59 | 3.4% | 1.5 × 10¹⁷ | | Venezuela | 28.5 million | 7.6% | 1.2% | 18% | 6.38 | 6.1% | 1.5 × 10¹⁷ | | Mozambique | 35.6 million | 2% | 0.031% | 24% | 5.06 | 4.8% | 1.5 × 10¹⁷ | | Morocco | 38.4 million | 2.7% | 0.64% | 18% | 4.66 | 4.5% | 1.5 × 10¹⁷ | | Peru | 34.6 million | 4.7% | 0.46% | 15% | 4.98 | 4.8% | 1.4 × 10¹⁷ | | Angola | 39 million | 3.3% | 0.3% | 16% | 4.39 | 4.2% | 1.4 × 10¹⁷ | | Saudi Arabia | 37 million | 3.1% | 0.7% | 16% | 4.56 | 4.3% | 1.4 × 10¹⁷ | | South Korea | 51.7 million | 4.8% | 0.87% | 8.5% | 3.20 | 3% | 1.4 × 10¹⁷ | | Kazakhstan | 20.8 million | 11% | 0.34% | 19% | 7.93 | 7.6% | 1.4 × 10¹⁷ | | Yemen | 41.8 million | 3.8% | 0.096% | 13% | 3.88 | 3.7% | 1.3 × 10¹⁷ | | Ghana | 35.1 million | 2.3% | 0.046% | 18% | 4.12 | 3.9% | 1.2 × 10¹⁷ | | Iraq | 47 million | 6.9% | 0.41% | — | 2.92 | 2.8% | 1.1 × 10¹⁷ | | Australia | 27.6 million | 8.2% | 0.21% | 11% | 4.97 | 4.7% | 1.1 × 10¹⁷ | | Sri Lanka | 21.8 million | 5.9% | 1.5% | 18% | 6.28 | 6% | 1.1 × 10¹⁷ | | Nepal | 29.6 million | 2.4% | 0.38% | 18% | 4.38 | 4.2% | 1.1 × 10¹⁷ | | Malawi | 22.2 million | 2% | 0.068% | 26% | 5.64 | 5.4% | 1 × 10¹⁷ | | Taiwan | 23.3 million | 4.5% \* | 0.73% \* | 17% \* | 5.28 | 5% | 1 × 10¹⁷ | | Zambia | 21.9 million | 2.5% | 0.073% | 25% \* | 5.54 | 5.3% | 10 × 10¹⁶ | | Cameroon | 29.9 million | 1.9% | 0.11% | 18% | 4.00 | 3.8% | 9.8 × 10¹⁶ | | Syria | 25.6 million | 5.4% \* | 1% | 13% | 4.64 | 4.4% | 9.8 × 10¹⁶ | | Côte d’Ivoire | 32.7 million | 1.8% | 0.083% | 15% | 3.55 | 3.4% | 9.5 × 10¹⁶ | | Madagascar | 32.7 million | 1.7% | 0.067% | 16% | 3.50 | 3.3% | 9.4 × 10¹⁶ | | Belarus | 9.09 million | 19% | 1.7% | 13% | 10.63 | 10% | 7.9 × 10¹⁶ | | Netherlands | 18.1 million | 7.5% | 0.23% | 14% | 5.09 | 4.9% | 7.6 × 10¹⁶ | | Romania | 19 million | 6.5% | 0.67% | 12% | 4.79 | 4.6% | 7.5 × 10¹⁶ | | Cambodia | 17.8 million | 3.1% | 1.1% | 18% | 5.06 | 4.8% | 7.4 × 10¹⁶ | | Rwanda | 14.6 million | 2.2% | 0.24% | 25% | 5.83 | 5.6% | 7 × 10¹⁶ | | Sweden | 10.6 million | 14% | 0.14% | 14% | 7.85 | 7.5% | 6.8 × 10¹⁶ | | Ecuador | 18.3 million | 4.2% | 0.23% | 14% | 4.42 | 4.2% | 6.6 × 10¹⁶ | | Israel | 10.1 million | 9.5% | 1.7% | 16% | 7.69 | 7.3% | 6.4 × 10¹⁶ | | Niger | 27.9 million | 1.2% | 0.036% | 13% | 2.78 | 2.6% | 6.4 × 10¹⁶ | | Tunisia | 12.3 million | 6.6% | 0.39% | 18% | 6.27 | 6% | 6.4 × 10¹⁶ | | Azerbaijan | 10.2 million | 12% | 0.8% | 16% | 7.37 | 7% | 6.2 × 10¹⁶ | | Chile | 19.9 million | 5.4% | 0.57% | 5.8% | 3.79 | 3.6% | 6.2 × 10¹⁶ | | Zimbabwe | 17 million | 2.8% | 0.3% | 16% | 4.36 | 4.2% | 6.1 × 10¹⁶ | | Guatemala | 18.7 million | 2.6% | 0.23% | 14% | 3.88 | 3.7% | 6 × 10¹⁶ | | Senegal | 18.9 million | 2.4% | 0.1% | 15% | 3.79 | 3.6% | 5.9 × 10¹⁶ | | Bolivia | 12.6 million | 4.9% | 0.56% | 19% | 5.63 | 5.4% | 5.8 × 10¹⁶ | | Czechia | 10.9 million | 11% \* | 0.25% | 13% | 6.49 | 6.2% | 5.8 × 10¹⁶ | | Burkina Faso | 24.1 million | 1.5% | 0.046% | 12% | 2.88 | 2.8% | 5.7 × 10¹⁶ | | Hungary | 9.51 million | 14% | 0.48% | 9.4% | 7.25 | 6.9% | 5.7 × 10¹⁶ | | Tajikistan | 10.8 million | 5.3% | 0.16% | 21% | 5.96 | 5.7% | 5.3 × 10¹⁶ | | Burundi | 14.4 million | 1.4% | 0.22% | 21% | 4.39 | 4.2% | 5.2 × 10¹⁶ | | Portugal | 10.8 million | 10% \* | 0.48% | 10% | 5.73 | 5.5% | 5.1 × 10¹⁶ | | Jordan | 11.5 million | 6.1% | 1% | 13% | 5.22 | 5% | 4.9 × 10¹⁶ | | Chad | 21 million | 1.2% | 0.21% | 13% | 2.87 | 2.7% | 4.9 × 10¹⁶ | | Mali | 25.2 million | 1.2% | 0.16% | 10% | 2.37 | 2.3% | 4.9 × 10¹⁶ | | Sierra Leone | 8.82 million | 1.6% | 0.1% | 34% | 6.76 | 6.5% | 4.9 × 10¹⁶ | | Dominican Republic | 11.5 million | 6.4% | 0.62% | 14% | 5.16 | 4.9% | 4.9 × 10¹⁶ | | Greece | 10.4 million | 8.8% | 1.4% | 11% | 5.68 | 5.4% | 4.9 × 10¹⁶ | | Belgium | 11.9 million | 9.2% | 0.2% | 7.3% | 4.54 | 4.3% | 4.5 × 10¹⁶ | | South Sudan | 12.2 million | 2.8% \* | 0.43% | 18% | 4.43 | 4.2% | 4.4 × 10¹⁶ | | Benin | 14.8 million | 1.2% | 0.081% | 17% | 3.58 | 3.4% | 4.4 × 10¹⁶ | | Papua New Guinea | 10.8 million | 2.7% | 0.037% | 21% | 4.81 | 4.6% | 4.3 × 10¹⁶ | | Turkmenistan | 7.62 million | 6.5% \* | 0.75% | 20% \* | 6.77 | 6.5% | 4.2 × 10¹⁶ | | Kyrgyzstan | 7.34 million | 7.6% | 0.29% | 20% | 6.78 | 6.5% | 4.1 × 10¹⁶ | | Serbia | 6.55 million | 14% | 0.49% | 11% | 7.54 | 7.2% | 4.1 × 10¹⁶ | | Denmark | 6.01 million | 16% | 0.25% | 13% | 8.00 | 7.6% | 3.9 × 10¹⁶ | | Switzerland | 9.09 million | 8.6% | 0.22% | 12% | 5.28 | 5% | 3.9 × 10¹⁶ | | Libya | 7.46 million | 6.5% \* | 0.71% \* | 19% | 6.38 | 6.1% | 3.9 × 10¹⁶ | | Norway | 5.61 million | 16% | 0.45% | 15% | 7.95 | 7.6% | 3.7 × 10¹⁶ | | Ireland | 5.48 million | 12% | 0.16% | 18% | 7.60 | 7.2% | 3.4 × 10¹⁶ | | Bulgaria | 6.43 million | 11% | 0.58% | 11% | 6.22 | 5.9% | 3.3 × 10¹⁶ | | Laos | 7.87 million | 4.7% | 1.6% | 15% | 5.00 | 4.8% | 3.2 × 10¹⁶ | | Finland | 5.65 million | 12% | 0.39% | 14% | 6.91 | 6.6% | 3.2 × 10¹⁶ | | El Salvador | 6.37 million | 3.7% | 0.66% | 14% | 6.06 | 5.8% | 3.2 × 10¹⁶ | | Honduras | 11 million | 2.5% | 0.21% | 12% | 3.50 | 3.3% | 3.2 × 10¹⁶ | | Slovakia | 5.41 million | 13% | 0.33% | 12% | 6.99 | 6.7% | 3.1 × 10¹⁶ | | Guinea | 15.1 million | 0.86% | 0.086% | 12% | 2.46 | 2.4% | 3.1 × 10¹⁶ | | United Arab Emirates | 11.5 million | 6.2% | 0.55% | 3.4% | 3.23 | 3.1% | 3.1 × 10¹⁶ | | Togo | 8.59 million | 1.5% | 0.12% | 20% | 4.23 | 4% | 3 × 10¹⁶ | | Oman | 5.49 million | 9.4% | 0.86% | 14% | 6.52 | 6.2% | 2.9 × 10¹⁶ | | Paraguay | 7.01 million | 5.1% | 0.41% | 15% | 5.06 | 4.8% | 2.9 × 10¹⁶ | | Nicaragua | 7.01 million | 3.8% | 0.17% | 16% | 4.82 | 4.6% | 2.8 × 10¹⁶ | | Kuwait | 4.87 million | 13% | 0.51% | 7.4% | 6.79 | 6.5% | 2.7 × 10¹⁶ | | New Zealand | 5.32 million | 8.5% \* | 0.19% | 17% | 6.16 | 5.9% | 2.7 × 10¹⁶ | | Costa Rica | 5.15 million | 6.3% | 0.19% | 16% | 6.20 | 5.9% | 2.6 × 10¹⁶ | | Austria | 9.21 million | 4.2% | 0.25% | 11% | 3.36 | 3.2% | 2.5 × 10¹⁶ | | Panama | 4.57 million | 7.5% | 0.61% | 14% | 6.23 | 5.9% | 2.3 × 10¹⁶ | | Croatia | 3.88 million | 13% | 0.52% | 12% | 6.99 | 6.7% | 2.2 × 10¹⁶ | | Mongolia | 3.57 million | 8.7% | 0.5% | 20% | 7.34 | 7% | 2.2 × 10¹⁶ | | Georgia | 3.94 million | 7.7% | 0.66% | 15% | 6.40 | 6.1% | 2.1 × 10¹⁶ | | Palestine | 5.41 million | 3.1% | — | 17% | 4.45 | 4.3% | 2 × 10¹⁶ | | Mauritania | 5.32 million | 2.7% | 0.4% | 18% | 4.50 | 4.3% | 2 × 10¹⁶ | | Singapore | 6.11 million | 5.6% | 0.97% | 6.2% | 3.73 | 3.6% | 1.9 × 10¹⁶ | | Haiti | 11.9 million | 1.9% | 0.0084% | 6.1% \* | 1.91 | 1.8% | 1.9 × 10¹⁶ | | Namibia | 3.09 million | 5.3% | 0.52% | 25% | 7.23 | 6.9% | 1.8 × 10¹⁶ | | Lithuania | 2.89 million | 14% | 1.3% | 12% | 7.73 | 7.4% | 1.8 × 10¹⁶ | | Uruguay | 3.38 million | 7.5% | 0.65% | 16% | 6.17 | 5.9% | 1.7 × 10¹⁶ | | Armenia | 3.09 million | 8.8% | 1.5% | 14% | 6.76 | 6.5% | 1.7 × 10¹⁶ | | Republic of the Congo | 6.48 million | 2.5% \* | 0.19% | 12% | 3.12 | 3% | 1.7 × 10¹⁶ | | Central African Republic | 5.51 million | 2.7% \* | 0.18% | 14% | 3.66 | 3.5% | 1.7 × 10¹⁶ | | Bosnia and Herzegovina | 3.14 million | 10% | 0.35% | 11% | 6.23 | 5.9% | 1.6 × 10¹⁶ | | Liberia | 5.73 million | 3.6% | 0.035% | 6.5% | 3.28 | 3.1% | 1.5 × 10¹⁶ | | Eritrea | 3.61 million | 3.5% \* | 5.6% | 17% | 5.19 | 5% | 1.5 × 10¹⁶ | | Lebanon | 5.85 million | 3.8% | 1.4% | 4.6% | 3.12 | 3% | 1.5 × 10¹⁶ | | Somalia | 19.7 million | 2% | 0.071% | 1.2% | 0.92 | 0.88% | 1.5 × 10¹⁶ | | Moldova | 2.36 million | 12% | 0.25% | 15% | 7.64 | 7.3% | 1.5 × 10¹⁶ | | Botswana | 2.56 million | 6.6% | 0.35% | 20% | 5.99 | 5.7% | 1.3 × 10¹⁶ | | Jamaica | 2.84 million | 7% | 0.21% | 12% | 5.24 | 5% | 1.2 × 10¹⁶ | | Slovenia | 2.13 million | 12% | 0.33% | 13% | 6.92 | 6.6% | 1.2 × 10¹⁶ | | Latvia | 1.85 million | 14% | 0.49% | 13% | 7.94 | 7.6% | 1.2 × 10¹⁶ | | Albania | 2.35 million | 8.5% | 0.34% | 13% | 5.97 | 5.7% | 1.2 × 10¹⁶ | | Gambia | 2.82 million | 2.5% | 0.14% | 21% | 4.66 | 4.5% | 1.1 × 10¹⁶ | | Gabon | 2.59 million | 5.7% | 0.27% | 11% | 4.63 | 4.4% | 9.9 × 10¹⁵ | | Qatar | 2.97 million | 8% | 0.74% | 4.5% | 3.93 | 3.8% | 9.6 × 10¹⁵ | | Lesotho | 2.36 million | 3.6% | 0.085% | 18% | 4.88 | 4.7% | 9.5 × 10¹⁵ | | Trinidad and Tobago | 1.37 million | 13% | 0.37% | 14% | 8.24 | 7.9% | 9.3 × 10¹⁵ | | North Macedonia | 1.82 million | 8.9% | 0.88% | 14% | 6.15 | 5.9% | 9.2 × 10¹⁵ | | Estonia | 1.37 million | 12% | 0.51% | 13% | 7.39 | 7% | 8.3 × 10¹⁵ | | Timor-Leste | 1.42 million | 7.7% | 0.14% | 23% | 6.91 | 6.6% | 8 × 10¹⁵ | | Kosovo | 1.58 million | 9.1% \* | 0.45% \* | 13% \* | 6.15 | 5.9% | 8 × 10¹⁵ | | Eswatini | 1.26 million | 5% | 0.24% | 26% | 7.22 | 6.9% | 7.5 × 10¹⁵ | | Bahrain | 1.6 million | 5.8% | 1.2% | 9.7% | 4.50 | 4.3% | 5.9 × 10¹⁵ | | Bhutan | 796,682 | 10% | 0.75% | 19% | 8.88 | 8.5% | 5.8 × 10¹⁵ | | Guinea-Bissau | 2.25 million | 2.4% | 0.18% | 11% | 3.08 | 2.9% | 5.7 × 10¹⁵ | | Fiji | 933,154 | 6.7% | 0.43% | 24% | 7.36 | 7% | 5.6 × 10¹⁵ | | Cyprus | 1.37 million | 9.2% | 0.95% | 7.3% | 4.93 | 4.7% | 5.5 × 10¹⁵ | | Mauritius | 1.24 million | 8.7% | 0.24% | 7.5% | 4.99 | 4.8% | 5.1 × 10¹⁵ | | Maldives | 529,676 | 18% | 0.94% | 14% | 10.83 | 10% | 4.7 × 10¹⁵ | | Djibouti | 1.18 million | 5.9% | 1.1% | 10% | 4.76 | 4.5% | 4.6 × 10¹⁵ | | Guyana | 835,986 | 7.4% | 0.36% | 18% | 6.67 | 6.4% | 4.6 × 10¹⁵ | | Montenegro | 623,129 | 13% | 1.9% | 15% | 8.47 | 8.1% | 4.3 × 10¹⁵ | | Equatorial Guinea | 1.94 million | 4.1% | 0.052% | 3% | 2.50 | 2.4% | 4 × 10¹⁵ | | Suriname | 639,850 | 10% | 0.31% | 15% | 7.06 | 6.7% | 3.7 × 10¹⁵ | | Brunei | 466,330 | 17% | 1.7% | 12% | 9.28 | 8.9% | 3.6 × 10¹⁵ | | Comoros | 882,847 | 6.4% | 0.12% \* | 13% | 4.80 | 4.6% | 3.5 × 10¹⁵ | | Cape Verde | 527,326 | 8.1% | 0.19% | 21% | 7.60 | 7.2% | 3.3 × 10¹⁵ | | Solomon Islands | 838,645 | 5.5% | — | 12% | 4.58 | 4.4% | 3.2 × 10¹⁵ | | Malta | 579,704 | 14% | 0.35% | 6.3% | 6.45 | 6.2% | 3.1 × 10¹⁵ | | Iceland | 392,404 | 14% \* | — | 16% | 7.74 | 7.4% | 2.5 × 10¹⁵ | | Luxembourg | 686,970 | 5.7% | 0.15% | 12% | 4.21 | 4% | 2.4 × 10¹⁵ | | Bahamas | 403,033 | 12% | 0.5% | 9.3% | 6.68 | 6.4% | 2.2 × 10¹⁵ | | Vanuatu | 335,169 | 3.9% | — | 33% | 7.26 | 6.9% | 2 × 10¹⁵ | | Barbados | 282,623 | 9.8% | 0.35% | 11% | 6.28 | 6% | 1.5 × 10¹⁵ | | São Tomé and Príncipe | 240,254 | 2.6% | 0.42% | 26% | 5.68 | 5.4% | 1.1 × 10¹⁵ | | Samoa | 219,306 | 4.8% | — | 21% | 5.93 | 5.7% | 1.1 × 10¹⁵ | | Belize | 422,924 | 4.5% | 0.47% | 5.1% | 3.08 | 2.9% | 1.1 × 10¹⁵ | | Saint Lucia | 180,149 | 9.1% | — | 13% | 6.27 | 6% | 9.3 × 10¹⁴ | | Seychelles | 122,730 | 16% | — | 12% | 8.81 | 8.4% | 8.9 × 10¹⁴ | | Kiribati | 136,488 | 9.4% | — | 19% | 6.74 | 6.4% | 7.6 × 10¹⁴ | | Grenada | 117,303 | 11% | — | 17% | 7.52 | 7.2% | 7.3 × 10¹⁴ | | Antigua and Barbuda | 94,209 | 15% | — | 11% | 8.35 | 8% | 6.5 × 10¹⁴ | | Tonga | 103,742 | 8.8% | 0.5% \* | 17% | 6.92 | 6.6% | 5.9 × 10¹⁴ | | Micronesia | 113,683 | 7.3% | — | 19% \* | 6.10 | 5.8% | 5.7 × 10¹⁴ | | Saint Vincent and the Grenadines | 99,924 | 5.9% \* | — | 18% | 5.92 | 5.7% | 4.9 × 10¹⁴ | | Andorra | 82,904 | 9.1% \* | — | 11% | 5.75 | 5.5% | 3.9 × 10¹⁴ | | Marshall Islands | 36,282 | 17% | — | 22% | 10.91 | 10% | 3.3 × 10¹⁴ | | Dominica | 65,871 | 5.5% \* | — | 9.4% | 4.30 | 4.1% | 2.3 × 10¹⁴ | | Monaco | 38,341 | 13% | — | 9.4% | 7.25 | 6.9% | 2.3 × 10¹⁴ | | Saint Kitts and Nevis | 46,922 | 5.5% \* | 0.37% \* | 16% | 5.45 | 5.2% | 2.1 × 10¹⁴ | | Liechtenstein | 41,024 | 9.1% \* | — | 12% | 5.94 | 5.7% | 2 × 10¹⁴ | | Palau | 17,663 | 22% | — | 12% | 10.99 | 10% | 1.6 × 10¹⁴ | | San Marino | 34,109 | 7.8% | — | 8.6% \* | 4.80 | 4.6% | 1.3 × 10¹⁴ | | Nauru | 12,025 | 14% | — | 23% | 9.38 | 9% | 9.3 × 10¹³ | | Tuvalu | 9,492 | 17% | — | 20% | 10.23 | 9.8% | 8 × 10¹³ | Shares are of residents. \* estimated from the regional median, or an estimate in the source. Notes on each state appear in the chart’s details. ## Animal societies We treat a typical group of a social species as an organisation. Its share directed is the time spent in coordinated group activity, with the same weights. Coordinated group action (a joint hunt, travel the group decides, colony-set work) is directed, 1.0\. Time spent with the group but not in coordinated action is restricted, 0.5\. Time alone counts for nothing. Neurons are the cortex or pallium, or the whole brain for insects. So this table isn't on the same scale as the organisation charts, which count whole human brains. Only the Bigg’s orca and the sperm whale have measured time budgets. Every other share is our estimate from the field studies. Species with no neuron count take the figure for the nearest relative that has one (dog for wolf and wild dog, banded mongoose for meerkat, chimpanzee for bonobo, striped for spotted hyena, Eurasian jay for pinyon jay). A Hadza hunter-gatherer camp is included for scale. | Group | Members | Neurons each | Waking hours | Coordinated | With the group | c | Neuron-equivalents | | ------------------------------ | -------------- | ------------- | ------------ | ----------- | -------------- | --- | ------------------ | | Leafcutter ant colony | 2.5 million \* | 2.5 × 10⁵ \* | 20 | 60% \* | 100% \* | 80% | 5 × 10¹¹ | | Chimpanzee community | 100 | 7.4 × 10⁹ \* | 14.3 | 3% \* | 65% \* | 34% | 2.5 × 10¹¹ | | Bigg’s orca group | 6 | 4.3 × 10¹⁰ | 21 | 82% | 100% | 91% | 2.4 × 10¹¹ | | Hadza camp (humans, for scale) | 25 | 1.6 × 10¹⁰ | 16 | 25% \* | 80% \* | 53% | 2.1 × 10¹¹ | | Bonobo community | 59 | 7.4 × 10⁹ \* | 14.3 | 5% \* | 80% \* | 43% | 1.9 × 10¹¹ | | Resident orca matriline | 6 | 4.3 × 10¹⁰ | 21 | 40% \* | 100% \* | 70% | 1.7 × 10¹¹ | | Baboon troop | 30 | 2.9 × 10⁹ | 12.5 | 25% \* | 95% \* | 60% | 5.2 × 10¹⁰ | | Honeybee colony | 60,000 | 9.6 × 10⁵ | 17 | 70% \* | 100% \* | 85% | 4.9 × 10¹⁰ | | Bottlenose dolphin alliance | 6 \* | 1.3 × 10¹⁰ \* | 20 | 30% \* | 80% \* | 55% | 4.2 × 10¹⁰ | | Sperm whale social unit | 8 | 8.5 × 10⁹ \* | 22.3 | 40% | 90% | 65% | 4.1 × 10¹⁰ | | Elephant family | 10 \* | 5.6 × 10⁹ | 22 | 25% \* | 90% \* | 57% | 3.2 × 10¹⁰ | | Pinyon jay flock | 100 \* | 5.3 × 10⁸ \* | 13 | 30% \* | 90% \* | 60% | 3.2 × 10¹⁰ | | Spotted hyena clan | 45 \* | 5 × 10⁸ \* | 14 | 10% \* | 50% \* | 30% | 6.7 × 10⁹ | | African wild dog pack | 14 | 5.3 × 10⁸ \* | 12 | 33% \* | 100% \* | 67% | 4.8 × 10⁹ | | Wolf pack | 8 | 5.3 × 10⁸ \* | 13 | 45% \* | 80% \* | 63% | 2.6 × 10⁹ | | Meerkat group | 15 \* | 1.2 × 10⁸ \* | 12 | 15% \* | 100% \* | 57% | 1 × 10⁹ | | Naked mole-rat colony | 78 | 5.3 × 10⁶ | 16 | 40% \* | 100% \* | 70% | 2.9 × 10⁸ | \* estimated. Group sizes, time budgets and call repertoires: research/animal-groups-research.json in the site’s data, with the field studies each figure comes from. ## Political parties A party is counted by the time it sets (the meetings and study its rules require), or by the time its members say they give it. Ruling communist parties set meetings by rule, and we estimate how long they last. Surveys of members’ time exist for the British parties and, pooled, for Canada’s. Every other party takes the average of those surveys, about 2.4 hours a month. That's a stand-in, marked as such, for a member of a mass party with no attendance rule. US parties have no members, so they are counted by registered voters and the share of all adults who worked on a campaign (3.5%) or went to a rally (5.5%) in 2020\. The chart covers every party that reports at least a million members, plus smaller parties in Germany, Britain, Canada, Brazil, Cuba and South Africa. Parties without a published membership (Nigeria’s PDP, Bangladesh’s Awami League and BNP, Ghana’s NPP and NDC, Kenya’s parties) are left out, as are those whose latest figure is more than ten years old: Aam Aadmi Party (India; latest figure 2014); Pakistan Tehreek-e-Insaf (Pakistan; latest figure 2012); MPLA (Angola; latest figure 2008). ### Chinese Communist Party: 0.94%, 8.2 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | 22 required meetings and 12 theme days a year, \~1½ h each \* | 100% | 0.98 | 1 (directed) | 0.98 | | **Total** | | | | **0.98** | 101 million members (CCP Organization Department, 2025 statistical bulletin (30 June 2026)). 7.6% of members work in party and government organs, where the state also directs them. Sources: Regulations on the Work of Party Branches (2018). ### Bharatiya Janata Party (India): 0.52%, 6.3 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 140 million members (BJP president J.P. Nadda, 14 Sept 2025, Visakhapatnam: '14 crore members, of which two crore are active':). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Indian National Congress: 0.52%, 1.2 × 10¹⁶ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 26 million members (Existing parties-research.json entry; Wikipedia list:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### AIADMK (India): 0.52%, 9 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 20 million members (Wikipedia list (ref 6), 2023 party claim:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### DMK (India): 0.52%, 9 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 20 million members (Deccan Herald / press: DMK membership 'over 2 crore' after \~1 crore enrolled:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Workers’ Party of Korea: 1.4%, 7.6 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Weekly cell meeting and study session \* | 100% | 1.5 | 1 (directed) | 1.50 | | **Total** | | | | **1.50** | 6.17 million members (Estimate from the Eighth Congress delegate ratio (2021)). Cadres are expected to study two hours a day; their number is unknown, so this is not counted. Sources: Library of Congress country study (1993); Radio Free Asia (2019). ### Prosperity Party (Ethiopia): 0.52%, 7 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 15.7 million members (Party congress, Jan 31 2025, 15.7M members (ENA/press via search):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### TVK (India): 0.52%, 6.7 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 15 million members (Party/press claim of 15M+ as of Sept 2025 (search result; Wikipedia list ref 7):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Chama Cha Mapinduzi (Tanzania): 0.52%, 5.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 13 million members (CCM digital registration system, 13,000,670 verified members, May 2025 (via Wikipedia/search):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### All Progressives Congress (Nigeria): 0.52%, 5.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 12.9 million members (APC claim of 12.9M registered members after the Jan-Feb 2026 e-registration (disputed by ADC support group):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### AK Party (Turkey): 0.52%, 5.2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 11.7 million members (Court of Cassation Chief Public Prosecutor's party registry, 1 July 2026 update (Jan 2026: 11,543,301):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Morena (Mexico): 0.52%, 5.2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 11.6 million members (INE validated militant roster (triennial review), Sept 2026: 11,629,541 valid affiliations after INE struck \~2.69M:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Telugu Desam Party (India): 0.52%, 4.5 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 10.1 million members (Press: TDP membership drive crossed 1 crore in Jan 2025 (Wikipedia list ref 14):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Cambodian People’s Party: 0.52%, 3.1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 7 million members (Party claim of 7M+ members, 2023 (Wikipedia CPP article):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### FRELIMO (Mozambique): 0.52%, 2.7 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 6 million members (FRELIMO president Daniel Chapo at 5th Central Committee session: grassroots census shows 'just over six million members' (April 2026):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Democratic Party (US): 0.06%, 2.3 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Campaign work and rallies (ANES 2020, all adults) \* | 100% | 0.06 | 1 (directed) | 0.06 | | **Total** | | | | **0.06** | 44.9 million members (Ballotpedia, partisan affiliations of registered voters, June 2025:). US parties have no members; these are voters registered with the party in 30 states and DC. Sources: American National Election Studies (2020); Schwenzfeier and Settle. ### Democratic Party of Korea: 0.52%, 2.2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 5 million members (South Korea National Election Commission party registration/membership statistics, 2024 (figure via Namu Wiki/press citing NEC; NEC page). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Communist Party of Vietnam: 0.44%, 2.1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | -------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Monthly branch meeting, \~2 h \* | 100% | 0.46 | 1 (directed) | 0.46 | | **Total** | | | | **0.46** | 5.6 million members (Party figures via press report (2025)). Sources: Regulation 29-QĐ/TW. ### People Power Party (South Korea): 0.52%, 2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 4.44 million members (NEC 2024 membership statistic via Namu Wiki/press: 4,439,796 (Wikipedia list shows 4,449,281 for 2023):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Republican Party (US): 0.06%, 2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ---------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Campaign work and rallies (ANES 2020, all adults) \* | 100% | 0.06 | 1 (directed) | 0.06 | | **Total** | | | | **0.06** | 38 million members (Same Ballotpedia source, June 2025 (38.0M, 31.01% of registered voters in reporting areas):). US parties have no members; these are voters registered with the party in 30 states and DC. Sources: American National Election Studies (2020); Schwenzfeier and Settle. ### PSUV (Venezuela): 0.52%, 1.9 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 4.24 million members (PSUV, March 2024: 4,240,032 members took part in assemblies/UBCh backing Maduro's candidacy:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### ZANU-PF (Zimbabwe): 0.52%, 1.8 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 4.06 million members (Central Committee report to 22nd Annual People's Conference, Oct 2025: 4,058,350 verified members across 81,167 cells/villages:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### UMNO (Malaysia): 0.52%, 1.5 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 3.25 million members (UMNO, 31 Aug 2026: 3,251,456 members (3.525M on 15 Jan 2026):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Justicialist Party (Argentina): 0.52%, 1.4 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 3.1 million members (Cámara Nacional Electoral affiliate registry at Dec 2024 (via Infobae, 16 Mar 2025):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Colorado Party (Paraguay): 0.52%, 1.3 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 3 million members (ANR leadership: affiliates 'exceed 3 million' after 141,000 new affiliations (Aug 2025):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### United Russia: 0.52%, 1.2 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 2.6 million members (Party statements mid-2025: \~2.6M members plus 900k supporters (via Parlamentskaya Gazeta/search):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### UzLiDeP (Uzbekistan): 0.52%, 1 × 10¹⁵ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 2.31 million members (Live counter on party site). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PLD (Dominican Republic): 0.52%, 9.7 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 2.18 million members (PLD roster filed with JCE, 17 Aug 2023 (Law 33-18 art. 9):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### MDB (Brazil): 0.52%, 9 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 2.02 million members (TSE filiados statistics, July 2026 (via Gazeta do Paraná):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### CHP (Turkey): 0.52%, 8.4 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.88 million members (Court of Cassation party registry, 1 July 2026 (Jan 2026: 1,922,757):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Radical Civic Union (Argentina): 0.52%, 8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.79 million members (Same CNE registry, Dec 2024:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Workers’ Party, PT (Brazil): 0.52%, 7.5 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.67 million members (TSE July 2026 (via Gazeta do Paraná, search summary):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PRM (Dominican Republic): 0.52%, 6.9 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.55 million members (PRM roster deposited with the Central Electoral Board (JCE), Aug 2026:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Authentic Radical Liberal Party (Paraguay): 0.52%, 6.9 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.55 million members (Wikipedia list (ref 29), 2022 TSJE-based; press 2026 says PLRA 'exceeds 1.5 million':). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Partido Federal ng Pilipinas: 0.52%, 6.7 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.5 million members (Wikipedia list (ref 30):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PAS (Malaysia): 0.52%, 5.8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.3 million members (PAS Sec-Gen Takiyuddin Hassan: 1.3 million members, Sept 2025:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PRD (Brazil): 0.52%, 5.8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.29 million members (Wikipedia list (ref 28, TSE 2025):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Progressistas (Brazil): 0.52%, 5.8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.29 million members (TSE July 2026 (search summary of same source)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PSDB (Brazil): 0.52%, 5.6 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.26 million members (TSE July 2026 (search summary of same source)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PKR (Malaysia): 0.52%, 5.2 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.15 million members (Wikipedia list (ref 32):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Economic Freedom Fighters (South Africa): 0.52%, 4.9 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.09 million members (Wikipedia list (ref 34):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### PDT (Brazil): 0.52%, 4.8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.07 million members (TSE July 2026 (search summary of Gazeta do Paraná source)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### União Brasil: 0.52%, 4.8 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.07 million members (TSE July 2026 (search summary of Gazeta do Paraná source)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### CPI(M) (India): 0.52%, 4.6 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1.02 million members (CPI(M) 24th Congress organisation report, Madurai, April 2025 (membership 10,19,009 in 2024, 9,85,757 in 2021):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Liberal Democratic Party (Japan): 0.52%, 4.5 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1 million members (LDP announcement (Sec-Gen Suzuki), end-2025 party membership 1,003,298, down \~25,000, third straight decline:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### FLN (Algeria): 0.52%, 4.5 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 1 million members (Wikipedia list (ref 37):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. The membership is the party’s own claim. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Liberal Party, PL (Brazil): 0.52%, 4.3 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 952,881 members (TSE July 2026 (947,5k at end of April):). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### African National Congress: 0.52%, 3.1 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 688,454 members (Existing entry (2023 audited membership); Wikipedia list shows 769,000 (2015). 5th NGC report (Apr 2026) PDF could not be text-extracted:). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Conservative Party of Canada: 0.46%, 2.7 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Party activity, mean across members (five parties pooled) \* | 100% | 0.48 | 1 (directed) | 0.48 | | **Total** | | | | **0.48** | 678,708 members (Ian Bailey, 'Federal Conservatives say they have 678,708 members, record for a Canadian political party', Globe and Mail, 29 Jul 2022). Members are those registered for a leadership race. Sources: Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Communist Party of Cuba: 0.44%, 2.7 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Monthly cell meeting, \~2 h \* | 100% | 0.46 | 1 (directed) | 0.46 | | **Total** | | | | **0.46** | 700,000 members (Party figures (2021)). Sources: Statutes of the Communist Party of Cuba, Art. 31. ### CDU (Germany): 0.52%, 1.6 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 364,202 members (Niedermayer, 'Parteimitglieder in Deutschland: Version 2025', Arbeitshefte Otto-Stammer-Zentrum Nr. 33, FU Berlin, Table 1 (31 Dec 2024), text extracted from PDF). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### SPD (Germany): 0.52%, 1.6 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 357,116 members (Niedermayer 2025 Table 1, same PDF). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Labour Party (UK): 0.55%, 1.6 × 10¹⁴ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity, mean across members | 100% | 0.58 | 1 (directed) | 0.57 | | **Total** | | | | **0.57** | 333,235 members (Labour Party accounts (2024)). The time survey is from 1999; 2024 campaign surveys report only the most active shares. Sources: Seyd and Whiteley (2004), Party Politics 10(4), 1999 survey. ### Greens (Germany): 0.52%, 7 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 155,296 members (Niedermayer 2025 Table 1, same PDF (+23.3% vs 2023; 183,761 per a snippet for end-2025, not verified)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Liberal Party of Canada: 0.46%, 6.5 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Party activity, mean across members (five parties pooled) \* | 100% | 0.48 | 1 (directed) | 0.48 | | **Total** | | | | **0.48** | 163,836 members (Wikipedia results table citing the Liberal Party's official leadership results page: 163,836 eligible registered Liberals, 151,899 voted (92.7%), 9 Mar 2025). Members are those registered for a leadership race. Sources: Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### CSU (Germany): 0.52%, 5.6 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 125,153 members (Niedermayer 2025 Table 1, same PDF). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### New Democratic Party (Canada): 0.46%, 4 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ------------------------------------------------------------ | ------------------- | ------------ | ------------ | ------------- | | Party activity, mean across members (five parties pooled) \* | 100% | 0.48 | 1 (directed) | 0.48 | | **Total** | | | | **0.48** | 100,542 members (100,542 registered members eligible in the March 2026 leadership vote, per Wikipedia infobox (no inline citation; text says party reported 'approximately 100,000'); turnout 70.55%). Members are those registered for a leadership race. Sources: Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ### Conservative Party (UK): 0.35%, 3.7 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity, mean across members | 100% | 0.37 | 1 (directed) | 0.37 | | **Total** | | | | **0.37** | 123,000 members (Press estimate (2025)). The time survey is from 1992\. Sources: Seyd and Whiteley (2004), Party Politics 10(4), 1992 survey. ### AfD (Germany): 0.52%, 2.3 × 10¹³ neuron-equivalents | Practice | Members who keep it | Hours a week | Weight | Counted hours | | ----------------------------------------------------------- | ------------------- | ------------ | ------------ | ------------- | | Party activity: mean of member surveys elsewhere (proxy) \* | 100% | 0.55 | 1 (directed) | 0.55 | | **Total** | | | | **0.55** | 51,335 members (Niedermayer 2025 Table 1, same PDF (+29.6% vs 2023)). No survey of this party’s members’ time exists, so the mean of the surveys that do is used. Sources: Seyd and Whiteley (2004), Party Politics 10(4); Cross and Young (2004), The Contours of Political Party Membership in Canada, Party Politics 10(4). ## Corporations Paid hours are directed time, with weight 1.0\. No company publishes its employees’ hours. So each company uses the average hours actually worked per employee in its industry, in the country where most of its workforce is. That average includes part-time workers. We don't count conduct rules outside work, or dormitory rules where workers live on site. | Corporation | Employees | Hours a week | c | Neuron-equivalents | | ------------------------------------ | ------------ | ------------------------------------------------------------ | --- | ------------------ | | Walmart | 2.1 million | 36.3 (retail and wholesale, United States) | 35% | 6.3 × 10¹⁶ | | State Grid | 1.36 million | 49 (all enterprises, China †) | 47% | 5.5 × 10¹⁶ | | Amazon | 1.58 million | 36.3 (retail and wholesale, United States †) | 35% | 4.7 × 10¹⁶ | | China National Petroleum | 1.03 million | 49 (all enterprises, China †) | 47% | 4.1 × 10¹⁶ | | JD.com | 951,420 | 49 (all enterprises, China †) | 47% | 3.8 × 10¹⁶ | | Accenture | 779,000 | 57.58 (professional services, India †) | 55% | 3.7 × 10¹⁶ | | BYD | 869,622 | 49 (all enterprises, China †) | 47% | 3.5 × 10¹⁶ | | China Post Group | 719,448 | 49 (all enterprises, China †) | 47% | 2.9 × 10¹⁶ | | Tata Consultancy Services | 584,510 | 58.23 (information and communication, India †) | 56% | 2.8 × 10¹⁶ | | Foxconn (Hon Hai) | 633,167 | 49 (all enterprises, China †) | 47% | 2.5 × 10¹⁶ | | Allied Universal | 770,000 | 36.52 (administrative and support services, United States †) | 35% | 2.3 × 10¹⁶ | | Russian Railways (RZD) | 677,363 | 39.96 (transport and storage, Russia †) | 38% | 2.2 × 10¹⁶ | | Teleperformance | 446,716 | 58.89 (administrative and support services, India †) | 56% | 2.2 × 10¹⁶ | | Sinopec | 513,434 | 49 (all enterprises, China †) | 47% | 2.1 × 10¹⁶ | | Reliance Industries | 419,911 | 59.57 (manufacturing, India †) | 57% | 2.1 × 10¹⁶ | | Capgemini | 423,400 | 58.23 (information and communication, India †) | 56% | 2 × 10¹⁶ | | Volkswagen Group | 662,942 | 35.95 (manufacturing, Germany) | 34% | 2 × 10¹⁶ | | China Mobile | 468,496 | 49 (all enterprises, China †) | 47% | 1.9 × 10¹⁶ | | Agricultural Bank of China | 457,835 | 49 (all enterprises, China †) | 47% | 1.8 × 10¹⁶ | | Concentrix | 455,000 | 46.71 (administrative and support services, Philippines †) | 45% | 1.7 × 10¹⁶ | | DHL Group | 583,998 | 35.81 (transport and storage, Germany †) | 34% | 1.7 × 10¹⁶ | | Cognizant | 351,600 | 58.23 (information and communication, India) | 56% | 1.7 × 10¹⁶ | | Luxshare Precision | 416,197 | 49 (all enterprises, China †) | 47% | 1.7 × 10¹⁶ | | Gazprom | 501,000 | 40.47 (mining and energy extraction, Russia †) | 39% | 1.7 × 10¹⁶ | | ICBC | 409,758 | 49 (all enterprises, China †) | 47% | 1.6 × 10¹⁶ | | China Resources | 397,398 | 49 (all enterprises, China †) | 47% | 1.6 × 10¹⁶ | | ISS | 325,000 | 58.89 (administrative and support services, India †) | 56% | 1.6 × 10¹⁶ | | Infosys | 328,594 | 58.23 (information and communication, India †) | 56% | 1.6 × 10¹⁶ | | Schwarz Group | 604,000 | 31.49 (retail and wholesale, Germany) | 30% | 1.6 × 10¹⁶ | | FedEx | 474,200 | 39.98 (transport and storage, United States †) | 38% | 1.6 × 10¹⁶ | | AVIC | 384,000 | 49 (all enterprises, China †) | 47% | 1.5 × 10¹⁶ | | Compass Group | 590,000 | 31.7 (accommodation and food service, United States †) | 30% | 1.5 × 10¹⁶ | | China Telecom | 381,436 | 49 (all enterprises, China †) | 47% | 1.5 × 10¹⁶ | | Jardine Matheson | 443,000 | 41.93 (all employees, Indonesia †) | 40% | 1.5 × 10¹⁶ | | China Construction Bank | 378,344 | 49 (all enterprises, China †) | 47% | 1.5 × 10¹⁶ | | UPS | 460,000 | 39.98 (transport and storage, United States †) | 38% | 1.5 × 10¹⁶ | | China State Construction Engineering | 370,272 | 49 (all enterprises, China †) | 47% | 1.5 × 10¹⁶ | | FEMSA | 368,776 | 47.09 (retail and wholesale, Mexico †) | 45% | 1.4 × 10¹⁶ | | Home Depot | 470,000 | 36.3 (retail and wholesale, United States †) | 35% | 1.4 × 10¹⁶ | | Magnit | 394,000 | 39.69 (retail and wholesale, Russia †) | 38% | 1.3 × 10¹⁶ | | Toyota | 390,927 | 39.6 (manufacturing, Japan †) | 38% | 1.3 × 10¹⁶ | | X5 Group | 389,000 | 39.69 (retail and wholesale, Russia †) | 38% | 1.3 × 10¹⁶ | | Bank of China | 313,746 | 49 (all enterprises, China †) | 47% | 1.3 × 10¹⁶ | | Target | 415,000 | 36.3 (retail and wholesale, United States †) | 35% | 1.2 × 10¹⁶ | | Japan Post Holdings | 360,000 | 41.6 (transport and storage, Japan †) | 40% | 1.2 × 10¹⁶ | | China Railway Construction (CRCC) | 304,927 | 49 (all enterprises, China †) | 47% | 1.2 × 10¹⁶ | | CHN Energy (China Energy Investment) | 303,418 | 49 (all enterprises, China †) | 47% | 1.2 × 10¹⁶ | | Bosch | 412,400 | 35.95 (manufacturing, Germany) | 34% | 1.2 × 10¹⁶ | | China Railway Group (CREC) | 302,527 | 49 (all enterprises, China †) | 47% | 1.2 × 10¹⁶ | | Berkshire Hathaway | 387,800 | 37.75 (all employees, United States) | 36% | 1.2 × 10¹⁶ | | Kroger | 403,000 | 36.3 (retail and wholesale, United States) | 35% | 1.2 × 10¹⁶ | | UnitedHealth Group | 390,000 | 36.87 (health care, United States †) | 35% | 1.2 × 10¹⁶ | | Ahold Delhaize | 384,000 | 36.3 (retail and wholesale, United States †) | 35% | 1.1 × 10¹⁶ | | NTT | 344,196 | 40.2 (information and communication, Japan †) | 38% | 1.1 × 10¹⁶ | | TJX Companies | 377,000 | 36.3 (retail and wholesale, United States †) | 35% | 1.1 × 10¹⁶ | | Sodexo | 426,464 | 31.7 (accommodation and food service, United States †) | 30% | 1.1 × 10¹⁶ | | Edeka | 417,500 | 31.49 (retail and wholesale, Germany †) | 30% | 1.1 × 10¹⁶ | | Marriott International | 414,000 | 31.7 (accommodation and food service, United States †) | 30% | 1.1 × 10¹⁶ | | Rosneft | 320,000 | 40.47 (mining and energy extraction, Russia †) | 39% | 1.1 × 10¹⁶ | | JPMorgan Chase | 318,512 | 40.14 (finance and insurance, United States) | 38% | 1.1 × 10¹⁶ | | PepsiCo | 306,000 | 40.7 (manufacturing, United States) | 39% | 1 × 10¹⁶ | | Costco | 341,000 | 36.3 (retail and wholesale, United States) | 35% | 1 × 10¹⁶ | | Starbucks | 381,000 | 31.7 (accommodation and food service, United States) | 30% | 9.9 × 10¹⁵ | | Rewe Group | 380,000 | 31.49 (retail and wholesale, Germany) | 30% | 9.8 × 10¹⁵ | | HCA Healthcare | 320,000 | 36.87 (health care, United States †) | 35% | 9.7 × 10¹⁵ | | Securitas | 322,000 | 36.52 (administrative and support services, United States †) | 35% | 9.7 × 10¹⁵ | | Siemens | 318,000 | 35.95 (manufacturing, Germany †) | 34% | 9.4 × 10¹⁵ | | Walgreens Boots Alliance | 312,000 | 36.3 (retail and wholesale, United States) | 35% | 9.3 × 10¹⁵ | | Tesco | 354,744 | 31.81 (retail and wholesale, United Kingdom †) | 30% | 9.3 × 10¹⁵ | | CVS Health | 300,000 | 36.3 (retail and wholesale, United States) | 35% | 8.9 × 10¹⁵ | | CK Hutchison | 300,000 | 35.08 (all employees, United Kingdom †) | 33% | 8.6 × 10¹⁵ | The chart covers every company with at least 300,000 employees. A company that belongs to a larger one in the list (PetroChina within CNPC) is counted only in the parent; staffing firms’ placed workers are not their employees and are not counted. Hours: ILOSTAT, mean weekly hours actually worked per employee by economic activity, latest year. China has no series by industry, so its companies use the National Bureau of Statistics mean for enterprise employees (2024). Where a company does not publish where its staff work, the country is inferred from its operations (†). Employees: company annual reports and the Fortune Global 500 (2025). Data version 2026.10.02\. [Download (JSON)](https://simulation-hypothesis.com/entities/collectives.json). --- title: "Consciousness indicators for AI · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/indicators description: "The fourteen indicators from Butlin, Long and colleagues (2023), taken from six scientific theories of consciousness." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Consciousness indicators # Consciousness indicators for AI In 2023 nineteen researchers in neuroscience, philosophy and machine learning listed the properties that the leading scientific theories say a conscious system would have. Then they checked today’s AI against that list. ## Recurrent processing theory * **RPT-1** Input modules using algorithmic recurrence * **RPT-2** Input modules generating organised, integrated perceptual representations ## Global workspace theory * **GWT-1** Multiple specialised systems capable of operating in parallel (modules) * **GWT-2** Limited capacity workspace, entailing a bottleneck in information flow and a selective attention mechanism * **GWT-3** Global broadcast: availability of information in the workspace to all modules * **GWT-4** State-dependent attention, giving rise to the capacity to use the workspace to query modules in succession to perform complex tasks ## Computational higher-order theories * **HOT-1** Generative, top-down or noisy perception modules * **HOT-2** Metacognitive monitoring distinguishing reliable perceptual representations from noise * **HOT-3** Agency guided by a general belief-formation and action selection system, and a strong disposition to update beliefs in accordance with the outputs of metacognitive monitoring * **HOT-4** Sparse and smooth coding generating a "quality space" ## Attention schema theory * **AST-1** A predictive model representing and enabling control over the current state of attention ## Predictive processing * **PP-1** Input modules using predictive coding ## Agency and embodiment * **AE-1** Agency: Learning from feedback and selecting outputs so as to pursue goals, especially where this involves flexible responsiveness to competing goals * **AE-2** Embodiment: Modeling output-input contingencies, including some systematic effects, and using this model in perception or control ## Their conclusion Their assessment: “no current system appears to be a strong candidate for consciousness.” They add that, if computational functionalism is true, conscious AI systems “could realistically be built in the near term.” Butlin P, Long R, Elmoznino E, Bengio Y, Birch J, et al. (2023). Consciousness in Artificial Intelligence: Insights from the Science of Consciousness. arXiv:2308.08708\. https://arxiv.org/abs/2308.08708 (Table 1 text read directly from the PDF) --- title: "Escherichia coli · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ecoli description: "A single cell with no neurons. It steers toward food and has a chemical memory that lasts a few seconds." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › No neurons # Escherichia coli Escherichia coli A single cell with no neurons. It steers toward food and has a chemical memory that lasts a few seconds. Neurons 0 measured · no neurons (single-celled bacterium) ## Evidence * Chemotaxis uses a short-term molecular memory. The cell compares current attractant concentration with the level a few seconds earlier, through methylation of its receptors. That's a temporal comparison, not a nervous system. Segall JE, Block SM, Berg HC (1986) Temporal comparisons in bacterial chemotaxis. Proc Natl Acad Sci USA 83(23):8987-8991\. doi:10.1073/pnas.83.23.8987. In the trees [Stop the free rider · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-pubgoods) Assess it against the published criteria --- title: "Slime mould · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/physarum description: "A single giant cell with no neurons. It solves mazes and grows efficient transport networks." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › No neurons # Slime mould Physarum polycephalum A single giant cell with no neurons. It solves mazes and grows efficient transport networks. Neurons 0 measured · no neurons (single giant multinucleate cell) ## Evidence * An amoeboid plasmodium found the shortest path through a maze. Nakagaki T, Yamada H, Toth A (2000) Maze-solving by an amoeboid organism. Nature 407(6803):470\. doi:10.1038/35035159. * Its network of tubes organises itself. Its cost, efficiency and fault tolerance are comparable to the Tokyo rail network. Tero A, Takagi S, Saigusa T, Ito K, Bebber DP, Fricker MD, Yumiki K, Kobayashi R, Nakagaki T (2010) Rules for biologically inspired adaptive network design. Science 327(5964):439-442\. doi:10.1126/science.1177894. Assess it against the published criteria --- title: "Sensitive plant · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/mimosa description: "A plant whose leaves fold when touched. One study reported that it learns to ignore harmless touches. A later re-analysis disputed that." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › No neurons # Sensitive plant Mimosa pudica A plant whose leaves fold when touched. One study reported that it learns to ignore harmless touches. A later re-analysis disputed that. This result comes from a single laboratory, and claims of learning in plants are contested. Neurons 0 measured · no neurons (plant) ## Evidence * Reported habituation: the leaflets stopped folding after repeated harmless drops, and the response lasted for weeks. Gagliano M, Renton M, Depczynski M, Mancuso S (2014) Experience teaches plants to learn faster and forget slower in environments where it matters. Oecologia 175(1):63-72\. doi:10.1007/s00442-013-2873-7. * A re-analysis found the evidence wasn't enough to show habituation. Biegler R (2017). Insufficient evidence for habituation in Mimosa pudica. Oecologia 186:33-35\. doi:10.1007/s00442-017-4012-3. Assess it against the published criteria --- title: "Sponge · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/sponge description: "An animal with no neurons or synapses that still contracts its whole body in a coordinated way." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › No neurons # Sponge Porifera (e.g. Amphimedon queenslandica) An animal with no neurons or synapses that still contracts its whole body in a coordinated way. Neurons 0 measured · no neurons or synapses Leys SP (2015) Elements of a 'nervous system' in sponges. J Exp Biol 218(4):581-591\. doi:10.1242/jeb.110817. ## Evidence * Sponges have no neurons or synapses, but they coordinate whole-body contractions (for example, 'sneezing') with non-neuronal signalling. Leys SP (2015) Elements of a 'nervous system' in sponges. J Exp Biol 218(4):581-591\. doi:10.1242/jeb.110817. Assess it against the published criteria --- title: "Hydra · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/hydra description: "A small freshwater cnidarian. It's controlled by a diffuse nerve net and has no brain." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Nerve nets, no brain # Hydra Hydra vulgaris A small freshwater cnidarian. It's controlled by a diffuse nerve net and has no brain. Neurons about 3,000 to 5,000 estimate · whole nerve net; no exact count exists Bode H, Berking S, David CN, Gierer A, Schaller H, Trenkner E (1973) Quantitative analysis of cell types during growth and morphogenesis in Hydra. Wilhelm Roux Arch Entwickl Mech Org 171(4):269-285\. doi:10.1007/BF00577725. ## Evidence * Its behaviour (contracting, feeding, somersaulting) is driven by a nerve net with no brain. Calcium imaging of the whole animal has mapped its groups of neurons. Dupre C, Yuste R (2017) Non-overlapping neural networks in Hydra vulgaris. Curr Biol 27(8):1085-1097\. doi:10.1016/j.cub.2017.02.049. Assess it against the published criteria --- title: "Box jellyfish · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/jellyfish description: "A box jellyfish has no central brain, yet it showed associative learning." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Nerve nets, no brain # Box jellyfish Tripedalia cystophora A box jellyfish has no central brain, yet it showed associative learning. Neurons No published count ## Evidence * It showed associative learning (a visual cue paired with a mechanosensory cue). The learning happens in the rhopalial nervous system, even though the animal has no centralised brain. Bielecki J, Dam Nielsen SK, Nachman G, Garm A (2023) Associative learning in the box jellyfish Tripedalia cystophora. Curr Biol 33(19):4150-4159.e5\. doi:10.1016/j.cub.2023.08.056. Assess it against the published criteria --- title: "Roundworm · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/celegans description: "A worm about a millimetre long with exactly 302 neurons. It was the first animal to have its complete wiring diagram mapped." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Roundworm Caenorhabditis elegans A worm about a millimetre long with exactly 302 neurons. It was the first animal to have its complete wiring diagram mapped. Neurons 302 measured · whole nervous system (hermaphrodite) White JG, Southgate E, Thomson JN, Brenner S (1986) The structure of the nervous system of the nematode Caenorhabditis elegans. Phil Trans R Soc Lond B 314(1165):1-340\. doi:10.1098/rstb.1986.0056. ## Evidence * It shows habituation, associative learning and memory. Its full connectome is known (now updated for both sexes). Cook SJ, Jarrell TA, Brittin CA, Wang Y, et al. (2019) Whole-animal connectomes of both Caenorhabditis elegans sexes. Nature 571(7763):63-71\. doi:10.1038/s41586-019-1352-7. * A review of learning and memory in the worm. Ardiel EL, Rankin CH (2010). An elegant mind: learning and memory in C. elegans. Learn Mem 17:191-201\. doi:10.1101/lm.960510. In the trees [OpenWorm · Simulations](https://simulation-hypothesis.com/trees/simulations?n=min-openworm)[A worm’s whole wiring · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=celegans-connectome-1986) Assess it against the published criteria --- title: "Fruit fly · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/drosophila description: "The largest complete brain wiring diagram mapped so far, covering about 139,000 neurons." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Fruit fly Drosophila melanogaster The largest complete brain wiring diagram mapped so far, covering about 139,000 neurons. Neurons 139,255 measured · whole adult brain (proofread neurons, one female); excludes ventral nerve cord Dorkenwald S, Matsliah A, Sterling AR, Schlegel P, et al.; FlyWire Consortium (2024) Neuronal wiring diagram of an adult brain. Nature 634(8032):124-138\. doi:10.1038/s41586-024-07558-y. ## Evidence * Flies learn visual place memory in a virtual arena. Ofstad TA, Zuker CS, Reiser MB (2011) Visual place learning in Drosophila melanogaster. Nature 474(7350):204-207\. doi:10.1038/nature10131. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. Assess it against the published criteria --- title: "Honeybee · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/honeybee description: "About a million neurons, and bees can learn abstract concepts such as same and different." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Honeybee Apis mellifera About a million neurons, and bees can learn abstract concepts such as same and different. Neurons about 1 million estimate · whole brain Menzel R (2001). Searching for the memory trace in a mini-brain, the honeybee. Learn Mem 8:53-62, citing Witthöft (1967). ## Evidence * Bees learn the concepts of 'sameness' and 'difference'. Giurfa M, Zhang S, Jenett A, Menzel R, Srinivasan MV (2001) The concepts of 'sameness' and 'difference' in an insect. Nature 410(6831):930-933\. doi:10.1038/35073582. * Agitated (shaken) bees show a pessimistic-like cognitive bias, an affect-like state. Bateson M, Desire S, Gartside SE, Wright GA (2011) Agitated honeybees exhibit pessimistic cognitive biases. Curr Biol 21(12):1070-1073\. doi:10.1016/j.cub.2011.05.017. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. In the trees [Police the egg-layers · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-police) Assess it against the published criteria --- title: "Ant (Camponotus / Formica) · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ant description: "A small brain that handles long-distance navigation by counting steps (path integration) and remembering landmarks." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Ant (Camponotus / Formica) Camponotus spp. A small brain that handles long-distance navigation by counting steps (path integration) and remembering landmarks. Neurons No published count ## Evidence * Desert ants navigate long distances using path integration and visual landmark memory, with a tiny brain. Wehner R (2003) Desert ant navigation: how miniature brains solve complex tasks. J Comp Physiol A 189(8):579-588\. doi:10.1007/s00359-003-0431-1. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. In the trees [One queen, many workers · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-eusocial) Assess it against the published criteria --- title: "Portia jumping spider · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/portia description: "A jumping spider that plans detours. It takes routes that lead away from its prey and out of sight." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Portia jumping spider Portia fimbriata / labiata A jumping spider that plans detours. It takes routes that lead away from its prey and out of sight. Neurons No published count ## Evidence * It makes detours to reach prey, planning routes that first lead away from the prey and out of sight. Tarsitano MS, Jackson RR (1997) Araneophagic jumping spiders discriminate between detour routes that do and do not lead to prey. Anim Behav 53(2):257-266\. doi:10.1006/anbe.1996.0372. Assess it against the published criteria --- title: "Shore crab / crayfish · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/decapod description: "Crabs and crayfish. A 2021 government review found strong evidence that true crabs are sentient." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Shore crab / crayfish Carcinus maenas; Procambarus / Astacus spp. Crabs and crayfish. A 2021 government review found strong evidence that true crabs are sentient. Neurons No published count ## Evidence * Shore crabs learn to avoid a shelter that gives shocks. They also trade off avoiding shocks against how good the shelter is. That fits the pain criteria. Magee B, Elwood RW (2013) Shock avoidance by discrimination learning in the shore crab (Carcinus maenas) is consistent with a key criterion for pain. J Exp Biol 216(3):353-358\. doi:10.1242/jeb.072041. ## The 2021 sentience review Confidence that each of the eight [sentience criteria](https://simulation-hypothesis.com/entities/sentience) is met, for true crabs (brachyura): 1. high The animal possesses receptors sensitive to noxious stimuli (nociceptors) 2. very high The animal possesses integrative brain regions capable of integrating information from different sensory sources 3. low The animal possesses neural pathways connecting the nociceptors to the integrative brain regions 4. very high The animal's behavioural response to a noxious stimulus is modulated by chemical compounds affecting the nervous system (e.g. local anaesthetics, analgesics, opioid-type systems) 5. low The animal shows motivational trade-offs, in which the disvalue of a noxious or threatening stimulus is weighed against the value of an opportunity for reward, leading to flexible decision-making 6. very high The animal shows flexible self-protective behaviour (e.g. wound-tending, guarding, grooming, rubbing) of a type likely to involve representing the bodily location of an injury or noxious stimulus 7. high The animal shows associative learning in which noxious stimuli become associated with neutral stimuli, and/or novel ways of avoiding noxious stimuli are learned through reinforcement (habituation and sensitisation do not count) 8. very low The animal shows that it values a putative analgesic or anaesthetic when injured (e.g. self-administers it, or learns to prefer a location where it is available) The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. In the trees [Crabs and octopuses review · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-birch)[The UK’s Animal Welfare (Sentience) Act 2022 · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-sentience-act) Assess it against the published criteria --- title: "Common octopus · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/octopus description: "Most of its neurons are in its arms. A 2021 review found very strong evidence that it's sentient." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Invertebrates with brains # Common octopus Octopus vulgaris Most of its neurons are in its arms. A 2021 review found very strong evidence that it's sentient. Neurons 500 million estimate · whole nervous system: about 300 million in the arms, 200 million in the central brain Young JZ (1963) The number and sizes of nerve cells in Octopus. Proc Zool Soc Lond 140(2):229-254\. doi:10.1111/j.1469-7998.1963.tb01862.x; Young JZ (1971) The Anatomy of the Nervous System of Octopus vulgaris. Oxford: Clarendon Press. ## Evidence * A review of the behavioural evidence for consciousness in cephalopods. Mather JA (2008) Cephalopod consciousness: Behavioural evidence. Conscious Cogn 17(1):37-48\. doi:10.1016/j.concog.2006.11.006. ## The 2021 sentience review Confidence that each of the eight [sentience criteria](https://simulation-hypothesis.com/entities/sentience) is met, for octopods: 1. very high The animal possesses receptors sensitive to noxious stimuli (nociceptors) 2. very high The animal possesses integrative brain regions capable of integrating information from different sensory sources 3. high The animal possesses neural pathways connecting the nociceptors to the integrative brain regions 4. high The animal's behavioural response to a noxious stimulus is modulated by chemical compounds affecting the nervous system (e.g. local anaesthetics, analgesics, opioid-type systems) 5. medium The animal shows motivational trade-offs, in which the disvalue of a noxious or threatening stimulus is weighed against the value of an opportunity for reward, leading to flexible decision-making 6. very high The animal shows flexible self-protective behaviour (e.g. wound-tending, guarding, grooming, rubbing) of a type likely to involve representing the bodily location of an injury or noxious stimulus 7. very high The animal shows associative learning in which noxious stimuli become associated with neutral stimuli, and/or novel ways of avoiding noxious stimuli are learned through reinforcement (habituation and sensitisation do not count) 8. high The animal shows that it values a putative analgesic or anaesthetic when injured (e.g. self-administers it, or learns to prefer a location where it is available) The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. In the trees [Crabs and octopuses review · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-birch)[The UK’s Animal Welfare (Sentience) Act 2022 · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-sentience-act) Assess it against the published criteria --- title: "Zebrafish · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/zebrafish description: "A small fish widely used in neuroscience. Its neurons haven't been fully counted. The adult brain has about 10 million cells." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Fish and amphibians # Zebrafish Danio rerio A small fish widely used in neuroscience. Its neurons haven't been fully counted. The adult brain has about 10 million cells. Neurons No published count ## Evidence * Fish have nociceptors and change their behaviour in ways linked to pain. This was shown in trout, and it's used here as the reference for fish, not as a result for zebrafish. Sneddon LU, Braithwaite VA, Gentle MJ (2003) Do fishes have nociceptors? Evidence for the evolution of a vertebrate sensory system. Proc R Soc Lond B 270(1520):1115-1121\. doi:10.1098/rspb.2003.2349. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. Assess it against the published criteria --- title: "Cleaner wrasse · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/wrasse description: "A reef fish that passed a version of the mirror mark test. People disagree about what that shows." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Fish and amphibians # Cleaner wrasse Labroides dimidiatus A reef fish that passed a version of the mirror mark test. People disagree about what that shows. Neurons No published count ## Evidence * It passed the mirror mark test: it reacted to a coloured mark visible only in its reflection. How to interpret that is debated. Kohda M, Hotta T, Takeyama T, Awata S, et al. (2019) If a fish can pass the mark test, what are the implications for consciousness and self-awareness testing in animals? PLoS Biol 17(2):e3000021\. doi:10.1371/journal.pbio.3000021. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. Assess it against the published criteria --- title: "Frog · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/frog description: "The 2024 New York Declaration says there's a realistic possibility of conscious experience in amphibians." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Fish and amphibians # Frog Anura (e.g. Xenopus / Rana) The 2024 New York Declaration says there's a realistic possibility of conscious experience in amphibians. Neurons No published count ## Evidence * Amphibians are covered by the New York Declaration's 'realistic possibility' of conscious experience in all vertebrates. New York Declaration on Animal Consciousness (2024). https://sites.google.com/nyu.edu/nydeclaration/declaration. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds at least a realistic possibility of conscious experience in all vertebrates and in many invertebrates, including cephalopods, decapod crustaceans and insects. Assess it against the published criteria --- title: "Rock pigeon · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/pigeon description: "Hundreds of millions of neurons in a small brain. Pigeons can sort complex images into categories." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Birds # Rock pigeon Columba livia Hundreds of millions of neurons in a small brain. Pigeons can sort complex images into categories. Neurons 310 million measured · whole brain (isotropic fractionator) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. In the cerebral cortex (or bird pallium) about 72 million (pallium, derived from telencephalon counts) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Common raven · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/raven description: "Over two billion neurons, densely packed. Ravens remember individual competitors." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Birds # Common raven Corvus corax Over two billion neurons, densely packed. Ravens remember individual competitors. Neurons 2.17 billion measured · whole brain (isotropic fractionator) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. In the cerebral cortex (or bird pallium) 1.2 billion (pallium) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. ## Evidence * Ravens judge competitors based on what happened in earlier play-caching. Bugnyar T, Schwab C, Schloegl C, Kotrschal K, Heinrich B (2007) Ravens judge competitors through experience with play caching. Curr Biol 17(20):1804-1808\. doi:10.1016/j.cub.2007.09.048. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "New Caledonian crow · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/nccrow description: "It makes hooked tools from twigs and wire. Its neurons haven't been counted." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Birds # New Caledonian crow Corvus moneduloides It makes hooked tools from twigs and wire. Its neurons haven't been counted. Neurons No published count ## Evidence * It makes hooked tools. Weir AAS, Chappell J, Kacelnik A (2002) Shaping of hooks in New Caledonian crows. Science 297(5583):981\. doi:10.1126/science.1073433. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "African grey parrot · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/greyparrot description: "About 1.6 billion neurons. Decades of laboratory study of numerosity and categorisation." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Birds # African grey parrot Psittacus erithacus About 1.6 billion neurons. Decades of laboratory study of numerosity and categorisation. Neurons 1.57 billion measured · whole brain (isotropic fractionator) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. In the cerebral cortex (or bird pallium) about 850 million (pallium, derived from telencephalon counts) Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113. ## Evidence * Long-term lab studies of numerical and categorical concepts in a grey parrot. Pepperberg IM (1999) The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots. Cambridge, MA: Harvard University Press. doi:10.4159/9780674041998. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Mouse · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/mouse description: "About 71 million neurons. Mice show facial expressions of pain that can be measured." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Mouse Mus musculus About 71 million neurons. Mice show facial expressions of pain that can be measured. Neurons 70.9 million measured · whole brain (isotropic fractionator) Herculano-Houzel S, Mota B, Lent R (2006). Cellular scaling rules for rodent brains. PNAS 103:12138-12143\. doi:10.1073/pnas.0604911103. In the cerebral cortex (or bird pallium) about 13.7 million Herculano-Houzel S, Mota B, Lent R (2006). Cellular scaling rules for rodent brains. PNAS 103:12138-12143\. doi:10.1073/pnas.0604911103. ## Evidence * Mice show a facial expression that codes for pain. Langford DJ, Bailey AL, Chanda ML, Clarke SE, et al. (2010) Coding of facial expressions of pain in the laboratory mouse. Nat Methods 7(6):447-449\. doi:10.1038/nmeth.1455. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Rat · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/rat description: "About 200 million neurons. Rats release trapped cagemates." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Rat Rattus norvegicus About 200 million neurons. Rats release trapped cagemates. Neurons 200 million measured · whole brain (isotropic fractionator) Herculano-Houzel S, Mota B, Lent R (2006). Cellular scaling rules for rodent brains. PNAS 103:12138-12143\. doi:10.1073/pnas.0604911103. In the cerebral cortex (or bird pallium) 31 million Herculano-Houzel S, Lent R (2005). Isotropic fractionator. J Neurosci 25:2518-2521\. doi:10.1523/JNEUROSCI.4526-04.2005. ## Evidence * Rats free trapped cagemates. This has been interpreted as empathy-driven helping. Ben-Ami Bartal I, Decety J, Mason P (2011). Empathy and pro-social behavior in rats. Science 334:1427-1430\. doi:10.1126/science.1210789. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Domestic cat · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/cat description: "About 250 million neurons in the cerebral cortex." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Domestic cat Felis catus About 250 million neurons in the cerebral cortex. Neurons 1.22 billion measured · whole brain Jardim-Messeder D et al. (2017). Dogs have the most neurons, though not the largest brain: trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species. Front Neuroanat 11:118\. doi:10.3389/fnana.2017.00118. In the cerebral cortex (or bird pallium) 250 million Jardim-Messeder D et al. (2017). Dogs have the most neurons, though not the largest brain: trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species. Front Neuroanat 11:118\. doi:10.3389/fnana.2017.00118. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Domestic dog · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/dog description: "Up to about 600 million cortical neurons, depending on the dog. That's more than cats." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Domestic dog Canis familiaris Up to about 600 million cortical neurons, depending on the dog. That's more than cats. Neurons 1.8 to 2.6 billion, depending on the dog measured · whole brain Jardim-Messeder D et al. (2017). Dogs have the most neurons, though not the largest brain: trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species. Front Neuroanat 11:118\. doi:10.3389/fnana.2017.00118. In the cerebral cortex (or bird pallium) 429 to 623 million, depending on the dog Jardim-Messeder D et al. (2017). Dogs have the most neurons, though not the largest brain: trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species. Front Neuroanat 11:118\. doi:10.3389/fnana.2017.00118. ## Evidence * fMRI scans of awake dogs show reward-related responses in the caudate to trained cues. Berns GS, Brooks AM, Spivak M (2012) Functional MRI in awake unrestrained dogs. PLoS ONE 7(5):e38027\. doi:10.1371/journal.pone.0038027. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Domestic pig · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/pig description: "Pigs learn what a mirror shows and use it to find food." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Domestic pig Sus scrofa domesticus Pigs learn what a mirror shows and use it to find food. Neurons 2.22 billion measured · whole brain, one domestic pig Jelsing J, Nielsen R, Olsen AK, Grand N, Hemmingsen R, Pakkenberg B (2006) The postnatal development of neocortical neurons and glial cells in the Gottingen minipig and the domestic pig brain. J Exp Biol 209(8):1454-1462\. doi:10.1242/jeb.02141\. Whole brain: Kazu RS, Maldonado J, Mota B, Manger PR, Herculano-Houzel S (2014) Cellular scaling rules for the brain of Artiodactyla include a highly folded cortex with few neurons. Front Neuroanat 8:128\. doi:10.3389/fnana.2014.00128. In the cerebral cortex (or bird pallium) 432 million in the neocortex (stereology); 293 million by fractionator Jelsing J, Nielsen R, Olsen AK, Grand N, Hemmingsen R, Pakkenberg B (2006) The postnatal development of neocortical neurons and glial cells in the Gottingen minipig and the domestic pig brain. J Exp Biol 209(8):1454-1462\. doi:10.1242/jeb.02141\. Whole brain: Kazu RS, Maldonado J, Mota B, Manger PR, Herculano-Houzel S (2014) Cellular scaling rules for the brain of Artiodactyla include a highly folded cortex with few neurons. Front Neuroanat 8:128\. doi:10.3389/fnana.2014.00128. ## Evidence * Pigs learn what a mirror image stands for, and use it to find food. Broom DM, Sena H, Moynihan KL (2009) Pigs learn what a mirror image represents and use it to obtain information. Anim Behav 78(5):1037-1041\. doi:10.1016/j.anbehav.2009.07.027. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Bottlenose dolphin · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/dolphin description: "Passes mirror self-recognition tests. There's no measured neuron count for the bottlenose dolphin." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Bottlenose dolphin Tursiops truncatus Passes mirror self-recognition tests. There's no measured neuron count for the bottlenose dolphin. Neurons No published count ## Evidence * Dolphins pass mirror self-recognition tests. Reiss D, Marino L (2001) Mirror self-recognition in the bottlenose dolphin: A case of cognitive convergence. Proc Natl Acad Sci USA 98(10):5937-5942\. doi:10.1073/pnas.101086398. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. In the trees [Dolphins as persons · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-india) Assess it against the published criteria --- title: "African elephant · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/elephant description: "257 billion neurons, three times as many as a human, almost all in the cerebellum." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # African elephant Loxodonta africana 257 billion neurons, three times as many as a human, almost all in the cerebellum. Neurons 257 billion measured · whole brain (\~98% in cerebellum) Herculano-Houzel S et al. (2014). The elephant brain in numbers. Front Neuroanat 8:46\. doi:10.3389/fnana.2014.00046. In the cerebral cortex (or bird pallium) 5.6 billion Herculano-Houzel et al. 2014. ## Evidence * Asian elephants pass the mirror mark test. Plotnik JM, de Waal FBM, Reiss D (2006) Self-recognition in an Asian elephant. Proc Natl Acad Sci USA 103(45):17053-17057\. doi:10.1073/pnas.0608062103. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. Assess it against the published criteria --- title: "Chimpanzee · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/chimp description: "One of our two closest living relatives (along with the bonobo). It passes the mirror test." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Chimpanzee Pan troglodytes One of our two closest living relatives (along with the bonobo). It passes the mirror test. Neurons about 28 billion (predicted from scaling rules, not counted) estimate · whole brain Herculano-Houzel S, Kaas JH (2011), prediction from primate scaling rules. In the cerebral cortex (or bird pallium) 3.7 billion in one hemisphere (measured) Collins CE et al. (2016). Cortical cell and neuron density estimates in one chimpanzee hemisphere. PNAS 113:740-745\. doi:10.1073/pnas.1524208113. ## Evidence * Chimpanzees pass the mirror mark test. Gallup GG Jr (1970) Chimpanzees: self-recognition. Science 167(3914):86-87\. doi:10.1126/science.167.3914.86. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. In the trees [Make peace after a fight · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-chimp-repair)[Share, and be owed · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-foodshare) Assess it against the published criteria --- title: "Human · Animals and other organisms · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/human description: "86 billion neurons, 16 billion of them in the cerebral cortex. We're the only species whose members can give verbal reports of their experience." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Mammals # Human Homo sapiens 86 billion neurons, 16 billion of them in the cerebral cortex. We're the only species whose members can give verbal reports of their experience. Neurons 86.1 billion measured · whole brain (isotropic fractionator, 4 male brains) Azevedo FAC et al. (2009). Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain. J Comp Neurol 513:532-541\. doi:10.1002/cne.21974. In the cerebral cortex (or bird pallium) 16.3 billion Azevedo et al. 2009 (16.34 B cortex; value confirmed in Olkowicz 2016 supplement). ## Evidence * Verbal report is the reference standard for consciousness. The New York Declaration (2024) restates the case for animals. The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds. In the trees [Rank and file rule the boss · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-reverse)[Shame the boaster · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-norms) Assess it against the published criteria --- title: "Ant colonies · Collective systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/c-ants description: "Colonies pick the better nest because individual ants follow a quorum threshold. No ant compares the sites overall." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Collective systems # Ant colonies Colonies pick the better nest because individual ants follow a quorum threshold. No ant compares the sites overall. What’s measured Recruitment rates, quorum thresholds and the choices colonies make between nest sites of different quality. ## Evidence * Colonies pick the better nest because individual ants follow a quorum threshold. No ant compares the sites overall. Pratt SC, Mallon EB, Sumpter DJT, Franks NR (2002) Quorum sensing, recruitment, and collective decision-making during colony emigration by the ant Leptothorax albipennis. Behav Ecol Sociobiol 52(2):117-127\. doi:10.1007/s00265-002-0487-x. Research on collective intelligence studies how groups decide. It doesn't claim that the group itself has experiences. In the trees [One queen, many workers · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-eusocial) --- title: "Honeybee swarms · Collective systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/c-bees description: "Swarms pick the best cavity through competition between scouts and a quorum. Stop signals provide cross-inhibition, which breaks deadlocks." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Collective systems # Honeybee swarms Swarms pick the best cavity through competition between scouts and a quorum. Stop signals provide cross-inhibition, which breaks deadlocks. What’s measured Counts of scout dances, support for each nest site, the quorum at the chosen site, and stop signals. ## Evidence * Swarms pick the best cavity through competition between scouts and a quorum. Stop signals provide cross-inhibition, which breaks deadlocks. Seeley TD (2010). Honeybee Democracy. Princeton UP; Seeley TD et al. (2012). Stop signals provide cross inhibition in collective decision-making by honeybee swarms. Science 335:108-111\. doi:10.1126/science.1210361. Research on collective intelligence studies how groups decide. It doesn't claim that the group itself has experiences. In the trees [Police the egg-layers · Ethics](https://simulation-hypothesis.com/trees/ethics?n=e-police) --- title: "Starling flocks · Collective systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/c-starlings description: "Each bird tracks a fixed number of neighbours (about 6-7), not every bird within a fixed distance. This is called topological, not metric, interaction." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Collective systems # Starling flocks Each bird tracks a fixed number of neighbours (about 6-7), not every bird within a fixed distance. This is called topological, not metric, interaction. What’s measured 3D positions of individual birds in flocks of up to about 2,600, reconstructed by stereo photography. ## Evidence * Each bird tracks a fixed number of neighbours (about 6-7), not every bird within a fixed distance. This is called topological, not metric, interaction. Ballerini M, Cabibbo N, Candelier R, Cavagna A, et al. (2008) Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study. Proc Natl Acad Sci USA 105(4):1232-1237\. doi:10.1073/pnas.0711437105. Research on collective intelligence studies how groups decide. It doesn't claim that the group itself has experiences. --- title: "Fish shoals · Collective systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/c-fish description: "Shoals use quorum rules to decide. Large groups can sense environmental gradients that no single fish can." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Collective systems # Fish shoals Shoals use quorum rules to decide. Large groups can sense environmental gradients that no single fish can. What’s measured The rules individual fish follow when they interact, and the quorum-based decisions shoals make. ## Evidence * Shoals use quorum rules to decide. Large groups can sense environmental gradients that no single fish can. Ward AJW, Sumpter DJT, Couzin ID, Hart PJB, Krause J (2008) Quorum decision-making facilitates information transfer in fish shoals. Proc Natl Acad Sci USA 105(19):6948-6953\. doi:10.1073/pnas.0710344105. Research on collective intelligence studies how groups decide. It doesn't claim that the group itself has experiences. --- title: "Rule-based expert systems · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-expert description: "Programs that encode a domain expert's knowledge as explicit if-then rules." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Rule-based expert systems Programs that encode a domain expert's knowledge as explicit if-then rules. An inference engine applies the rules in sequence to reach conclusions, usually with an explanation of its reasoning. Programs that encode a domain expert's knowledge as explicit if-then rules. An inference engine applies the rules in sequence to reach conclusions, usually with an explanation of its reasoning. People wrote down everything the system knows. It learns nothing from data. These programs were prominent in the 1970s-80s. ## Sources * Buchanan BG, Shortliffe EH (1984). Rule-Based Expert Systems: The MYCIN Experiments. Addison-Wesley. Assess it against the published criteria --- title: "Game-tree search engines (chess) · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-chess description: "Programs that enumerate possible move sequences to a fixed depth and score the resulting positions with a hand-built evaluation function." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Game-tree search engines (chess) Programs that enumerate possible move sequences to a fixed depth and score the resulting positions with a hand-built evaluation function. They prune branches that can't change the choice (minimax with alpha-beta pruning). Programs that enumerate possible move sequences to a fixed depth and score the resulting positions with a hand-built evaluation function. They prune branches that can't change the choice (minimax with alpha-beta pruning). Their strength comes from search speed and a well-tuned evaluation, not from general understanding. ## Sources * Shannon CE (1950). Programming a computer for playing chess. Philosophical Magazine 41:256-275. * Campbell M, Hoane AJ, Hsu F-h (2002). Deep Blue. Artificial Intelligence 134:57-83. Assess it against the published criteria --- title: "Deep reinforcement learning agents · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-drl description: "Neural networks trained by trial and error to maximise a reward signal." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Deep reinforcement learning agents Neural networks trained by trial and error to maximise a reward signal. They learn a policy or value function by interacting with an environment, often a simulated one such as a game. Neural networks trained by trial and error to maximise a reward signal. They learn a policy or value function by interacting with an environment, often a simulated one such as a game. They can reach superhuman skill at narrow tasks, but they're optimised for a single reward goal. ## Sources * Mnih V, Kavukcuoglu K, Silver D, Rusu AA, et al. (2015) Human-level control through deep reinforcement learning. Nature 518(7540):529-533\. doi:10.1038/nature14236. * Silver D et al. (2016). Mastering the game of Go with deep neural networks and tree search. Nature 529:484-489\. doi:10.1038/nature16961. Assess it against the published criteria --- title: "Large language models · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-llm description: "Transformer neural networks trained to predict the next token in very large text corpora, then often tuned on human feedback." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Large language models Transformer neural networks trained to predict the next token in very large text corpora, then often tuned on human feedback. Transformer neural networks trained to predict the next token in very large text corpora, then often tuned on human feedback. They use self-attention over the whole context window. One 2020 paper reported a scale of 175 billion parameters. They produce fluent language, so human-sounding output is a poor test of inner experience. In the trees [Transformer architecture · Technology](https://simulation-hypothesis.com/trees/technology?n=transformer)[Generative agents · Simulations](https://simulation-hypothesis.com/trees/simulations?n=min-park)[Indicators of AI awareness · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-butlin)[Taking AI welfare seriously · Ethics](https://simulation-hypothesis.com/trees/ethics?n=c-long) ## Sources * Vaswani A et al. (2017). Attention is all you need. NeurIPS. arXiv:1706.03762. * Brown TB et al. (2020). Language models are few-shot learners. NeurIPS 33\. arXiv:2005.14165 (175B parameters). Assess it against the published criteria --- title: "Embodied robots · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-robots description: "Machines with sensors and actuators that act in the physical world." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Embodied robots Machines with sensors and actuators that act in the physical world. They often use layered reactive control instead of a central world model, so behaviour emerges from the loop between body and environment. ## Sources * Brooks RA (1991) Intelligence without representation. Artif Intell 47(1-3):139-159\. doi:10.1016/0004-3702(91)90053-M. Assess it against the published criteria --- title: "Neuromorphic hardware · Artificial systems · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/ai-neuromorphic description: "Chips whose circuits imitate spiking neurons and synapses. They are event-driven and use little power, unlike a conventional processor-and-memory design." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Artificial systems # Neuromorphic hardware Chips whose circuits imitate spiking neurons and synapses. They are event-driven and use little power, unlike a conventional processor-and-memory design. Chips whose circuits imitate spiking neurons and synapses. They are event-driven and use little power, unlike a conventional processor-and-memory design. One published chip has one million digital neurons and 256 million synapses. ## Sources * Mead C (1990). Neuromorphic electronic systems. Proc IEEE 78:1629-1636. * Merolla PA, Arthur JV, Alvarez-Icaza R, Cassidy AS, et al. (2014) A million spiking-neuron integrated circuit with a scalable communication network and interface. Science 345(6197):668-673\. doi:10.1126/science.1254642. Assess it against the published criteria --- title: "Whole-brain emulation · Hypothetical minds · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/h-wbe description: "Scanning a brain in fine detail and running a software model of it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Hypothetical minds # Whole-brain emulation unobserved Proposed in the literature. Nobody has observed one. Scanning a brain in fine detail and running a software model of it. Scanning a brain in fine detail and running a software model of it. The roadmap lists eleven emulation levels, with increasing biological detail, from high-level computational modules up to molecular and quantum scale. Its estimates of the processing a human brain needs are about 10^18 FLOPS for a spiking-network model, 10^22 for electrophysiology and 10^25 for the metabolome. Unobserved: nobody has built a human-scale emulation. In the trees [Whole-brain emulation · Technology](https://simulation-hypothesis.com/trees/technology?n=wbe)[Whole-brain emulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-wbe)[Whole-brain emulation · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=s-wbe) ## Sources * Sandberg A, Bostrom N (2008) Whole Brain Emulation: A Roadmap. Technical Report #2008-3, Future of Humanity Institute, Oxford University. --- title: "Simulated minds in ancestor simulations · Hypothetical minds · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/h-ancestor description: "Bostrom's trilemma: either almost no civilisations reach a posthuman stage, or almost none run ancestor simulations, or we almost certainly live in one." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Hypothetical minds # Simulated minds in ancestor simulations unobserved Proposed in the literature. Nobody has observed one. Bostrom's trilemma: either almost no civilisations reach a posthuman stage, or almost none run ancestor simulations, or we almost certainly live in one. Bostrom's trilemma: either almost no civilisations reach a posthuman stage, or almost none run ancestor simulations, or we almost certainly live in one. It assumes the mind doesn't depend on what it runs on (substrate independence). It's a philosophical argument, not an observation. In the trees [Ancestor simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-ancestor) ## Sources * Bostrom N (2003). Are we living in a computer simulation? Philosophical Quarterly 53(211):243-255\. doi:10.1111/1467-9213.00309. --- title: "Boltzmann brains · Hypothetical minds · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/h-boltzmann description: "Brain-like observers that appear out of rare thermal or quantum fluctuations." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Hypothetical minds # Boltzmann brains unobserved Proposed in the literature. Nobody has observed one. Brain-like observers that appear out of rare thermal or quantum fluctuations. Brain-like observers that appear out of rare thermal or quantum fluctuations. In some cosmological models they'd outnumber ordinary observers, and that's treated as a problem for the theory. Purely theoretical. ## Sources * Albrecht A, Sorbo L (2004) Can the universe afford inflation? Phys Rev D 70(6):063528\. doi:10.1103/PhysRevD.70.063528. * Carroll SM (2017). Why Boltzmann brains are bad. arXiv:1702.00850. --- title: "Mind uploading via gradual replacement · Hypothetical minds · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/h-uploading description: "Replacing neurons one by one with functionally identical artificial parts." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Hypothetical minds # Mind uploading via gradual replacement unobserved Proposed in the literature. Nobody has observed one. Replacing neurons one by one with functionally identical artificial parts. Replacing neurons one by one with functionally identical artificial parts. Chalmers discusses this in his analysis of the singularity. He uses a fading-qualia argument to say that functional organisation suffices for consciousness. That claim is contested. Unobserved. In the trees [Mind uploading · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-upload)[The choice to stay · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=p-choice) ## Sources * Chalmers DJ (2010) The Singularity: a philosophical analysis. J Conscious Stud 17(9-10):7-65. --- title: "Superintelligence · Hypothetical minds · Entities · Simulation Hypothesis" url: https://simulation-hypothesis.com/entities/h-superintelligence description: "A hypothetical intellect greatly exceeding human performance in virtually all domains." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Entities](https://simulation-hypothesis.com/entities) › Hypothetical minds # Superintelligence unobserved Proposed in the literature. Nobody has observed one. A hypothetical intellect greatly exceeding human performance in virtually all domains. Bostrom's book analyses the routes to it (whole-brain emulation, biological cognition, AI), its forms and the control problems. A hypothetical intellect greatly exceeding human performance in virtually all domains. Bostrom's book analyses the routes to it (whole-brain emulation, biological cognition, AI), its forms and the control problems. The definition doesn't say whether it would be conscious. Unobserved. In the trees [Superintelligence · Technology](https://simulation-hypothesis.com/trees/technology?n=asi) ## Sources * Bostrom N (2014). Superintelligence: Paths, Dangers, Strategies. Oxford University Press. --- title: "Fundamental physics · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/fundamental-physics description: "Quarks, nuclei, plasmas and quantum matter: the smallest systems simulated, and among the most computationally expensive." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 1 of 18 # Fundamental physics Quarks, nuclei, plasmas and quantum matter: the smallest systems simulated, and among the most computationally expensive. The foundation of the hierarchy. These simulations start from fundamental theory, the Standard Model and quantum mechanics, and compute its consequences. They come closest to generating physical phenomena from first principles. They also explain why the Sandbox's finest matter floors take so much computing. ## Particles and fields ### Lattice QCD Quarks and gluons on a four-dimensional grid of spacetime points, used to compute the masses and properties of protons, neutrons and other hadrons from the strong force alone. Question it answers: What is the mass of a proton, starting from nothing but the theory? Leaves out: The grid spacing and box size are compromises. Results are extrapolated towards the continuum and infinite volume, but never reach them. Runs on: about 10^17 FLOPS rough a national supercomputer allocation, weeks of a large partition. Since: 1979 Creutz’s Monte Carlo study of pure SU(2) lattice gauge theory, without quarks; quarks entered later [source](https://doi.org/10.1103/PhysRevLett.43.553) In the simulations tree: [Lattice gauge Monte Carlo](https://simulation-hypothesis.com/trees/simulations?n=mat-lqcd) [Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Collider event generation Each proton–proton collision in an accelerator, from the hard scatter through parton showers to the spray of hadrons that reaches the detector. Question it answers: What would the data look like if a proposed new particle were real? Leaves out: Approximates the quantum interference between all contributing processes by retaining only the dominant ones, with parameters tuned to match past data. Runs on: about 10^15 FLOPS rough a grid-computing cluster, processing billions of simulated collisions. Since: 1982 early computerised parton-shower event generators for collider physics. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Detector response Every particle leaving a collision, stepped through layers of silicon, calorimeter and magnet, depositing energy as it goes. Question it answers: Which real signals will the detector miss, and which will it fake? Leaves out: Assumes the detector's geometry and calibration are exactly as designed, whereas ageing cables and radiation damage progressively degrade them. Runs on: about 10^15 FLOPS rough a university or grid-computing cluster, millions of CPU-hours a year. Since: 1974 CERN's first general particle-transport code for detector design. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Cosmic-ray air showers One very energetic particle from space hitting the upper atmosphere and cascading into billions of secondaries on the way down. Question it answers: What kind of particle, from how far away, made the pattern our ground detectors saw? Leaves out: Relies on collision models extrapolated far beyond any energy an accelerator has tested. Runs on: about 10^14 FLOPS rough a small cluster or powerful workstation, hours per shower set. Since: 1961 early Monte Carlo models of cosmic-ray particle cascades. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Accelerator beam dynamics Bunches of charged particles circling through magnets for millions of turns, pushed by the fields and by each other. Question it answers: Does the beam remain tightly focused, or does it gradually diverge and strike the walls? Leaves out: Idealises the magnets as built to specification, when real ones have small manufacturing errors that matter over millions of turns. Runs on: about 10^13 FLOPS rough a desktop workstation or small cluster, minutes per lattice design. Since: 1959 early computer tracking studies for the first strong-focusing synchrotrons. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Subatomic ### Neutrino detector simulation Light or charge from a neutrino interacting deep in a tank of water, ice or liquid, tracked through the detector to work out what a real event looks like. Question it answers: What signal would this kind of neutrino leave, and can we tell it apart from background? Leaves out: A real detector's cables, bubbles and rock overburden add noise no simulation fully anticipates. Runs on: about 10^15 FLOPS rough a university or collaboration cluster, weeks per detector design. Since: 1987 detector simulations built to interpret the 1987 supernova neutrino burst. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Generative calorimeter shower models A neural network trained on full particle-transport runs that produces the energy deposits of a shower in a detector at a tiny fraction of the cost. Question it answers: Can a trained generator stand in for the slowest part of a detector simulation? Leaves out: It reproduces the statistics of the training runs, not new physics, and drifts outside the energies it has seen. Runs on: about 10^16 FLOPS rough Training on millions of full shower events, then cheap sampling Since: 2017 CaloGAN, a generative adversarial network for 3D electromagnetic showers (2017) [source](https://arxiv.org/abs/1705.02355) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Subatomic ### Flow-based sampling for lattice field theory A trained normalising flow proposes whole field configurations on a lattice, which are then corrected by an exact accept-or-reject step so the answer stays unbiased. Question it answers: Can learned samplers beat the critical slowing down of ordinary lattice Monte Carlo? Leaves out: Demonstrated mostly in low-dimensional toy theories; training cost grows quickly with lattice volume. Runs on: about 10^17 FLOPS rough Training plus large lattice ensembles Since: 2019 Flow-based generative models for Markov chain Monte Carlo in lattice field theory (2019) [source](https://arxiv.org/abs/1904.12072) [Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Subatomic ## Nuclei and radiation ### Nuclear structure Protons and neutrons bound in a nucleus, computed from the forces between them. Question it answers: Which isotopes can exist at all, and what shapes do they take? Leaves out: The force between nucleons is still not known exactly, so every nucleus is computed from an approximation to it. Runs on: about 10^15 FLOPS rough a university cluster, days for one heavy nucleus. Since: 1965 early shell-model diagonalisation calculations on a mainframe. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Reactor core physics Neutrons born, scattered, absorbed and splitting nuclei inside a power reactor, coupled to heat and coolant flow. Question it answers: Does the chain reaction stay steady as the fuel burns down? Leaves out: Cannot fully capture every crack, weld and flow path in an ageing real reactor. Runs on: about 10^15 FLOPS rough a university or industry cluster, hours per core cycle. Since: 1948 Ulam, von Neumann and Metropolis's first Monte Carlo neutron runs on ENIAC. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Subatomic ### Radiation transport Particles passing through matter, one interaction at a time: radiotherapy beams in a patient, cosmic rays in a spacecraft hull. Question it answers: How much dose lands in the tumour, and how much in everything around it? Leaves out: Treats the body or hull as a fixed geometry, omitting its motion during exposure, such as respiration. Runs on: about 10^13 FLOPS rough a hospital physics workstation or small cluster, minutes per plan. Since: 1968 first Monte Carlo dose calculations proposed for radiotherapy planning. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Nuclear criticality safety Monte Carlo neutron transport through stored or handled fissile material, checking that no accidental chain reaction can start. Question it answers: Could this arrangement of fissile material go critical by accident? Leaves out: Assumes the geometry and material recorded on the declaration match what is actually present, so the result is only as reliable as the documentation. Runs on: about 10^13 FLOPS rough a desktop workstation; minutes to hours per configuration. Since: 1957 early computerised criticality calculations after wartime accidents prompted formal safety rules. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Radioactivation and decay chains Materials exposed to neutrons or radiation building up new radioactive isotopes, then decaying through chains towards stability. Question it answers: How radioactive will this material be, and for how long, after it is irradiated? Leaves out: Nuclear data for rare, short-lived isotopes is patchier than for common ones, so minor pathways carry more guesswork. Runs on: about 10^12 FLOPS rough a laptop; a full decay-chain calculation takes seconds. Since: 1962 early computer codes for activation and decay in reactor materials. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Fusion breeding blanket neutronics Neutrons from a fusion reaction slowing down in the surrounding blanket, breeding the tritium fuel and depositing the heat that would drive a turbine. Question it answers: Does the blanket breed enough tritium to keep the reactor fuelled? Leaves out: Modelled on a design that does not exist yet at full scale, so key material behaviour is extrapolated. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per design variant. Since: 1980 early neutronics studies for proposed fusion reactor blankets. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Nuclear lattice effective field theory Protons and neutrons placed on a spacetime lattice and interacting through a chiral effective theory, solved by Monte Carlo to give nuclear structure. Question it answers: Can the excited states of light nuclei, such as the Hoyle state of carbon-12, be computed from nucleon forces? Leaves out: Limited to light and medium nuclei; sign problems restrict which systems can be reached. Runs on: about 10^18 FLOPS rough Large Monte Carlo runs on leadership machines Since: 2011 Ab initio calculation of the Hoyle state (2011) [source](https://doi.org/10.1103/PhysRevLett.106.192501) [Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Time-dependent nuclear mean-field dynamics Colliding and fissioning nuclei followed in real time, each nucleon moving in the average field of all the others as it evolves. Question it answers: What happens to two nuclei as they touch, fuse or bounce apart? Leaves out: A mean field cannot describe quantum tunnelling between different outcomes or the fluctuations that split fission yields. Runs on: about 10^15 FLOPS rough three-dimensional Skyrme-type time-dependent runs on a cluster. Since: 1976 Bonche, Koonin and Negele's one-dimensional time-dependent Hartree-Fock calculation of nuclear collisions. [source](https://doi.org/10.1103/physrevc.13.1226) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Subatomic ### Neutron-star crust pasta dynamics The deepest layer of a neutron star crust, where neutrons and protons form rods and sheets, followed with molecular dynamics to find its stiffness and how it scatters neutrinos. Question it answers: What shapes does matter take at the base of a neutron star crust? Leaves out: The nucleon interaction is a simple fitted potential and the box is far smaller than a real crust. Runs on: about 10^15 FLOPS rough molecular dynamics of tens of thousands of nucleons, repeated across densities. Since: 2004 Horowitz, Perez-Garcia and Piekarewicz's molecular dynamics of nonuniform neutron-rich matter and its neutrino opacity. [source](https://doi.org/10.1103/physrevc.69.045804) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Subatomic ## Plasma ### Fusion plasma turbulence A hydrogen plasma hotter than the Sun’s core, confined by a magnetic field, together with the turbulent transport that drives heat loss. Question it answers: How big does the machine need to be before it makes more energy than it takes? Leaves out: Full turbulence at reactor scale is still too expensive, so most runs simulate a slice and extrapolate. Runs on: about 10^17 FLOPS rough a national supercomputer, a large allocation for weeks. Since: 1983 early gyrokinetic turbulence codes for tokamak plasmas. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Particle-in-cell plasma Millions of charged macro-particles moving through electric and magnetic fields stored on a grid, used for lasers hitting plasma and wakefield acceleration. Question it answers: Can a plasma wave accelerate electrons in centimetres instead of kilometres? Leaves out: Each simulated particle stands for many real ones, which blurs the fine graininess of an actual plasma. Runs on: about 10^16 FLOPS rough a large GPU cluster, days for a full wakefield run. Since: 1959 Buneman and Dawson's first electrostatic particle-in-cell plasma runs. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Plasma equilibrium and stability The whole shape of a magnetically confined plasma, checked against the pressure and current it can support before it kinks, tears or disrupts. Question it answers: Will this plasma configuration hold its shape, or collapse? Leaves out: Real disruptions often start from small imperfections and impurities that an idealised equilibrium does not include. Runs on: about 10^15 FLOPS rough a university cluster, hours per equilibrium scan. Since: 1958 early computed equilibria for the first magnetic confinement devices. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Inertial confinement implosion A small capsule of fuel driven inward by intense radiation until it is hot and dense enough to fuse, modelled as radiation, hydrodynamics and burning plasma together. Question it answers: Will the fuel compress evenly enough to ignite before it blows itself apart? Leaves out: Tiny asymmetries in the drive seed instabilities that break the spherical symmetry the simplest runs assume. Runs on: about 10^16 FLOPS rough a large cluster or supercomputer partition, days per design. Since: 1972 early radiation-hydrodynamics simulations of laser-driven fuel capsules. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Magnetic reconnection Magnetic field lines in a plasma breaking and rejoining, converting stored field energy into heat and fast particles. Question it answers: How fast can magnetic field lines actually break and reconnect? Leaves out: The real process spans scales from electron orbits to whole star systems that no single run covers at once. Runs on: about 10^15 FLOPS rough a university cluster, days for one reconnection event. Since: 1963 early computed models of field-line reconnection following Sweet and Parker's theory. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Industrial plasma processing Ions and reactive species in a low-temperature plasma striking and etching a surface, used to shape materials at microscopic precision. Question it answers: Will the plasma etch or coat the surface evenly? Leaves out: Surface chemistry at the wall is still simplified far below the detail a real contaminated chamber has. Runs on: about 10^13 FLOPS rough a workstation or small cluster, hours per process recipe. Since: 1985 early computer models of plasma etching for surface processing. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Molecules ### Laser wakefield acceleration Particle-in-cell runs of an intense laser pulse driving a plasma wave that traps and accelerates electrons over millimetres. Question it answers: How can a plasma wave accelerate electrons to high energy in a very short distance? Leaves out: Ionisation, radiation reaction and laser-target imperfections are usually idealised. Runs on: about 10^18 FLOPS rough 3D particle-in-cell, billions of particles over many wave periods Since: 2002 Highly non-linear broken-wave (bubble) regime simulations (2002) [source](https://doi.org/10.1007/s003400200795) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Atoms ### Stellarator configuration optimisation The shape of a twisted magnetic bottle for fusion plasma, adjusted by computer until particle orbits stay confined and the equilibrium is stable without a driven current. Question it answers: What three-dimensional magnetic shape traps a hot plasma best? Leaves out: Optimised shapes are judged on idealised equilibria; turbulence and coil tolerances come later and often spoil the result. Runs on: about 10^15 FLOPS rough thousands of equilibrium and orbit calculations inside an optimisation loop. Since: 1988 Nuhrenberg and Zille's computed quasi-helically symmetric stellarators. [source](https://doi.org/10.1016/0375-9601%2888%2990080-1) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Fields ### Tokamak edge pedestal and ELM modelling The steep-edged layer at the rim of a tokamak plasma and the periodic bursts that throw heat onto the wall, computed from magnetohydrodynamic stability of the edge. Question it answers: How high can the edge pressure climb before the plasma erupts? Leaves out: Stability thresholds are well predicted but the full nonlinear burst, with its kinetic and wall physics, is still beyond routine forecasting. Runs on: about 10^16 FLOPS rough nonlinear extended-MHD runs of one burst on a large allocation. Since: 2002 Snyder and colleagues' peeling-ballooning model of edge localised modes and the pedestal. [source](https://doi.org/10.1063/1.1449463) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Tokamak whole-device modelling Heating, transport, equilibrium, edge and wall models for a whole fusion device coupled into one integrated workflow that predicts a full discharge. Question it answers: Can a complete plasma discharge be predicted before the machine is built? Leaves out: Most modules are reduced models tuned to past machines, so predictions for a new regime carry wide uncertainty. Runs on: about 10^16 FLOPS rough coupled reduced and high-fidelity modules run for a full discharge. Since: 2015 Imbeaux and colleagues' integrated modelling and analysis suite for ITER, the first applications of a standard data model linking such modules. [source](https://doi.org/10.1088/0029-5515/55/12/123006) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Fields ### Collisionless shock simulation Shock waves in space plasma where particles never collide, with ions followed individually and electrons as a fluid so the shock front forms from the fields alone. Question it answers: How do ions get accelerated at a shock where nothing collides? Leaves out: Electrons are treated as a fluid and the box is a tiny patch of a shock, so large-scale structure is missing. Runs on: about 10^16 FLOPS rough large hybrid kinetic runs in two or three dimensions. Since: 1985 Quest's hybrid simulations of high-Mach-number collisionless perpendicular shocks. [source](https://doi.org/10.1103/physrevlett.54.1872) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Dusty plasma and Yukawa-system simulation Charged grains suspended in a plasma, modelled as particles repelling through a screened potential that freeze into crystals or melt into liquids. Question it answers: At what coupling strength does a cloud of charged grains crystallise? Leaves out: The screened-repulsion potential replaces the plasma and ignores wakes and grain charging that real dust clouds show. Runs on: about 10^12 FLOPS rough molecular dynamics of up to a million grains for long times. Since: 1994 Hamaguchi and Farouki's thermodynamics of strongly coupled Yukawa systems from Monte Carlo and molecular dynamics. [source](https://doi.org/10.1063/1.467954) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### One-component plasma simulation Charges immersed in a uniform neutralising background, simulated to find the equation of state and crystallisation of the dense matter inside white dwarfs and giant planets. Question it answers: At what density does dense stellar matter freeze? Leaves out: The uniform electron background stands in for the real, polarisable electrons. Runs on: about 10^10 FLOPS rough Monte Carlo of tens of thousands of ions, modest by modern standards. Since: 1966 Brush, Sahlin and Teller's Monte Carlo study of a one-component plasma. [source](https://doi.org/10.1063/1.1727895) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Subatomic ### Learned plasma control in simulation A reinforcement-learning controller practises shaping and holding a tokamak plasma by commanding the magnet coils in a fast simulation of its equilibrium and evolution, then is run on the real device. Question it answers: Can a controller learned entirely in simulation hold a hot plasma in a requested shape? Leaves out: The training model leaves out turbulence and fast instabilities, so the controller is trusted only inside the conditions it captures. Runs on: about 10^16 FLOPS rough days of training on a few hundred accelerators, running the plasma model millions of times. Since: 2022 Degrave and colleagues' deep reinforcement learning controller trained in simulation and run on a tokamak. [source](https://doi.org/10.1038/s41586-021-04301-9) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Fields ## Quantum matter and computers ### Quantum many-body systems Many interacting electrons or spins on a lattice, handled with tensor networks and quantum Monte Carlo because the exact state is far too big to store. Question it answers: Why do some materials superconduct, and could one do it at room temperature? Leaves out: Tensor networks and quantum Monte Carlo both fail on some of the most interesting frustrated or fermionic systems. Runs on: about 10^16 FLOPS rough a large cluster or supercomputer partition, days per material. Since: 1980 Ceperley and Alder's first accurate quantum Monte Carlo of the electron gas. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Subatomic ### Quantum computer emulation A classical computer storing the full quantum state of a register of qubits and applying gates to it. Memory doubles with every qubit added. Question it answers: Does this quantum algorithm work before anyone builds the hardware to run it? Leaves out: The memory needed doubles with every extra qubit, so it can only ever emulate the small cases with no quantum advantage. Runs on: about 10^15 FLOPS rough a memory-heavy cluster node; doubles in cost with each extra qubit. Since: 1996 early classical simulators of small quantum circuits. [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Subatomic ### Analogue quantum simulation One controllable quantum system, such as ultracold atoms in a lattice of laser light, tuned to behave like another that is too hard to compute. Question it answers: If a classical computer cannot solve the model, can a controllable physical system be made to do it instead? Leaves out: Informs only on the one model it was built to emulate, not necessarily on the real material that motivated it. Runs on: no computer. the atoms themselves compute; a control computer only records results. Since: 2002 Greiner and colleagues’ superfluid-to-Mott-insulator transition of ultracold atoms in an optical lattice, later read as an early analogue quantum simulation [source](https://www.nature.com/articles/415039a) In the simulations tree: [Cold-atom quantum simulator](https://simulation-hypothesis.com/trees/simulations?n=mat-qanalog) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Atoms ### Quantum error correction A quantum computer's qubits and the noise that corrupts them, checked against a code designed to detect and fix errors before they spread. Question it answers: Does this error-correcting code actually protect the computation, given realistic noise? Leaves out: Real noise is correlated and drifts over time in ways that idealised models rarely capture. Runs on: about 10^15 FLOPS rough a memory-heavy cluster node; larger codes cost far more. Since: 1996 early simulations testing the first proposed error-correcting codes. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Subatomic ### Topological quantum matter Electrons on a lattice arranged so that their collective state depends on its overall shape rather than local details, computed to find quantum Hall states and other topological phases. Question it answers: Does this material host a phase of matter protected by its topology rather than its symmetry? Leaves out: Telling a genuinely topological state from a very similar ordinary one can hinge on numerical precision most runs cannot quite reach. Runs on: about 10^16 FLOPS rough a large cluster or supercomputer partition, days per candidate system. Since: 1988 early numerical studies following the theoretical discovery of topological order. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Ultracold atomic gas dynamics A cloud of atoms cooled until they share one quantum wavefunction, evolved with the mean-field equation that describes a Bose-Einstein condensate. Question it answers: How does the condensate oscillate, split or form vortices when perturbed? Leaves out: The mean-field equation misses the individual atom correlations that matter close to a phase transition. Runs on: about 10^13 FLOPS rough a workstation; minutes to hours per trapped cloud. Since: 1995 modelling built around the first laboratory Bose-Einstein condensates. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Atoms ### Digital quantum simulation on hardware A quantum computer built from controllable qubits runs a sequence of gates that imitates the evolution of another such system. Question it answers: Can a programmable quantum device reproduce the dynamics of a model too large for classical memory? Leaves out: Noise limits depth, and the Trotter approximation introduces its own error. Runs on: no computer. Quantum hardware, not classical FLOPS; verification on conventional machines only at small size Since: 2011 Universal digital quantum simulation with trapped ions (2011) [source](https://doi.org/10.1126/science.1208001) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Subatomic ### Lattice gauge theory on quantum hardware A few-qubit quantum computer evolves a lattice gauge theory in real time, a task that is hard for classical Monte Carlo because of the sign problem. Question it answers: Can real-time dynamics of a gauge theory be run on a quantum computer? Leaves out: Only one spatial dimension and a handful of sites so far. Runs on: no computer. Small qubit counts; classical cost of cross-checking grows exponentially Since: 2016 Real-time dynamics of lattice gauge theories with a few-qubit quantum computer (2016) [source](https://arxiv.org/abs/1605.04570) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)floor: Subatomic ### Neural-network quantum states A neural network represents the wavefunction of a many-body system, and its parameters are tuned by variational Monte Carlo to find ground states and dynamics. Question it answers: Can a neural network compactly encode a quantum state that is too large to store exactly? Leaves out: The accuracy depends on network design, and the optimisation can stall in poor minima. Runs on: about 10^16 FLOPS rough Training with variational Monte Carlo on accelerators Since: 2016 Solving the quantum many-body problem with artificial neural networks (2016) [source](https://arxiv.org/abs/1606.02318) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Subatomic ### Superconducting vortex dynamics The tubes of magnetic flux that thread a type-II superconductor, followed as they move, pin on defects and dissipate energy, using a time-dependent field theory for the superconducting state. Question it answers: How do magnetic vortices move and get stuck inside a superconductor? Leaves out: The phenomenological field theory ignores microscopic electron behaviour and is valid only near the transition temperature. Runs on: about 10^14 FLOPS rough three-dimensional time-dependent Ginzburg-Landau runs on a cluster. Since: 1996 Gropp and colleagues' numerical simulation of vortex dynamics in type-II superconductors. [source](https://doi.org/10.1006/jcph.1996.0022) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Path-integral Monte Carlo of quantum fluids Each quantum particle is represented as a ring of linked copies, sampled at finite temperature to compute superfluid helium and other bosonic liquids from the interaction alone. Question it answers: Why does liquid helium flow without friction below two kelvin? Leaves out: Fermions suffer the sign problem, so electrons and helium-3 need approximations that introduce uncontrolled error. Runs on: about 10^14 FLOPS rough billions of path samples for a bulk liquid. Since: 1984 Pollock and Ceperley's path-integral simulation of quantum many-body systems and superfluid helium. [source](https://doi.org/10.1103/physrevb.30.2555) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Stabilizer circuit simulation A classical computer tracks a quantum circuit built only from Clifford gates by following how a small table of Pauli operators changes, instead of storing the full state. This lets error-correction circuits with thousands of qubits be run. Question it answers: How often does an error-correcting code fail when every gate, measurement and idle step is noisy? Leaves out: Only circuits made of Clifford operations and Pauli measurements can be tracked this way, so universal quantum computation is out of reach. Runs on: about 10^12 FLOPS rough millions of noisy shots of a large code patch on a workstation cluster. Since: 2004 Aaronson and Gottesman's improved algorithm for simulating stabilizer circuits in polynomial time. [source](https://doi.org/10.1103/physreva.70.052328) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Learned error-correction decoders A neural network is trained on simulated error patterns from a quantum code to read the measured syndromes and infer which correction to apply. Question it answers: Can a learned decoder fix errors in a quantum memory faster or more accurately than a hand-designed algorithm? Leaves out: The decoder only knows the noise model it was trained on, and real hardware drifts and has correlated errors the simulation did not include. Runs on: about 10^15 FLOPS rough training on billions of simulated syndromes on GPU nodes. Since: 2016 Torlai and Melko's neural decoder for topological codes (arXiv 2016, published 2017). [source](https://arxiv.org/abs/1610.04238) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Quantum network simulation Nodes holding qubits, entangled links and noisy photon channels modelled as discrete events in time, so that protocols for sharing entanglement across a network can be tested. Question it answers: How fast and how faithfully could two distant nodes share entanglement through repeaters and lossy fibre? Leaves out: Hardware noise is reduced to a few parametrised models, and no network at scale exists to check the predicted rates against. Runs on: about 10^11 FLOPS rough many long runs of a network protocol on a single server. Since: 2021 Coopmans and colleagues' NetSquid, a discrete-event simulator for quantum networks. [source](https://doi.org/10.1038/s42005-021-00647-8) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules [◂ Video games](https://simulation-hypothesis.com/simulations/video-games)[Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology) --- title: "Astronomy and cosmology · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/astronomy-cosmology description: "The universe from its first minutes to the cosmic web, and the stars, planets and black holes within it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 2 of 18 # Astronomy and cosmology The universe from its first minutes to the cosmic web, and the stars, planets and black holes within it. We can't rerun the universe, so astronomers build models of it. Cosmological simulations are the nearest real thing to the Sandbox's "whole universe" scale. They stay tractable because a single particle stands in for roughly a million suns. ## The universe as a whole ### Cosmological N-body Dark matter as billions of particles, grown under gravity from an almost uniform early universe into the cosmic web of filaments, walls and voids. Question it answers: Does our model of the universe grow the same large-scale structure telescopes see? Leaves out: One particle stands for a million suns, so nothing smaller than a galaxy is really there. Runs on: about 10^17.5 FLOPS rough a large fraction of a national supercomputer, for weeks. Since: 1970 Peebles’s 300-point model of the formation of a galaxy cluster, among the earliest; N-body runs of star clusters began with von Hoerner in 1960 [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Galaxy formation Gas cooling, star formation and supernova explosions, and black-hole accretion driving outflows, all layered on top of the dark-matter web. Question it answers: Why do galaxies come in the shapes and sizes they do? Leaves out: Star formation and black-hole feedback are represented by tunable sub-grid prescriptions, not derived from first principles. Runs on: about 10^17 FLOPS rough a large slice of a national supercomputer, weeks of runtime. Since: 1992 early combined gravity-plus-gas simulations of forming galaxies. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Big Bang nucleosynthesis The first twenty minutes, when the universe was a nuclear reactor making hydrogen, helium and a trace of lithium. Question it answers: Do the predicted element ratios match the oldest gas we can measure? Leaves out: Assumes the early universe was perfectly homogeneous, although it contained small inhomogeneities. Runs on: about 10^12 FLOPS rough a laptop; the whole calculation takes seconds. Since: 1967 Wagoner, Fowler and Hoyle's first computed light-element abundances. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Subatomic ### Cosmic microwave background Ripples in the hot plasma of the young universe, evolved until the light was released 380,000 years after the Big Bang. Question it answers: Which cosmological parameters produce the pattern of hot and cold spots we observe? Leaves out: Assumes the standard cosmological model is correct and fits only its small set of parameters. Runs on: about 10^13 FLOPS rough a desktop workstation; minutes per parameter set. Since: 1996 Seljak and Zaldarriaga's fast Boltzmann code for the microwave sky. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Cosmic reionization Ultraviolet light from the first stars and galaxies spreading through and ionising the neutral hydrogen filling the early universe. Question it answers: What reionised the universe after the cosmic dark ages? Leaves out: The faint, faraway sources doing most of the ionising are still below what any telescope can see directly, so their numbers are extrapolated. Runs on: about 10^17 FLOPS rough a large share of a national supercomputer, for weeks. Since: 1999 early radiative-transfer simulations of the first ionised bubbles. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Intergalactic medium and the Lyman-alpha forest The thin gas strung between galaxies, evolved under gravity and heating until its absorption pattern matches the flickering forest of lines in a distant quasar's spectrum. Question it answers: How much ordinary matter is out there in the gas between galaxies, and how hot is it? Leaves out: Depends on assumptions about how ultraviolet light from galaxies heats the gas, which is not directly observed. Runs on: about 10^16 FLOPS rough a university or national cluster, weeks per simulated volume. Since: 1994 early hydrodynamic simulations reproducing the Lyman-alpha forest. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Wave dark matter simulations The universe is evolved with dark matter treated as a coherent quantum wave obeying the Schrodinger and Poisson equations instead of as classical particles. Question it answers: What would cosmic structure look like if dark matter were an ultralight wave? Leaves out: The wave resolution requirement makes large volumes hard, and baryons are mostly left out. Runs on: about 10^19 FLOPS rough Large adaptive-mesh wave simulations Since: 2014 Cosmic structure as the quantum interference of a coherent dark wave (2014) [source](https://arxiv.org/abs/1406.6586) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Constrained simulations of the local universe Cosmological runs whose initial conditions are tuned so that the evolved volume reproduces the observed neighbours of our galaxy, including nearby clusters. Question it answers: Can we simulate the actual structures around the Milky Way rather than a typical patch of universe? Leaves out: Constraints come from noisy distance data, so the match is statistical rather than exact. Runs on: about 10^19 FLOPS rough Large N-body or hydrodynamic runs from constrained initial conditions Since: 2010 Constrained Local UniversE Simulations (CLUES) (2010) [source](https://arxiv.org/abs/1005.2687) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Cosmological emulators A modest set of expensive cosmological simulations is used to train a fast interpolator that predicts statistics such as the matter power spectrum for nearby parameter values. Question it answers: Can we predict structure for thousands of parameter choices from only a few dozen simulations? Leaves out: It only covers the parameter range and statistics it was trained on. Runs on: about 10^18 FLOPS rough Design of dozens of N-body runs, then near-free predictions Since: 2010 The Coyote Universe III: simulation suite and precision emulator (2010) [source](https://doi.org/10.1088/0004-637X/713/2/1322) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Fields ### Stellar population synthesis The combined light of many generations of stars added up from stellar evolution tracks and spectra, to read ages, masses and star-formation history from a galaxy's colours. Question it answers: What mixture of stars gives a galaxy its colour? Leaves out: Stellar tracks and spectral libraries carry their own uncertainties, such as for late stages of evolution. Runs on: about 10^9 FLOPS rough inexpensive spectra synthesis, repeated across a grid of ages and metallicities. Since: 1983 Bruzual's spectral evolution of galaxies, early-type systems. [source](https://doi.org/10.1086/161352) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Galactic chemical evolution The build-up of heavy elements in a galaxy over time, from gas inflow, star formation, stellar death and gas outflow, written as a set of coupled rate equations. Question it answers: How did a galaxy accumulate its iron and oxygen? Leaves out: Mixing and gas flows are lumped into a few free parameters, so the model fits but does not predict. Runs on: about 10^8 FLOPS rough cheap rate-equation integration, scanned across parameters. Since: 1968 Tinsley's model of the evolution of the stars and gas in galaxies. [source](https://doi.org/10.1086/149455) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Semi-analytic galaxy formation Galaxies painted onto the merging halos of a dark-matter simulation with simple rules for cooling, star formation and feedback, tracing every galaxy at low cost. Question it answers: How many galaxies of each size do dark-matter halos host? Leaves out: The recipes for star formation and feedback are tuned rather than derived. Runs on: about 10^13 FLOPS rough rules applied to millions of merger trees, far cheaper than hydrodynamics. Since: 1993 Kauffmann, White and Guiderdoni's galaxy formation within merging dark-matter haloes. [source](https://doi.org/10.1093/mnras/264.1.201) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Self-interacting dark matter simulation Dark-matter particles allowed to scatter off each other, so halo cores flatten and satellites change shape, tested against galaxy observations. Question it answers: Do dark-matter particles collide, and does it soften galaxy cores? Leaves out: The cross-section is a free number, and baryonic feedback can mimic or hide the same core. Runs on: about 10^16 FLOPS rough N-body runs with a scattering step added. Since: 2000 Yoshida, Springel, White and Tormen's weakly self-interacting dark matter and the structure of dark halos. [source](https://doi.org/10.1086/317306) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Massive-neutrino cosmological simulation Neutrinos with a small mass added to a structure-formation run as particles or a grid fluid, so the effect on the growth of the cosmic web can be measured. Question it answers: How much does the mass of the neutrino slow cosmic structure growth? Leaves out: Thermal noise from the neutrinos makes particle schemes noisy, and their mass is itself unknown. Runs on: about 10^17 FLOPS rough large-volume N-body runs with an added neutrino component. Since: 2008 Brandbyge, Hannestad, Haugboelle and Thomsen's effect of thermal neutrino motion on the non-linear matter power spectrum. [source](https://doi.org/10.1088/1475-7516/2008/08/020) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Modified-gravity structure formation N-body runs in which gravity departs from general relativity on large scales, with a screening mechanism that restores it nearby, so the cosmos can be tested for new forces. Question it answers: Would a change to gravity leave a signature in cosmic structure? Leaves out: Each theory needs its own tailored solver, and screening is expensive to follow accurately. Runs on: about 10^17 FLOPS rough N-body runs solving an extra nonlinear field equation at every step. Since: 2008 Oyaizu's nonlinear evolution of f(R) cosmologies, methodology. [source](https://doi.org/10.1103/physrevd.78.123524) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Weak-lensing ray tracing through simulated universes Light rays traced through the matter of a large simulation to forecast how galaxy shapes are slightly distorted, so surveys can be calibrated. Question it answers: How much are distant galaxy shapes sheared by the intervening matter? Leaves out: Multiple-plane approximations and finite resolution blur the smallest lensing structures. Runs on: about 10^16 FLOPS rough ray tracing through hundreds of N-body snapshots. Since: 2000 Jain, Seljak and White's ray-tracing simulations of weak lensing by large-scale structure. [source](https://doi.org/10.1086/308384) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Cosmic string network evolution A network of thin, stretched defects left over from an early phase transition, evolved to see how many loops and long strings survive and how they would gravitate. Question it answers: Do cosmic strings, if they exist, settle into a pattern that stays scale-free? Leaves out: Field-theory runs cannot reach realistic string widths, and the scaling regime is only approached by extrapolation. Runs on: about 10^14 FLOPS rough Nambu-Goto or field-theory simulations in an expanding box. Since: 1985 Albrecht and Turok's computed evolution of cosmic strings. [source](https://doi.org/10.1103/physrevlett.54.1868) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Early-universe lattice field dynamics Scalar fields on a lattice evolved through the end of inflation to see how the energy of the inflaton is passed into particles in a violent resonant burst. Question it answers: How did the universe heat up after inflation? Leaves out: Classical fields stand in for quantum fluctuations, which is valid only while occupation numbers are large. Runs on: about 10^13 FLOPS rough classical lattice field runs of up to a few thousand points per side. Since: 1996 Khlebnikov and Tkachev's classical decay of the inflaton. [source](https://doi.org/10.1103/physrevlett.77.219) [Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Subatomic ### Galactic cosmic-ray propagation Charged particles from supernovae wandering through the Galaxy under diffusion, energy loss and nuclear reactions, to predict what reaches Earth and the gamma rays they emit. Question it answers: How do cosmic rays diffuse through the Galaxy, and what do they leave behind? Leaves out: The Galaxy's magnetic field and gas distribution are smoothed, so diffusion coefficients are fitted. Runs on: about 10^12 FLOPS rough numerical solution of a transport equation across a grid of parameters. Since: 1998 Strong and Moskalenko's propagation of cosmic-ray nucleons in the Galaxy. [source](https://doi.org/10.1086/306470) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Differentiable cosmological simulation A particle-mesh simulation of structure growth written so that gradients flow through it, letting the initial conditions or parameters be adjusted to fit observed galaxies directly. Question it answers: Which starting density field and cosmology reproduce the galaxies we actually see? Leaves out: The fast particle-mesh scheme is coarse on small scales, so it fits large structures but not the inside of galaxies. Runs on: about 10^16 FLOPS rough hundreds of GPU hours per fitted volume. Since: 2020 Modi and colleagues' FlowPM, a distributed TensorFlow particle-mesh cosmological solver. [source](https://arxiv.org/abs/2010.11847) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Synthetic sky survey catalogues and images A mock universe of galaxies, stars and transients is drawn from simulations, then turned into the pixel images a survey telescope and its pipeline would record, with noise, blending and instrument effects. Question it answers: Would the survey's software recover the true cosmology from a sky whose truth we know? Leaves out: The mock sky contains only the physics and instrument effects its authors thought to include, so unforeseen systematics stay unforeseen. Runs on: about 10^17 FLOPS rough months on a few supercomputer allocations for catalogue and image generation. Since: 2021 The LSST Dark Energy Science Collaboration's DC2 simulated sky survey. [source](https://doi.org/10.3847/1538-4365/abd62c) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Galaxy collision and merger simulation Two galaxies treated as discs of test stars passing each other under gravity, to show how tidal tails, bridges and mergers form. Question it answers: Do the long streams of stars seen around some galaxies come from a past close encounter? Leaves out: Early versions ignore the gravity of the stars on each other and on the gas, and any one match to a real pair is only one possible history. Runs on: about 10^12 FLOPS rough hours to days on a workstation for a modern high-resolution merger. Since: 1972 Toomre and Toomre's restricted three-body calculations of galactic bridges and tails. [source](https://doi.org/10.1086/151823) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Stars ### Stellar evolution A star as nested shells of gas, burning through its fuel from birth to white dwarf, neutron star or black hole. Question it answers: How long does a star of this mass live, and how does it die? Leaves out: Treats convection and rotation with parametrised prescriptions rather than solving the turbulence directly. Runs on: about 10^12 FLOPS rough a laptop; a full evolutionary track takes minutes. Since: 1955 Hoyle and Schwarzschild's early computed models of red giant stars. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Core-collapse supernovae The last second of a massive star: the core collapsing, neutrinos flooding out, and a shock wave that either blows the star apart or stalls. Question it answers: What mechanism drives the explosion of a massive star? Leaves out: The mechanism that revives the stalled shock is not yet settled, and models differ from star to star. Runs on: about 10^17 FLOPS rough a large share of a national supercomputer, for months. Since: 1966 Colgate and White's first computer models of core collapse. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Star formation Cold gas clouds collapsing under gravity into clusters of stars, with turbulence and magnetic fields pushing back. Question it answers: Why do stars form with the spread of masses they do? Leaves out: Cannot yet resolve both a whole cloud and the tiny scales where a single star actually forms. Runs on: about 10^16 FLOPS rough a university or national cluster, weeks for one cloud. Since: 1969 Larson's first computed collapse of a protostellar cloud. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Stellar oscillations Sound and gravity waves ringing through a star's interior, computed to predict the pattern of brightness flickers a telescope would see. Question it answers: What does a star's wobble tell us about what is inside it? Leaves out: Only the outer layers are well constrained. The very core is still a matter of inference, not direct measurement. Runs on: about 10^12 FLOPS rough a laptop; a full oscillation spectrum takes minutes. Since: 1975 early computed oscillation models compared against the Sun's observed five-minute pulsations. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Binary star evolution Two stars orbiting close enough to pull gas from one another, swap mass, merge or end as a bound pair of compact remnants. Question it answers: Will this pair of stars end as a merger, a surviving pair, or a source of gravitational waves? Leaves out: Mass transfer between two stars is still represented by a small set of tunable prescriptions rather than derived from first principles. Runs on: about 10^12 FLOPS rough a laptop; a population of binaries evolves in minutes. Since: 1967 early computed models of mass transfer between close binary stars. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Stellar atmospheres and spectra Light escaping through the outer layers of a star, computed against temperature and composition to predict the spectrum a telescope would record. Question it answers: What is this star made of, and how hot is its surface? Leaves out: Assumes a smooth, calm atmosphere, when starspots and convection cells actually roughen the real surface. Runs on: about 10^13 FLOPS rough a workstation; hours per star modelled. Since: 1967 early computed model atmospheres compared against measured stellar spectra. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Supernova neutrino flavour evolution The dense stream of neutrinos leaving a collapsing star, followed as they scatter off one another and change flavour, which affects the explosion and the elements forged. Question it answers: How do neutrinos swap flavour in the crowd inside a supernova? Leaves out: The full problem is too large to solve alongside the explosion, so flavour physics is treated in small, simplified boxes. Runs on: about 10^15 FLOPS rough coupled quantum kinetic equations in a few dimensions. Since: 2006 Duan, Fuller, Carlson and Qian's simulation of coherent nonlinear neutrino flavour transformation in the supernova environment. [source](https://doi.org/10.1103/physrevd.74.105014) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Subatomic ### Stellar surface convection simulation The boiling surface layers of a star computed in three dimensions with radiation, to reproduce granulation and the shapes of spectral lines. Question it answers: What does the surface of a star look like, and how do its lines form? Leaves out: Only a thin patch is modelled, and the deep layers beneath are imposed from one-dimensional stellar models. Runs on: about 10^15 FLOPS rough three-dimensional radiation hydrodynamics of a surface patch. Since: 1998 Stein and Nordlund's simulations of solar granulation. [source](https://doi.org/10.1086/305678) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Common-envelope evolution A compact star spiralling inside the swollen outer layers of its companion, expelling the gas or merging, followed with hydrodynamics to see which close binaries survive. Question it answers: Does the spiralling star eject the envelope or merge with the core? Leaves out: Runs last far less than the real event and cannot cool the gas, so final separations remain uncertain. Runs on: about 10^16 FLOPS rough three-dimensional hydrodynamic runs of a few orbits. Since: 1996 Rasio and Livio's hydrodynamic simulations of common-envelope systems. [source](https://doi.org/10.1086/177975) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Binary population synthesis Millions of binary stars evolved with fast rules for mass transfer, tides and supernova kicks, to predict how many mergers, novae and gravitational-wave sources a galaxy holds. Question it answers: How many black-hole and neutron-star binaries does a galaxy make? Leaves out: Fast fitting formulae replace detailed stellar models, so rare outcomes hinge on the assumed rules. Runs on: about 10^12 FLOPS rough millions of binaries evolved using analytic fits. Since: 2002 Hurley, Tout and Pols's rapid evolution of binary stars including tides, for population studies. [source](https://doi.org/10.1046/j.1365-8711.2002.05038.x) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Collapsar and gamma-ray burst jets A massive star collapsing into a black hole and driving a jet through the stellar envelope, followed with relativistic hydrodynamics to see whether a burst can escape. Question it answers: Can a jet from a collapsing star break out to make a gamma-ray burst? Leaves out: Jet launching is imposed by hand, because the central engine is too small and fast to follow with the envelope. Runs on: about 10^16 FLOPS rough axisymmetric to three-dimensional relativistic hydrodynamics. Since: 1999 MacFadyen and Woosley's collapsars simulations of gamma-ray bursts and explosions in failed supernovae. [source](https://doi.org/10.1086/307790) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Astrochemical reaction networks Hundreds of gas-phase and grain-surface reactions integrated in a cold interstellar cloud to predict which molecules form and how they deplete as stars begin to condense. Question it answers: Which molecules form in a cold cloud, and how fast? Leaves out: Many rate coefficients are measured only at room temperature or are guessed. Runs on: about 10^8 FLOPS rough stiff rate equations for thousands of species, cheap per cloud. Since: 1973 Herbst and Klemperer's model of the formation and depletion of molecules in dense interstellar clouds. [source](https://doi.org/10.1086/152436) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Interstellar magnetised turbulence A compressible, magnetised gas stirred in a periodic box to find how quickly turbulence loses energy, which sets how fast clouds collapse into stars. Question it answers: How fast does turbulence in interstellar gas die away? Leaves out: Numerical dissipation stands in for the real small-scale physics, and the box has no walls or gravity. Runs on: about 10^15 FLOPS rough three-dimensional MHD runs at high resolution. Since: 1998 Stone, Ostriker and Gammie's dissipation in compressible magnetohydrodynamic turbulence. [source](https://doi.org/10.1086/311718) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Planets and orbits ### Planet formation Dust in a disc around a young star sticking into pebbles, planetesimals and eventually planets. Question it answers: How does a disc of dust end up as a solar system? Leaves out: The step from pebble to planetesimal, kilometres across, is still more assumed than derived. Runs on: about 10^15 FLOPS rough a university cluster, days to weeks for one disc. Since: 1978 Greenberg and colleagues' first numerical planetesimal accretion runs. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Orbital dynamics The planets pulling on each other over billions of years, and asteroids and comets threading between them. Question it answers: Is the solar system stable, and will this asteroid hit anything? Leaves out: Chaos means a tiny rounding error can flip the answer after long enough. Runs on: about 10^13 FLOPS rough a desktop computer; billions of years fit in days. Since: 1988 Sussman and Wisdom's digital orrery found chaos in Pluto's orbit. [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-threebody) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Planetary and exoplanet atmospheres Climate models adapted to other worlds: different gases, gravity, rotation and starlight. Question it answers: Could liquid water survive on the surface of this planet? Leaves out: Applies Earth-calibrated cloud and chemistry parametrisations to atmospheres that may behave very differently. Runs on: about 10^15 FLOPS rough a university cluster, days per simulated planet-year. Since: 1969 Leovy and Mintz's first general-circulation model of Mars. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Planetary interiors and dynamos Hot, convecting rock or metal deep inside a planet, modelled to see whether it generates a magnetic field and how heat escapes to the surface. Question it answers: Why does this planet have a magnetic field, and why does another one, similar in size, not? Leaves out: Runs at a viscosity and rotation rate far gentler than a real planetary core, then scaled up by assumption. Runs on: about 10^16 FLOPS rough a national cluster, weeks for one interior model. Since: 1995 early three-dimensional computer models of the geodynamo generating Earth's field. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Impact cratering An asteroid or comet striking a planet, modelled from the shockwave through the ground to the crater, debris and climate effects left behind. Question it answers: How big a crater, and how much damage, would this impactor cause? Leaves out: The strength and internal structure of the impactor are usually inferred from its size and speed alone. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per impact scenario. Since: 1980 early hydrocode simulations of impact craters, spurred by the dinosaur-extinction hypothesis. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Exoplanet detection and characterisation The dimming or wobble a planet would cause in its star's light, computed to compare against real telescope data and pull out its size and orbit. Question it answers: Is that dip in brightness really a planet, and if so, how big is it? Leaves out: Starspots and stellar jitter can mimic a planet's signal closely enough to fool an automated search. Runs on: about 10^13 FLOPS rough a workstation; minutes to hours per candidate signal. Since: 1984 early computed light-curve models used to plan the first exoplanet searches. [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Giant-impact simulations Smoothed-particle hydrodynamics of two planet-sized bodies colliding, tracking the melt and debris that may assemble into a moon. Question it answers: Could a collision between young planets have produced the Moon? Leaves out: Outcomes depend on equation of state and on the assumed initial spin and angle. Runs on: about 10^17 FLOPS rough Millions of SPH particles with realistic equations of state Since: 2001 Origin of the Moon in a giant impact near the end of Earth's formation (2001) [source](https://doi.org/10.1038/35089010) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Planet population synthesis Fast semi-analytic planet-formation models are run for thousands of simulated systems to produce a statistical population that is compared with exoplanet surveys. Question it answers: What mix of planet masses and orbits does a given formation theory predict? Leaves out: Each system is a simplified one-dimensional model, not a full hydrodynamic run. Runs on: about 10^14 FLOPS rough Thousands of cheap one-dimensional disc runs Since: 2004 Toward a deterministic model of planetary formation I (2004) [source](https://doi.org/10.1086/381724) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Exoplanet atmosphere retrieval A model atmosphere run thousands of times against a transmission or emission spectrum to infer temperature and molecular abundances. Question it answers: What is the air of a distant planet made of? Leaves out: One-dimensional models are fitted to data of limited quality, so degenerate solutions are common. Runs on: about 10^12 FLOPS rough millions of spectrum evaluations in a Bayesian sampler. Since: 2009 Madhusudhan and Seager's temperature and abundance retrieval method for exoplanet atmospheres. [source](https://doi.org/10.1088/0004-637x/707/1/24) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Habitable-zone climate modelling A one-dimensional climate model of a rocky planet at different distances from its star, balancing starlight, greenhouse gases and clouds to find where liquid water can last. Question it answers: How far from its star can a planet be and keep liquid water? Leaves out: One column cannot represent clouds or day-night contrast, so edges of the zone move with three-dimensional models. Runs on: about 10^6 FLOPS rough a one-dimensional radiative-convective column, light enough for a laptop. Since: 1993 Kasting, Whitmire and Reynolds's habitable zones around main-sequence stars. [source](https://doi.org/10.1006/icar.1993.1010) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Planetesimal formation by streaming instability Dust grains in a gas disk clumping into the first kilometre-sized bodies, simulated with particles and gas to see whether turbulence can concentrate them enough to collapse. Question it answers: How do pebbles clump into the first planetary building blocks? Leaves out: Small boxes cover a patch of the disk, and the particle sizes are a narrow range. Runs on: about 10^16 FLOPS rough three-dimensional local box runs with hundreds of millions of particles. Since: 2007 Johansen and colleagues' rapid planetesimal formation in turbulent circumstellar disks. [source](https://doi.org/10.1038/nature06086) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Planet-disk interaction and migration A planet embedded in the gas disk it formed from, which pulls a spiral wake that drags it inward or outward. Question it answers: Why do planets move from where they formed? Leaves out: Migration rate is sensitive to disk thermodynamics and viscosity, which are poorly known. Runs on: about 10^14 FLOPS rough hydrodynamic disk runs for thousands of orbits. Since: 2000 Kley's hydrodynamic simulations of the migration of a system of protoplanets. [source](https://doi.org/10.1046/j.1365-8711.2000.03495.x) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Extreme gravity and space plasma ### Black hole mergers Einstein’s equations solved directly as two black holes spiral together, producing the gravitational-wave signal detectors listen for. Question it answers: What waveform should we see from two black holes of these masses? Leaves out: The last fraction of a second before merger still needs approximations no computer fully resolves. Runs on: about 10^16.5 FLOPS rough a large cluster, weeks for one waveform. Since: 1964 Hahn and Lindquist's first computed head-on collision of two black holes. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Accretion discs and jets Magnetised gas spiralling into a black hole, heating up and launching jets that run for thousands of light years. Question it answers: How does a black hole shine brighter than the galaxy around it? Leaves out: Cannot track the disc down to the black hole's own scale and the wider galaxy at once. Runs on: about 10^16 FLOPS rough a large cluster, weeks for a global disc run. Since: 1991 Balbus and Hawley's simulations revealing the magnetorotational instability. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Space weather The solar wind and eruptions from the Sun striking Earth’s magnetic field. Question it answers: Will this solar storm damage satellites or power grids, and when does it arrive? Leaves out: Predicts the arrival time of an eruption with moderate accuracy and its strength with considerably less. Runs on: about 10^15 FLOPS rough a national forecasting centre's cluster, run several times a day. Since: 1978 early global MHD simulations of the solar wind hitting Earth's field. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Neutron star mergers Two neutron stars spiralling together and colliding, tracked through Einstein's equations and nuclear physics at once to see what debris and light are flung out. Question it answers: Does this merger make a black hole, and does it forge the heavy elements found on Earth? Leaves out: The nuclear physics of matter this dense is still not fully known, so the debris composition carries real uncertainty. Runs on: about 10^17 FLOPS rough a large share of a national supercomputer, for weeks. Since: 1990 early relativistic hydrodynamics simulations of colliding neutron stars. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Pulsar magnetospheres The whirling magnetic field and plasma around a spinning neutron star, computed to see how it beams radio waves and high-energy particles into space. Question it answers: Why does a pulsar's beam sweep periodically across the line of sight, and what determines its shape? Leaves out: The plasma right at the star's surface, where the beam actually forms, is still poorly understood physically. Runs on: about 10^15 FLOPS rough a university cluster, days per magnetosphere model. Since: 1999 early global simulations of a pulsar's rotating magnetic field. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Solar interior and dynamo Hot plasma convecting and rotating inside the Sun, modelled to see how it winds up magnetic field into the eleven-year sunspot cycle. Question it answers: Why does the Sun's magnetic activity rise and fall on an eleven-year cycle? Leaves out: Cannot yet reproduce the cycle's period and amplitude reliably without tuning the model towards the observed values. Runs on: about 10^16 FLOPS rough a national cluster, weeks for one simulated cycle. Since: 1983 early three-dimensional convection simulations of the solar interior. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Gravitational-wave template banks from numerical relativity Hundreds to thousands of simulated black-hole mergers spanning mass ratios and spins, calibrated into waveform models that detectors match against data. Question it answers: What does the signal of any given black-hole merger look like? Leaves out: Catalogues are sparse in the parameter space, so the waveform models between them are fits, not simulations. Runs on: about 10^17 FLOPS rough thousands of merger runs, each weeks on a cluster. Since: 2013 Mroue and colleagues' catalogue of 174 binary black hole simulations for gravitational-wave astronomy. [source](https://doi.org/10.1103/physrevlett.111.241104) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Gravitational-wave mock data challenges Simulated detector data with many injected sources and realistic noise, used to test whether analysis pipelines can recover the astrophysical signals hidden inside. Question it answers: Can an analysis pipeline find and measure every source buried in the noise? Leaves out: Noise is idealised and the injected source population is assumed, so real-data complications are missing. Runs on: about 10^14 FLOPS rough many long data streams with thousands of overlapping sources. Since: 2006 The Mock LISA Data Challenges, the first community blind tests of space-based gravitational-wave analysis. [source](https://doi.org/10.1063/1.2405108) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Magnetar magnetosphere and flare simulation The twisted magnetic field outside a magnetar, the neutron star with the strongest known fields, followed as it builds up stress, reconnects and releases flares. Question it answers: How does a neutron star's twisted field blow off energy in a flare? Leaves out: Force-free physics forgets the plasma's inertia and the pair-production that drives real flares. Runs on: about 10^16 FLOPS rough relativistic force-free runs on a cluster. Since: 2012 Parfrey, Beloborodov and Hui's simulation of twisting, reconnecting magnetar magnetospheres. [source](https://doi.org/10.1088/2041-8205/754/1/l12) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Black-hole shadow and image rendering Light rays traced through the curved spacetime around a black hole and its hot gas to predict the ring-shaped image a telescope would see. Question it answers: What does the glowing gas around a black hole look like from Earth? Leaves out: The gas model is a post-processing guess, so the image depends on assumed electron temperatures and magnetic field. Runs on: about 10^15 FLOPS rough ray tracing through thousands of accretion simulation snapshots. Since: 2000 Falcke, Melia and Agol's simulated image of the shadow of the black hole at the Galactic centre. [source](https://doi.org/10.1086/312423) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Tidal disruption of stars by black holes A star pulled apart by a massive black hole, its debris stretched into a stream that falls back and lights up, followed with hydrodynamics. Question it answers: How much of a shredded star falls into the black hole, and how bright is the flare? Leaves out: The radiation that makes the flare visible is only approximated, so the light curve is inferred, not simulated end to end. Runs on: about 10^16 FLOPS rough smoothed-particle or grid runs with a general-relativistic treatment. Since: 1989 Evans and Kochanek's hydrodynamic simulation of the tidal disruption of a star by a massive black hole. [source](https://doi.org/10.1086/185567) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Kilonova radiative transfer The glowing cloud of heavy-element debris from a neutron-star merger, modelled with radioactive heating and radiation transport to predict its light and colour. Question it answers: How bright and how red is the afterglow of a neutron-star merger? Leaves out: Opacities of the heaviest elements rest on incomplete atomic data and dominate the uncertainty in predicted colour. Runs on: about 10^14 FLOPS rough multi-dimensional Monte Carlo radiation transport with atomic opacity data. Since: 2010 Metzger and colleagues' model of electromagnetic counterparts powered by r-process radioactive decay. [source](https://doi.org/10.1111/j.1365-2966.2010.16864.x) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Radiation belt modelling High-energy electrons and protons trapped in the magnetic field around a planet, moved by diffusion, injection and loss to predict hazards for satellites. Question it answers: Why do belts of trapped radiation swell and drain during magnetic storms? Leaves out: Wave-particle diffusion rates are parametrised from limited measurements, a main source of error. Runs on: about 10^13 FLOPS rough three-dimensional diffusion runs over storm intervals. Since: 1995 Beutier and Boscher's three-dimensional model of the electron radiation belt. [source](https://doi.org/10.1029/94ja03066) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Neural inference for gravitational waves A neural network is trained on millions of simulated merger signals in synthetic detector noise so that it can output the likely masses, spins and distance of a new event almost instantly. Question it answers: Can the properties of a black-hole merger be inferred in seconds, early enough to point telescopes at it? Leaves out: It is only as good as the waveform model and noise it was trained on, and unusual signals can fall outside what it learned. Runs on: about 10^17 FLOPS rough weeks of GPU training on simulated waveforms. Since: 2021 Dax and colleagues' neural posterior estimation for gravitational-wave events. [source](https://arxiv.org/abs/2106.12594) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields [◂ Fundamental physics](https://simulation-hypothesis.com/simulations/fundamental-physics)[Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate) --- title: "Earth and climate · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/earth-climate description: "Weather, climate, oceans, ice, earthquakes, floods and fire: the planet as a set of coupled equations. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 3 of 18 # Earth and climate Weather, climate, oceans, ice, earthquakes, floods and fire: the planet as a set of coupled equations. The planet is a coupled system of atmosphere, ocean, ice, rock and biosphere. These simulations discretise it into grid cells and integrate it forward in time. Weather forecasting is the most familiar use. ## Climate ### Earth system models Atmosphere, ocean, sea ice, land and the carbon cycle coupled on a global grid and run for centuries. Question it answers: How warm does the planet get under a given path of emissions? Leaves out: Clouds are still represented by parametrisations, the single largest source of disagreement between models. Runs on: about 10^17 FLOPS rough a large share of a national supercomputer, for months. Since: 1969 Manabe and Bryan's first coupled ocean-atmosphere climate model. In the simulations tree: [Coupled ocean-atmosphere](https://simulation-hypothesis.com/trees/simulations?n=p-manabebryan) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Palaeoclimate The same models run over ice ages and deep time, with different continents, orbits and atmospheres. Question it answers: What set off the ice ages, and what does the past say about how sensitive climate is? Leaves out: Ancient coastlines, ice and vegetation are reconstructed from sparse evidence, then treated as known inputs. Runs on: about 10^17 FLOPS rough similar to a modern climate run, a supercomputer share for months. Since: 1977 Manabe and Hahn's first GCM simulation of ice-age climate. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Ice sheets and sea level Glaciers and ice sheets flowing, melting and calving into the sea. Question it answers: How fast could the ice sheets add to sea level this century? Leaves out: The physics of how ice suddenly fractures and slides is still poorly captured. Runs on: about 10^15 FLOPS rough a university cluster, days to weeks per simulated century. Since: 1976 Mahaffy's early finite-difference computer model of an ice sheet. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Integrated assessment models Energy, economy, land use and climate linked in one model, used to compare policy pathways. Question it answers: What mix of energy and land use keeps warming below a given limit, and at what cost? Leaves out: Reduces the whole economy and climate to a handful of equations, so the answer depends heavily on the discount rate chosen. Runs on: about 10^12 FLOPS rough a laptop; a full run takes seconds to minutes. Since: 1992 Nordhaus's DICE model, the first widely used climate-economy model. [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Regional climate downscaling A global climate model's coarse output used to drive a finer regional one over one country or mountain range. Question it answers: What does global warming actually mean for the weather in this valley? Leaves out: Inherits the biases of whichever global model it is nested inside, just at higher resolution. Runs on: about 10^16 FLOPS rough a national cluster, weeks for one regional projection. Since: 1989 early nested regional climate models run over a limited area. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Solar geoengineering Climate models run with a deliberate intervention added, such as reflective particles injected into the upper atmosphere, to see what it would change. Question it answers: Could deliberately reducing incoming sunlight offset warming, and what side effects would it have? Leaves out: No intervention of this kind has been carried out at scale, so every result depends on how well the model represents aerosols never observed under such deployment. Runs on: about 10^17 FLOPS rough a large share of a national supercomputer, for months. Since: 1992 early climate model experiments testing a hypothetical volcanic-style intervention. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### World-Earth models Climate models coupled to simple dynamic representations of human behaviour, so that emissions, policy and social change respond to the state of the planet. Question it answers: How do social tipping and climate feedbacks interact over centuries? Leaves out: Behavioural rules are hypotheses, and spatial climate detail is coarse. Runs on: about 10^14 FLOPS rough Reduced-complexity models run in large ensembles Since: 2018 Earth system modelling with complex dynamic human societies: the copan:CORE framework (2018) [source](https://doi.org/10.5194/esd-2017-126) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Global cloud-resolving models Atmosphere models whose grid is fine enough, a few kilometres, to represent deep convection explicitly across the whole globe. Question it answers: Can tropical cloud systems be simulated directly instead of through parameters? Leaves out: Runs are short, and turbulence and cloud microphysics are still approximated. Runs on: about 10^18 FLOPS rough Weeks of simulated time on the largest machines Since: 2007 A Madden-Julian oscillation event realistically simulated by a global cloud-resolving model (2007) [source](https://doi.org/10.1126/science.1148443) In the simulations tree: [Global cloud-resolving model](https://simulation-hypothesis.com/trees/simulations?n=p-miura) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Superparameterisation A small cloud-resolving model is embedded inside each column of a coarse global one to replace the usual convection scheme. Question it answers: Can explicit cloud physics improve a climate model without a full global fine grid? Leaves out: The embedded models are small and do not talk to neighbouring columns. Runs on: about 10^16 FLOPS rough Embedded 2D cloud models multiply cost many times Since: 2001 Coupling cloud processes with the large-scale dynamics using the cloud-resolving convection parameterization (2001) [source](https://doi.org/10.1175/1520-0469%282001%29058<0978:CCPWTL>2.0.CO;2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Extreme-event attribution Large ensembles of climate runs with and without human influence give the odds of a specific heatwave, flood or storm in each world. Question it answers: How much did human emissions change the chance of this particular event? Leaves out: Results depend on how well the model reproduces the event type at that scale. Runs on: about 10^17 FLOPS rough Hundreds to thousands of ensemble members Since: 2004 Human contribution to the European heatwave of 2003 (2004) [source](https://doi.org/10.1038/nature03089) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Volunteer-computed perturbed-physics ensembles Thousands of copies of a climate model, each with slightly different physical parameters, run on donated home computers. Question it answers: How wide is the range of warming consistent with uncertain model physics? Leaves out: Model structure is fixed; only parameters are varied. Runs on: about 10^17 FLOPS rough Tens of thousands of model runs Since: 2005 Uncertainty in predictions of the climate response to rising levels of greenhouse gases (2005) [source](https://doi.org/10.1038/nature03301) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Initial-condition large ensembles A single climate model is run dozens of times from slightly different starts to separate forced change from internal variability. Question it answers: What part of a regional trend is the climate's own noise? Leaves out: It captures variability within one model, not differences across them. Runs on: about 10^18 FLOPS rough Dozens of centuries-long coupled runs Since: 2015 The CESM Large Ensemble Project (2015) [source](https://doi.org/10.1175/BAMS-D-13-00255.1) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Learned climate emulators A neural network trained on climate-model output steps the atmosphere forward for decades or centuries at a tiny fraction of the cost. Question it answers: Can a trained surrogate reproduce multi-decade climate statistics quickly? Leaves out: It inherits the biases of its training model and may fail outside the climates it saw. Runs on: about 10^15 FLOPS rough Training on model archives, then cheap long runs Since: 2023 A fast, skillful learned global atmospheric model for climate prediction (2023) [source](https://arxiv.org/abs/2310.02074) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Fields ### Earth-system digital twins Continuously updated, high-resolution models of the planet, fed by observations and built to answer what-if questions for users. Question it answers: What would happen to a region if a given decision or event occurred? Leaves out: The twin is only as faithful as its models and data, and interactive scenarios are limited. Runs on: about 10^19 FLOPS rough Km-scale global models plus assimilation Since: 2021 The digital revolution of Earth-system science (2021) [source](https://doi.org/10.1038/s43588-021-00023-0) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Fields ### Radiative-convective climate model A single column of atmosphere in balance between radiation and convection, used to find how much a planet warms when carbon dioxide or humidity changes. Question it answers: How much does a column of air warm when its greenhouse gas doubles? Leaves out: It has no winds, clouds or ocean transport, so it gives a reference warming rather than a forecast. Runs on: about 10^4 FLOPS rough a one-dimensional column, quick on a laptop. Since: 1967 Manabe and Wetherald's thermal equilibrium of the atmosphere with a given distribution of relative humidity. [source](https://doi.org/10.1175/1520-0469%281967%29024<0241:teotaw>2.0.co;2) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Energy-balance climate model Earth reduced to latitude bands that absorb and emit heat and trade it by transport, enough to show ice-albedo feedback and tipping between climate states. Question it answers: Could a runaway of ice cover freeze the whole planet? Leaves out: The picture ignores dynamics and weather, so it informs but does not forecast. Runs on: about 10^3 FLOPS rough a handful of equations; seconds on any computer. Since: 1969 Sellers's global climatic model based on the energy balance of the earth-atmosphere system. [source](https://doi.org/10.1175/1520-0450%281969%29008<0392:agcmbo>2.0.co;2) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Rules ### Dynamic global vegetation and carbon-cycle modelling Plants, soils and their carbon exchange simulated across the globe, with vegetation types competing and shifting as climate changes. Question it answers: How much carbon will the land absorb or release as the climate warms? Leaves out: Plant types are lumped into a few functional classes, and nutrient and disturbance feedback are crude. Runs on: about 10^14 FLOPS rough multi-century global runs, often on a coarse grid. Since: 1996 Foley and colleagues' integrated biosphere model of land surface processes, terrestrial carbon balance and vegetation dynamics. [source](https://doi.org/10.1029/96gb02692) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Fields ### Coupled carbon-cycle and climate simulation A climate model with the land and ocean carbon cycle inside it, so warming can change how much the Earth takes up and feed back on itself. Question it answers: Will warming turn land and ocean from absorbers of carbon into sources? Leaves out: Land carbon response varies widely between models because of soil and vegetation assumptions. Runs on: about 10^17 FLOPS rough multi-century coupled climate runs on a supercomputer. Since: 2000 Cox, Betts, Jones, Spall and Totterdell's acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. [source](https://doi.org/10.1038/35041539) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Ocean ecosystem and biogeochemistry modelling Nutrients, plankton and detritus advected and cycled through the ocean, to predict productivity and the carbon carried to the deep. Question it answers: How much carbon does ocean life carry into the deep sea? Leaves out: Plankton groups are a few lumped compartments with fitted rates. Runs on: about 10^15 FLOPS rough a biogeochemical module within an ocean general circulation model. Since: 1990 Fasham, Ducklow and McKelvie's nitrogen-based model of plankton dynamics in the oceanic mixed layer. [source](https://doi.org/10.1357/002224090784984678) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Fields ### Learned subgrid parameterisation A neural network trained on a cloud-resolving model replaces the hand-written rules for storms and clouds that are too small for a coarse global climate model. Question it answers: Can a coarse climate model get small-scale clouds right by learning them from a finer one? Leaves out: The network can drift into unstable or unphysical states when the climate moves outside the conditions it was trained on. Runs on: about 10^16 FLOPS rough training on a small set of fine simulations, then cheap use inside the climate model. Since: 2018 Rasp, Pritchard and Gentine's deep-learning representation of subgrid processes in a climate model. [source](https://doi.org/10.1073/pnas.1810286115) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ## Weather and air ### Numerical weather prediction Today’s observed atmosphere stepped forward hours to days, usually as an ensemble of slightly different starting points. Question it answers: Will it rain here on Thursday, and how sure are we? Leaves out: Skill collapses past about ten days, however fine the grid. Runs on: about 10^17 FLOPS rough a national weather centre's supercomputer, a few percent of it for hours. Since: 1950 Charney, Fjortoft and von Neumann's first numerical forecast. In the simulations tree: [First computer forecast](https://simulation-hypothesis.com/trees/simulations?n=p-eniac) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Machine-learned weather Neural networks trained on decades of past weather, producing forecasts in seconds rather than hours. Question it answers: Can a learned emulator forecast as well as the physics it was trained on? Leaves out: Learns the patterns in past weather, so it struggles with the kind of extreme event it has not seen before. Runs on: about 10^14 FLOPS rough a single high-end GPU; forecasts in seconds rather than hours. Since: 2022 first learned weather models to match physics-based forecast skill. [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Fields ### Tropical cyclones Hurricanes and typhoons at high resolution: their tracks, intensity and rainfall. Question it answers: Where will the storm make landfall, and how strong will it be? Leaves out: The eye and eyewall are still smaller than most models can properly resolve. Runs on: about 10^16 FLOPS rough a national forecasting centre's cluster, run for each active storm. Since: 1969 Ooyama's early numerical model of a hurricane's development. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Air quality and dispersion Pollutants, smoke and volcanic ash carried, mixed and chemically transformed by the wind. Question it answers: Where does the plume go, and is the air safe to breathe or fly through? Leaves out: Emissions inventories, the input the whole forecast depends on, are often out of date or estimated. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per pollution event. Since: 1970 early computerised Gaussian plume models for smokestack pollution. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Seasonal forecasting An ensemble of climate-length model runs, started from today's ocean and atmosphere, aimed at the odds for a whole season rather than any single day. Question it answers: Will this winter be warmer or wetter than average? Leaves out: Cannot say what the weather will be on any given day, only how the odds are shifted. Runs on: about 10^17 FLOPS rough a national forecasting centre's supercomputer, an ensemble of runs each season. Since: 1986 early dynamical seasonal forecasts using ocean-coupled models. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Severe convective storms A single thunderstorm or supercell, resolved down to the scale of its updraft and downdraft, to see whether it spins up a tornado or drops large hail. Question it answers: Will this storm produce a tornado, and where? Leaves out: Needs a grid fine enough to see a tornado, which is too expensive to run everywhere a storm could form. Runs on: about 10^16 FLOPS rough a national cluster, hours for one storm at very high resolution. Since: 1975 early three-dimensional computer models of a single thunderstorm. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Generative ensemble weather forecasting A diffusion model samples many plausible weather futures for the next two weeks, giving probabilities for each variable at global scale. Question it answers: Can a learned model supply calibrated forecast uncertainty cheaply? Leaves out: It is tied to reanalysis data and offers no physical guarantee on rare extremes. Runs on: about 10^16 FLOPS rough Training on decades of reanalysis, minutes per ensemble member Since: 2023 GenCast: diffusion-based ensemble forecasting for medium-range weather (2023) [source](https://arxiv.org/abs/2312.15796) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Ensemble weather forecasting A forecast run many times from slightly different starting states, so the spread shows how uncertain the weather is and how likely each outcome is. Question it answers: How confident can a weather forecast be, and what could happen instead? Leaves out: Starting-state perturbations only partly capture model error, so the spread is often too narrow. Runs on: about 10^16 FLOPS rough dozens of global forecasts every day, each a large run. Since: 1974 Leith's theoretical skill of Monte Carlo forecasts. [source](https://doi.org/10.1175/1520-0493%281974%29102<0409:tsomcf>2.0.co;2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Atmospheric reanalysis A fixed modern forecast model run over decades of past observations, blending them into a consistent, gap-free record of the atmosphere. Question it answers: What were the winds, temperatures and pressures at every place and time in the past? Leaves out: Changes in the observing system over time leave artificial trends in the record. Runs on: about 10^17 FLOPS rough decades of assimilation cycles on a supercomputer. Since: 1996 Kalnay and colleagues' NCEP/NCAR 40-year reanalysis project. [source](https://doi.org/10.1175/1520-0477%281996%29077<0437:tnyrp>2.0.co;2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Atmospheric boundary-layer large-eddy simulation The lowest kilometre of the atmosphere, where turbulent eddies mix heat, moisture and pollutants, with the large eddies resolved and the small ones modelled. Question it answers: How do turbulent eddies carry heat and moisture upward from the ground? Leaves out: Surface exchange and sub-grid mixing are parametrised, which limits accuracy near the ground. Runs on: about 10^14 FLOPS rough a few kilometres of domain at tens of metres resolution. Since: 1972 Deardorff's numerical investigation of neutral and unstable planetary boundary layers. [source](https://doi.org/10.1175/1520-0469%281972%29029<0091:nionau>2.0.co;2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Global storm-resolving simulation A whole-planet atmosphere model at a few kilometres of resolution so that thunderstorm clusters and tropical storms appear without a convection parametrisation. Question it answers: What does the atmosphere do when storms are resolved instead of approximated? Leaves out: Cloud microphysics and turbulence below a few kilometres remain parametrised, and runs are too short to study climate. Runs on: about 10^19 FLOPS rough weeks on the largest machines for a few simulated months. Since: 2008 Satoh and colleagues' nonhydrostatic icosahedral atmospheric model for global cloud-resolving simulations. [source](https://doi.org/10.1016/j.jcp.2007.02.006) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Mineral dust emission and transport Wind lifting desert dust, carrying it across seas and depositing it, to find its effect on radiation, ocean nutrients and air quality. Question it answers: How much desert dust enters the air and where does it go? Leaves out: Emission thresholds depend on soil and surface properties that are poorly mapped. Runs on: about 10^14 FLOPS rough a dust module inside an atmosphere model over years. Since: 1994 Tegen and Fung's model of mineral dust in the atmosphere: sources, transport and optical thickness. [source](https://doi.org/10.1029/94jd01928) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Urban surface energy-balance modelling Streets, roofs and walls treated as a canyon exchanging heat, moisture and momentum with the air, to predict urban heat islands and building cooling needs. Question it answers: Why is a city hotter than the countryside around it? Leaves out: Cities are reduced to idealised canyons, so building detail and traffic heat are approximated. Runs on: about 10^12 FLOPS rough a canyon scheme within an atmospheric model over a metropolitan area. Since: 2000 Masson's physically-based scheme for the urban energy budget in atmospheric models. [source](https://doi.org/10.1023/a:1002463829265) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Thermosphere and ionosphere modelling The upper atmosphere at 100 to 600 kilometres, heated by sunlight and particles, with winds and electric currents that change satellite drag and radio signals. Question it answers: How does solar activity change the upper atmosphere and radio propagation? Leaves out: The lower boundary and the energy from above are imposed from sparse data. Runs on: about 10^13 FLOPS rough coupled upper-atmosphere simulation over days of space weather. Since: 1988 Roble, Ridley, Richmond and Dickinson's coupled thermosphere/ionosphere general circulation model. [source](https://doi.org/10.1029/gl015i012p01325) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Water ### Ocean circulation Currents, eddies, heat and salt moving through the world’s oceans. Question it answers: Could the great overturning currents of the Atlantic slow down? Leaves out: The eddies that mix heat and carbon are mostly smaller than the grid, so their effect must be parametrised. Runs on: about 10^16 FLOPS rough a large cluster, weeks for a multi-decade run. Since: 1969 Bryan's first computer model of the global ocean circulation. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Tsunamis and storm surge Waves raised by earthquakes or storms, crossing the ocean and running up onto the coast. Question it answers: How high will the water reach, and which streets flood first? Leaves out: Coastal defences and drainage are usually simplified far below the resolution of the run-up itself. Runs on: about 10^13 FLOPS rough a workstation; minutes for a coastal warning run. Since: 1969 Aida's early numerical experiments modelling a tsunami. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Rivers and floods Rain falling on a catchment, soaking in or running off into streams, rivers and floodplains. Question it answers: How big a flood does this storm make, and where? Leaves out: Soil and land use are averaged over the catchment, hiding the one field or gully that actually floods. Runs on: about 10^12 FLOPS rough a laptop; a catchment run takes minutes. Since: 1966 Crawford and Linsley's Stanford Watershed rainfall-runoff model. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Fields ### Groundwater Water moving slowly through soil and rock in aquifers. Question it answers: How long can we pump this aquifer before the wells run dry? Leaves out: Subsurface rock and soil properties are mapped from boreholes hundreds of metres apart, so most of the aquifer is inferred. Runs on: about 10^12 FLOPS rough a laptop or workstation; minutes to hours per aquifer. Since: 1968 Pinder and Bredehoeft's early finite-difference aquifer model. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Sea ice Floating ice on the ocean surface, cracking, ridging, drifting and melting under wind, waves and warmth. Question it answers: How much of the Arctic Ocean will still be covered in ice by the end of summer? Leaves out: Treats a heterogeneous field of cracked, ridged floes as a smooth continuous sheet. Runs on: about 10^15 FLOPS rough a university or national cluster, weeks coupled to an ocean run. Since: 1969 early computer models of drifting Arctic sea ice. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Ocean wave forecasting Wind blowing over open water, generating and steering swell and chop, tracked to forecast wave height and direction for ships and coasts. Question it answers: How rough will the sea be here tomorrow? Leaves out: Performs poorly on the steepest, breaking crests, which matter most for maritime safety. Runs on: about 10^15 FLOPS rough a national forecasting centre's cluster, run several times a day. Since: 1956 early numerical wave forecasting following wartime swell-prediction methods. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Flood inundation modelling Water from a river or storm spreading across a floodplain on a terrain grid, to map depth and extent for insurance and planning. Question it answers: Which streets and fields go under water in a flood? Leaves out: Terrain accuracy and the inflow hydrograph dominate the error, not the numerics. Runs on: about 10^12 FLOPS rough two-dimensional shallow-water or raster models of a river basin. Since: 2000 Bates and De Roo's simple raster-based model for flood inundation simulation. [source](https://doi.org/10.1016/s0022-1694%2800%2900278-x) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Fields ### Coastal and estuarine circulation modelling Tides, rivers and winds moving water, salt and sediment through bays and estuaries on a terrain-following grid. Question it answers: How do tides and rivers mix water along a coast? Leaves out: Small-scale mixing and bathymetry errors limit the accuracy near shore. Runs on: about 10^12 FLOPS rough three-dimensional regional model with year-long runs. Since: 1987 Blumberg and Mellor's description of a three-dimensional coastal ocean circulation model. [source](https://doi.org/10.1029/co004p0001) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Marine debris and Lagrangian drift modelling Virtual particles carried by simulated or observed ocean currents to find where floating plastic, oil or larvae go. Question it answers: Where do floating plastics from a coast end up? Leaves out: Windage, wave drift and the sinking or fragmenting of particles are poorly known. Runs on: about 10^12 FLOPS rough millions of particles advected through a year of ocean flow. Since: 2012 van Sebille, England and Froyland's origin, dynamics and evolution of ocean garbage patches from observed surface drifters. [source](https://doi.org/10.1088/1748-9326/7/4/044040) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Petroleum and gas reservoir simulation Oil, gas and water flowing through the pores of a rock reservoir toward wells, to plan drilling and predict how much can be recovered. Question it answers: How much oil will a field yield, and where should the wells go? Leaves out: Rock properties between wells are inferred from sparse data, so uncertainty is usually larger than the numerics. Runs on: about 10^13 FLOPS rough multiphase flow in a geological model of millions of cells. Since: 1955 Peaceman and Rachford's numerical solution of parabolic and elliptic differential equations, the basis of early reservoir simulators. [source](https://doi.org/10.1137/0103003) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Glacial isostatic adjustment and sea-level fingerprints The Earth's crust rebounding as ice sheets melt and the oceans redistributing, to predict regional sea-level change and the gravity field. Question it answers: Why does sea level fall in some places as the ice melts and rise in others? Leaves out: Mantle viscosity beneath the plates is poorly constrained and varies from region to region. Runs on: about 10^12 FLOPS rough viscoelastic Earth models solved on a sphere. Since: 1976 Farrell and Clark's calculation of postglacial sea level. [source](https://doi.org/10.1111/j.1365-246x.1976.tb01252.x) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Geological carbon-dioxide storage simulation Injected carbon dioxide spreading, rising and dissolving in a saline rock formation, with trapping by caprock, capillarity and mineral reactions followed over centuries. Question it answers: Will the gas stay underground, and where does it go? Leaves out: The rock below the borehole is known only from a few wells and surveys, so permeability and faults are guessed with wide uncertainty. Runs on: about 10^15 FLOPS rough weeks on a cluster for a basin-scale model over thousands of years. Since: 2002 The Lawrence Berkeley intercomparison of numerical codes for geologic disposal of CO2. [source](https://doi.org/10.2172/813566) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Reactive transport in the subsurface Water carrying chemicals through rock or soil while minerals dissolve, precipitate and exchange ions, solved together with the flow. Question it answers: How do the chemistry and the plumbing of an aquifer or repository change each other over time? Leaves out: Reaction rates measured in a laboratory are applied to rock whose reactive surface area in the ground is unknown. Runs on: about 10^14 FLOPS rough days on a cluster for a three-dimensional field site. Since: 1985 Lichtner's continuum model for coupled chemical reactions and mass transport in hydrothermal systems. [source](https://doi.org/10.1016/0016-7037%2885%2990172-3) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Solid Earth and landscape ### Mantle convection and plate tectonics Hot rock creeping inside the planet over hundreds of millions of years, carrying the plates on top. Question it answers: Why does Earth have plate tectonics when its neighbours do not? Leaves out: Runs millions of simulated years at once, so it cannot also show a single earthquake. Runs on: about 10^15 FLOPS rough a university cluster, weeks for one long run. Since: 1974 McKenzie, Roberts and Weiss's first numerical mantle convection model. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Earthquakes and seismic waves Faults rupturing and the waves spreading through the crust to shake the ground. Question it answers: How hard will this city shake if that fault breaks? Leaves out: The rupture's starting point and the fault's exact roughness are still assumed rather than known in advance. Runs on: about 10^16 FLOPS rough a national or university cluster, days for a large fault rupture. Since: 1968 Alterman and Karal's early finite-difference model of seismic waves. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Volcanic eruptions and lava flows Magma rising, erupting and flowing downhill as lava, ash or fast-moving hot clouds. Question it answers: Which villages lie in the path if the volcano erupts? Leaves out: Cannot predict when an eruption starts, only what happens once one already has. Runs on: about 10^13 FLOPS rough a workstation or small cluster, hours per scenario. Since: 1980 early computer models of lava flowing downhill from a vent. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Fields ### Landscape evolution Rivers cutting valleys, hillslopes creeping and coasts eroding over thousands to millions of years. Question it answers: How did this landscape get its shape? Leaves out: Compresses millions of years into a run, so any single storm or rockfall is smoothed away. Runs on: about 10^13 FLOPS rough a workstation; days for a million-year landscape. Since: 1991 Willgoose and colleagues' early computed landscape evolution model. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Fields ### Wildfire spread Fire moving across fuel, terrain and wind, cell by cell. Question it answers: Where will the fire front be in six hours? Leaves out: Wind, the biggest driver of a real fire's behaviour, is usually simplified to a steady average. Runs on: about 10^13 FLOPS rough a workstation or laptop; minutes for a spreading fire front. Since: 1972 Rothermel's fire-spread equations, soon computerised for forecasting. [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-forestfire) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Landslides and debris flows A slope of soil, rock or mud failing and moving downhill, tracked as it accelerates, spreads out and buries the terrain below. Question it answers: How far will this slope travel once it fails, and how fast? Leaves out: The moment a slope actually fails is still harder to predict than what happens once it has. Runs on: about 10^13 FLOPS rough a workstation or small cluster, hours per slope scenario. Since: 1980 early computer runout models for a failing slope. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Physics-based seismic hazard Earthquake rupture and wave propagation simulations replace empirical attenuation rules to give shaking at each site. Question it answers: How strongly would the ground shake here for each possible rupture? Leaves out: Needs a known velocity model, and high frequencies are hard to resolve. Runs on: about 10^18 FLOPS rough Many rupture scenarios, each a 3D wave simulation Since: 2010 CyberShake: a physics-based seismic hazard model for Southern California (2010) [source](https://doi.org/10.1007/s00024-010-0161-6) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Geodynamo simulation Convection of liquid iron in Earth's core generating and sustaining the magnetic field, including its random reversals. Question it answers: How does Earth's core make its magnetic field, and why does it flip? Leaves out: Viscosity and conductivity values are far from real, so the flow is much smoother than inside Earth. Runs on: about 10^18 FLOPS rough months on a supercomputer for a dynamo that still runs far from Earth-like conditions. Since: 1995 Glatzmaier and Roberts's three-dimensional self-consistent simulation of a geomagnetic field reversal. [source](https://doi.org/10.1038/377203a0) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Full-waveform seismic inversion Seismic waves run repeatedly through a trial Earth model, which is adjusted until synthetic and recorded waves match, to image rock structure. Question it answers: What does the rock beneath us look like, as seen by the waves that crossed it? Leaves out: The inversion can lock onto wrong solutions unless the starting model is close. Runs on: about 10^17 FLOPS rough thousands of wave simulations inside an optimisation loop. Since: 1984 Tarantola's inversion of seismic reflection data in the acoustic approximation. [source](https://doi.org/10.1190/1.1441754) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Spectral-element seismic wave propagation Earthquake waves propagating through a three-dimensional model of the crust or the whole Earth with high-order elements that follow topography and layers. Question it answers: How do waves travel through the real, lumpy Earth? Leaves out: Earth models are uncertain in small-scale structure and attenuation, so short periods are less reliable. Runs on: about 10^17 FLOPS rough whole-Earth runs resolving periods of a few seconds. Since: 1998 Komatitsch and Vilotte's spectral element method for seismic response of two- and three-dimensional structures. [source](https://doi.org/10.1785/bssa0880020368) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Earthquake-cycle simulation A fault loaded slowly by plate motion, with friction that sticks and slips, simulated through many cycles of quiet buildup and sudden rupture. Question it answers: How do earthquakes repeat on a fault over centuries? Leaves out: The friction law is laboratory-derived and extrapolated to depths and speeds never measured. Runs on: about 10^14 FLOPS rough rate-and-state fault cycles over thousands of years. Since: 1986 Tse and Rice's crustal earthquake instability in relation to the depth variation of frictional slip properties. [source](https://doi.org/10.1029/jb091ib09p09452) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Stochastic earthquake-catalogue models Synthetic earthquake sequences generated from a statistical model in which each shock raises the chance of aftershocks, to forecast clustering and hazard. Question it answers: How likely are aftershocks after a large earthquake? Leaves out: The model captures statistical clustering but has no physics of fault stress. Runs on: about 10^6 FLOPS rough stochastic catalogues cost little, and a long ensemble runs on a workstation. Since: 1988 Ogata's statistical models for earthquake occurrences and residual analysis for point processes. [source](https://doi.org/10.1080/01621459.1988.10478560) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Land-surface model The exchange of water, heat and carbon dioxide between soil, plants and air, written as a surface component for atmosphere and climate models. Question it answers: How do plants and soil control the heat and water moving between ground and air? Leaves out: Vegetation is described by a few parameters per cell, and water movement in soil is highly simplified. Runs on: about 10^12 FLOPS rough a one-dimensional column per grid cell inside climate models. Since: 1986 Sellers, Mintz, Sud and Dalcher's simple biosphere model for use within general circulation models. [source](https://doi.org/10.1175/1520-0469%281986%29043<0505:asbmfu>2.0.co;2) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Coupled fire and atmosphere models A fire front and the wind it creates are solved together, so heat from the fire pulls air in, changes the flow and in turn alters how the fire spreads and throws embers and smoke. Question it answers: How does a fire reshape the wind that drives it? Leaves out: Combustion and fuel are represented by simple rate laws, so extreme behaviour such as crown fires and spotting is only roughly captured. Runs on: about 10^14 FLOPS rough days on a cluster for one large fire at tens-of-metres resolution. Since: 1996 Clark, Jenkins and Coen's coupled atmosphere-fire model of fire-line dynamics. [source](https://doi.org/10.1175/1520-0450%281996%29035%3C0875:ACAMCF%3E2.0.CO;2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields [◂ Astronomy and cosmology](https://simulation-hypothesis.com/simulations/astronomy-cosmology)[Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials) --- title: "Chemistry and materials · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/chemistry-materials description: "Electrons, bonds, liquids, crystals and fracture: the behaviour of matter before it is synthesised. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 4 of 18 # Chemistry and materials Electrons, bonds, liquids, crystals and fracture: the behaviour of matter before it is synthesised. Materials and reactions can be simulated before they are made: electrons for chemistry, atoms for mechanics, grains for microstructure. Computational chemistry is one of the largest consumers of supercomputer time. ## Electrons and bonds ### Electronic structure The electrons of a molecule or crystal, solved from quantum mechanics to get shapes, energies and colours. Question it answers: Is this molecule stable, and what colour is it? Leaves out: The exact quantum many-electron problem is unsolvable, so every method leans on an approximation somewhere. Runs on: about 10^15 FLOPS rough a university cluster, hours to days per molecule or crystal. Since: 1953 early Hartree-Fock calculations run on some of the first computers. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Reaction dynamics Bonds breaking and forming during a chemical reaction, often with the reacting core treated quantum mechanically and the surroundings classically. Question it answers: Which path does the reaction take, and how fast? Leaves out: The boundary between the quantum core and the classical surroundings is a modelling choice, not a real line. Runs on: about 10^15 FLOPS rough a university cluster, days per reaction studied. Since: 1976 Warshel and Levitt's first combined quantum and classical reaction model. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Computational materials screening Thousands of candidate compounds calculated automatically, sometimes with learned shortcuts, to find ones with useful properties. Question it answers: Which of these ten thousand candidates would make a better battery or solar cell? Leaves out: Filters candidates by easy-to-compute properties, which are not always those that matter for making the material. Runs on: about 10^16 FLOPS rough a large cluster, running thousands of calculations in parallel. Since: 2006 early high-throughput calculations screening candidate materials. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Atoms ### Excited states and photochemistry A molecule after it absorbs a photon, computed as it relaxes, twists or breaks apart on a different energy surface than its ground state. Question it answers: What does this molecule do in the instant after it absorbs light? Leaves out: Excited-state methods are less reliable than ground-state ones, and the cheapest ones can get it entirely wrong. Runs on: about 10^15 FLOPS rough a university cluster, hours to days per molecule. Since: 1984 early time-dependent quantum chemistry calculations of excited molecules. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Spectroscopy prediction A molecule's nuclei and electrons computed to predict where its magnetic resonance, infrared or other spectral lines will fall, checked against a measured spectrum. Question it answers: Does this computed spectrum match what the instrument actually recorded, confirming the structure? Leaves out: Gets noticeably worse for the heavier atoms and more flexible molecules that matter most in practice. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per molecule. Since: 1974 early computed nuclear magnetic resonance shifts compared against measured spectra. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Solvation free energy A molecule's electrons recomputed as if sitting inside a continuous approximation of a solvent, to get how much energy dissolving it costs or releases. Question it answers: How readily will this molecule dissolve, and does the solvent change how it reacts? Leaves out: Replaces the solvent with a smooth average field, omitting specific interactions such as a hydrogen bond to an individual water molecule at a critical site. Runs on: about 10^14 FLOPS rough a workstation or small cluster, minutes to hours per molecule. Since: 1981 early continuum solvation models added to quantum chemistry calculations. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Machine-learned interatomic potentials A neural network is fit to electronic-structure energies and then drives molecular dynamics with near-quantum accuracy at classical cost. Question it answers: Can quantum-level forces be had for millions of atoms over nanoseconds? Leaves out: Accuracy is limited to the chemistries and geometries in the training set. Runs on: about 10^17 FLOPS rough Training on thousands of quantum calculations, then large MD Since: 2007 Generalized neural-network representation of high-dimensional potential-energy surfaces (2007) [source](https://doi.org/10.1103/PhysRevLett.98.146401) In the simulations tree: [Learned surrogate models](https://simulation-hypothesis.com/trees/simulations?n=m-learned) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Universal interatomic potentials A single graph neural network trained on a large materials database predicts energies and forces for most of the periodic table. Question it answers: Can one learned model replace a separate fitted potential for each material? Leaves out: Accuracy varies by element and often softens the potential-energy surface. Runs on: about 10^17 FLOPS rough Training on millions of structures, cheap inference Since: 2022 A universal graph deep learning interatomic potential for the periodic table (2022) [source](https://arxiv.org/abs/2202.02450) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Atoms ### Quantum chemistry on quantum computers A variational quantum algorithm prepares and measures a molecule's electronic state on a real device, with a classical optimiser tuning the circuit. Question it answers: Can a quantum processor find the ground-state energy of a small molecule? Leaves out: Only very small molecules so far, with noise dominating the error. Runs on: no computer. Quantum hardware; classical checks small Since: 2014 A variational eigenvalue solver on a photonic quantum processor (2014) [source](https://doi.org/10.1038/ncomms5213) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Molecules ### Ab initio molecular dynamics Atoms moving in time with the forces recomputed from the electrons at every step, so bonds break and form without a pre-set force field. Question it answers: How do atoms move and bond when their forces come directly from quantum mechanics? Leaves out: Only hundreds of atoms for picoseconds can be followed, and density-functional errors enter every force. Runs on: about 10^16 FLOPS rough hundreds of atoms for tens of picoseconds on a large allocation. Since: 1985 Car and Parrinello's unified approach for molecular dynamics and density-functional theory. [source](https://doi.org/10.1103/physrevlett.55.2471) In the simulations tree: [Ab initio molecular dynamics](https://simulation-hypothesis.com/trees/simulations?n=mat-abinitio) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Path-integral molecular dynamics Atomic nuclei treated as quantum objects by representing each as a ring of linked copies, so tunnelling and zero-point motion shift hydrogen bonds and diffusion. Question it answers: How much do the quantum effects of hydrogen change the behaviour of water and ice? Leaves out: Real-time quantum behaviour is not recovered, only equilibrium and approximate dynamical properties. Runs on: about 10^15 FLOPS rough tens of copies per atom multiply the cost of classical dynamics. Since: 1984 Parrinello and Rahman's path-integral simulation of an electron trapped in molten salt. [source](https://doi.org/10.1063/1.446740) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Real-time electron dynamics The electron cloud of a molecule or crystal followed in time as a light pulse hits it, to find absorption spectra and ultrafast response. Question it answers: How do electrons respond in the first femtoseconds after light arrives? Leaves out: The approximate exchange-correlation functional misses some excitations, and ions are usually frozen. Runs on: about 10^16 FLOPS rough a time-stepped density-functional run over many thousand steps. Since: 1996 Yabana and Bertsch's time-dependent local-density approximation in real time. [source](https://doi.org/10.1103/physrevb.54.4484) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Atoms ### Quantum wavepacket dynamics The nuclei of a small molecule treated as a quantum wave moving across the energy surface, to follow reaction, tunnelling and vibration exactly. Question it answers: How does a molecule vibrate and react when its nuclei obey quantum mechanics? Leaves out: Cost grows steeply with the number of atoms, so only small molecules are tractable. Runs on: about 10^13 FLOPS rough multiconfigurational propagation for tens of degrees of freedom. Since: 1990 Meyer, Manthe and Cederbaum's multiconfigurational time-dependent Hartree approach. [source](https://doi.org/10.1016/0009-2614%2890%2987014-i) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Molecules ### Transition-state and reaction-path search The lowest-energy route between two arrangements of atoms found by relaxing a chain of intermediate images, to get reaction barriers and rates. Question it answers: What barrier must atoms cross when a molecule or defect changes shape? Leaves out: It finds routes that exist near the guess and can miss the true lowest barrier. Runs on: about 10^14 FLOPS rough each image needs an electronic-structure calculation, repeated across the chain. Since: 1998 Jonsson, Mills and Jacobsen's nudged elastic band method for minimum energy paths. [source](https://doi.org/10.1142/9789812839664%5F0016) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Atoms ### Automated reaction-mechanism generation Rules generate every reaction a set of molecules could undergo, then a rate model prunes them to a mechanism for combustion or pyrolysis. Question it answers: Which reactions matter when a fuel burns or breaks down? Leaves out: Rate coefficients are estimated from group rules, and uncommon pathways are sparsely tested. Runs on: about 10^8 FLOPS rough network growth over thousands of species, plus kinetic runs. Since: 1994 Broadbelt, Stark and Klein's computer generated pyrolysis modelling with on-the-fly species and reaction generation. [source](https://doi.org/10.1021/ie00028a003) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Quantum Monte Carlo for electrons Random walkers sample the many-electron wavefunction directly, giving near-exact energies of molecules and solids without the density-functional approximation. Question it answers: What is the accurate energy of this electron system, as a benchmark for cheaper methods? Leaves out: The fermion sign problem is avoided by fixing the nodes of the wavefunction, which makes the answer depend on that guess. Runs on: about 10^17 FLOPS rough millions of core-hours for a molecular crystal. Since: 1980 Ceperley and Alder's stochastic calculation of the ground state of the electron gas. [source](https://doi.org/10.1103/physrevlett.45.566) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Learned density functionals A machine-learning model maps the electron density to the energy, replacing the hand-built approximations in density-functional theory. Question it answers: Can a fitted functional beat the hand-designed ones that chemists have used for decades? Leaves out: The fitted functional is reliable only for the kinds of molecules and conditions represented in its training data. Runs on: about 10^16 FLOPS rough training on high-accuracy reference energies, then a standard-cost electronic-structure run. Since: 2012 Snyder, Rupp, Hansen, Müller and Burke's machine-learned density functionals for a model system. [source](https://doi.org/10.1103/physrevlett.108.253002) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Neural-network wavefunctions for molecules A neural network is used as the many-electron wavefunction of a molecule and trained by variational Monte Carlo to reach near-exact energies. Question it answers: How accurately can a learned wavefunction describe the electrons of a small molecule? Leaves out: Cost climbs steeply with the number of electrons, so only small molecules have been reached. Runs on: about 10^18 FLOPS rough days on tens of GPUs for one molecule. Since: 2019 Pfau and colleagues' FermiNet, a deep neural network solution of the many-electron Schrödinger equation. [source](https://arxiv.org/abs/1909.02487) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ## Molecules in motion ### Liquids and solutions Water and other liquids as millions of interacting molecules, with solutes dissolved in them. Question it answers: Why does water show anomalous properties, and how does salt dissolve? Leaves out: The force field between atoms is fitted to a small set of properties and is not guaranteed to reproduce the rest. Runs on: about 10^14 FLOPS rough a desktop GPU; billions of molecule-steps per second. Since: 1964 Rahman’s molecular dynamics of liquid argon; water followed with Rahman and Stillinger in 1971 [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ### Polymers and soft matter Long-chain molecules, gels, foams and liquid crystals, usually coarse-grained into beads. Question it answers: How does a plastic stretch, and how does a gel set? Leaves out: Coarse-graining throws away the fast atomic motion, so the timing of some processes is only approximate. Runs on: about 10^14 FLOPS rough a desktop GPU or small cluster, hours per system. Since: 1962 Verdier and Stockmayer's early lattice Monte Carlo model of a polymer chain. [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Combustion Flames as fluid flow coupled to hundreds of chemical reactions. Question it answers: How do we burn fuel cleaner, or stop an engine knocking? Leaves out: Hundreds of real reactions are simplified to the dozens a computer can afford to track each step. Runs on: about 10^16 FLOPS rough a large cluster, days for a full engine cycle. Since: 1955 early numerical solutions of the laminar flame equations. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Colloids and nanoparticle assembly Thousands of nanoparticles or colloidal grains driven by thermal fluctuations of the surrounding fluid, adhering, ordering or aggregating as they collide. Question it answers: Will these particles self-assemble into an ordered structure, or aggregate disordered? Leaves out: The details of a particle's surface coating strongly affect the outcome and are usually reduced to a single adhesion parameter. Runs on: about 10^13 FLOPS rough a workstation or desktop GPU, hours per assembly run. Since: 1986 early Brownian dynamics simulations of colloidal particles in suspension. [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Glass formation A liquid cooled so fast in simulation that its molecules jam into a disordered solid before they can crystallise. Question it answers: Why does this liquid freeze into a disordered glass instead of an ordered crystal? Leaves out: Simulated cooling is always far faster than any real glass has ever been cooled, by many orders of magnitude. Runs on: about 10^14 FLOPS rough a desktop GPU or small cluster, hours to days per run. Since: 1976 early molecular dynamics simulations of a liquid quenched into a glass. [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ### Molten salts and ionic liquids Ions rather than neutral molecules, interacting through strong Coulomb forces in a liquid with no solvent at all. Question it answers: How well does this liquid conduct charge, and how do its ions move? Leaves out: The strong electrostatic forces between ions are harder to capture in a force field than those of neutral molecules and are often only approximated. Runs on: about 10^14 FLOPS rough a desktop GPU or small cluster, hours per liquid studied. Since: 1983 early molecular dynamics simulations of a molten salt. [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ### Reactive force-field dynamics Molecular dynamics with bond-order potentials that let bonds form and break during the run, at far lower cost than quantum methods. Question it answers: How do bonds break and form in thousands of atoms over nanoseconds? Leaves out: Parameters are fitted per chemistry, and electrons are not treated explicitly. Runs on: about 10^16 FLOPS rough Millions of atoms for nanoseconds Since: 2001 ReaxFF: a reactive force field for hydrocarbons (2001) [source](https://doi.org/10.1021/jp004368u) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Metadynamics and enhanced sampling Molecular dynamics in which a history-dependent bias pushes the system out of local minima to map rare events and free-energy surfaces. Question it answers: How high are the barriers between states that plain dynamics never crosses? Leaves out: The result depends on picking good collective variables. Runs on: about 10^17 FLOPS rough Many biased trajectories on a few chosen variables Since: 2002 Escaping free-energy minima (2002) [source](https://doi.org/10.1073/pnas.202427399) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Learned equilibrium samplers A generative network is trained to draw independent molecular configurations from the Boltzmann distribution, avoiding long trajectories. Question it answers: Can rare states of a molecule be sampled directly instead of waiting for them? Leaves out: Dynamics and kinetics are lost, and training is hard for large systems. Runs on: about 10^16 FLOPS rough Training plus reweighting Since: 2018 Boltzmann Generators: sampling equilibrium states of many-body systems with deep learning (2018) [source](https://arxiv.org/abs/1812.01729) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ### Kinetic Monte Carlo Atoms hopping on a surface or in a crystal chosen at random with probabilities set by their rates, so processes that take seconds or hours are reached. Question it answers: How does a surface or crystal change over the long times between atomic jumps? Leaves out: Every possible event and its rate must be listed in advance, so surprising mechanisms are missed. Runs on: about 10^11 FLOPS rough millions of events, with rates computed beforehand from first principles. Since: 1975 Bortz, Kalos and Lebowitz's event-driven Monte Carlo algorithm for Ising spin systems. [source](https://doi.org/10.1016/0021-9991%2875%2990060-1) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Atoms ### Coarse-grained molecular dynamics Groups of several atoms merged into single beads so membranes, polymers and self-assembling lipids can be followed for microseconds over larger boxes. Question it answers: How do large molecular assemblies form over microseconds? Leaves out: Merging atoms discards detail such as hydrogen-bond directionality, and time is not strictly physical. Runs on: about 10^16 FLOPS rough millions of beads over microseconds. Since: 2007 Marrink and colleagues' coarse-grained force field for biomolecular simulations. [source](https://doi.org/10.1021/jp071097f) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Molecules ### Dissipative particle dynamics Soft beads that stand for clumps of fluid interact with friction and random kicks, giving correct hydrodynamics for polymers and colloids at large scales. Question it answers: How do polymer and surfactant fluids flow and self-organise at mesoscopic scales? Leaves out: Soft potentials allow chains to cross unphysically unless corrected. Runs on: about 10^14 FLOPS rough millions of beads over long times. Since: 1992 Hoogerbrugge and Koelman's simulation of microscopic hydrodynamic phenomena with dissipative particle dynamics. [source](https://doi.org/10.1209/0295-5075/19/3/001) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Molecules ### Enhanced-sampling free-energy methods Simulations nudged to cross high barriers, such as adding history-dependent bias, so rare events and free-energy landscapes can be computed. Question it answers: What is the free-energy cost of a rare change, such as nucleation or binding? Leaves out: The answer depends on the choice of collective variables, and a missing one gives a wrong landscape. Runs on: about 10^16 FLOPS rough long biased runs along chosen variables. Since: 2002 Laio and Parrinello's escaping free-energy minima by metadynamics. [source](https://doi.org/10.1073/pnas.202427399) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Adsorption in porous materials Gas molecules inserted and removed at random in a model of a porous solid, to predict how much a zeolite or framework material will adsorb. Question it answers: How much gas does a porous material hold at a given pressure? Leaves out: Rigid-framework and fixed-charge approximations misjudge flexible materials. Runs on: about 10^13 FLOPS rough millions of insertions per state point, thousands of structures. Since: 1975 Adams's grand canonical ensemble Monte Carlo for a Lennard-Jones fluid. [source](https://doi.org/10.1080/00268977500100221) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Polymer self-consistent field theory Chains replaced by a density field that feels its own average pull, so block copolymers and blends can be solved for their ordered patterns without tracking individual chains. Question it answers: What pattern will a block copolymer self-assemble into? Leaves out: Mean-field theory ignores fluctuations, which matter near phase boundaries. Runs on: about 10^12 FLOPS rough solving diffusion equations on a grid in three dimensions. Since: 1965 Edwards's statistical mechanics of polymers with excluded volume. [source](https://doi.org/10.1088/0370-1328/85/4/301) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Chain-growth Monte Carlo for polymers Long molecular chains built one bond at a time with weights, to measure their size, entropy and excluded-volume behaviour. Question it answers: How big is a long flexible chain, and why does it not cross itself? Leaves out: Weights grow unevenly with chain length, so very long ones need resampling tricks. Runs on: about 10^9 FLOPS rough millions of chains, far cheaper than dynamics. Since: 1955 Rosenbluth and Rosenbluth's Monte Carlo calculation of the average extension of molecular chains. [source](https://doi.org/10.1063/1.1741967) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ## Solids ### Magnetism and phase transitions Spins on a lattice flipping at random, the classic Ising model and its descendants, used to study how order appears at a critical temperature. Question it answers: Why does a magnet lose its magnetism at exactly one temperature? Leaves out: A real magnet has details of shape and impurity that the idealised lattice omits by construction. Runs on: about 10^12 FLOPS rough a laptop; billions of spin flips per second. Since: 1953 the Metropolis accept–reject Monte Carlo method, later the standard tool for spin models; the 1953 paper itself simulated hard disks [source](https://zhanggroup.org/teaching/literature/Metropolis1953.pdf) In the simulations tree: [Metropolis algorithm](https://simulation-hypothesis.com/trees/simulations?n=m-mcmc) [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-ising) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Fracture and defects Atoms at the tip of a crack, and the defects that let metals bend instead of shattering. Question it answers: Why does this material crack instead of bending? Leaves out: A crack tip only a few atoms wide still has to stand in for one that runs through a whole beam. Runs on: about 10^14 FLOPS rough a desktop GPU or small cluster, hours per crack run. Since: 1976 Ashurst and Hoover's early molecular dynamics simulation of a crack tip. [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Microstructure Crystal grains forming and growing as a metal solidifies or is heat-treated, often with the phase-field method. Question it answers: Which heat treatment gives the strongest alloy? Leaves out: Grain boundaries are treated as smooth mathematical surfaces, not the messy defects they really are. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per solidifying alloy. Since: 1991 Chen and Khachaturyan's early phase-field model of a growing microstructure. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Granular materials Sand, grain, powders and pills as millions of individual particles colliding and jamming. Question it answers: Why does the silo jam, and how does an avalanche start? Leaves out: Real grains are rough and irregular; simulated ones are almost always idealised spheres. Runs on: about 10^14 FLOPS rough a desktop GPU or small cluster, millions of grains at once. Since: 1979 Cundall and Strack's first discrete element model of granular particles. [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-sand) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Dislocation dynamics Line defects threading through a crystal's lattice, tracked as they move, multiply and tangle to produce permanent bending or stretching. Question it answers: Why does this metal bend rather than snap, and how strong is it really? Leaves out: Treats dislocations as clean lines in an otherwise perfect crystal, when real metals are full of other defects they interact with. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours to days per run. Since: 1990 early discrete dislocation dynamics simulations of crystal plasticity. [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Atoms ### Thin film growth Atoms arriving one by one on a surface and sticking, hopping or burying each other as a film builds up layer by layer. Question it answers: Will this film grow smooth, or rough and full of defects? Leaves out: Real deposition chambers have contamination and uneven flow that an idealised flux of atoms does not include. Runs on: about 10^13 FLOPS rough a workstation; hours per simulated film. Since: 1966 early kinetic Monte Carlo models of atoms arriving on a growing surface. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Radiation-damage cascades in materials A fast atom knocked into a crystal, followed as it displaces neighbours and leaves vacancies, to predict how irradiated metals degrade. Question it answers: How many atoms does a single impact knock out of a crystal? Leaves out: Defects then evolve for years, far beyond the cascade, and need other methods to bridge the gap. Runs on: about 10^13 FLOPS rough millions of atoms for tens of picoseconds, repeated for many impact directions. Since: 1960 Gibson, Goland, Milgram and Vineyard's dynamics of radiation damage in a copper lattice. [source](https://doi.org/10.1103/physrev.120.1229) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Atoms ### Alloy cluster expansion The energy of an alloy written as a sum over small clusters of neighbouring atoms, so the order and phase diagram can be sampled with Monte Carlo. Question it answers: Which arrangements of atoms does an alloy prefer, and when does it order? Leaves out: The expansion is fixed to a given lattice and can miss vibrational and magnetic contributions. Runs on: about 10^12 FLOPS rough hundreds of first-principles energies, then cheap lattice Monte Carlo. Since: 1984 Sanchez, Ducastelle and Gratias's generalised cluster description of multicomponent systems. [source](https://doi.org/10.1016/0378-4371%2884%2990096-7) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)floor: Atoms ### Crystal plasticity finite-element modelling Metal grains deforming by slip on specific crystal planes, with their individual orientations, to predict strength, texture and forming behaviour. Question it answers: How do crystal orientations decide how a metal bends and hardens? Leaves out: Hardening laws are fitted to tests and carry no memory of individual dislocations. Runs on: about 10^12 FLOPS rough finite-element models of thousands of grains. Since: 1982 Peirce, Asaro and Needleman's analysis of nonuniform and localised deformation in ductile single crystals. [source](https://doi.org/10.1016/0001-6160%2882%2990005-0) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Micromagnetic simulation The direction of magnetisation in a magnet, discretised into cells, with exchange, anisotropy and stray fields, to follow how domains form and switch. Question it answers: How does the magnetisation of a nanomagnet switch? Leaves out: Temperature is treated crudely, and cells larger than the exchange length lose detail. Runs on: about 10^12 FLOPS rough finite-difference runs with millions of cells. Since: 1988 Schabes and Bertram's three-dimensional micromagnetic study of magnetisation processes in ferromagnetic cubes. [source](https://doi.org/10.1063/1.341858) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Organic semiconductor charge transport Electrons or holes hopping between disordered molecules, simulated with random walks to predict mobility in plastic electronics. Question it answers: How fast do charges move through a disordered organic material? Leaves out: Hop rates are assumed forms and the morphology is idealised. Runs on: about 10^11 FLOPS rough Monte Carlo hops on large lattices. Since: 1993 Bassler's Monte Carlo simulation of charge transport in disordered organic photoconductors. [source](https://doi.org/10.1002/pssb.2221750102) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Molecules ### Lattice thermal-conductivity calculation Heat carried by lattice vibrations, with their scattering rates from first principles, to predict thermal conductivity of a crystal without fitting. Question it answers: How well does a crystal carry heat, from atoms alone? Leaves out: Strongly anharmonic and disordered materials need extra treatment. Runs on: about 10^15 FLOPS rough thousands of force calculations in a supercell. Since: 2007 Broido, Malorny, Birner, Mingo and Stewart's intrinsic lattice thermal conductivity of semiconductors from first principles. [source](https://doi.org/10.1063/1.2822891) [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Atoms ### Diffusion-limited aggregation Particles wandering at random until they stick to a growing cluster, producing branching fractals like dendrites and mineral deposits. Question it answers: Why do random walkers grow branching fractal clusters? Leaves out: It models only one idealised growth rule, with no surface energy or chemistry. Runs on: about 10^8 FLOPS rough millions of walkers on a lattice. Since: 1981 Witten and Sander's diffusion-limited aggregation, a kinetic critical phenomenon. [source](https://doi.org/10.1103/physrevlett.47.1400) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Generative models of crystals A diffusion or variational model trained on known crystals proposes new periodic structures, which are then checked and relaxed with quantum-mechanical calculations. Question it answers: Can a model dream up stable new materials rather than screening known ones? Leaves out: Most proposed structures are unstable or unmakeable, and the model does not know how to synthesise any of them. Runs on: about 10^18 FLOPS rough weeks of GPU training, then a pipeline of electronic-structure checks. Since: 2021 Xie and colleagues' crystal diffusion variational autoencoder for periodic material generation. [source](https://arxiv.org/abs/2110.06197) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ## Reactions, catalysis and electrochemistry ### Catalysis A reacting molecule sticking to a catalyst's surface, computed step by step to find the path that lowers the energy needed for the reaction. Question it answers: Which surface, and which arrangement of atoms on it, speeds up this reaction the most? Leaves out: Real catalysts have defects, poisons and ageing that a clean, perfect model surface never has to deal with. Runs on: about 10^15 FLOPS rough a university cluster, days per candidate catalyst surface. Since: 1995 early quantum calculations mapping a reaction path across a catalyst surface. [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Battery and electrochemical cell modelling A whole battery or fuel cell, its electrodes, electrolyte and interfaces, modelled together through charge, discharge and heating over many cycles. Question it answers: How many cycles will this cell survive before it degrades, and how hot will it get? Leaves out: Degradation over years of real use is still mostly extrapolated from short accelerated tests, not directly simulated. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per simulated cycling test. Since: 1975 early mathematical models of a battery electrode's charge and discharge. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Corrosion A metal surface losing atoms to an electrochemical reaction with its environment, tracked as it pits, thins or forms a protective layer. Question it answers: How long will this metal last before it corrodes through? Leaves out: Real corrosion depends strongly on local contamination, surface scratches and stray currents that an ideal model omits. Runs on: about 10^13 FLOPS rough a workstation; hours per corrosion scenario. Since: 1970 early computer models of pitting and electrochemical corrosion. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Crystallisation Molecules or ions in a supersaturated solution finding each other and locking into a growing crystal lattice, used to predict how a compound will crystallise. Question it answers: What shape and size of crystals will this process actually produce? Leaves out: Nucleation, the very first cluster forming, happens on a scale and speed still too fast to observe or fully compute directly. Runs on: about 10^13 FLOPS rough a workstation or small cluster, hours per batch simulated. Since: 1988 early computed models of nucleation and growth from a supersaturated solution. [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Molecules ### Chemical reactor engineering Fluid flow, mixing, heat and hundreds of reaction steps inside an industrial vessel, modelled together to predict how much product comes out. Question it answers: Will this reactor design mix and cool fast enough to get a clean, safe reaction? Leaves out: Scaling up from a small test reactor to a full industrial one still loses accuracy in ways engineers correct for by experience. Runs on: about 10^15 FLOPS rough a university or industrial cluster, days per design studied. Since: 1970 early computational fluid dynamics models of an industrial chemical reactor. [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Polymerisation kinetics Small molecules linking up one reaction step at a time into long chains, tracked to predict how long they grow and how uniform they end up. Question it answers: How long will the polymer chains be, and how much will that vary? Leaves out: Side reactions that branch or terminate chains early are usually simplified into a few average rates. Runs on: about 10^12 FLOPS rough a laptop; a full batch simulation takes minutes. Since: 1968 early computed kinetic models of a chain-growth polymerisation. [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Fuel-cell membrane and transport modelling Water, protons and gas moving through the membrane and electrodes of a fuel cell, to predict performance and when it dries out or floods. Question it answers: How do water and charge move through a fuel cell membrane? Leaves out: Membrane transport relies on fitted laws, and liquid water in pores is hard to model. Runs on: about 10^10 FLOPS rough two- or three-dimensional cell models, light on a workstation. Since: 1991 Springer, Zawodzinski and Gottesfeld's polymer electrolyte fuel cell model. [source](https://doi.org/10.1149/1.2085971) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Pore-network modelling A porous rock or electrode reduced to a network of pores and throats, through which fluid invades step by step, to predict flow and capillary behaviour. Question it answers: How does fluid fill and move through a porous material? Leaves out: Real pore shapes are simplified to tubes and spheres. Runs on: about 10^10 FLOPS rough networks of up to millions of pores, cheap compared with direct flow. Since: 1956 Fatt's network model of porous media. [source](https://doi.org/10.2118/574-g) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields [◂ Earth and climate](https://simulation-hypothesis.com/simulations/earth-climate)[Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine) --- title: "Life and medicine · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/life-medicine description: "Proteins, cells, organs, patients and epidemics: biology from the molecular scale to the population. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 5 of 18 # Life and medicine Proteins, cells, organs, patients and epidemics: biology from the molecular scale to the population. Biology is simulated at every level of organisation: atoms in a protein, reactions in a cell, cells in a tissue, organs in a body, bodies in a population. Each level uses a different method. Coupling the levels is still an open problem. ## Molecules of life ### Protein folding and dynamics A protein as tens of thousands of atoms, shaking, folding and changing shape in water. Question it answers: How does this chain of amino acids fold into a functional three-dimensional structure? Leaves out: Even long runs cover microseconds at most, far short of many real folding times. Runs on: about 10^16 FLOPS rough a GPU cluster running microseconds of all-atom dynamics Since: 1977 McCammon, Gelin and Karplus's first protein dynamics simulation In the simulations tree: [Protein dynamics](https://simulation-hypothesis.com/trees/simulations?n=life-protein) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Molecular docking and drug binding Candidate drug molecules tried in the pocket of a target protein. Question it answers: Which of a million molecules will stick to this target? Leaves out: Docking scores are approximate; most predicted binders never work in the lab. Runs on: about 10^15 FLOPS rough a university cluster docking millions of candidate molecules Since: 1982 Kuntz and colleagues' DOCK, the first automated molecular docking program [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Membranes and ion channels The fatty skin of a cell and the protein gates that let ions through it. Question it answers: How does a nerve cell open and close its channels? Leaves out: Real channels gate over milliseconds, far longer than most simulations reach. Runs on: about 10^16 FLOPS rough a GPU cluster simulating a lipid bilayer and its channels Since: 1982 van der Ploeg and Berendsen's dynamics of a lipid bilayer [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Whole virus particles Every atom of a virus shell, sometimes a hundred million of them, simulated at once. Question it answers: How does the virus hold together, and how does it come apart inside a cell? Leaves out: Runs cover nanoseconds to microseconds, far short of a real infection cycle. Runs on: about 10^17 FLOPS rough a national supercomputer simulating a hundred-million-atom shell Since: 2006 Freddolino and Schulten's simulation of a satellite tobacco mosaic virus [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### RNA folding and structure An RNA strand as a chain of bases pairing with itself, folding into a specific three-dimensional shape rather than the straight double helix of DNA. Question it answers: How does a strand of RNA settle into the shape that enables it to act as a catalyst or a regulatory switch? Leaves out: Predicted structures often need experimental correction, and function does not follow automatically from shape. Runs on: about 10^12 FLOPS rough a desktop workstation running free-energy folding software Since: 1981 Zuker and Stiegler's minimum-free-energy RNA folding algorithm [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Enzyme catalysis The active site of an enzyme, its substrate and the surrounding protein, modelled with quantum mechanics where bonds break and classical mechanics everywhere else. Question it answers: How does this enzyme speed up a reaction by a factor of a billion? Leaves out: Only a small part of the protein gets the expensive quantum treatment, and where to draw that line is a modelling choice. Runs on: about 10^15 FLOPS rough a university cluster running combined quantum and classical calculations Since: 1976 Warshel and Levitt's combined quantum and classical model of an enzyme reaction [First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)[Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Atoms ### Coarse-grained DNA and RNA models Each nucleotide is a rigid body with a few interaction sites, allowing simulation of folding, hybridisation and nanostructures. Question it answers: How do strands pair, fold and assemble into designed structures? Leaves out: Atomic detail and ions are replaced by effective interactions. Runs on: about 10^14 FLOPS rough Millions of nucleotides on GPUs Since: 2011 oxDNA, a coarse-grained DNA model (2011) [source](https://doi.org/10.1063/1.3552946) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ### Learned protein structure prediction A neural network trained on known structures and evolutionary data predicts the folded shape of a protein from its sequence. Question it answers: What three-dimensional shape does this amino-acid chain fold into? Leaves out: It gives a static structure, not the folding pathway or dynamics. Runs on: about 10^18 FLOPS rough Training at large scale; minutes per prediction Since: 2018 Improved protein structure prediction using potentials from deep learning (2020, CASP13 entry 2018) [source](https://doi.org/10.1038/s41586-019-1923-7) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Molecules ### Generative protein ensembles A generative model trained on structures and simulations produces many conformations of a protein rather than a single shape. Question it answers: Which alternative shapes can a protein adopt? Leaves out: Populations of states are only as good as the training simulations. Runs on: about 10^16 FLOPS rough Training plus cheap sampling Since: 2024 AlphaFold meets flow matching for generating protein ensembles (2024) [source](https://arxiv.org/abs/2402.04845) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Molecules ### Volunteer-computed molecular dynamics Thousands of independent short trajectories of one molecule run on donated home computers and are combined to see folding events. Question it answers: Can many short runs together reveal a slow molecular process? Leaves out: Trajectories are short and independent, so statistics must be stitched together. Runs on: about 10^17 FLOPS rough Aggregate of volunteer machines Since: 2000 Screen savers of the world unite! (2000), the distributed folding project [source](https://doi.org/10.1126/science.290.5498.1903) [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)floor: Molecules ## Cells ### Stochastic biochemistry Reactions inside a cell fired one at a time at random, because there are too few molecules to average. Question it answers: Why do genetically identical cells behave differently? Leaves out: Usually assumes the cell's interior is well mixed, which often does not hold. Runs on: about 10^12 FLOPS rough a desktop workstation running a stochastic reaction simulation Since: 1977 Gillespie's exact stochastic simulation algorithm for chemical kinetics [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Molecules ### Gene regulatory networks Genes switching each other on and off, as a network of interactions. Question it answers: How does a cell decide what kind of cell to become? Leaves out: Most real regulatory networks are only partly known, so links are often inferred. Runs on: about 10^12 FLOPS rough a desktop workstation simulating a gene network's dynamics Since: 1969 Kauffman's random Boolean networks of gene regulation [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Metabolic networks Every chemical reaction a cell uses to turn food into energy and parts, balanced as a network of fluxes. Question it answers: Which gene should we switch off to make this microbe produce more of a useful compound? Leaves out: Assumes a steady state and an optimal objective a real cell may not pursue. Runs on: about 10^12 FLOPS rough a desktop workstation solving a genome-scale flux balance model Since: 1986 early flux balance analysis of a cell's metabolic network [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Molecules ### Whole-cell models Every gene and every class of molecule in a single bacterium, followed through one full division cycle. Question it answers: Can we predict a living cell from its parts list? Leaves out: Only one simple bacterium has ever been modelled this completely. Runs on: about 10^14 FLOPS rough a university cluster running one division cycle of a bacterium Since: 2012 Karr and colleagues' whole-cell model of Mycoplasma genitalium [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Molecules ### Pattern formation Chemicals diffusing and reacting across a growing tissue, the mechanism Alan Turing proposed for stripes and spots. Question it answers: How do reaction-diffusion mechanisms account for animal coat patterns and for digit formation in a limb? Leaves out: Real tissues use mechanical forces and more signals than a two-chemical model. Runs on: about 10^12 FLOPS rough a desktop workstation solving reaction-diffusion equations on a grid Since: 1952 Turing's reaction-diffusion computations for The Chemical Basis of Morphogenesis In the simulations tree: [Turing’s reaction-diffusion](https://simulation-hypothesis.com/trees/simulations?n=life-turing) [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-patterns) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Cells ### Tissue and tumour growth Individual cells dividing, moving, competing for oxygen and dying. Question it answers: How does a tumour grow, and how might a treatment schedule stop it? Leaves out: Division and death rates inside a real tumour are hard to measure directly. Runs on: about 10^13 FLOPS rough a university cluster tracking thousands of individual dividing cells Since: 1993 early cellular automaton models of solid tumour growth [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Cells ### Cell perturbation-response models A model trained on single-cell data predicts how a cell's gene expression changes after a drug or gene edit it was not measured with. Question it answers: What will a cell do after an intervention nobody has yet tried? Leaves out: Correlational; it extrapolates poorly to cell types or drugs far from training data. Runs on: about 10^16 FLOPS rough Large single-cell training sets Since: 2019 scGen predicts single-cell perturbation responses (2019) [source](https://doi.org/10.1038/s41592-019-0494-8) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Cells ### Tumour evolution agent-based models Individual cancer cells on a grid divide, mutate and compete in a changing microenvironment of oxygen and acid. Question it answers: How do tumour shape and aggressive traits emerge from selection pressure? Leaves out: Rules are simplified, and blood supply and immune cells are often absent. Runs on: about 10^11 FLOPS rough Millions of cells on one node Since: 2006 Tumor morphology and phenotypic evolution driven by selective pressure from the microenvironment (2006) [source](https://doi.org/10.1016/j.cell.2006.09.042) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Cells ### Microbial community metabolic models Genome-scale metabolic networks of several species are joined so that waste from one becomes food for another. Question it answers: How do gut or soil microbes share nutrients and stabilise together? Leaves out: Assumes steady state and optimal growth, ignoring regulation and space. Runs on: about 10^11 FLOPS rough Linear programming across many species Since: 2007 Metabolic modeling of a mutualistic microbial community (2007) [source](https://doi.org/10.1038/msb4100131) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ### Tumour growth and therapy response A solid tumour treated as a mass fed by diffusing oxygen and nutrient, with a growing proliferating rim and a starved necrotic core, then exposed to radiation or drugs. Question it answers: How fast does a tumour grow, and how much does a given dose shrink it? Leaves out: Real tumours vary between patients and within themselves. The model uses averaged parameters and a simplified geometry. Runs on: about 10^12 FLOPS rough a three-dimensional reaction-diffusion model with treatment schedules over weeks of simulated time. Since: 1972 Greenspan, models for the growth of a solid tumour by diffusion. [source](https://doi.org/10.1002/sapm1972514317) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Tumour microenvironment evolution Individual cancer cells on a grid compete for oxygen and space while gradients of acidity select for new phenotypes, so the tumour evolves as it grows. Question it answers: Does the surrounding tissue push a tumour towards more invasive cells? Leaves out: Cell rules are simplified and parameters are hard to measure in living tumours. Runs on: about 10^12 FLOPS rough hybrid agent-continuum runs over simulated months on a workstation or small cluster. Since: 2006 Anderson and colleagues, hybrid discrete-continuum model of microenvironment-driven phenotypic evolution. [source](https://doi.org/10.1016/j.cell.2006.09.042) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Cells ### Tumour-induced blood vessel growth Endothelial cells sprout and migrate up a chemical gradient released by a tumour, forming a branching vessel network that feeds it. Question it answers: How does a tumour recruit a blood supply, and what happens if the signal is blocked? Leaves out: Vessel flow, remodelling and the real chemistry of signalling are heavily simplified. Runs on: about 10^11 FLOPS rough two- or three-dimensional sprouting runs on a workstation. Since: 1998 Anderson and Chaplain, continuous and discrete models of tumour-induced angiogenesis. [source](https://doi.org/10.1006/bulm.1998.0042) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Cells ### Cancer drug response and resistance dynamics Populations of normal, sensitive and resistant cancer cells change under drug therapy, so a patient first improves and then may relapse. Question it answers: How long will a drug control the disease before resistance appears? Leaves out: Only the compartments that can be measured are modelled, and stem-cell behaviour is inferred. Runs on: about 10^8 FLOPS rough ordinary differential equations fitted to patient blood measurements. Since: 2005 Michor and colleagues, dynamics of chronic myeloid leukaemia. [source](https://doi.org/10.1038/nature03669) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Cells ### Blood cell production dynamics Stem cells, progenitors and mature blood cells are linked by feedback with delays, producing stable counts or oscillations when the control fails. Question it answers: Why do some blood disorders cycle, and what restores normal production? Leaves out: Real marrow has spatial structure and many cell types that are lumped. Runs on: about 10^6 FLOPS rough delay differential equations on a laptop. Since: 1978 Mackey, a unified hypothesis for aplastic anaemia and periodic haematopoiesis. [source](https://doi.org/10.1182/blood.v51.5.941.941) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Bacterial colony growth and biofilms Each bacterial cell is simulated as an individual with its own size, growth and position, feeding on diffusing nutrient inside a colony or biofilm. Question it answers: How do colonies take their shape and how do cells on the inside survive? Leaves out: Cell behaviour is simplified and the chemistry of real biofilm matrix is not captured. Runs on: about 10^11 FLOPS rough individual-based growth of millions of cells on a cluster. Since: 1998 Kreft, Booth and Wimpenny, BacSim, a simulator for individual-based modelling of bacterial colony growth. [source](https://doi.org/10.1099/00221287-144-12-3275) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Cells ## Bodies ### The heart Electrical waves across heart muscle and the squeeze and blood flow they drive. Question it answers: Will this drug or this device make an irregular heartbeat worse? Leaves out: Individual variation between real hearts is still hard to capture in one model. Runs on: about 10^16 FLOPS rough a university cluster running one beat of whole-heart electromechanics Since: 1960 Noble’s computer model of the action potential of a single Purkinje fibre cell; models of the whole heart came later [source](https://www.nature.com/articles/188495b0) In the simulations tree: [Cardiac cell model](https://simulation-hypothesis.com/trees/simulations?n=life-noble) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Blood flow Blood moving through arteries, veins and devices like stents and valves. Question it answers: Where is this artery likely to weaken or clog? Leaves out: Vessel walls are often treated as rigid, which misses real elasticity. Runs on: about 10^15 FLOPS rough a university cluster running a patient-specific artery flow simulation Since: 1989 Perktold and colleagues' finite-element model of carotid artery flow [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Breathing and airways Air moving through the branching airways and the particles carried in it. Question it answers: Where do inhaled medicines, or pollutants, end up? Leaves out: Most models use one idealised airway tree rather than a specific person's. Runs on: about 10^14 FLOPS rough a university cluster simulating airflow through a branching airway tree Since: 1993 early fluid dynamics models of airflow in the bronchial tree [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Musculoskeletal biomechanics Bones, joints and muscles as a linked mechanical system, walking, lifting and falling. Question it answers: Which muscles take the strain, and how should this implant be shaped? Leaves out: Forces inside a real limb are estimated indirectly, not measured. Runs on: about 10^12 FLOPS rough a desktop workstation solving a musculoskeletal model of one movement Since: 1990 Delp and colleagues' computer models of musculoskeletal motion [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Immune response Immune cells and pathogens meeting, multiplying and signalling inside the body. Question it answers: Why do some infections clear and others become chronic? Leaves out: Real immune signalling is far more complex than any model tracks in full. Runs on: about 10^13 FLOPS rough a university cluster running an agent-based immune simulation Since: 1992 Celada and Seiden's cellular automaton model of the immune response [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Pharmacokinetics A drug absorbed, spread through the body’s compartments, broken down and cleared. Question it answers: What dose, how often, for someone of this age and weight? Leaves out: A population-average model can miss how one particular patient handles a drug. Runs on: about 10^10 FLOPS rough a desktop workstation solving a compartmental drug model Since: 1937 Teorell's two-compartment model of drug distribution [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### In silico clinical trials Populations of virtual patients with realistic variation, given a treatment before or alongside a real trial. Question it answers: Who is this treatment likely to help, and who could it harm? Leaves out: Regulators still require real trials alongside. Virtual patients can't fully replace them. Runs on: about 10^14 FLOPS rough a university cluster running thousands of virtual patients Since: 2011 by 2011, early in silico trials submitted alongside evidence for a device [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Cardiac digital twins Heart models fitted to one patient's scans and signals and used to predict how that heart responds to a therapy. Question it answers: How will this patient's heart respond to a particular treatment? Leaves out: Fit quality depends on imaging data, and tissue properties are inferred. Runs on: about 10^15 FLOPS rough Personalised electromechanical runs plus fitting Since: 2020 The 'Digital Twin' to enable the vision of precision cardiology (2020) [source](https://doi.org/10.1093/eurheartj/ehaa159) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Neural predictive models of sensory brain areas A neural network trained on recorded responses becomes a stand-in for a brain area, letting researchers test stimuli in silico that excite neurons most. Question it answers: Which stimulus drives a given neuron hardest? Leaves out: Predictions need verification on the real tissue and cover only the tested animals. Runs on: about 10^16 FLOPS rough Training on recordings, then unlimited virtual trials Since: 2019 Inception loops discover what excites neurons most using deep predictive models (2019) [source](https://doi.org/10.1038/s41593-019-0517-x) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Cells ### Brain-stimulation field models Finite-element head models trace how current from electrodes or coils spreads through scalp, skull and brain tissue. Question it answers: Where in the brain does the electric field from a stimulator land? Leaves out: Tissue conductivities are uncertain, and neural response is not simulated. Runs on: about 10^12 FLOPS rough Finite-element solves on individual head meshes Since: 2009 Gyri-precise head model of transcranial direct current stimulation (2009) [source](https://doi.org/10.1016/j.brs.2009.03.005) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Virtual-population drug exposure models Whole-body drug transport models run across a synthetic population that varies in age, genes and organ function. Question it answers: How much will drug levels differ across children, the elderly and patients with organ disease? Leaves out: Depends on measured enzyme and transporter data. Runs on: about 10^11 FLOPS rough Thousands of virtual subjects on a workstation Since: 2009 The Simcyp population-based ADME simulator (2009) [source](https://doi.org/10.1517/17425250802691074) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Gut microbiome community models Dozens of bacterial species in the intestine interact through competition and cross-feeding, with their abundances tracked over time under diet or antibiotic disturbance. Question it answers: Which species stay stable in a gut, and which disturbance can tip the community? Leaves out: Interaction strengths are inferred from noisy data and may not hold outside the sampled conditions. Runs on: about 10^10 FLOPS rough generalised Lotka-Volterra fitting and metabolic community simulation on a workstation. Since: 2013 Stein and colleagues, ecological modelling from time-series inference of intestinal microbiota. [source](https://doi.org/10.1371/journal.pcbi.1003388) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ### Surgical planning with patient-specific models A scan is turned into a personal anatomical model, a surgical option is virtually applied, and flow or stress is computed to compare outcomes before operating. Question it answers: Which surgical option gives this patient the best result? Leaves out: Tissue properties are assumed from averages and healing after surgery is not modelled. Runs on: about 10^14 FLOPS rough one flow or stress solve per candidate plan, hours on a cluster. Since: 1999 Taylor and colleagues, predictive medicine using computational techniques for therapeutic decision-making. [source](https://doi.org/10.1002/%28sici%291097-0150%281999%294:5<231::aid-igs1>3.0.co;2-z) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Heart valve fluid-structure interaction A flexible valve leaflet and the blood flowing around it are computed together, as the leaflet is pushed open and slammed shut by the flow it controls. Question it answers: How does a valve open and close, and how does a replacement valve change the flow? Leaves out: Leaflet material properties and the surrounding muscle motion are simplified. Runs on: about 10^15 FLOPS rough moving-boundary fluid solves on a cluster. Since: 1972 Peskin, flow patterns around heart valves, introducing the immersed boundary method. [source](https://doi.org/10.1016/0021-9991%2872%2990065-4) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Bone adaptation and implant remodelling Finite-element models of bone in which tissue is added where stress is high and removed where it is low, over months and years. Question it answers: How will bone change around an implant over time? Leaves out: The remodelling rule is a phenomenological law and varies between patients. Runs on: about 10^11 FLOPS rough iterative finite-element solves on a workstation. Since: 1987 Huiskes and colleagues, adaptive bone-remodelling theory applied to prosthetic design. [source](https://doi.org/10.1016/0021-9290%2887%2990030-3) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Musculoskeletal models for surgery Bones, joints and muscle-tendon actuators of the leg or arm are modelled so that a surgical change, such as a tendon transfer, can be tested for its effect on movement. Question it answers: Will transferring this tendon improve how the patient walks? Leaves out: Muscle activation is estimated, not measured, and nerve control is not modelled. Runs on: about 10^9 FLOPS rough inverse dynamics and muscle optimisation on a laptop. Since: 1990 Delp and colleagues, an interactive graphics-based model of the lower extremity to study orthopaedic surgery. [source](https://doi.org/10.1109/10.102791) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Radiotherapy dose calculation Photons or protons are followed through a patient scan by Monte Carlo transport to compute the radiation dose delivered to a tumour and to healthy tissue. Question it answers: Does the planned beam deliver the dose to the tumour while sparing nearby organs? Leaves out: The scan is a snapshot, so patient motion and anatomy change during treatment are approximations. Runs on: about 10^13 FLOPS rough millions to billions of histories per plan on a cluster or GPU. Since: 1988 Mackie and colleagues, photon energy deposition kernels generated with the EGS Monte Carlo code. [source](https://doi.org/10.1088/0031-9155/33/1/001) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Virtual anatomical phantoms for imaging Digital human bodies with detailed organs and beating or breathing motion, used as the subject for simulated scans so image methods can be tested against known truth. Question it answers: Can this scanner and algorithm recover a known abnormality? Leaves out: The phantom is a shape model fitted to a few subjects and does not capture the full range of anatomy. Runs on: about 10^11 FLOPS rough ray-tracing or transport simulation per scan on a workstation. Since: 2010 Segars and colleagues, the 4D XCAT phantom for multimodality imaging research. [source](https://doi.org/10.1118/1.3480985) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Magnetic resonance image simulation The physics of nuclear spins in a magnetic field is simulated through a pulse sequence to generate synthetic scans of a virtual body. Question it answers: What image would this sequence produce for this tissue? Leaves out: Tissue relaxation values are averages and motion and hardware imperfections are modelled only partly. Runs on: about 10^12 FLOPS rough Bloch-equation simulation of a full volume on a GPU. Since: 2005 Benoit-Cattin and colleagues, the SIMRI interactive MRI simulator. [source](https://doi.org/10.1016/j.jmr.2004.09.027) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Fracture healing simulation Mechanical strain in the healing gap of a broken bone decides whether tissue forms as cartilage, new bone or fibrous scar. Question it answers: Will this fracture fixation allow the bone to heal? Leaves out: The tissue-differentiation rule is empirical and blood supply is simplified. Runs on: about 10^10 FLOPS rough finite-element solves over simulated weeks on a workstation. Since: 1999 Claes and Heigele, local stress and strain along bony surfaces predicting the course and type of fracture healing. [source](https://doi.org/10.1016/s0021-9290%2898%2900153-5) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Within-host virus dynamics Free virus, infected cells and target cells inside one patient are tracked, and their change after starting treatment reveals how fast virus is made and cleared. Question it answers: How quickly does the virus replicate inside a person, and what does treatment change? Leaves out: Tissue structure and sites of infection other than blood are not represented. Runs on: about 10^7 FLOPS rough a few coupled differential equations fitted to a patient time series. Since: 1996 Perelson and colleagues, HIV-1 dynamics in vivo. [source](https://doi.org/10.1126/science.271.5255.1582) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Coronary flow reserve from scans Blood flow through the coronary arteries is computed from a heart scan to estimate whether a narrowing is restricting flow enough to need a stent. Question it answers: Is this narrowing enough to starve the heart muscle of blood? Leaves out: Boundary conditions at the small vessels are estimated from the patient rather than measured. Runs on: about 10^14 FLOPS rough one patient-specific flow solve per scan on a cluster. Since: 2013 Taylor and colleagues, CFD applied to cardiac CT for noninvasive quantification of fractional flow reserve. [source](https://doi.org/10.1016/j.jacc.2012.11.083) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Cochlear mechanics Sound waves in the fluid of the inner ear are coupled to the vibrating membrane inside the cochlea, generating the travelling wave that sorts pitches. Question it answers: How does the ear turn sound into a place-coded signal? Leaves out: The active amplification by hair cells is represented by approximated feedback. Runs on: about 10^10 FLOPS rough finite-difference solves of the cochlear fluid on a workstation. Since: 1981 Neely, a finite-difference solution of a two-dimensional model of the cochlea. [source](https://doi.org/10.1121/1.385820) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Whole-body integrative physiology Blood pressure, kidney, fluid balance and hormones are linked into one model of the circulation and its regulation. Question it answers: How does the body regulate blood pressure, and what happens when one organ fails? Leaves out: Each organ is a lumped compartment and cellular detail is absent. Runs on: about 10^6 FLOPS rough hundreds of differential equations on a laptop. Since: 1972 Guyton, Coleman and Granger, circulation: overall regulation. [source](https://doi.org/10.1146/annurev.ph.34.030172.000305) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### Bioheat transfer and hyperthermia Heat conduction in tissue with blood flow carrying heat away, used to predict temperature during fever, heat stress or heat-based cancer treatment. Question it answers: How hot does the tissue get and how deep does the heat go? Leaves out: Blood perfusion is treated as a uniform heat sink. Runs on: about 10^9 FLOPS rough finite-element heat solves on a workstation. Since: 1948 Pennes, analysis of tissue and arterial blood temperatures in the resting human forearm. [source](https://doi.org/10.1152/jappl.1948.1.2.93) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Kidney nephron transport models Water, salt and urea moving through the loops and tubules of the kidney, solved as coupled flows to show how urine becomes concentrated. Question it answers: How does the countercurrent arrangement of tubules let the kidney concentrate urine? Leaves out: Tubule properties and three-dimensional layout are measured in few species, so parameters are extrapolated from animals. Runs on: about 10^9 FLOPS rough minutes to hours on a workstation. Since: 1966 Stephenson's analysis of concentration in renal counterflow systems. [source](https://doi.org/10.1016/s0006-3495%2866%2986676-6) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Vocal fold and voice production models The vocal folds as masses on springs driven by air from the lungs, coupled to the shape of the throat and mouth, to produce voiced sound. Question it answers: What physical settings of the folds make a clear, breathy or rough voice? Leaves out: The folds are reduced to a few masses, so tissue layers and full three-dimensional airflow are not captured. Runs on: about 10^8 FLOPS rough seconds to minutes per sentence of voiced sound. Since: 1972 Ishizaka and Flanagan's two-mass model of the vocal cords for synthesising voiced sounds. [source](https://doi.org/10.1002/j.1538-7305.1972.tb02651.x) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Circadian clock models Coupled oscillators standing for the body clock respond to light and the timing of rest, predicting how sleep and alertness shift with changes in schedule or travel. Question it answers: How long does it take the body clock to adjust after a flight or a change of shift? Leaves out: A few oscillators stand in for a whole network of neurons, and people differ widely in clock period and light sensitivity. Runs on: about 10^5 FLOPS rough seconds on a laptop. Since: 1982 Kronauer and colleagues' mathematical model of the human circadian system with two interacting oscillators. [source](https://doi.org/10.1152/ajpregu.1982.242.1.r3) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ## Public health ### Compartment epidemic models A population divided into susceptible, infected and recovered, with rates flowing between them. Question it answers: How big will this outbreak get, and when will it peak? Leaves out: Assumes homogeneous mixing, with every person meeting every other at the same rate, which real contact patterns do not satisfy. Runs on: about 10^9 FLOPS rough a laptop solving a handful of coupled epidemic equations Since: 1927 Kermack and McKendrick's equations for a closed epidemic [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-epidemic) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Agent-based epidemics A synthetic population of a whole city or country, each person with a household, school or workplace, and contacts along which disease spreads. Question it answers: Which measures slow the spread most, at the least cost? Leaves out: Requires detailed household, school and workplace data that many countries lack. Runs on: about 10^16 FLOPS rough a university cluster simulating a country-scale synthetic population Since: 2005 Longini, Ferguson and colleagues' agent-based influenza pandemic models [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-epidemic) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Pathogen evolution Mutations appearing and spreading in a virus or bacterium as it passes between hosts. Question it answers: How fast could resistance to this drug evolve? Leaves out: Real mutation and fitness landscapes are far more complex than a handful of loci. Runs on: about 10^12 FLOPS rough a desktop workstation simulating drug-resistance evolution Since: 1990 early stochastic models of drug-resistance evolution in HIV [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Disease burden and health economic modelling A disease and its treatments followed as probabilities of illness, disability, cost and death, used to compare which health interventions do the most good per pound spent. Question it answers: Which treatment or programme gives the most healthy years of life for the money? Leaves out: Assigning a number to a year of life or suffering is a value judgement presented as arithmetic. Runs on: about 10^11 FLOPS rough a desktop workstation running a cohort cost-effectiveness model Since: 1993 the World Bank's global disability-adjusted life year burden-of-disease study [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Outbreak genomic epidemiology Pathogen genomes sampled during an outbreak, used to build a family tree of infections and infer who most likely infected whom and how fast it is growing. Question it answers: How is this outbreak actually spreading, behind what contact tracing alone can see? Leaves out: Only cases that get sequenced show up in the tree, so a thin or biased sample can mislead. Runs on: about 10^13 FLOPS rough a university cluster building trees from thousands of genomes Since: 2013 real-time genomic tracking of an Ebola outbreak in West Africa [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Environmental and chemical exposure risk assessment How a population's exposure to a pollutant, food contaminant or radiation dose translates into a probability of harm, run across the range of uncertainty in the data. Question it answers: How much of this chemical is safe for a whole population to be exposed to? Leaves out: Extrapolating from high test doses in animals to low doses in people is a persistent judgement call. Runs on: about 10^11 FLOPS rough a desktop workstation running a Monte Carlo dose-response model Since: 1983 the US National Research Council's framework for chemical risk assessment [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Mobility-network epidemic models Disease spread simulated across a global network of cities connected by commuting and air-travel data. Question it answers: How fast will an outbreak reach other regions and countries? Leaves out: Mixing inside each city is simplified, and behaviour change is not modelled. Runs on: about 10^12 FLOPS rough Stochastic runs across thousands of subpopulations Since: 2009 Multiscale mobility networks and the spatial spreading of infectious diseases (2009) [source](https://doi.org/10.1073/pnas.0906910106) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Individual-based malaria models Simulated people, mosquitoes and parasites follow within-host infection and transmission to test control strategies. Question it answers: Which mix of nets, drugs and vaccines would cut malaria transmission? Leaves out: Mosquito ecology and local health systems are modelled coarsely. Runs on: about 10^13 FLOPS rough Many stochastic runs of a simulated village Since: 2008 Towards a comprehensive simulation model of malaria epidemiology and control (2008) [source](https://doi.org/10.1017/S0031182008000371) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Scenario modelling hubs Several modelling teams run the same what-if assumptions about vaccines or variants, and the projections are combined into one ensemble. Question it answers: What range of futures follows from each policy or variant assumption? Leaves out: Scenarios are conditional, not predictions of what will happen. Runs on: about 10^12 FLOPS rough Multi-team ensemble of epidemic models Since: 2020 US COVID-19 Scenario Modeling Hub, from December 2020 [source](https://doi.org/10.1016/j.epidem.2023.100738) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Digital contact-tracing models Transmission models with an app-based tracing step estimate how fast tracing and isolation must be to stop spread. Question it answers: How quickly must contacts be traced to bring an epidemic under control? Leaves out: Uptake and compliance are assumed values. Runs on: about 10^9 FLOPS rough Branching-process or agent runs Since: 2020 Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing (2020) [source](https://doi.org/10.1126/science.abb6936) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Antimicrobial resistance spread Susceptible and resistant bacteria compete inside patients and spread between them under different antibiotic policies such as cycling, mixing or combination treatment. Question it answers: Which treatment policy slows the rise of resistant infections? Leaves out: Resistance costs and transmission rates are poorly measured, and the results depend on them. Runs on: about 10^9 FLOPS rough compartment and individual-based hospital models on a laptop. Since: 1997 Bonhoeffer, Lipsitch and Levin, evaluating treatment protocols to prevent antibiotic resistance. [source](https://doi.org/10.1073/pnas.94.22.12106) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Malaria transmission and intervention models Mosquito biting, parasite development, human immunity and interventions such as bed nets or vaccines are simulated together in a village or country. Question it answers: Which combination of controls can reduce or eliminate malaria? Leaves out: Mosquito ecology and local human behaviour are poorly measured. Runs on: about 10^11 FLOPS rough individual-based simulation of a country over decades on a cluster. Since: 2008 Smith and colleagues, towards a comprehensive simulation model of malaria epidemiology and control. [source](https://doi.org/10.1017/s0031182008000371) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Indoor airborne transmission simulation Breathing, coughing and talking release droplets and aerosols into a room, and fluid dynamics tracks where they go and how much a second person inhales. Question it answers: How far does exhaled virus travel, and how much do masks or ventilation reduce exposure? Leaves out: Infectious dose and real room conditions vary more widely than any simulation setup assumes. Runs on: about 10^14 FLOPS rough large-eddy simulation of a room with particle tracking on a cluster. Since: 2020 Mittal, Ni and Seo, the flow physics of COVID-19, reviewing computational studies of respiratory flows. [source](https://doi.org/10.1017/jfm.2020.330) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Tobacco-control policy simulation Smoking starts, quits and deaths in a country are projected under taxes, bans and campaigns, producing the change in prevalence and lives saved. Question it answers: How many lives would a tax or smoking ban save? Leaves out: Policy effects are taken from past evidence and may not transfer to new settings. Runs on: about 10^6 FLOPS rough population projection model on a laptop. Since: 2000 Levy, Cummings and Hyland, a simulation of the effects of youth initiation policies on overall cigarette use. [source](https://doi.org/10.2105/ajph.90.8.1311) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Vaccine allocation optimisation An epidemic model is combined with an optimiser that chooses which age or risk groups receive scarce vaccine first. Question it answers: Who should be vaccinated first to save the most lives? Leaves out: Contact patterns and vaccine effectiveness are uncertain, and the best group depends on the aim. Runs on: about 10^8 FLOPS rough optimisation over many epidemic runs on a workstation. Since: 2009 Medlock and Galvani, optimising influenza vaccine distribution. [source](https://doi.org/10.1126/science.1175570) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Virtual imaging trials Simulated patients, scanners and readers are used to compare imaging technologies without enrolling real people. Question it answers: Does a new imaging device find cancers as well as the current one? Leaves out: Virtual lesions and readers are models that may miss real clinical variety. Runs on: about 10^13 FLOPS rough thousands of simulated images on a cluster. Since: 2018 Badano and colleagues, in silico imaging trial of digital breast tomosynthesis versus full-field mammography. [source](https://doi.org/10.1001/jamanetworkopen.2018.5474) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Epidemics on contact networks Disease spreads between nodes of a network whose degree distribution may be highly uneven, and the outcome depends on the hubs. Question it answers: At what level of transmissibility does an epidemic take off on a network with hubs? Leaves out: Real contact networks change over time and are only partly observed. Runs on: about 10^7 FLOPS rough Monte Carlo spread on million-node networks on a workstation. Since: 2001 Pastor-Satorras and Vespignani, epidemic spreading in scale-free networks. [source](https://doi.org/10.1103/physrevlett.86.3200) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Mosquito population dynamics Eggs, larvae, pupae and adults of a disease-carrying mosquito develop in containers under local temperature and rainfall, giving the number that bite. Question it answers: How many mosquitoes will there be next season, and what does removing breeding sites do? Leaves out: Breeding sites are hard to count and vary street by street. Runs on: about 10^7 FLOPS rough life-table simulation on a laptop. Since: 1993 Focks and colleagues, a dynamic life-table model for Aedes aegypti. [source](https://doi.org/10.1093/jmedent/30.6.1003) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Cancer screening microsimulation Individual life histories with the natural course of cancer are simulated with and without screening to estimate cases found and deaths prevented. Question it answers: How many deaths does a screening programme avert, and at what cost in overdiagnosis? Leaves out: The unobserved early course of cancer must be assumed. Runs on: about 10^9 FLOPS rough millions of simulated lives on a workstation. Since: 1985 Habbema and colleagues, the MISCAN simulation program for the evaluation of screening. [source](https://doi.org/10.1016/0169-2607%2885%2990048-3) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Obesity and diet agent-based models Agents with weight, income and neighbours eat and move, and the spread of body weight across the population shifts under food price or policy changes. Question it answers: Which interventions bend population weight over decades? Leaves out: Behaviour is reduced to a few rules and long-term evidence is thin. Runs on: about 10^8 FLOPS rough population agent-based simulation on a workstation. Since: 2007 Hammond and Epstein, exploring price-independent mechanisms in the obesity epidemic. [source](https://doi.org/10.2139/ssrn.1024287) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Organ allocation policy simulation Patients on a transplant waiting list, arriving donor organs and allocation rules are simulated to compare waiting time and survival. Question it answers: Which allocation rule yields the most life-years and the fairest wait? Leaves out: Organ quality and the decisions of patients and centres are simplified. Runs on: about 10^8 FLOPS rough event simulation of years of waiting lists on a laptop. Since: 2000 Zenios, Chertow and Wein, dynamic allocation of kidneys to candidates on the transplant waiting list. [source](https://doi.org/10.1287/opre.48.4.549.12418) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Ambulance and fire station deployment models Emergency calls arrive at random, units are dispatched, and a queueing model gives response times for each location and district layout. Question it answers: Where should stations and units be placed to cut response time? Leaves out: Travel times and the true spread of demand are assumed. Runs on: about 10^7 FLOPS rough queueing and Monte Carlo on a laptop. Since: 1974 Larson, a hypercube queueing model for facility location and redistricting in urban emergency services. [source](https://doi.org/10.1016/0305-0548%2874%2990076-8) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Synthetic patient record generation Artificial people are given diseases, treatments and encounters from published clinical rules, to produce realistic health records that contain no real person. Question it answers: Can software and analytics be tested on realistic records without exposing anyone's data? Leaves out: The records carry only the patterns put into the generator, so rare diseases and real care pathways are thinly represented. Runs on: about 10^10 FLOPS rough a laptop-scale run for a million patients. Since: 2010 Buczak and colleagues' data-driven approach for creating synthetic electronic medical records. [source](https://doi.org/10.1186/1472-6947-10-59) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ## Drug discovery and pharmacology ### Predictive toxicology A candidate drug's structure compared to databases of known toxic molecules, or run through models trained on lab and animal data, before it is ever synthesised. Question it answers: Is this molecule likely to damage the liver, heart or genes before we make it? Leaves out: Predictions are only as reliable as the past toxic molecules on which the model was trained, and biological exceptions continue to emerge. Runs on: about 10^13 FLOPS rough a university cluster running a trained toxicity prediction model Since: 2000 early structure-activity relationship models used to screen drugs for toxicity [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Pharmacodynamic modelling How the concentration of a drug at its target translates into an effect on the body, from receptor binding up to a measured symptom or biomarker. Question it answers: How much effect will a given dose actually produce, and for how long? Leaves out: Assumes a clean concentration-effect relationship that tolerance and disease progression can disrupt. Runs on: about 10^10 FLOPS rough a desktop workstation solving a handful of coupled effect equations Since: 1968 early receptor-occupancy models linking drug concentration to effect [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Clinical trial design simulation Thousands of hypothetical trials run against assumed patient variation and drug effects, to choose a trial's size, duration and rules for stopping early. Question it answers: How many patients does this trial actually need, and when can we stop it safely? Leaves out: The simulated trial is only as realistic as the assumptions about patient response that are supplied to it. Runs on: about 10^12 FLOPS rough a small cluster running thousands of simulated trial replicates Since: 1994 early simulation studies used to plan adaptive clinical trial designs [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Drug repurposing network models Drugs, genes, proteins and diseases linked in one large network, searched for existing drugs whose known connections suggest an unexpected new use. Question it answers: Could a drug already approved for one disease also treat another? Leaves out: A network link is a hint, not proof; most suggested repurposings still fail when tested. Runs on: about 10^12 FLOPS rough a desktop workstation searching a large drug-gene-disease network Since: 2011 early network-based screens for drug repurposing candidates [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Molecules ### Drug formulation and delivery modelling A tablet dissolving, a patch releasing or a nanoparticle carrying a drug through the body, followed as diffusion and reaction over minutes to days. Question it answers: How fast and where does this drug actually reach its target once swallowed or injected? Leaves out: Lab dissolution rigs and real digestion do not always agree. Runs on: about 10^11 FLOPS rough a desktop workstation solving diffusion and release equations Since: 1961 Higuchi's mathematical model of drug release from a solid matrix [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Molecules ### Vaccine antigen design The surface of a pathogen protein simulated at atomic detail to find or engineer the shapes the immune system will best recognise and remember. Question it answers: Which piece of this pathogen makes the best target for a vaccine? Leaves out: A shape that looks like a good target on screen still has to work in a real immune system. Runs on: about 10^15 FLOPS rough a university cluster running atomic simulations of candidate antigens Since: 2013 structure-based design of a stabilised respiratory virus antigen [Molecular dynamics](https://simulation-hypothesis.com/simulations/methods#m-molecular-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Atoms ### Closed-loop diabetes control in silico A population of virtual people with type 1 diabetes, with meals and glucose-insulin dynamics, used to test delivery control algorithms before human trials. Question it answers: Would this control algorithm keep glucose safe across many different people? Leaves out: Real behaviour such as stress, illness and sensor faults is only partly captured. Runs on: about 10^9 FLOPS rough long virtual-day simulations of hundreds of subjects on a laptop. Since: 2009 Kovatchev and colleagues, in silico preclinical trials of closed-loop control of type 1 diabetes. [source](https://doi.org/10.1177/193229680900300106) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies [◂ Chemistry and materials](https://simulation-hypothesis.com/simulations/chemistry-materials)[Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour) --- title: "Ecology, evolution and animal behaviour · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/ecology-behaviour description: "Ant colonies, flocks, food webs, forests and genes across generations. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 6 of 18 # Ecology, evolution and animal behaviour Ant colonies, flocks, food webs, forests and genes across generations. Organisms acting on local rules, and the colonies, flocks and ecosystems that emerge. Agent-based simulation grew up largely in ecology. A flock or an ant trail is a paradigm case of a pattern that no individual designs. ## Collective behaviour ### Ant colony foraging Individual ants laying and following pheromone trails, with no leader and no map. Question it answers: How does a colony find the shortest path to food when no ant knows the way? Leaves out: Real ants also use sight, sound and taste, which most trail models ignore. Runs on: about 10^11 FLOPS rough a desktop workstation simulating thousands of foraging ants Since: 1990 Deneubourg and colleagues' model of Argentine ant trail formation [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-ants) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Honeybee colonies Foragers, nurses and scouts sharing work, and swarms choosing a new home by a kind of vote. Question it answers: How does a swarm choose the best nest site without a leader? Leaves out: Assumes bees follow fixed simple rules, though real bees vary and can be wrong. Runs on: about 10^11 FLOPS rough a desktop workstation simulating a swarm's nest-site choice Since: 2003 Passino and Seeley's model of honeybee nest-site selection [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Flocking and schooling Each bird or fish steering by three local rules: separation, alignment with neighbours, and cohesion. Question it answers: How do thousands of animals turn together as one? Leaves out: Real flocks respond to predators and terrain the three simple rules leave out. Runs on: about 10^13 FLOPS rough a gaming GPU simulating thousands of steered agents Since: 1987 Craig Reynolds's boids model of flocking [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-flock) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Termite mound building Termites dropping and moving soil pellets, and the air flowing through the structure they build. Question it answers: How do insects with tiny brains build ventilated towers? Leaves out: Real termite behaviour depends on chemical and structural cues only partly captured. Runs on: about 10^12 FLOPS rough a university cluster simulating pellet-dropping termites and airflow Since: 1999 Bonabeau and Theraulaz's stigmergic models of termite construction [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Slime mould aggregation Free-living amoebae releasing and following a chemical signal to stream together into a single slug-like body when food runs out. Question it answers: How do independent cells with no nervous system agree to become one body? Leaves out: Lab conditions are far cleaner than the soil the real organism lives in. Runs on: about 10^12 FLOPS rough a desktop workstation running a chemotaxis aggregation model Since: 1970 Keller and Segel's model of slime mould chemotactic aggregation [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Cells ### Bacterial swarming and quorum sensing Millions of bacteria sensing each other's chemical signals to switch, together, into a coordinated behaviour such as swarming across a surface or lighting up. Question it answers: How does a bacterial population know when there are enough of it to act together? Leaves out: Lab strains grown in a dish behave more uniformly than a real mixed microbial community. Runs on: about 10^12 FLOPS rough a desktop workstation running an agent-based colony model Since: 1994 early simulations of quorum-sensing circuits coordinating bacterial behaviour [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Cells ### Locust marching bands Individual insects align with neighbours at high density, and bands begin to march together in a common direction. Question it answers: At what density do locusts switch from random wandering to marching? Leaves out: Habitat structure and food are not included, and real swarms involve flight. Runs on: about 10^7 FLOPS rough self-propelled particle simulation on a workstation. Since: 2006 Buhl and colleagues, from disorder to order in marching locusts. [source](https://doi.org/10.1126/science.1125142) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Populations ## Individual animals ### Movement and foraging Animals searching a landscape for food, modelled as random walks and decision rules. Question it answers: Is this animal searching efficiently, and what does it know about where food is? Leaves out: Fitting a walk statistic does not establish what the animal is actually sensing. Runs on: about 10^11 FLOPS rough a desktop workstation fitting a random-walk foraging model Since: 1996 Viswanathan and colleagues' Levy flight model of albatross foraging [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Migration and navigation Birds, turtles or whales travelling thousands of kilometres using sun, stars, smell or the magnetic field. Question it answers: Which cues could get a first-year bird to the right continent? Leaves out: Which cues real animals rely on, and how they combine them, is still debated. Runs on: about 10^11 FLOPS rough a desktop workstation simulating cue-based bird navigation Since: 1996 early simulations of magnetic and celestial cue use in bird navigation [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Animal locomotion Fish swimming, insects flying and animals running, with the fluid or ground pushing back. Question it answers: How does a bumblebee fly, and why do fish swim in formation? Leaves out: Simplified wing and body shapes miss details a real animal's surfaces provide. Runs on: about 10^14 FLOPS rough a university cluster running a fluid-body flight or swimming simulation Since: 1994 early fluid dynamics models of insect flight [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Evolution of behaviour Strategies such as fight, share or cheat, played against each other over many generations. Question it answers: Why would an animal ever help an unrelated neighbour? Leaves out: Strategies come from a menu the modeller picked, not the full space of behaviour. Runs on: about 10^11 FLOPS rough a desktop workstation running an evolutionary game tournament Since: 1981 Axelrod and Hamilton's simulated evolution of cooperation strategies [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Bodies ### Birdsong and vocal learning models A young bird's brain circuit for copying a tutor's song, modelled as a sensorimotor loop that compares its own babbling to a memorised template. Question it answers: How does a young bird turn babbling into an accurate copy of an adult's song? Leaves out: Models built to explain songbirds do not obviously generalise to vocalisation in other animals. Runs on: about 10^12 FLOPS rough a desktop workstation training a sensorimotor learning model Since: 2002 early computational models of song learning in the zebra finch [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Dynamic energy budget modelling One animal's whole energy budget followed over its life: what it eats, and how it splits between staying alive, growing and reproducing. Question it answers: How will this animal grow and reproduce under a given food supply and temperature? Leaves out: A small set of universal parameters cannot capture the specific features of every species. Runs on: about 10^10 FLOPS rough a desktop workstation solving a small set of energy-flow equations Since: 1986 Kooijman's dynamic energy budget theory for individual organisms [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ## Populations and ecosystems ### Predator–prey dynamics Numbers of hunters and hunted rising and falling in linked cycles, the Lotka–Volterra equations and their descendants. Question it answers: Why do lynx and hare populations oscillate cyclically? Leaves out: Real populations have age structure, space and multiple prey the model ignores. Runs on: about 10^9 FLOPS rough a laptop solving the Lotka-Volterra equations Since: 1925 Lotka and Volterra's predator-prey equations [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-wator) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Food webs Who eats whom across a whole ecosystem, and how energy moves through it. Question it answers: What happens to the rest of the system if one species disappears? Leaves out: Real feeding links are harder to measure than the model networks assume. Runs on: about 10^10 FLOPS rough a desktop workstation analysing a model food web's stability Since: 1972 Robert May's stability analysis of model food webs [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Forest dynamics Individual trees germinating, competing for light and dying across centuries. Question it answers: What will this forest look like in two hundred years? Leaves out: How a tree species will respond to a changing climate is still hard to calibrate. Runs on: about 10^13 FLOPS rough a university cluster tracking individual trees over centuries Since: 1970 Botkin, Janak and Wallis's JABOWA gap model of forest succession [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Fisheries and wildlife management Fish or animal stocks under harvest, with birth, growth and uncertainty. Question it answers: How many can be caught each year without the population collapsing? Leaves out: Stock assessments depend on catch data that can be incomplete or misreported. Runs on: about 10^11 FLOPS rough a desktop workstation running a stock assessment model Since: 1957 Beverton and Holt's dynamic model of exploited fish populations [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Species ranges Where species can live, and how their ranges shift as climate changes. Question it answers: Where will this species be able to survive in fifty years? Leaves out: Assumes climate is the main limit on range, understating competition and dispersal. Runs on: about 10^11 FLOPS rough a desktop workstation fitting a bioclimatic range model Since: 1986 early bioclimatic envelope models predicting species distributions [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Wildlife disease Infection moving through animal populations, and sometimes spilling over into people. Question it answers: Could this disease wipe out the population, and can vaccination bait stop it? Leaves out: Contact rates between wild animals are hard to observe directly. Runs on: about 10^12 FLOPS rough a university cluster simulating disease spread through a wild population Since: 1991 early simulation models of rabies spread through fox populations [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### General ecosystem models A mechanistic model in which every organism type, from plankton to large animals, eats, grows, reproduces and disperses by shared rules across the globe. Question it answers: Can global patterns of ecosystem structure emerge from rules for individual organisms? Leaves out: Individual species are not tracked, only functional groups. Runs on: about 10^14 FLOPS rough Cohort-based global runs for many simulated years Since: 2014 Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model (2014) [source](https://doi.org/10.1371/journal.pbio.1001841) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Metapopulation dynamics A species lives in many habitat patches in a landscape, going extinct in some and recolonising others, and the model asks whether the whole persists. Question it answers: Will a species survive in a fragmented landscape? Leaves out: Dispersal is represented by a simple kernel and local habitat quality is held fixed. Runs on: about 10^8 FLOPS rough patch occupancy simulation on a laptop. Since: 1994 Hanski, a practical model of metapopulation dynamics. [source](https://doi.org/10.2307/5591) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Individual-based ecological models Each plant or animal is represented separately with its own state, so that population patterns arise from many individual lives. Question it answers: What population patterns arise from the interactions of individuals? Leaves out: Parameters for each individual are hard to measure and validation is difficult. Runs on: about 10^9 FLOPS rough individual-based simulation of a landscape on a workstation. Since: 1988 Huston, DeAngelis and Post, new computer models unify ecological theory. [source](https://doi.org/10.2307/1310870) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Coral reef resilience models Corals, algae and grazing fish compete on a reef through growth, grazing and disturbance, and the model asks whether a reef can flip from coral to algae. Question it answers: How much grazing keeps a reef from tipping to algae? Leaves out: Larval supply and the effects of warming are modelled in simplified ways. Runs on: about 10^8 FLOPS rough spatial reef simulations on a workstation. Since: 2007 Mumby, Hastings and Edwards, thresholds and the resilience of Caribbean coral reefs. [source](https://doi.org/10.1038/nature06252) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Spatial host-parasitoid and pest lattices Hosts and parasitoids live on a grid with local movement, and complex spiral and chaotic patterns emerge that stabilise otherwise unstable interactions. Question it answers: Can space let predators and prey coexist when they could not otherwise? Leaves out: Real landscapes are not uniform grids. Runs on: about 10^6 FLOPS rough coupled-map lattices on a laptop. Since: 1991 Hassell, Comins and May, spatial structure and chaos in insect population dynamics. [source](https://doi.org/10.1038/353255a0) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)floor: Populations ### Fisheries management strategy evaluation A simulated fish stock and its fishery are run under different harvest rules, with noisy data and uncertainty fed back into each rule, to find rules that work despite error. Question it answers: Which harvest rule keeps a stock healthy when we do not know its size? Leaves out: Operating models rest on assumptions about stock biology and fishers that may be wrong. Runs on: about 10^9 FLOPS rough thousands of simulated management projections on a cluster. Since: 1999 Butterworth and Punt, experiences in evaluating and implementing management procedures. [source](https://doi.org/10.1006/jmsc.1999.0532) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Trophic mass-balance ecosystem models A marine food web is described as balanced flows of biomass between groups, then run through time to see the effect of fishing or changes of predators. Question it answers: What happens to the whole ecosystem when one species is fished harder? Leaves out: Groups are lumped and diet data are patchy. Runs on: about 10^7 FLOPS rough balance and time-dynamic runs on a laptop. Since: 1997 Walters, Christensen and Pauly, structuring dynamic models of exploited ecosystems from trophic mass-balance assessments. [source](https://doi.org/10.1023/a:1018479526149) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Plankton ecosystem models Nutrients, phytoplankton, zooplankton and detritus in the ocean surface layer are linked by growth, grazing and sinking. Question it answers: How does plankton production respond to light, nutrient and mixing? Leaves out: Many species are lumped into a few groups and parameters differ by region. Runs on: about 10^10 FLOPS rough coupled to ocean circulation models on a cluster. Since: 1990 Fasham, Ducklow and McKelvie, a nitrogen-based model of plankton dynamics in the oceanic mixed layer. [source](https://doi.org/10.1357/002224090784984678) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Lake eutrophication models Nutrients, algae, plants and fish in a shallow lake are modelled to ask when clear water flips to murky and how it can be restored. Question it answers: How much nutrient can a lake take before turning murky, and will restoration reverse it? Leaves out: Each lake needs its own calibration and sediment dynamics are uncertain. Runs on: about 10^7 FLOPS rough ordinary differential equations on a laptop. Since: 1995 Janse and Van Liere, PCLake, a modelling tool for evaluating lake restoration scenarios. [source](https://doi.org/10.2166/wst.1995.0332) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Marine larval dispersal and connectivity Virtual larvae are released from reefs and carried by modelled ocean currents, building a map of which populations supply which others. Question it answers: Which reefs seed which, and how large should a protected area be? Leaves out: Larval behaviour and mortality are poorly observed. Runs on: about 10^12 FLOPS rough particle tracking in ocean model output on a cluster. Since: 2006 Cowen and colleagues, scaling of connectivity in marine populations. [source](https://doi.org/10.1126/science.1122039) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Honeybee colony and landscape models A whole bee colony's brood, workers and stores simulated day by day, with foragers drawing from flowers across a landscape and facing mites, pesticide and weather. Question it answers: Will this colony survive the winter in this landscape? Leaves out: The landscape's flower supply and the bees' decisions are simplified, and queen failure and disease are only crudely included. Runs on: about 10^9 FLOPS rough minutes per colony-year on a laptop. Since: 2014 Becher and colleagues' BEEHAVE model of honeybee colony dynamics and foraging. [source](https://doi.org/10.1111/1365-2664.12222) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Pollination service across landscapes Wild bee nesting sites and flower resources are mapped across a landscape, and each crop field is given an estimate of the pollinators visiting it. Question it answers: How much crop pollination does the surrounding habitat provide, and what if it is removed? Leaves out: Bee foraging is reduced to distance decay from nests, and bee abundance is a weak guide to actual crop yield. Runs on: about 10^8 FLOPS rough seconds to minutes per region on a laptop. Since: 2009 Lonsdorf and colleagues' model of pollination services across agricultural landscapes. [source](https://doi.org/10.1093/aob/mcp069) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Fields ### Wind seed and pollen dispersal models Seeds and pollen released into turbulent air are carried downwind and fall at random, building up a distribution of where they land. Question it answers: How far do the seeds of a plant travel, and how fast can it spread? Leaves out: Rare long jumps matter most to spread but are the hardest to measure, so the tail of the distribution is poorly known. Runs on: about 10^8 FLOPS rough minutes on a laptop. Since: 1989 Okubo and Levin's theoretical framework for data analysis of wind dispersal of seeds and pollen. [source](https://doi.org/10.2307/1937537) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Near-term ecological forecasting An ecosystem model is run forward days to years and updated each time new observations arrive, as weather forecasting is done. Question it answers: Can the state of a lake, forest or fishery be forecast next season, with honest error bars? Leaves out: Ecological data are sparse compared with weather data, and processes are less well known, so forecasts often only just beat a simple baseline. Runs on: about 10^12 FLOPS rough ensembles of thousands of runs refreshed on a cluster. Since: 2018 Dietze and colleagues' framework for iterative near-term ecological forecasting. [source](https://doi.org/10.1073/pnas.1710231115) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Size-spectrum ecosystem models All organisms in an ecosystem grouped by body size, with energy moving from small to large as they eat and are eaten, and growth and mortality set by size alone. Question it answers: How does fishing pressure reshape the balance of small and large fish in the sea? Leaves out: Species identity is ignored, so predators with the same size but different diets are treated as the same. Runs on: about 10^9 FLOPS rough minutes to hours on a workstation. Since: 1978 Silvert and Platt's time-dependent equation for energy flux through the pelagic ecosystem by size. [source](https://doi.org/10.4319/lo.1978.23.4.0813) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Neutral community models A community of species treated as identical in birth, death and dispersal, with only chance and migration deciding which are common. Question it answers: How much of the pattern of species abundance needs no differences among them at all? Leaves out: Real species clearly differ, so the model works as a null baseline rather than a description of any one community. Runs on: about 10^9 FLOPS rough minutes on a laptop. Since: 1976 Caswell's neutral model analysis of community structure. [source](https://doi.org/10.2307/1942257) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ## Evolution ### Population genetics Gene variants drifting, mutating and being selected through generations. Question it answers: How much of the variation we see is chance, and how much is selection? Leaves out: Real populations violate the simplifying assumptions of random mating and constant size. Runs on: about 10^12 FLOPS rough a university cluster simulating drift and selection across a genome Since: 1964 early computer simulations of genetic drift under the neutral theory [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Coalescent and phylogenetic simulation Family trees of genes or species, simulated backwards in time to test methods for reading real DNA. Question it answers: Can the method recover the true history from the DNA? Leaves out: Assumes a simple population history; real demography is more complex. Runs on: about 10^11 FLOPS rough a desktop workstation simulating gene trees backward in time Since: 1983 Hudson's early coalescent simulation software for population genetics [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Origin of life Simple chemicals forming networks that copy themselves and compete. Question it answers: How could chemistry cross the line into biology? Leaves out: No simulation has yet produced anything that would count as alive. Runs on: about 10^12 FLOPS rough a desktop workstation simulating self-replicating chemical networks Since: 1971 Eigen and Schuster's hypercycle models of self-replicating chemistry [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Molecules ### Host-parasite coevolution Hosts developing defences and parasites evolving ways around them, each generation's simulated population responding to the other in a modelled arms race with no fixed winner. Question it answers: Does a host-parasite arms race reach equilibrium, or does it continue indefinitely with neither side gaining a lasting advantage? Leaves out: Real hosts and parasites coevolve with everything else in their environment at the same time. Runs on: about 10^11 FLOPS rough a desktop workstation running a multi-generation coevolution model Since: 1990 early simulations testing the Red Queen hypothesis of coevolution [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Speciation and macroevolution models Lineages splitting, persisting and going extinct across millions of simulated years, testing what patterns of diversity and family-tree shape simple rules would produce. Question it answers: Could the pattern of species we see have come from simple birth and death of lineages alone? Leaves out: Fossil and genetic records are patchy, so many different rules can fit the same pattern. Runs on: about 10^10 FLOPS rough a desktop workstation simulating birth-death branching processes Since: 1969 early birth-death models of diversification used to study evolutionary trees [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Sexual selection and mate choice evolution A simulated population in which an ornament and a preference for it evolve together, testing whether female choice alone can run away to an extreme. Question it answers: Can mate choice alone drive a trait to an extravagant, costly extreme? Leaves out: Assumes preference and trait are simply heritable, which is simpler than most real mate choice. Runs on: about 10^10 FLOPS rough a desktop workstation running a genetic model of coupled traits Since: 1981 Lande's population-genetic model of runaway sexual selection [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Adaptive dynamics of coevolution A trait evolves by mutations of small effect that are tested against the current population, leading to evolutionary stable states or splitting into branches. Question it answers: Where does evolution settle, and when does a lineage split? Leaves out: Assumes rare mutations and simple trait spaces. Runs on: about 10^6 FLOPS rough analysis and simulation on a laptop. Since: 1996 Dieckmann and Law, the dynamical theory of coevolution derived from stochastic ecological processes. [source](https://doi.org/10.1007/bf02409751) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ### Gene drive population models A genetic element that spreads faster than ordinary inheritance is released into a modelled population to ask whether it could suppress or alter a pest species. Question it answers: Would a gene drive spread through a wild population, and could resistance stop it? Leaves out: Real dispersal and the evolution of resistance are poorly known before a release. Runs on: about 10^8 FLOPS rough spatial population simulations with genetics on a workstation. Since: 2003 Burt, site-specific selfish genes as tools for the control and genetic engineering of natural populations. [source](https://doi.org/10.1098/rspb.2002.2319) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Forward-time genome simulation Every individual and its genome is followed through generations, with selection, linkage and varied demography, to see how real DNA patterns come about. Question it answers: What do selection and population history leave behind in the genomes of a species? Leaves out: Population sizes are scaled down to keep the run feasible, which distorts the balance of selection and drift. Runs on: about 10^14 FLOPS rough days on a cluster for a large population over many generations. Since: 2013 Messer's SLiM, a forward-time simulator of evolution with selection and linkage. [source](https://doi.org/10.1534/genetics.113.152181) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Animal contest strategies Individuals meeting at random to contest a resource choose among fixed strategies, and the mix settles at one no mutant can improve on. Question it answers: When is fighting or backing down the better policy, given what others do? Leaves out: Animals are reduced to a short list of strategies with no learning, memory or individual differences. Runs on: about 10^6 FLOPS rough seconds on a laptop. Since: 1973 Maynard Smith and Price's 'The logic of animal conflict'. [source](https://doi.org/10.1038/246015a0) [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ## Conservation and reserve design ### Population viability analysis A small, threatened population's births, deaths and catastrophes rolled forward many times to estimate the chance it survives, and for how long. Question it answers: How likely is this population to go extinct in the next hundred years? Leaves out: Small samples of a rare species leave the input numbers themselves highly uncertain. Runs on: about 10^10 FLOPS rough a desktop workstation running thousands of stochastic trajectories Since: 1980 early stochastic models estimating extinction risk for endangered species [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Reserve and corridor design Candidate sites and the links between them scored against cost and the species they would protect, searched for the smallest network of reserves that covers the most. Question it answers: Which set of land parcels protects the most species for the least cost? Leaves out: Optimises for the species data that exist, which is a small fraction of what actually lives there. Runs on: about 10^10 FLOPS rough a desktop workstation solving a reserve-selection optimisation Since: 1988 early systematic reserve-selection algorithms for conservation planning [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Reintroduction and translocation planning A small founder group released into new or former habitat, followed forward to see whether it establishes, given the area's carrying capacity and the founders' genetics. Question it answers: Will releasing these animals here actually establish a lasting population? Leaves out: Habitat quality and disease risk at the release site are often estimated roughly rather than measured. Runs on: about 10^10 FLOPS rough a desktop workstation running a founder-population model Since: 1990 early simulation models used to plan the reintroduction of a large mammal [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Invasive species spread An introduced species spreading across a landscape cell by cell, and the effect of barriers, culling or biological control on how far it gets. Question it answers: How fast will this invader spread, and where should control effort go first? Leaves out: New invaders often spread in ways no past invasion prepared the model for. Runs on: about 10^10 FLOPS rough a desktop workstation running a landscape spread model Since: 1951 Skellam's diffusion model of a spreading population [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Poaching and anti-poaching patrol games Rangers and poachers as players in a repeated game over a map of a protected area, used to decide where patrols should go when they cannot be everywhere. Question it answers: Where should limited rangers patrol to do the most against a strategic poacher? Leaves out: Assumes a rational, patient poacher, when much of it is opportunistic. Runs on: about 10^10 FLOPS rough a desktop workstation solving a security game over a patrol map Since: 2014 early security-game models applied to wildlife ranger patrol scheduling [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Rewilding and trophic cascade modelling A predator or other keystone species added back to a food web, followed through its knock-on effects on prey, vegetation and even rivers. Question it answers: What happens to the rest of the ecosystem if we bring this species back? Leaves out: The famous cascades took decades to unfold and are easier to model after the fact than to predict. Runs on: about 10^10 FLOPS rough a desktop workstation running a multi-species food-web model Since: 1995 wolves reintroduced to Yellowstone, later modelled for cascading effects [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations [◂ Life and medicine](https://simulation-hypothesis.com/simulations/life-medicine)[Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food) --- title: "Agriculture and food · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/agriculture-food description: "Fields, herds, ponds and supply chains, run forward to estimate whether supply will meet demand. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 7 of 18 # Agriculture and food Fields, herds, ponds and supply chains, run forward to estimate whether supply will meet demand. People modelled farming on paper long before computers: rotation plans, yield tables and breeding records go back centuries. Digital models now couple weather, soil chemistry, disease spread and market shocks in a single run. They can forecast a harvest, herd growth or a shortage in advance. The same kind of model works from irrigation timing in one field to famine early warning for a whole region. It also reaches past the farm gate, to fermenting, cooking, chilling and tracking food. ## Crops and soil ### Crop growth and yield models A field of a single crop reduced to pools of leaf area, biomass and grain, driven day by day by weather, sowing date and management. Question it answers: How much will this field yield, and when should it be planted? Leaves out: Treats the field as spatially uniform, so variation inside it such as waterlogged or under-seeded patches is not represented. Runs on: about 10^10 FLOPS rough a laptop, seconds per field-season Since: 1965 by 1965, de Wit's early crop growth models in the Netherlands [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Soil water and nutrient transport Water infiltrating through soil layers and nutrients moving, binding and leaching, tracked cell by cell down the profile. Question it answers: How much water and fertiliser reaches the roots, and how much washes away? Leaves out: Soil is never as neatly layered as the model's grid assumes. Runs on: about 10^10 FLOPS rough a desktop machine for a season-long profile run Since: 1972 by 1972, early soil water balance models for irrigation research [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Pest and plant disease spread Insects, fungi or bacteria spreading across a crop or region, carried by wind, rain, animals or trade, against weather that helps or hinders them. Question it answers: How far and how fast will an outbreak spread, and where should it be contained? Leaves out: Assumes reported outbreaks are the true extent, which they rarely are. Runs on: about 10^11 FLOPS rough a university cluster for a regional, multi-season run Since: 1980 by 1980, computer models of wheat rust and potato blight spread [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Irrigation scheduling Soil moisture and crop water demand tracked forward day by day to decide when and how much to irrigate. Question it answers: When does this field need water, and how much? Leaves out: Assumes the pump, the canal and the weather forecast all behave. Runs on: about 10^9 FLOPS rough runs on a farm computer or phone app Since: 1975 by 1975, water-balance scheduling models for irrigated farms [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Soil erosion and land degradation Rainfall, runoff and tillage stripping soil from slopes, tracked as sediment moving downhill and out of the field. Question it answers: How much topsoil will this field lose, and which practices slow it? Leaves out: Calibrated mostly on temperate farmland, so it travels badly to other climates. Runs on: about 10^10 FLOPS rough a desktop machine for a catchment-scale run Since: 1965 by 1965, the Universal Soil Loss Equation and its computer descendants [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Crop breeding simulation Virtual crosses between plant varieties, run forward through simulated generations to predict which combination of genes yields the best variety. Question it answers: Which cross is worth making in the field, out of millions of possible ones? Leaves out: A gene's effect on paper is not always what it does in a real paddock. Runs on: about 10^12 FLOPS rough a university cluster screening thousands of virtual crosses Since: 1990 by 1990, genetic simulation used in plant breeding programmes [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Precision agriculture optimisation A field split into small patches, each with its own soil and yield history, to work out the best seed, water and fertiliser rate for each one. Question it answers: How much input does this exact patch need, not the whole field? Leaves out: Needs good sensor data, which most farms still do not have everywhere. Runs on: about 10^10 FLOPS rough a farm laptop processing one field's sensor maps Since: 1995 by 1995, yield-mapping and variable-rate application models [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Fields ### Multi-model crop ensembles Many crop models run with the same weather and climate inputs so the spread shows the uncertainty in yield projections. Question it answers: How uncertain is a yield projection under future climate? Leaves out: Pests, extreme events and management change are handled unevenly. Runs on: about 10^12 FLOPS rough Dozens of models over global grids Since: 2013 The Agricultural Model Intercomparison and Improvement Project, AgMIP (2013) [source](https://doi.org/10.1016/j.agrformet.2012.09.011) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Soil organic carbon turnover Carbon in soil moves between pools that decay at different rates under temperature, moisture and inputs from plants. Question it answers: Is a field gaining or losing soil carbon, and what changes that? Leaves out: Pools are conceptual and cannot be measured directly. Runs on: about 10^5 FLOPS rough monthly pool simulations on a laptop. Since: 1977 Jenkinson and Rayner, the turnover of soil organic matter in some of the Rothamsted classical experiments. [source](https://doi.org/10.1097/00010694-197705000-00005) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Fields ### Agricultural catchment pollution models Rainfall, crops, soil and farm practice in a river basin are simulated to give runoff of water, sediment and nutrients. Question it answers: How much nutrient or sediment reaches the river under different farming practice? Leaves out: Calibration needs many data and field-level management is guessed. Runs on: about 10^9 FLOPS rough basin-scale daily simulations on a workstation. Since: 1998 Arnold and colleagues, large area hydrologic modelling and assessment, model development. [source](https://doi.org/10.1111/j.1752-1688.1998.tb05961.x) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Global gridded crop model ensembles Many crop models run on the world grid under the same climate scenarios, and their spread shows the uncertainty in projected yield. Question it answers: How much will world crop yield change under climate scenarios, and how uncertain is that? Leaves out: Models share missing processes such as pests and extreme heat. Runs on: about 10^13 FLOPS rough many crop models run globally for decades on a cluster. Since: 2013 Rosenzweig and colleagues, the Agricultural Model Intercomparison and Improvement Project protocols. [source](https://doi.org/10.1016/j.agrformet.2012.09.011) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Fields ### Farm agent-based models of land use and adoption Farm households with their own land, labour and neighbours decide what to grow and which technology to adopt, with spatial spread of innovations. Question it answers: How will farmers respond to a price, subsidy or technology? Leaves out: Farmer decisions are modelled by simplified rules. Runs on: about 10^8 FLOPS rough regional agent-based runs on a workstation. Since: 2001 Berger, agent-based spatial models applied to agriculture for technology diffusion and resource use. [source](https://doi.org/10.1111/j.1574-0862.2001.tb00205.x) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Pesticide resistance management models A pest population under spraying evolves resistance, and strategies such as refuges, rotation and mixtures are compared. Question it answers: Which spraying strategy delays resistance the longest? Leaves out: Costs of resistance and pest movement are uncertain. Runs on: about 10^6 FLOPS rough population genetic models on a laptop. Since: 1977 Comins, the management of pesticide resistance. [source](https://doi.org/10.1016/0022-5193%2877%2990206-5) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Agrivoltaic light-sharing models Solar panels above crops cast moving shade on them, so the layout, light reaching the leaves and crop growth are simulated together with the electricity produced. Question it answers: How much food and energy can the same field give when both share the sunlight? Leaves out: Crop response to partial shade is known for only a few species, and water and temperature effects under the panels are simplified. Runs on: about 10^9 FLOPS rough hours on a workstation per layout and season. Since: 2011 Dupraz and colleagues' land-equivalent-ratio model of photovoltaic panels combined with food crops. [source](https://doi.org/10.1016/j.renene.2011.03.005) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Fields ### Plant architecture growth models A plant built up bud by bud from botanical rules for branching and ageing, giving the three-dimensional shape of a tree or crop as it grows. Question it answers: How does the branching habit of a plant decide how it fills space and catches light? Leaves out: Growth rules are fitted to one species and environment, and the response to wind, neighbours and damage is limited. Runs on: about 10^8 FLOPS rough seconds to minutes per plant. Since: 1988 de Reffye and colleagues' plant models faithful to botanical structure and development. [source](https://doi.org/10.1145/378456.378505) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Degree-day pest phenology models Heat accumulated each day above a threshold sets when insects emerge, breed and reach a stage where they harm a crop, so sprays can be timed. Question it answers: On which day will the pest reach the stage at which control works? Leaves out: Insects respond to temperature in a curve, not a straight line, and microclimate on the plant differs from the weather station. Runs on: about 10^4 FLOPS rough trivial on a laptop; run daily for many sites. Since: 1976 Allen's modified sine-wave method for calculating degree days for insects. [source](https://doi.org/10.1093/ee/5.3.388) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ### Sterile insect release models Mass-reared sterile males released into a wild population mate with females that then produce no offspring, and the numbers are followed as they fall. Question it answers: How many sterile insects must be released, and for how long, to wipe out a pest? Leaves out: Wild females may refuse the sterile males, and insects arriving from outside can undo the release. Runs on: about 10^5 FLOPS rough seconds to minutes on a laptop. Since: 1955 Knipling's analysis of insect control or eradication using sexually sterile males. [source](https://doi.org/10.1093/jee/48.4.459) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Land-use change agent models Landowners and farmers, each with their own goals and information, decide what to do with each parcel, and the land cover that results is mapped over decades. Question it answers: How will land cover change under a policy, a road or a crop price shift? Leaves out: Human decision rules are hard to measure, so they are often guessed, and the models are tuned to the past without evidence they continue. Runs on: about 10^8 FLOPS rough hours on a workstation. Since: 2003 Parker and colleagues' review of multi-agent systems for simulating land-use and land-cover change. [source](https://doi.org/10.1111/1467-8306.9302004) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ### Greenhouse climate models Heat, humidity and carbon dioxide balances of a greenhouse, with sun, vents, heating and the crop's own transpiration, to design and control the indoor climate. Question it answers: How should vents and heating be run to keep a crop warm and dry at least cost? Leaves out: Air is treated as well mixed, though real greenhouses have gradients, and crop feedback is simplified. Runs on: about 10^7 FLOPS rough seconds per day simulated, so a season runs in minutes. Since: 1985 Garzoli's simple greenhouse climate model (Acta Horticulturae). [source](https://doi.org/10.17660/actahortic.1985.174.52) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Fields ## Livestock and aquaculture ### Livestock herd and feed models A herd's growth, milk or meat output tracked against feed intake, breed and management, animal by animal or as a whole group. Question it answers: How much will this herd produce, and how much feed does it need to get there? Leaves out: Day-to-day individual variation in animal health and condition is not captured by feed-based models. Runs on: about 10^9 FLOPS rough runs on a farm computer per herd Since: 1970 by 1970, early beef and dairy production models [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Grazing and pasture management Grass growth and regrowth under grazing pressure, weather and soil fertility, used to plan how many animals a pasture can carry. Question it answers: How many animals can this pasture support without wearing it out? Leaves out: Pasture response to an early or unusually severe drought departs from the modelled growth curve. Runs on: about 10^9 FLOPS rough a laptop run per paddock per season Since: 1973 by 1973, pasture growth models for grazing systems [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Aquaculture and fish farming Fish or shellfish raised in ponds, cages or tanks, tracked against feed, oxygen, temperature and stocking density. Question it answers: How much stock should go in, and when should it come out, for the best yield? Leaves out: Disease outbreaks in a real pond rarely coincide with the warning the model provides. Runs on: about 10^9 FLOPS rough a laptop run per farm cycle Since: 1985 by 1985, bioenergetic growth models for farmed fish [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Livestock disease outbreak models A farm animal disease spreading between farms by animal transport, vehicles and wind, used to plan culling, movement bans and vaccination rings. Question it answers: How far will this outbreak spread, and which control measure stops it fastest? Leaves out: Farmers do not always report symptoms as fast as the model assumes. Runs on: about 10^11 FLOPS rough a university cluster for a national outbreak run Since: 2001 the UK's 2001 foot-and-mouth epidemic models [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Livestock breeding and genetics Virtual matings between animals, run forward through generations to predict milk yield, growth rate or disease resistance in the offspring. Question it answers: Which sire or dam should be bred next, out of a whole breeding population? Leaves out: Assumes the recorded pedigree is accurate, although errors in record-keeping and misattributed parentage occur in practice. Runs on: about 10^11 FLOPS rough a cluster run scoring a national breeding population Since: 1990 by 1990, BLUP-based genetic evaluation of dairy cattle [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Precision livestock monitoring Individual animals tracked by sensor for movement, feeding and temperature, compared against a simulated healthy baseline to flag problems early. Question it answers: Which individual animal, out of thousands, needs attention today? Leaves out: A sensor glitch looks exactly like a sick animal to the model. Runs on: about 10^10 FLOPS rough a farm server processing one barn's sensor feed Since: 2005 by 2005, sensor-driven dairy cattle monitoring systems [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Aquaculture pond bioenergetics Each fish in a pond has energy from feed and oxygen turned into growth, and the water's oxygen and waste are tracked alongside. Question it answers: How many fish, fed how much, grow fastest before the pond water goes bad? Leaves out: Disease, behaviour and weather shocks are mostly left out, so the model suits steady conditions best. Runs on: about 10^8 FLOPS rough minutes on a laptop. Since: 1985 Cuenco and colleagues' individual-fish bioenergetics and growth model for aquaculture ponds. [source](https://doi.org/10.1016/0304-3800%2885%2990001-8) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ## Food systems and processing ### Food supply chain simulation Grain, produce and processed food moving from farm to warehouse to shop, tracked against transport, storage losses and demand shocks. Question it answers: Where does the food system break first under a shortage or a shock? Leaves out: Real supply chains hide informal trade the model never sees. Runs on: about 10^10 FLOPS rough a cluster run for a national or regional network Since: 1985 by 1985, logistics simulation applied to food distribution [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Famine early warning models Rainfall, harvests, prices and conflict combined to flag which regions are heading towards food shortage months before it hits. Question it answers: Which regions will run short of food, and when? Leaves out: Depends on data from the places least able to report it. Runs on: about 10^10 FLOPS rough a cluster run scoring many regions each month Since: 1985 by 1985, government-led famine early warning systems in the Sahel [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Fermentation process modelling Yeast, bacteria or mould growing inside a vat of dough, must or mash, tracked as they consume sugars and produce alcohol, acid or gas. Question it answers: How long should this ferment, and at what temperature, for the result wanted? Leaves out: Wild fermentations bring in microbes the model was never told about. Runs on: about 10^9 FLOPS rough a laptop run per batch process Since: 1975 by 1975, kinetic models of brewing and baking fermentation [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Baking and thermal food processing Heat moving into dough, cans or packaged food, tracked to predict cooking, browning and how safely microbes are killed off. Question it answers: Is the centre of this product cooked through, and is it safe to eat? Leaves out: Ovens in the real world are never as even as the model's heat field. Runs on: about 10^9 FLOPS rough a laptop run per product design Since: 1970 by 1970, heat transfer models for canning and baking [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Cold chain and spoilage modelling Temperature drift in trucks, warehouses and shop fridges tracked against microbial growth to predict how much shelf life is lost. Question it answers: How much of this shipment will spoil before it reaches the shelf? Leaves out: Brief, severe temperature excursions, such as a door left open for ten minutes, cause more damage than the model averages suggest. Runs on: about 10^9 FLOPS rough a laptop run tracking one shipment's temperature log Since: 1990 by 1990, shelf-life prediction models for chilled food logistics [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Food safety and traceability simulation Contamination introduced at one point in the food system, traced forward through mixing, processing and distribution to see who ends up exposed. Question it answers: If contamination starts here, how far does it spread before recall catches it? Leaves out: Paper trails in the real supply chain have more gaps than the model assumes. Runs on: about 10^9 FLOPS rough a laptop run per contamination scenario Since: 1995 by 1995, traceability simulation following major contamination outbreaks [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Predictive food microbiology The growth and death of bacteria in food are modelled against temperature, acidity and water activity to estimate shelf life and safety. Question it answers: How fast will a pathogen grow in this food at this temperature? Leaves out: Food is more varied than a laboratory broth. Runs on: about 10^5 FLOPS rough growth curve fitting on a laptop. Since: 1994 Baranyi and Roberts, a dynamic approach to predicting bacterial growth in food. [source](https://doi.org/10.1016/0168-1605%2894%2990157-0) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Cells ### Quantitative microbial risk assessment Contamination, cooking, storage and eating are chained as probability distributions to estimate the chance of illness from a food. Question it answers: How likely is a person to become ill from this food, and which step matters most? Leaves out: Dose-response is poorly known for rare pathogens. Runs on: about 10^8 FLOPS rough Monte Carlo over a farm-to-fork chain on a laptop. Since: 1998 Cassin and colleagues, quantitative risk assessment for E. coli O157:H7 in ground beef hamburgers. [source](https://doi.org/10.1016/s0168-1605%2898%2900028-2) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Digestion and gastric flow simulation Stomach wall movement drives mixing and breakdown of food, and the flow and acid are computed to relate food structure to nutrient release. Question it answers: How quickly is a food broken down and absorbed in the stomach? Leaves out: Stomach wall motion and food rheology are simplified. Runs on: about 10^12 FLOPS rough moving-wall flow simulation on a cluster. Since: 2010 Kozu and colleagues, analysis of flow phenomena in gastric contents induced by human gastric peristalsis. [source](https://doi.org/10.1007/s11483-010-9183-y) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies [◂ Ecology, evolution and animal behaviour](https://simulation-hypothesis.com/simulations/ecology-behaviour)[Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society) --- title: "Human behaviour and society · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/human-society description: "Decisions, crowds, opinions, markets, past societies and whole populations. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 8 of 18 # Human behaviour and society Decisions, crowds, opinions, markets, past societies and whole populations. Here people are modelled as decision-makers, crowds, markets and populations. The models are kept simple on purpose. Often the point is to show how little individual intent it takes to produce a large social pattern. Anthropologists and archaeologists use the same tools to rebuild societies that no longer exist. That makes them the closest real analogue of the ancestor simulations in the hypothesis. ## Minds and decisions ### Cognitive architectures A computational model of human memory, attention and reasoning, run on the same task given to people in the lab. Question it answers: Does the model make the same mistakes, at the same speed, as people do? Leaves out: Fitting human reaction times does not prove the model uses the brain's actual mechanism. Runs on: about 10^12 FLOPS rough a desktop workstation running an architecture on a lab task Since: 1983 Newell's development of a unified cognitive architecture, Soar Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Models of decision-making Evidence building up at random until it crosses a threshold, used to explain choices and reaction times. Question it answers: Why do people trade speed for accuracy the way they do? Leaves out: Assumes evidence builds up at a constant noisy rate, a simplified neural picture. Runs on: about 10^9 FLOPS rough a laptop fitting a drift-diffusion model to choice data Since: 1978 Ratcliff's drift-diffusion model of decision-making Models: [Human](https://simulation-hypothesis.com/entities/human) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Models of learning Agents learning from reward and error, fitted to how people and animals behave in learning experiments. Question it answers: What learning rule best explains how people adapt to changing odds? Leaves out: Captures average behaviour well but often misses individual differences in learning. Runs on: about 10^10 FLOPS rough a desktop workstation fitting a reward-learning model Since: 1972 Rescorla and Wagner's model of associative learning Models: [Human](https://simulation-hypothesis.com/entities/human) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Social cognition and theory-of-mind models An agent's picture of what another believes, wants or knows, nested inside itself, used to explain how people predict and manipulate each other's behaviour. Question it answers: How many levels deep do people actually reason about what others are thinking? Leaves out: Most models cap belief-nesting at a small number of levels, although real reasoning is less regular. Runs on: about 10^10 FLOPS rough a desktop workstation running a nested belief-reasoning model Since: 1978 Premack and Woodruff's theory of mind, later formalised computationally Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Rules ### Emotion and affect modelling A simulated appraisal of a situation, such as threat or loss, turned into an emotional state that then biases the agent's later decisions. Question it answers: How does feeling afraid or angry actually change the choices that follow? Leaves out: Appraisal rules are the modeller's theory of emotion, not a direct read of anyone's feelings. Runs on: about 10^10 FLOPS rough a desktop workstation running an appraisal-based emotion model Since: 1988 Ortony, Clore and Collins's cognitive model of emotion Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Choice under risk and uncertainty modelling Gambles and decisions run through a model of how people actually weigh gains, losses and probabilities, rather than how a purely rational agent would. Question it answers: Why do people's choices under risk depart so consistently from the rational textbook answer? Leaves out: Fits average biases well, but any one person's choices can depart from the fitted curve. Runs on: about 10^10 FLOPS rough a desktop workstation fitting a prospect-theory choice model Since: 1992 Tversky and Kahneman's cumulative prospect theory of choice under risk Models: [Human](https://simulation-hypothesis.com/entities/human) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Language-model survey respondents A language model is prompted with a demographic profile and asked to answer survey questions as that person would. Question it answers: Can a model stand in for a survey sample to predict group responses? Leaves out: Inherits bias and homogeneity from the model's training text, and is weak on groups it saw little of. Runs on: about 10^14 FLOPS rough One model call per simulated respondent Since: 2022 Out of One, Many: using language models to simulate human samples (2022) [source](https://arxiv.org/abs/2209.06899) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Language-model behavioural experiments Language models are prompted as many different participants to replay classic experiments in psychology and economics. Question it answers: Does a model reproduce human results in a classic study? Leaves out: Replication may reflect memorised studies, and the model may not generalise to new designs. Runs on: about 10^14 FLOPS rough Many model calls per experiment Since: 2022 Using large language models to simulate multiple humans and replicate human subject studies (2022) [source](https://arxiv.org/abs/2208.10264) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ## Social dynamics ### Residential sorting Households moving when too few neighbours are like them, Thomas Schelling’s model of how mild preferences produce sharp divides. Question it answers: How much individual preference does it take to produce a divided city? Leaves out: Real segregation also involves income, discrimination and history mild preference alone cannot explain. Runs on: about 10^9 FLOPS rough a laptop running Schelling's segregation model on a grid Since: 1971 Schelling's original hand-run segregation model, later computerised In the simulations tree: [Schelling segregation](https://simulation-hypothesis.com/trees/simulations?n=soc-schelling) Models: [Human](https://simulation-hypothesis.com/entities/human) [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-schelling) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Bodies ### Opinion dynamics Agents nudging each other’s views through contact and networks. Question it answers: When does a group reach consensus, and when does it split into camps? Leaves out: Real opinions involve emotion and identity that simple averaging rules do not capture. Runs on: about 10^10 FLOPS rough a desktop workstation updating opinions across a social network Since: 1974 DeGroot's model of iterative opinion pooling, later simulated on networks [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Cooperation and norms Repeated games of trust and cheating between many players, with reputations and punishment. Question it answers: How do cooperation and fairness norms become stable? Leaves out: Real reputations and punishment are messier and slower than clean repeated games. Runs on: about 10^10 FLOPS rough a desktop workstation running repeated-game tournaments Since: 1980 Axelrod's computer tournaments of the repeated prisoner's dilemma Models: [Human](https://simulation-hypothesis.com/entities/human) [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Diffusion of ideas Innovations, habits and rumours spreading through social networks. Question it answers: Why do some ideas catch on and others never spread? Leaves out: Predicts adoption curves better than it explains why any one person switches. Runs on: about 10^10 FLOPS rough a desktop workstation simulating adoption across a social network Since: 1969 Bass's mathematical model of new product diffusion, later simulated [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Social network formation People making and breaking ties by rules such as friends of friends and similarity. Question it answers: Why do large networks show short path lengths between almost all pairs of nodes? Leaves out: Real tie-formation involves geography and institutions abstract rules skip. Runs on: about 10^10 FLOPS rough a desktop workstation growing a network under an attachment rule Since: 1999 Barabasi and Albert's preferential attachment model of network growth Models: [Human](https://simulation-hypothesis.com/entities/human) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Language evolution Agents inventing words and grammar to communicate, and passing them on. Question it answers: How can a shared vocabulary arise with nobody in charge? Leaves out: Real language has grammar and history far richer than the small vocabularies agents evolve. Runs on: about 10^10 FLOPS rough a desktop workstation running agents inventing a shared vocabulary Since: 1995 Steels's early simulations of agents inventing a shared vocabulary [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Cultural evolution Skills, tools and traditions copied, improved and lost across generations. Question it answers: Why do bigger, better-connected populations keep more complex technology? Leaves out: Treats culture like genes passed between people, missing how ideas get reinvented. Runs on: about 10^10 FLOPS rough a desktop workstation simulating trait transmission across generations Since: 1981 Cavalli-Sforza and Feldman's models of cultural transmission [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Language-model agent societies Dozens of software agents driven by a language model, each with memory and plans, live in a small simulated town and form social behaviour. Question it answers: What social patterns arise when agents plan and talk in natural language? Leaves out: Behaviour comes from the language model's training, and runs are costly and hard to reproduce. Runs on: about 10^15 FLOPS rough Thousands of model calls per simulated day Since: 2023 Generative Agents: interactive simulacra of human behavior (2023) [source](https://arxiv.org/abs/2304.03442) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Populated social-system prototypes A language model generates a community of simulated members with posts and replies so designers can test a social platform before launch. Question it answers: What behaviour might a new community design attract? Leaves out: Output varies between runs, and bad actors are only as realistic as the prompt. Runs on: about 10^13 FLOPS rough Many model calls per community Since: 2022 Social Simulacra (2022) [source](https://arxiv.org/abs/2208.04024) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Rules ### Language-model social platform simulation A platform with feeds, follows and recommendation is populated by up to a million model-driven users to study information spread and herding. Question it answers: How do posts, opinions and misinformation spread on a platform of model-driven users? Leaves out: Agents are far more uniform than real users, and real-world validation is limited. Runs on: about 10^17 FLOPS rough Large-scale model inference Since: 2024 OASIS: open agent social interaction simulations with one million agents (2024) [source](https://arxiv.org/abs/2411.11581) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Recommender feedback-loop simulation Simulated users and a recommender system interact over many rounds to show how recommendations change what users choose. Question it answers: Do recommendation systems narrow what people consume over time? Leaves out: User behaviour is a stylised model, not measured preference. Runs on: about 10^10 FLOPS rough Cheap repeated rounds Since: 2017 How algorithmic confounding in recommendation systems increases homogeneity and decreases utility (2017) [source](https://arxiv.org/abs/1710.11214) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Language-model user simulation for recommenders Language-model agents with taste profiles browse, rate and quit suggested items to stand in for users in tests of recommendation algorithms. Question it answers: How would users react to a new recommendation algorithm? Leaves out: Agent taste is only an approximation of real tastes. Runs on: about 10^14 FLOPS rough Many model calls per simulated user Since: 2023 On generative agents in recommendation (2023) [source](https://arxiv.org/abs/2310.10108) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Misinformation and rumour spread People in clusters decide to share a story according to how many of their contacts have shared it, so spread depends on network structure. Question it answers: What network structure lets a false story go viral? Leaves out: Platform algorithms and the motives of sharers are simplified. Runs on: about 10^7 FLOPS rough network contagion on a workstation. Since: 2018 Toernberg, echo chambers and viral misinformation: modelling fake news as complex contagion. [source](https://doi.org/10.1371/journal.pone.0203958) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Migration under climate stress Households decide whether to leave a region based on income, climate shocks and social ties, and the flows between areas are summed. Question it answers: How many people move if rainfall or farm income falls? Leaves out: Decision rules are assumed and migration is multi-causal. Runs on: about 10^8 FLOPS rough regional agent runs on a workstation. Since: 2011 Kniveton and colleagues, agent-based model simulations of future changes in migration flows for Burkina Faso. [source](https://doi.org/10.1016/j.gloenvcha.2011.09.006) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Human mobility and migration models The flow of people between places is predicted from populations and distances, using gravity or radiation-type rules. Question it answers: How many people travel between two places? Leaves out: Ignores transport costs, borders and individual differences. Runs on: about 10^6 FLOPS rough flow matrix calculation on a laptop. Since: 2012 Simini and colleagues, a universal model for mobility and migration patterns. [source](https://doi.org/10.1038/nature10856) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Synthetic population generation A full set of artificial households and individuals is built to match the known totals of a real city or country, giving each person an age, job, home and family. Question it answers: How can we get a realistic stand-in for everyone in a region without using anyone's real record? Leaves out: Only the totals the census publishes are matched, so correlations among traits that were not measured are invented. Runs on: about 10^9 FLOPS rough hours on a workstation for a country. Since: 1996 Beckman, Baggerly and McKay's creation of synthetic baseline populations. [source](https://doi.org/10.1016/0965-8564%2896%2900004-3) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ## Crowds ### Pedestrian and crowd dynamics Each walker steering around obstacles and other people by social forces. Question it answers: Where do crowds bottleneck in this station, and how do we prevent a crush? Leaves out: Real crowds panic and behave unpredictably in ways smooth force models miss. Runs on: about 10^13 FLOPS rough a university cluster simulating tens of thousands of walkers Since: 1995 Helbing and Molnar's social force model of pedestrian movement [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Crowd emotion and behavioural contagion A mood or action such as panic, cheering or laughter spreading from person to person through a dense crowd, faster than anyone decided to join in. Question it answers: How does a feeling or an action sweep through a crowd of strangers? Leaves out: Contagion rules are usually guessed from video footage after the fact, not measured live. Runs on: about 10^11 FLOPS rough a desktop workstation simulating mood spread through a crowd Since: 2000 early agent-based models of emotional contagion in crowd panic [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Collective action and tipping-point models Each person willing to join in only once enough others already have, so a crowd's move from quiet to acting together depends on the mix of individual thresholds. Question it answers: How many people acting first does it take before everyone else follows? Leaves out: Assumes everyone's threshold is fixed in advance, when real ones shift once a crowd starts moving. Runs on: about 10^9 FLOPS rough a laptop running a threshold cascade over a population Since: 1978 Granovetter's threshold model of collective behaviour [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Collective estimation and crowd wisdom Many independent, individually noisy guesses at a single number, pooled to see how much closer the average lands to the truth than any one person's guess. Question it answers: When does averaging many guesses beat asking one expert? Leaves out: The averaging effect fails once individual guesses cease to be independent. Runs on: about 10^9 FLOPS rough a laptop running a Monte Carlo aggregation of guesses Since: 1907 Francis Galton's analysis of a crowd's guesses at an ox's weight [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Protest mobilisation network models People deciding whether to join a protest based on how many of their own social ties are already going, spreading participation through a network rather than a crowd in one place. Question it answers: How does a protest movement grow from a few committed people to a mass turnout? Leaves out: Treats joining as a single yes-or-no decision, missing the small steps of real commitment. Runs on: about 10^10 FLOPS rough a desktop workstation simulating recruitment across a network Since: 1997 Kim and Bearman's network model of protest participation [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Mass gathering disease risk modelling The unusually dense, temporary mixing of people at a festival, pilgrimage or sporting event, modelled to estimate how fast an infection could spread and burn out once the crowd disperses. Question it answers: How much extra disease risk does bringing this many people together for a few days create? Leaves out: Once the crowd disperses, tracking where any resulting infections go next is largely out of reach. Runs on: about 10^12 FLOPS rough a university cluster simulating contacts across one gathering Since: 1987 modelling of a meningitis outbreak among pilgrims at a mass gathering [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ## Economies and markets ### Macroeconomic models A whole economy as representative households, firms, banks and a central bank reacting to each other. Question it answers: What happens to jobs and prices if interest rates rise? Leaves out: Representative-household models can miss dynamics from inequality. Runs on: about 10^12 FLOPS rough a desktop or small cluster solving a structural macroeconomic model Since: 1955 Klein and Goldberger's early computerised macroeconometric model [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Agent-based economies Thousands of individual households, firms and banks buying, selling, borrowing and failing. Question it answers: How do crises start from ordinary behaviour? Leaves out: Behaviour rules for the agents are chosen by the modeller, not measured from people. Runs on: about 10^13 FLOPS rough a university cluster simulating thousands of interacting households and firms Since: 1993 early agent-based computational economics models at the Santa Fe Institute [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Financial markets Traders with different strategies placing orders into a simulated market. Question it answers: Where do crashes and bubbles come from? Leaves out: Real markets have regulation, news and rare events toy trading rules leave out. Runs on: about 10^13 FLOPS rough a university cluster simulating many trading strategies interacting Since: 1994 Palmer, Arthur and colleagues’ Santa Fe artificial stock market [source](https://deepblue.lib.umich.edu/items/18b0197f-305e-40c5-b9bf-98ca56549ca5) In the simulations tree: [Artificial stock market](https://simulation-hypothesis.com/trees/simulations?n=soc-santafe) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Financial risk Thousands of possible futures for a portfolio, a bank or an insurer. Question it answers: How bad is a one-in-a-hundred-year loss? Leaves out: Assumes the future looks statistically like the past, which breaks down in a crisis. Runs on: about 10^13 FLOPS rough a bank or insurer's cluster running millions of Monte Carlo scenarios Since: 1994 risk management groups' early adoption of Monte Carlo value-at-risk models [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Market and auction design Bidders with strategies competing under different auction rules. Question it answers: Which set of rules gets the fairest price with the least gaming? Leaves out: Real bidders do not always behave as rationally as the strategies assume. Runs on: about 10^10 FLOPS rough a desktop workstation testing bidding strategies under auction rules Since: 1961 Vickrey's auction theory, later tested by simulation and experiment [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Artificial societies Agents gathering, trading and reproducing on a landscape of resources, from which wealth distributions and trade emerge. Question it answers: Which simple rules are enough to grow a society’s large-scale features? Leaves out: Simple rules can grow realistic-looking patterns for the wrong underlying reason. Runs on: about 10^10 FLOPS rough a desktop workstation running an agent landscape economy Since: 1996 Epstein and Axtell's Sugarscape model In the simulations tree: [Sugarscape](https://simulation-hypothesis.com/trees/simulations?n=soc-sugarscape) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### AI-designed economic policy simulation Learning agents act as workers in a simulated economy while a trained planner searches for tax policy that balances equality and productivity. Question it answers: What tax rule do learning agents and a planner converge to? Leaves out: Real people differ from learning agents, and economy structure is simple. Runs on: about 10^15 FLOPS rough Reinforcement learning at scale Since: 2020 The AI Economist (2020) [source](https://arxiv.org/abs/2004.13332) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Agent-based exchange simulators A simulated stock exchange with a full order book and time-stamped messages where trading agents, including learning ones, interact. Question it answers: How would a trading strategy or rule change affect a market? Leaves out: Agent behaviour is stylised, and market impact is hard to calibrate. Runs on: about 10^11 FLOPS rough Event-driven runs of thousands of agents Since: 2019 ABIDES: towards high-fidelity market simulation for AI research (2019) [source](https://arxiv.org/abs/1904.12066) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Housing market agent-based models Households with incomes, banks with lending rules and a limited housing stock interact to show how leverage and credit change prices and defaults. Question it answers: How do lending rules produce housing booms and busts? Leaves out: Household behaviour is rule-based and the data are of limited detail. Runs on: about 10^9 FLOPS rough hundreds of thousands of agents on a workstation. Since: 2012 Geanakoplos and colleagues, getting at systemic risk via an agent-based model of the housing market. [source](https://doi.org/10.1257/aer.102.3.53) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Dynamic stochastic general equilibrium models A representative household and firm choose over time under random shocks, and the model is used to trace how such disturbances and policy affect the economy. Question it answers: How does the economy respond to a shock or a change in interest rate? Leaves out: Assumes rational representative agents and cannot easily generate crises. Runs on: about 10^6 FLOPS rough perturbation or Bayesian estimation on a laptop. Since: 1982 Kydland and Prescott, time to build and aggregate fluctuations. [source](https://doi.org/10.2307/1913386) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Insurance catastrophe models Thousands of simulated storms, quakes or floods are applied to a property portfolio to estimate the losses an insurer might face. Question it answers: What is the loss exceeded once in 200 years? Leaves out: Rare extremes rest on short records and the vulnerability of buildings is estimated. Runs on: about 10^11 FLOPS rough large event catalogues on a cluster. Since: 1972 Friedman, insurance and the natural hazards. [source](https://doi.org/10.1017/s0515036100005699) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Financial contagion in interbank networks Banks linked by loans are shocked, and the failures that spread from one to the next are traced to measure systemic risk. Question it answers: How far does one bank failure spread through the system? Leaves out: Exposures are only partly observed and bank behaviour is fixed. Runs on: about 10^7 FLOPS rough clearing algorithms on a workstation. Since: 2001 Eisenberg and Noe, systemic risk in financial systems. [source](https://doi.org/10.1287/mnsc.47.2.236.9835) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Kinetic wealth exchange models Agents trade random amounts of money pairwise like colliding gas particles, and a distribution of wealth emerges. Question it answers: Do simple random exchanges produce the observed inequality? Leaves out: Exchange rules ignore production, credit and institutions. Runs on: about 10^6 FLOPS rough simulation of millions of exchanges on a laptop. Since: 2000 Dragulescu and Yakovenko, statistical mechanics of money. [source](https://doi.org/10.1007/s100510070114) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Rules ### Disaster economic ripple models An input-output model of how industries supply each other is hit by lost capacity after a disaster, and shortages cascade through the supply chain. Question it answers: What is the total economic cost when a disaster halts some industries? Leaves out: Fixed technical coefficients overstate rigidity and ignore firms switching suppliers. Runs on: about 10^6 FLOPS rough matrix models on a laptop. Since: 2008 Hallegatte, an adaptive regional input-output model applied to the economic cost of Katrina. [source](https://doi.org/10.1111/j.1539-6924.2008.01046.x) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Electricity market agent-based models Generators bid into a market repeatedly, learning from profit, and the price pattern shows how the rules affect outcomes. Question it answers: Do auction rules lead to lower prices or to collusive bidding? Leaves out: Learning rules for firms are assumed. Runs on: about 10^7 FLOPS rough repeated-auction simulation on a workstation. Since: 2001 Bower and Bunn, experimental analysis of the efficiency of uniform-price versus discriminatory auctions. [source](https://doi.org/10.1016/s0165-1889%2800%2900036-1) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Coupled epidemic and economy models An epidemic model is linked to an economy model, so that infection reduces work and spending, and economic choices change its spread. Question it answers: What is the trade-off between lives saved and output lost? Leaves out: Behaviour is assumed to be rational and uniform. Runs on: about 10^6 FLOPS rough dynamic optimisation on a laptop. Since: 2020 Eichenbaum, Rebelo and Trabandt, the macroeconomics of epidemics. [source](https://doi.org/10.3386/w26882) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Flash-crash market models Several types of trading agents, including fast automated sellers and slow fundamental buyers, interact in a model of a futures market to show how a sudden price collapse can build and recover. Question it answers: Can a large sell order and thin liquidity alone trigger a market-wide price plunge? Leaves out: The agents' strategies are simple stand-ins for real firms whose algorithms are secret, so the story it tells is plausible rather than verified. Runs on: about 10^11 FLOPS rough hours on a cluster for ensembles of trading days. Since: 2012 Paddrik and colleagues' agent-based model of the E-Mini S&P 500 futures market applied to the 2010 flash crash. [source](https://doi.org/10.1109/cifer.2012.6327800) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Algorithmic pricing collusion Pricing programs that learn from sales results are placed in a simulated market to see whether they come to charge high prices together without ever talking. Question it answers: Can independent sellers using learning algorithms come to keep prices above competitive levels? Leaves out: The markets are tiny, with a few firms and identical goods, and real firms use richer information and design. Runs on: about 10^9 FLOPS rough millions of repeated rounds on a workstation. Since: 2019 Calvano, Calzolari, Denicolò and Pastorello's study of AI algorithmic pricing and collusion. [source](https://doi.org/10.2139/ssrn.3304991) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Populations ### Language-model macroeconomic agents Language-model agents act as households and firms in a simulated economy, deciding in words how much to work, spend and save, and overall output and inflation are measured. Question it answers: Do agents that reason in language reproduce the patterns of real macroeconomies? Leaves out: The agents' behaviour comes from text they learned and may mirror what people write about economics rather than how they act. Runs on: about 10^16 FLOPS rough millions of model calls for a hundred agents over decades of simulated time. Since: 2023 Li and colleagues' EconAgent, language-model agents for simulating macroeconomic activities. [source](https://arxiv.org/abs/2310.10436) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Populations ## Anthropology and archaeology ### Reconstructed ancient societies The farming households of a past society, living on a simulated landscape rebuilt from climate and soil records, such as the ancestral Puebloan villages of the American Southwest. Question it answers: Why was this valley settled, and why was it abandoned? Leaves out: Depends on climate and crop-yield reconstructions that carry their own big uncertainties. Runs on: about 10^12 FLOPS rough a university cluster running centuries of simulated households Since: 2002 Axtell, Epstein, Dean, Gumerman and colleagues’ model of the Kayenta Anasazi in Long House Valley [source](https://profiles.wustl.edu/en/publications/population-growth-and-collapse-in-a-multiagent-model-of-the-kayen/) In the simulations tree: [Artificial Anasazi](https://simulation-hypothesis.com/trees/simulations?n=soc-anasazi) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Human dispersal Early human populations spreading across continents as climate and coastlines change. Question it answers: When and by which routes did people reach each continent? Leaves out: Routes and dates depend on climate and genetic estimates that keep changing. Runs on: about 10^12 FLOPS rough a university cluster simulating population spread across continents Since: 2008 by 2008, early agent-based simulations of out-of-Africa human dispersal Models: [Human](https://simulation-hypothesis.com/entities/human) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Populations ### Hunter-gatherer economies Bands foraging, moving camp and sharing food. Question it answers: Why did sharing food become universal among foragers? Leaves out: Ethnographic data from a handful of surviving groups stands in for a wider ancient variety. Runs on: about 10^11 FLOPS rough a desktop workstation simulating a band's foraging and sharing decisions Since: 1994 early agent-based models of forager food-sharing decisions [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Ancient trade and exchange Settlements linked by paths and sea routes, with goods and ideas moving between them. Question it answers: How did obsidian, pottery or ideas travel so far? Leaves out: Surviving artefacts are a thin and biased sample of everything that actually moved. Runs on: about 10^11 FLOPS rough a desktop workstation modelling exchange across a settlement network Since: 2007 by 2007, early network models of Roman-era trade routes [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Demographic microsimulation A synthetic population living out births, partnerships, migrations and deaths, year by year. Question it answers: How will the population age, and what does that mean for pensions and care? Leaves out: Errors in individual life-event probabilities compound across a simulated lifetime. Runs on: about 10^13 FLOPS rough a university cluster simulating a synthetic population's life events Since: 1957 Orcutt's original build of a microsimulation model of the American population Models: [Human](https://simulation-hypothesis.com/entities/human) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Monument construction and engineering reconstruction The structural loads, labour and logistics of an ancient monument, tested by simulating candidate construction methods against what the physical remains can and cannot support. Question it answers: Could this monument actually have been built the way tradition or a leading theory says? Leaves out: Several competing construction methods often fit the surviving evidence equally well. Runs on: about 10^11 FLOPS rough a desktop workstation running a structural and labour-logistics model Since: 1997 early simulations testing how Egyptian pyramid construction ramps could have worked [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ## Policy and organisations ### Tax and benefit microsimulation A proposed change to taxes or benefits applied to a large sample of real households. Question it answers: Who gains and who loses from this change, and by how much? Leaves out: Assumes people do not change behaviour in response to the policy, which they sometimes do. Runs on: about 10^12 FLOPS rough a university cluster applying rules to a large household sample Since: 1976 Orcutt and colleagues' DYNASIM microsimulation of US tax policy [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### World models Population, food, industry, resources and pollution as stocks and feedback loops on a global scale. Question it answers: What happens to a world with finite resources under continued growth? Leaves out: A handful of global stocks hides all regional and national variation. Runs on: about 10^10 FLOPS rough a desktop workstation solving a global stocks-and-flows model Since: 1971 Forrester’s World2, published in World Dynamics; World3 for The Limits to Growth followed in 1972 [source](https://en.wikipedia.org/wiki/World3) In the simulations tree: [World3](https://simulation-hypothesis.com/trees/simulations?n=soc-world3) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Organisations and teams Members, problems and decisions moving through an organisation. Question it answers: Why do organisations make the decisions they do? Leaves out: Real organisational politics and personality are hard to reduce to decision rules. Runs on: about 10^10 FLOPS rough a desktop workstation simulating decisions moving through an organisation Since: 1963 Cyert and March's simulation models of organisational decision-making [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Computable general equilibrium modelling A whole economy's industries, households and government rebuilt as a system of markets that must all clear at once, then shocked with a tax or trade policy to see where prices and output settle. Question it answers: How does a whole economy rebalance itself after this policy change? Leaves out: Assumes markets settle into a new equilibrium cleanly, neglecting the disorderly transition in practice. Runs on: about 10^11 FLOPS rough a small cluster solving a large system of market-clearing equations Since: 1972 Shoven and Whalley's applied general-equilibrium model of tax policy [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Institutional corruption and integrity modelling Officials and citizens deciding whether to bribe, report or comply, each responding to how common corruption already is and how likely getting caught seems. Question it answers: Why does corruption stay rare in some institutions and become the norm in others? Leaves out: Real corruption is hidden by design, so the numbers feeding the model are rough estimates. Runs on: about 10^10 FLOPS rough a desktop workstation running an agent-based compliance model Since: 2002 early agent-based models of how corruption spreads within an institution [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Policy diffusion network models One government's adoption of a law or programme spreading to others through the ties between them, whether neighbours, trading partners or shared professional networks. Question it answers: Why do some governments copy a policy quickly, and others never adopt it at all? Leaves out: Copying a policy on paper is easier to model than whether it works the same way elsewhere. Runs on: about 10^10 FLOPS rough a desktop workstation simulating adoption across a network of governments Since: 1990 by 1990, early network models of policy diffusion between governments [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Language-model agent organisations Language-model agents take on roles such as manager, programmer and tester and collaborate to produce software. Question it answers: Can a team of role-playing agents carry out a multi-step organisational task? Leaves out: Output depends on prompts, and real human organisational friction is absent. Runs on: about 10^14 FLOPS rough Many model calls per project Since: 2023 ChatDev: communicative agents for software development (2023) [source](https://arxiv.org/abs/2307.07924) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Language-grounded negotiation agents Agents combine a language model with strategic planning to negotiate and form alliances in a multi-player game by talking to each other. Question it answers: Can an agent persuade and plan with humans in an open-ended negotiation? Leaves out: Only one game's rules, and it cannot reason about long-term trust. Runs on: about 10^16 FLOPS rough Large training plus planning at play time Since: 2022 Human-level play in the game of Diplomacy by combining language models with strategic reasoning (2022) [source](https://doi.org/10.1126/science.ade9097) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Opioid epidemic system dynamics Stocks of prescription users, misusers, heroin users and the dead are linked by feedback and policy levers such as supply limits and treatment. Question it answers: Which policy mix reduces opioid deaths? Leaves out: Illicit supply changes faster than models adapt. Runs on: about 10^5 FLOPS rough stock-and-flow simulation on a laptop. Since: 2013 Wakeland and colleagues, modelling the impact of simulated educational interventions on pharmaceutical opioid use. [source](https://doi.org/10.1177/1090198113492767) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Exploratory modelling under deep uncertainty A model is run across thousands of combinations of unknown inputs and policies, to find strategies that are robust rather than optimal for a single forecast. Question it answers: Which policy is acceptable across the widest range of futures? Leaves out: The range of futures explored is still chosen by the analyst. Runs on: about 10^10 FLOPS rough ensembles of runs of a base model on a cluster. Since: 1993 Bankes, exploratory modelling for policy analysis. [source](https://doi.org/10.1287/opre.41.3.435) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Supply-chain dynamics and the bullwhip effect Orders and stock flow through factory, distributor and retailer with delays, and small changes in demand grow into large swings upstream. Question it answers: Why do small demand changes cause huge order swings upstream? Leaves out: Real firms respond to information that the model leaves out. Runs on: about 10^5 FLOPS rough stock-and-flow simulation on a laptop. Since: 1958 Forrester, industrial dynamics: a major breakthrough for decision makers. [source](https://doi.org/10.1007/978-3-642-27922-5%5F13) [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ## Law, justice and elections ### Electoral and voting system simulation The same set of voters and candidates run through different voting rules, such as first-past-the-post, ranked choice or proportional systems, to compare who would actually win. Question it answers: Would a different voting system have changed who won this election? Leaves out: Assumes voters' preferences stay fixed even though a different system would change how people vote. Runs on: about 10^10 FLOPS rough a desktop workstation running elections under alternative voting rules Since: 1975 early computer simulations comparing the outcomes of different voting rules [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Court and case-flow simulation Cases arriving, waiting for hearings and moving through stages of a court system, used to see where a backlog builds and what more judges or courtrooms would do to it. Question it answers: How long will it take to clear this court's backlog, and what would actually speed it up? Leaves out: Real case complexity and human discretion vary more than a queueing model assumes. Runs on: about 10^10 FLOPS rough a desktop workstation running a discrete-event model of case flow Since: 1976 early discrete-event simulations of US court case backlogs [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Sentencing and recidivism risk modelling A person's recorded history run through a statistical model that scores how likely they are to reoffend, used to inform parole, bail or sentencing decisions. Question it answers: How likely is this person to reoffend, based on people with a similar record? Leaves out: A score built from group statistics can be wrong for the one person it is applied to, in either direction. Runs on: about 10^11 FLOPS rough a desktop workstation fitting a risk model to case records Since: 1928 Burgess's actuarial scale predicting parole success, an early risk model [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Policing and patrol deployment simulation Patrol units and reported incidents across a city, used to test how different ways of assigning officers to areas change response times and coverage. Question it answers: Where should patrols be sent to cut response times the most? Leaves out: Historical crime data can embed past biases in where officers were deployed. Runs on: about 10^10 FLOPS rough a desktop workstation running a queueing model of patrol deployment Since: 1972 Larson's hypercube queuing model for police patrol deployment [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Bodies ### Legislative bargaining and coalition simulation Parties with positions on a policy space negotiating and forming coalitions to pass a bill or form a government, using rules for who proposes and who must agree. Question it answers: Which coalition will actually form, and what compromise will it settle on? Leaves out: Real coalitions form around personalities and history that a spatial model leaves out. Runs on: about 10^10 FLOPS rough a desktop workstation solving a spatial coalition-bargaining model Since: 1980 early simulations of spatial voting and coalition formation in parliaments [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Rules ### Jury decision-making simulation Individual jurors with different initial views, deliberating under rules such as majority or unanimity, to see what verdict and how much persuasion the group ends up producing. Question it answers: Does the verdict reflect the strength of the evidence, or only the dynamics of the deliberation? Leaves out: Lab juries deciding mock cases may not behave like real juries facing real stakes. Runs on: about 10^9 FLOPS rough a laptop running a social decision-scheme deliberation model Since: 1983 Davis and colleagues' social decision-scheme models of jury deliberation [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Crime hotspot dynamics Offenders move through a city and are drawn to places with past crime, producing hotspots that grow, move and respond to policing. Question it answers: How do hotspots form and can patrols move them? Leaves out: Offender motives are simplified and crime reporting is imperfect. Runs on: about 10^7 FLOPS rough agent-based city runs on a workstation. Since: 2008 Short and colleagues, a statistical model of criminal behaviour. [source](https://doi.org/10.1142/s0218202508003029) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations [◂ Agriculture and food](https://simulation-hypothesis.com/simulations/agriculture-food)[Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering) --- title: "Engineering and technology · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/engineering description: "Airflow over wings, structures under load, chips before fabrication, robots before construction. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 9 of 18 # Engineering and technology Airflow over wings, structures under load, chips before fabrication, robots before they are built. Almost nothing gets built today without simulating it first. Over the past fifty years, simulation has replaced most physical prototypes. The oldest form, the physical scale model, is still in use. ## Flow ### Aerodynamics Air flowing over wings, cars, buildings and wind turbines. Question it answers: How much drag, how much lift, and where does the flow break away? Leaves out: Turbulence is modelled, not resolved, so fine separation detail is approximate. Runs on: about 10^15 FLOPS rough a university or corporate HPC cluster, days per case Since: 1962 Hess and Smith's panel method for aircraft shapes [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Turbulence Every eddy of a turbulent flow resolved directly, from the largest swirl down to the smallest. Question it answers: What is turbulence actually doing, so that cheaper models can approximate it? Leaves out: Limited to modest Reynolds numbers; real flows outrun the largest machines. Runs on: about 10^17 FLOPS rough a national supercomputer, a large share, for weeks Since: 1972 Orszag and Patterson's first 3D direct numerical simulation [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Physical scale models Wind tunnels, wave tanks, river models and shaking tables: the oldest simulations, and still used to check the numerical ones. Question it answers: Does the real flow match what the computer predicted? Leaves out: Scale effects mean a small model does not always behave like the full-size thing. Runs on: no computer. no digital computing; real air, water or a shaking table instead Since: 1871 Frank Wenham built one of the first wind tunnels [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Cavitation simulation Bubbles forming and collapsing violently in fast-moving liquid, around ship propellers, pumps and valves. Question it answers: Where will cavitation erode this propeller or pump, and how do we design around it? Leaves out: Bubble collapse happens on scales finer than most simulations can afford to resolve everywhere. Runs on: about 10^15 FLOPS rough a university or shipyard cluster, hours per case Since: 1988 by 1988, early computational models of cavitating flow around propellers [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Multiphase and pipeline flow Oil, gas, water and slurries moving together through pipelines, wells and process plant. Question it answers: Will the pipeline run smoothly, or will slugs of liquid and gas choke it? Leaves out: Sudden slug formation is still one of the harder things to predict reliably. Runs on: about 10^14 FLOPS rough an energy company's cluster, hours per pipeline case Since: 1979 by 1979, early multiphase flow models for offshore oil and gas pipelines [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Ice accretion simulation Supercooled water droplets freezing onto aircraft wings and wind turbine blades in flight or in the wind. Question it answers: How much ice will build up, and will de-icing keep up with it? Leaves out: Real cloud droplet sizes and mixed-phase ice vary more than standard test conditions assume. Runs on: about 10^14 FLOPS rough an aerospace lab cluster, hours per icing case Since: 1988 by 1988, early computational icing codes support aircraft certification [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Physics-informed neural networks A neural network is trained so that its outputs satisfy a governing differential equation and observed data at once. Question it answers: Can a network learn the solution of a PDE with little or no mesh? Leaves out: Training is slow and unreliable for stiff or turbulent problems. Runs on: about 10^13 FLOPS rough Gradient-based training with automatic differentiation Since: 2017 Physics informed deep learning, part I (2017) [source](https://arxiv.org/abs/1711.10561) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Neural operators A network learns the map from a function, such as a boundary condition, to the solution of a PDE, so new inputs are answered in one pass. Question it answers: Can a trained model solve a whole family of PDEs instantly? Leaves out: Needs many solver runs for training and extrapolates poorly. Runs on: about 10^15 FLOPS rough Expensive data generation, then fast inference Since: 2019 DeepONet: learning nonlinear operators (2019), followed by Fourier neural operators (2020) [source](https://arxiv.org/abs/1910.03193) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Graph-network learned simulators A graph neural network trained on simulation data steps particles or mesh nodes forward to mimic fluids, cloth and solids. Question it answers: Can a neural net replace a physics solver for fluids and deformable objects? Leaves out: Errors build up over long rollouts and conservation is not guaranteed. Runs on: about 10^14 FLOPS rough Training on solver data, faster rollout Since: 2020 Learning to simulate complex physics with graph networks (2020) [source](https://arxiv.org/abs/2002.09405) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Learned fluid solvers A convolutional network replaces the pressure-projection step of a grid fluid solver to speed up smoke and liquid simulation. Question it answers: Can a trained network make an incompressible flow solver much faster? Leaves out: Stability and accuracy are only tested on flows similar to training. Runs on: about 10^12 FLOPS rough Training on solver data, fast inference Since: 2016 Accelerating Eulerian fluid simulation with convolutional networks (2016) [source](https://arxiv.org/abs/1607.03597) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Lattice-gas automata for fluid flow Particles hopping on a lattice with simple collision rules that reproduce the flow of a liquid or gas in the large, with no fluid-mechanics equations built in. Question it answers: Can a fluid's flow emerge from simple particle rules on a lattice? Leaves out: Noise from discrete particles and lack of Galilean invariance limit accuracy, which is why it was replaced. Runs on: about 10^11 FLOPS rough bit-wise rules on a lattice with millions of sites. Since: 1986 Frisch, Hasslacher and Pomeau's lattice-gas automata for the Navier-Stokes equation. [source](https://doi.org/10.1103/physrevlett.56.1505) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Rules ### Lattice Boltzmann flow simulation Fluid represented by distributions of particle velocities on a lattice, which stream and collide to give flow in complex geometry such as porous rock or blood vessels. Question it answers: How does a fluid flow through a very complicated geometry? Leaves out: The method is limited to low Mach numbers, and boundary treatment needs care. Runs on: about 10^15 FLOPS rough billions of lattice cells on graphics or cluster hardware. Since: 1988 McNamara and Zanetti's use of the Boltzmann equation to simulate lattice-gas automata. [source](https://doi.org/10.1103/physrevlett.61.2332) [Lattice field theory](https://simulation-hypothesis.com/simulations/methods#m-lattice)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Rarefied-gas direct simulation Molecules of a thin gas moved and collided at random, where the gas is too sparse to be a continuous fluid, as at the edge of space or inside tiny channels. Question it answers: How does a thin gas flow around a vehicle at the edge of the atmosphere? Leaves out: Each simulated particle stands for trillions of real ones, so statistical noise is high at low speeds. Runs on: about 10^14 FLOPS rough billions of simulated particles. Since: 1963 Bird's direct simulation of the approach to translational equilibrium in a rigid sphere gas. [source](https://doi.org/10.1063/1.1710976) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Molecules ### Wind-farm large-eddy simulation Turbulent air through a wind farm with the forces from each rotor added, to see how wakes interact and cut the power of turbines downwind. Question it answers: How much power does a wind farm lose to its own wakes? Leaves out: Turbine blades are replaced by force disks, and terrain and atmospheric stability change the results. Runs on: about 10^16 FLOPS rough large-eddy runs of a multi-kilometre domain with tens of turbines. Since: 2010 Calaf, Meneveau and Meyers's large-eddy simulation of fully developed wind-turbine array boundary layers. [source](https://doi.org/10.1063/1.3291077) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Fluid-structure interaction A moving fluid and a deforming body solved together, so flapping, vibration and flutter can be predicted for wings, bridges and valves. Question it answers: How does a flexible structure move in the flow around it? Leaves out: Mesh motion and strong added-mass effects make coupling expensive and sometimes unstable. Runs on: about 10^15 FLOPS rough coupled fluid and solid solvers iterated each step. Since: 1974 Hirt, Amsden and Cook's arbitrary Lagrangian-Eulerian method for flows at all speeds. [source](https://doi.org/10.1016/0021-9991%2874%2990051-5) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Fire dynamics large-eddy simulation Hot gas and smoke from a fire in a room, tunnel or building solved as a buoyant turbulent flow with simple combustion, to see how heat and fumes spread. Question it answers: How quickly will smoke fill this corridor, and when will people no longer see their way out? Leaves out: Combustion chemistry and soot are simplified, and real fuels, windows and furniture are only approximately described. Runs on: about 10^13 FLOPS rough days on a cluster for a large building fire. Since: 2000 McGrattan and colleagues' Fire Dynamics Simulator user's manual from the US National Institute of Standards and Technology. [source](https://doi.org/10.6028/nist.ir.6469) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Structures and machines ### Structural analysis Bridges, buildings, aircraft and parts under load, heat and vibration. Question it answers: Where is the weak point, and how much margin is left? Leaves out: Assumes idealised materials and loads; real defects are handled by margins, not physics. Runs on: about 10^14 FLOPS rough an engineering workstation or small cluster, hours per case Since: 1956 Turner, Clough, Martin and Topp's aircraft structural method [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Crash simulation Vehicles deforming in a collision, with virtual occupants inside. Question it answers: How do we protect the people inside? Leaves out: Occupant injury is estimated from dummy models, not real human tissue variability. Runs on: about 10^15 FLOPS rough an automaker's HPC cluster, hours per crash case Since: 1979 by 1979, national-laboratory explicit finite-element codes model vehicle impacts [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Multibody dynamics Machines as rigid parts joined by hinges, springs and gears: suspensions, engines, robot arms. Question it answers: Will the mechanism move as designed, and where do the loads go? Leaves out: Parts are treated as rigid or lightly flexible, missing fine vibration modes. Runs on: about 10^13 FLOPS rough an engineering desktop, minutes to hours Since: 1971 Sheth and Uicker's computer method for mechanism analysis [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Acoustics and vibration Sound waves in rooms, engines and cities, and vibration in structures. Question it answers: Will this hall achieve good acoustic quality, and will this bridge resonate audibly? Leaves out: Struggles with low frequencies, where wave effects dominate over rays. Runs on: about 10^14 FLOPS rough a workstation or small cluster, hours per case Since: 1968 Krokstad and colleagues modelled room acoustics by ray tracing [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Fatigue and crack growth A structure's slow damage from millions of small load cycles, tracked as cracks that grow and eventually fail. Question it answers: How many years or flight hours before this part needs replacing? Leaves out: Real flaws from manufacturing are more varied than the idealised starting cracks assumed. Runs on: about 10^14 FLOPS rough an engineering workstation or small cluster, hours per part Since: 1968 by 1968, early fracture-mechanics fatigue-life computer codes [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Tribology and contact mechanics Friction, wear and lubrication between moving surfaces in bearings, gears and joints. Question it answers: How long will this bearing last, and how much energy does friction waste? Leaves out: Surface roughness at the microscopic scale is approximated, not measured for each part. Runs on: about 10^13 FLOPS rough an engineering desktop, hours per contact case Since: 1970 by 1970, early elastohydrodynamic lubrication computer models [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Topology optimisation Material added and removed from a design space under loads until the lightest stiff shape appears, with holes and struts the engineer never drew. Question it answers: What is the lightest shape that still carries this load? Leaves out: Optimal shapes are often hard to manufacture and may be fragile to loads that were not considered. Runs on: about 10^13 FLOPS rough finite-element solves inside an optimisation loop with millions of variables. Since: 1988 Bendsoe and Kikuchi's generation of optimal topologies in structural design using a homogenisation method. [source](https://doi.org/10.1016/0045-7825%2888%2990086-2) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Peridynamic fracture modelling A solid represented as points interacting at a distance, so cracks start, branch and merge without any crack path defined beforehand. Question it answers: How does a crack choose its path through a brittle material? Leaves out: The interaction range and failure law must be calibrated to the material. Runs on: about 10^14 FLOPS rough meshless runs with millions of nodes. Since: 2000 Silling's reformulation of elasticity theory for discontinuities and long-range forces. [source](https://doi.org/10.1016/s0022-5096%2899%2900029-0) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Orbital-debris and satellite-collision modelling Satellites, fragments and rocket bodies tracked through decades of collisions and decay to find whether they feed on themselves and close useful orbits. Question it answers: How many collisions before debris makes an orbit unusable? Leaves out: Small untracked fragments, future launches and mitigation behaviour are uncertain. Runs on: about 10^11 FLOPS rough long Monte Carlo runs over many orbit populations. Since: 1978 Kessler and Cour-Palais's collision frequency of artificial satellites and the creation of a debris belt. [source](https://doi.org/10.1029/ja083ia06p02637) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Rules ### Co-simulation of linked models Separate simulations of a motor, a gearbox, a controller and a battery, each built in its own tool, are run together by trading data at agreed time steps. Question it answers: Does the whole machine work when every subsystem model, built by different teams, runs together? Leaves out: Exchanging data at fixed steps adds numerical error, and a stiff coupling can become unstable. Runs on: about 10^10 FLOPS rough hours on a workstation for a vehicle cycle. Since: 2011 Blochwitz and colleagues' Functional Mock-up Interface for tool-independent exchange of simulation models. [source](https://doi.org/10.3384/ecp11063105) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ## Electronics and computers ### Circuit simulation Every voltage and current in an electronic circuit, transistor by transistor. Question it answers: Does the circuit work, and how much power does it draw? Leaves out: Component models are fitted approximations; real silicon varies chip to chip. Runs on: about 10^13 FLOPS rough an engineering desktop, minutes per chip block Since: 1973 Nagel and Pederson's SPICE, a general circuit simulation program at Berkeley [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Chip logic simulation A digital chip design run one clock cycle at a time before it is manufactured. Question it answers: Does the chip compute the correct result before the cost of manufacture is incurred? Leaves out: Timing is approximated; a working simulation can still fail once manufactured. Runs on: about 10^14 FLOPS rough a design workstation or small server cluster, hours per run Since: 1965 by 1965, early gate-level simulators check digital logic designs [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Electromagnetics Radio waves, light and fields around antennas, circuits and optical devices. Question it answers: How well does this antenna radiate, and does this device leak interference? Leaves out: Fine geometric detail near the mesh limit gets smoothed away. Runs on: about 10^14 FLOPS rough a workstation or cluster, hours per design Since: 1966 Kane Yee's finite-difference time-domain method [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Computer network simulation Packets flowing through routers, links and protocols. Question it answers: Can the network sustain twice the traffic? Leaves out: Simplifies real hardware quirks and traffic patterns seen in production networks. Runs on: about 10^13 FLOPS rough a desktop or small server, minutes to hours Since: 1964 Leonard Kleinrock's queueing analysis of packet networks [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Emulation and virtual machines One machine imitating another exactly, instruction by instruction, so that its software runs unchanged. Question it answers: Can we run this old or future system on the hardware we have? Leaves out: Runs slower than the real hardware unless carefully optimised. Runs on: about 10^12 FLOPS rough a desktop computer, real time or faster Since: 1963 by 1963, early instruction-set simulators test computer designs before they exist [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Semiconductor device simulation Electrons and dopant atoms inside a single transistor, before it is turned into a circuit-level model. Question it answers: How will this transistor's shape and doping change how it switches? Leaves out: Simplifies quantum effects that matter most at the very smallest transistor sizes. Runs on: about 10^14 FLOPS rough a semiconductor company's cluster, hours per device Since: 1964 Gummel's numerical model of a bipolar transistor [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Atoms ### Network digital twins A virtual copy of a communication network, kept in sync with the real one, used to test changes before they are applied. Question it answers: What would happen to the network if this change were made? Leaves out: Fidelity depends on telemetry, and scale is limited. Runs on: about 10^12 FLOPS rough Packet-level or learned models Since: 2021 Digital twin networks: a survey (2021) [source](https://doi.org/10.1109/JIOT.2021.3079510) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Optical lithography simulation Light passing through a mask onto a photosensitive film to predict the circuit patterns printed on a chip, including blur and resist chemistry. Question it answers: Will the pattern on a mask print as intended on a chip? Leaves out: Resist chemistry and stochastic photon effects at tiny sizes are approximated. Runs on: about 10^13 FLOPS rough full-chip simulation for a layer. Since: 1975 Dill's optical lithography exposure model of resist. [source](https://doi.org/10.1109/t-ed.1975.18158) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Semiconductor process simulation The fabrication steps of a transistor, implanting, diffusing and oxidising, followed to predict doping profiles and shapes before the device model. Question it answers: What dopant profile and shape does a given fabrication recipe produce? Leaves out: Point-defect and interface models need calibration against each new process. Runs on: about 10^12 FLOPS rough two- or three-dimensional diffusion and reaction solves. Since: 1979 Antoniadis and Dutton's models for computer simulation of complete IC fabrication processes. [source](https://doi.org/10.1109/t-ed.1979.19452) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Atoms ### Processor thermal modelling Heat flowing through the layers of a chip and its package, driven by the changing power of functional blocks, to find hot spots and set throttling. Question it answers: Where does a processor overheat as its workload changes? Leaves out: The model uses power estimates, and package and cooling details are lumped. Runs on: about 10^8 FLOPS rough a compact thermal network that runs in seconds. Since: 2003 Skadron and colleagues' temperature-aware microarchitecture with a compact thermal model. [source](https://doi.org/10.1145/859618.859620) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Photonic-crystal band-structure calculation Light in a periodic arrangement of dielectric, solved for the frequencies that can and cannot propagate, to design waveguides and filters. Question it answers: Which colours of light can a periodic structure block? Leaves out: Perfect periodicity is assumed, so disorder, losses and finite size are added separately. Runs on: about 10^10 FLOPS rough plane-wave eigenvalue solves for each wave vector. Since: 1990 Ho, Chan and Soukoulis's demonstration of a photonic gap in periodic dielectric structures. [source](https://doi.org/10.1103/physrevlett.65.3152) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Stacked chip thermal modelling Heat moving through layers of silicon piled vertically and cooled by liquid between them, solved quickly enough to set the design of the stack. Question it answers: Can a stack of chips with channels of coolant keep every layer below its limit? Leaves out: Real chips have hot spots much smaller than the model's cells, so peak temperatures can be underestimated. Runs on: about 10^8 FLOPS rough minutes on a workstation. Since: 2010 Sridhar and colleagues' 3D-ICE compact transient thermal model for 3D chips with inter-tier liquid cooling. [source](https://doi.org/10.1109/iccad.2010.5653749) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ## Robotics and autonomy ### Robot simulation Robots with simulated sensors and motors in a physics engine, trained or tested before touching the real world. Question it answers: Will a controller learned in simulation work on the real robot? Leaves out: Contact and friction in the real world are still hard to match exactly. Runs on: about 10^13 FLOPS rough a desktop with a GPU, real time or faster Since: 1983 by 1983, early offline-programming simulators plan industrial robot arms [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Autonomous vehicle testing Self-driving software driving millions of virtual kilometres through rare and dangerous scenarios. Question it answers: How does the system handle the situation that happens once in a million kilometres? Leaves out: Rare real-world scenarios are still hard to capture, however many virtual kilometres are driven. Runs on: about 10^15 FLOPS rough a fleet of cloud GPU servers, run in parallel Since: 2004 simulation support for the early US self-driving vehicle grand challenges [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Swarm robotics Many simple robots coordinating by local rules, often borrowed from insects. Question it answers: Can a hundred cheap robots do what one expensive one cannot? Leaves out: Simple simulated robots do not capture real sensor noise and battery limits. Runs on: about 10^12 FLOPS rough a laptop, simulating tens to hundreds of robots Since: 1989 Gerardo Beni's early work on swarm intelligence and cellular robotics [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Digital twins A simulation kept continuously in step with a real machine, plant or building using its live sensor data. Question it answers: What is about to fail, and what happens if we change this setting? Leaves out: Accuracy is bounded by the sensor data supplied to it; gaps and drift accumulate. Runs on: about 10^13 FLOPS rough a cloud server continuously updating a plant model Since: 2002 Michael Grieves proposed pairing a product with a live virtual model [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Planetary rover mobility A rover's wheels and arm interacting with loose soil and rock on another world, before it ever drives there. Question it answers: Will the rover get stuck, and can its arm reach the sample? Leaves out: Extraterrestrial soil is known from only a handful of landing sites, so its behaviour is extrapolated. Runs on: about 10^13 FLOPS rough a space agency's cluster, hours per terrain case Since: 1997 wheel-soil simulations supporting the first successful Mars rover [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Exoskeleton and prosthetic control A wearable machine and a human body moving together, with the control system tuned before a person wears it. Question it answers: Will the device assist the wearer's movement, or work against it? Leaves out: Simulated bodies rarely capture one person's particular injury or gait exactly. Runs on: about 10^13 FLOPS rough a research lab desktop, real time per trial Since: 1990 by 1990, early powered-exoskeleton control simulations at research labs [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### GPU-parallel robot learning environments Thousands of simulated robots run at once on one GPU so that a reinforcement-learning policy can train in minutes. Question it answers: How quickly can a robot policy be learned using massive parallel simulation? Leaves out: Contact physics are simplified, so transfer needs care. Runs on: about 10^15 FLOPS rough Thousands of parallel physics environments on GPU Since: 2021 Isaac Gym: high performance GPU-based physics simulation for robot learning (2021) [source](https://arxiv.org/abs/2108.10470) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Domain-randomised sim-to-real training A policy is trained in a simulator whose looks and physics vary at random so it works in the real world. Question it answers: Can a policy trained only in simulation work on a real robot? Leaves out: Randomisation ranges must cover the real gap, which is hard to know. Runs on: about 10^14 FLOPS rough Large randomised training runs Since: 2017 Domain randomization for transferring deep neural networks from simulation to the real world (2017) [source](https://arxiv.org/abs/1703.06907) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Differentiable physics simulation A physics engine written so that gradients flow back through contacts and motion, letting designs or controllers be tuned by gradient descent. Question it answers: How should this controller or design change to improve its outcome? Leaves out: Gradients through hard contacts are noisy or misleading. Runs on: about 10^12 FLOPS rough Backward passes through many simulation steps Since: 2016 A differentiable physics engine for deep learning in robotics (2016) [source](https://arxiv.org/abs/1611.01652) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Adversarial driving-scenario generation An optimiser perturbs the paths of other road users in recorded scenes to find situations in which a self-driving system fails. Question it answers: Which realistic situations make an autonomy stack fail? Leaves out: A scenario that makes the system fail may almost never occur on real roads, so it says little about how often failures happen. Runs on: about 10^13 FLOPS rough Many closed-loop simulation runs Since: 2021 AdvSim: generating safety-critical scenarios for self-driving vehicles (2021) [source](https://arxiv.org/abs/2101.06549) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Open driving simulators with sensor models A game-engine world with traffic, weather and simulated cameras and lidar for developing and testing autonomous driving. Question it answers: How would a driving system see and act in varied conditions? Leaves out: Sensor and traffic realism do not match the real world exactly. Runs on: about 10^12 FLOPS rough Real-time rendering on GPUs Since: 2017 CARLA: an open urban driving simulator (2017) [source](https://arxiv.org/abs/1711.03938) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Learned legged locomotion A reinforcement-learning policy is trained to walk and run for a legged robot in a physics simulator, then is moved to the real machine. Question it answers: Can a robot learn to walk in simulation and keep its balance on real ground? Leaves out: Foot contact, motor delays and ground softness differ from the model, so a policy that works in simulation may fail on the machine. Runs on: about 10^16 FLOPS rough hours to days of GPU time per gait. Since: 2018 Tan and colleagues' sim-to-real learning of agile locomotion for quadruped robots. [source](https://arxiv.org/abs/1804.10332) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Learned humanoid locomotion A neural controller is trained in simulation for a two-legged human-shaped robot to walk over many kinds of ground, using a history of its own senses to adapt. Question it answers: Can a humanoid walk outdoors on stairs, grass and slopes using a policy learned without any real trials? Leaves out: Falls of a full-size humanoid are dangerous and costly, so testing is cautious and the policy's limits are not mapped. Runs on: about 10^17 FLOPS rough days on a GPU cluster. Since: 2023 Radosavovic and colleagues' real-world humanoid locomotion with reinforcement learning. [source](https://arxiv.org/abs/2303.03381) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Drone flight simulation Small aircraft with rotors, sensors and cameras flying through rendered scenes under simulated wind and physics, to develop autonomy and test it safely. Question it answers: Will this flight software keep the drone stable and avoid obstacles before it ever leaves the ground? Leaves out: Aerodynamics close to the ground, in gusts and between obstacles is simplified, so edge cases appear only on a real drone. Runs on: about 10^12 FLOPS rough real time on a gaming-class GPU, or thousands of runs in parallel. Since: 2017 Shah and colleagues' AirSim, visual and physical simulation for aerial and ground vehicles. [source](https://arxiv.org/abs/1705.05065) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Learned drone racing A control policy is trained in simulation to fly a quadrotor through a racing course at the limit of its speed, then flown on the real aircraft. Question it answers: Can a learned controller fly faster than a human champion pilot? Leaves out: The course is known and well lit, so the policy is not shown to work in unknown places or poor conditions. Runs on: about 10^16 FLOPS rough days of GPU training in simulation. Since: 2023 Kaufmann and colleagues' champion-level drone racing with deep reinforcement learning. [source](https://doi.org/10.1038/s41586-023-06419-4) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Soft robot simulation A robot made of rubbery material is modelled as a deformable solid by finite elements fast enough to control it in real time. Question it answers: How must the air pressure in the chambers be changed so the soft arm reaches a given point? Leaves out: Rubber properties change with temperature and age, and the model's speed requires a coarse mesh. Runs on: about 10^9 FLOPS rough real-time on a workstation. Since: 2013 Duriez's control of elastic soft robots based on a real-time finite element method. [source](https://doi.org/10.1109/icra.2013.6631138) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Tactile sensor simulation The touch images that a camera-based skin sensor would capture when pressed on objects are rendered in simulation, so robot hands can learn to feel. Question it answers: Can a robot learn to handle objects by touch without wearing out real sensors? Leaves out: The gel's soft deformation is rendered approximately, so sim-to-real gaps are larger for fine texture. Runs on: about 10^10 FLOPS rough real-time on a gaming-class GPU. Since: 2020 Wang and colleagues' TACTO, a fast open-source simulator for vision-based tactile sensors. [source](https://arxiv.org/abs/2012.08456) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ## Spaceflight and energy ### Spacecraft trajectories Paths through the gravity of the Sun, planets and moons, including gravity assists. Question it answers: What is the cheapest route to this moon, and when do we launch? Leaves out: Assumes known gravity and no perturbations; real navigation still requires course corrections. Runs on: about 10^12 FLOPS rough a laptop, seconds per candidate trajectory Since: 1959 early trajectory computations for the first Moon missions [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Atmospheric entry A spacecraft hitting the atmosphere at many kilometres a second, with the shock wave and heat around it. Question it answers: Will the heat shield survive? Leaves out: Rare flow chemistry at extreme speed is still an active source of uncertainty. Runs on: about 10^15 FLOPS rough a national or university HPC cluster, hours per case Since: 1958 by 1958, early ballistic-missile reentry heating calculations [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Batteries and fuel cells Ions and electrons moving through electrodes and electrolyte as a cell charges and ages. Question it answers: How can charging be made faster without accelerating degradation of the battery? Leaves out: Ageing over thousands of cycles is still extrapolated, not fully simulated. Runs on: about 10^14 FLOPS rough a university cluster, hours per cell design Since: 1993 Doyle, Fuller and Newman's porous-electrode battery model [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Fields ### Rocket engine simulation Hot combustion gas expanding through a rocket engine's nozzle, and the heat it dumps into the walls that must survive it. Question it answers: How much thrust does this engine produce, and will the nozzle and walls survive the heat? Leaves out: Combustion instability, where the flame itself starts to oscillate, is still hard to predict. Runs on: about 10^16 FLOPS rough a space agency or company's supercomputer share, hours per case Since: 1968 by 1968, early computational models of rocket combustion chambers [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Spacecraft thermal and power simulation Heat and electrical power moving through a satellite as sunlight, shadow and onboard equipment change. Question it answers: Will every part of the spacecraft stay within its safe temperature and power budget? Leaves out: Assumes surfaces age and degrade as expected, which years in orbit do not always confirm. Runs on: about 10^12 FLOPS rough a satellite engineer's desktop, minutes per orbit case Since: 1965 by 1965, early thermal-balance models for orbiting satellites [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Solar and wind farm yield simulation Sunlight or wind over a year matched against a farm's panels or turbines to predict how much energy it will produce. Question it answers: How much electricity will this farm actually generate, and is it worth building? Leaves out: A single unusual weather year can still depart sharply from the long-term average. Runs on: about 10^12 FLOPS rough a developer's desktop, minutes per site Since: 1981 by 1981, early computer wind-resource assessment for wind farm siting [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Mega-constellation collision risk Tens of thousands of satellites in shared low orbits are tracked against existing debris to estimate close approaches, avoidance manoeuvres and the effect of failures. Question it answers: How many collisions would a mega-constellation add, and how fast does it need to remove failed satellites? Leaves out: Future launch rates, failure rates and operator behaviour are assumptions, and small untracked fragments are poorly known. Runs on: about 10^14 FLOPS rough days on a cluster for decades of orbital evolution. Since: 2017 Radtke and colleagues' study of how mega-constellations interact with the space debris environment. [source](https://doi.org/10.1016/j.actaastro.2016.11.021) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Conjunction collision probability Two objects' predicted orbits, with their uncertainties, are used to compute the chance that they will hit when they pass close. Question it answers: Is it worth firing thrusters to dodge this close approach? Leaves out: Orbit uncertainties are often underestimated, and a single probability depends heavily on the assumed shape of the error. Runs on: about 10^6 FLOPS rough seconds per conjunction, run over thousands of objects. Since: 1999 Alfriend and colleagues' analysis of errors in probability of collision. [source](https://doi.org/10.1023/a:1010056509803) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ## Manufacturing and materials processing ### Metal casting and solidification Molten metal filling a mould and freezing, tracked for where it fills badly or shrinks into a defect. Question it answers: Will this casting fill properly, and where will the defects form? Leaves out: Real furnace and mould conditions vary more than a single simulated pour. Runs on: about 10^14 FLOPS rough an engineering firm's cluster, hours per case Since: 1985 by 1985, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Welding simulation Metal melting, mixing and cooling in the narrow zone around a weld, with the stresses that warp the finished part. Question it answers: Will the weld hold, and how much will the part distort afterward? Leaves out: Assumes clean, steady welding conditions that manual welding does not always provide. Runs on: about 10^14 FLOPS rough an engineering firm's cluster, hours per case Since: 1975 by 1975, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Additive manufacturing simulation A part built up layer by layer by a moving heat source, tracking the heating, melting and residual stress this leaves behind. Question it answers: Will the finished part warp or crack, and how should it be oriented on the build plate? Leaves out: Full-part simulations at true resolution are still too slow for most production schedules. Runs on: about 10^14 FLOPS rough an engineering firm's cluster, hours per case Since: 1995 by 1995, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Metal forming and stamping Sheet metal or a hot billet pressed, stamped or forged into its final shape. Question it answers: Will the metal crack or wrinkle before it reaches the final shape? Leaves out: Assumes a uniform starting sheet; real material batches vary more than that. Runs on: about 10^14 FLOPS rough an engineering firm's cluster, hours per case Since: 1980 by 1980, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Machining simulation A cutting tool removing metal as chips, with the forces, heat and wear this produces. Question it answers: How fast can we cut without breaking the tool or ruining the surface finish? Leaves out: Tool wear over many parts is still mostly estimated from past experience, not first principles. Runs on: about 10^13 FLOPS rough an engineering firm's cluster, hours per case Since: 1982 by 1982, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Injection moulding simulation Molten plastic filling a mould's cavities and cooling into its final shape. Question it answers: Will the mould fill evenly, and where will it warp or show defects? Leaves out: Real plastic batches vary in exactly how they flow, more than standard material data assumes. Runs on: about 10^13 FLOPS rough an engineering firm's cluster, hours per case Since: 1976 by 1976, early computer simulations of this manufacturing process [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields [◂ Human behaviour and society](https://simulation-hypothesis.com/simulations/human-society)[Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations) --- title: "Cities, infrastructure and operations · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/cities-operations description: "Traffic, queues, supply chains, water, power and the built environment. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 10 of 18 # Cities, infrastructure and operations Traffic, queues, supply chains, water, power and the built environment. Operations research grew out of the problem of moving people, goods and resources efficiently, and simulation is its main tool. These are some of the most commonly run simulations in industry and government, though you rarely see them. ## Movement ### Traffic flow Cars as individual drivers, as cells on a road that move by rules, or as a fluid flowing through the network. Question it answers: Why do jams arise without an evident cause, and will this junction relieve one? Leaves out: Individual driver quirks average out; one erratic driver's effect is lost. Runs on: about 10^13 FLOPS rough a city traffic authority's desktop or small cluster Since: 1955 Lighthill and Whitham's fluid theory of traffic flow [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-traffic) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Transport and land use Where people live, work and shop, and how they travel between them, over years to decades. Question it answers: If we build this rail line, how will the city change around it? Leaves out: Decades-long social change is hard to forecast from historical patterns alone. Runs on: about 10^14 FLOPS rough a metropolitan planning agency's server cluster Since: 1964 Ira Lowry's model of land use and transport in a metropolis [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Urban growth Cities spreading over land, cell by cell. Question it answers: Where will this city grow over the next thirty years? Leaves out: Cells grow by fixed rules; real politics and land ownership are harder to encode. Runs on: about 10^13 FLOPS rough a planning department's desktop, minutes per scenario Since: 1979 Waldo Tobler's cellular models of geographic change [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Fields ### Evacuation and emergency response People leaving buildings, stadiums or regions, and responders moving the other way. Question it answers: How long does it take to clear the building, and where do people get stuck? Leaves out: Panic and crowd-crush behaviour are simplified; real evacuations are more complex. Runs on: about 10^13 FLOPS rough a desktop or small cluster, minutes per scenario Since: 1995 Dirk Helbing's social force model of pedestrian crowds [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Public transit network simulation Buses and trains running to a timetable, with passengers choosing routes and transferring between them. Question it answers: If we change this timetable or route, how much time do passengers save? Leaves out: Assumes passengers know and follow the best route, whereas many take the most familiar one. Runs on: about 10^13 FLOPS rough a transit agency's server, minutes per scenario Since: 1970 by 1970, early computer models of bus and rail timetables [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Ride-hailing and dispatch simulation A fleet of vehicles matched to passenger requests as they arrive, with drivers repositioning between trips. Question it answers: How many vehicles do we need, and how long will passengers wait? Leaves out: Assumes drivers follow the dispatch system's suggestions, which real drivers do not always do. Runs on: about 10^13 FLOPS rough a company's cloud server, minutes per city scenario Since: 2000 by 2000, early simulation studies of dynamic vehicle dispatch [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Aircraft boarding simulation Passengers walking and stowing bags in a narrow aisle, simulated under different boarding orders to find the quickest way to fill a plane. Question it answers: Which boarding order fills an aircraft fastest? Leaves out: Real passengers ignore orders and travel in groups, which breaks idealised schemes. Runs on: about 10^6 FLOPS rough thousands of boarding runs, each seconds. Since: 2002 Van Landeghem and Beuselinck's simulation-based study of reducing passenger boarding time in airplanes. [source](https://doi.org/10.1016/s0377-2217%2801%2900294-6) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Populations ### Airport airside simulation Aircraft taxiing, queuing at runways and parked at gates, with controller rules and weather, to measure how much traffic an airport can handle. Question it answers: How many flights per hour can this airport take before delays explode? Leaves out: Controller and pilot decisions are reduced to rules, and delays at other airports spread in ways the model leaves out. Runs on: about 10^8 FLOPS rough minutes to hours on a workstation. Since: 1981 A flexible simulation model of airport airside operations, Transportation Research Part A. [source](https://doi.org/10.1016/0191-2607%2881%2990047-9) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Elevator traffic simulation Passengers arriving at random floors, with morning, noon and evening peaks, and cars stopping and dispatched by a control rule, to size lifts for a building. Question it answers: How many lifts and what dispatch rule keep waiting times short at the morning peak? Leaves out: Passenger arrivals follow measured or assumed patterns, and a change in how tenants use the building breaks them. Runs on: about 10^6 FLOPS rough seconds to minutes on a laptop. Since: 1993 Siikonen's elevator traffic simulation, in the journal Simulation. [source](https://doi.org/10.1177/003754979306100409) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Shared autonomous vehicle fleets A fleet of driverless taxis serving requests in a city, with each trip, wait, empty drive and parked time followed, to measure the vehicles needed, cost and congestion. Question it answers: How many shared self-driving cars could replace private cars in a city, and what would it do to traffic? Leaves out: Whether people would accept sharing rides, and what they would do with the time saved, is assumed and not known. Runs on: about 10^11 FLOPS rough hours to days on a workstation or cluster for a metropolitan region. Since: 2014 Fagnant and Kockelman's agent-based scenarios of the travel and environmental implications of shared autonomous vehicles. [source](https://doi.org/10.1016/j.trc.2013.12.001) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Populations ### Airspace fast-time simulation Flights moving through sectors and waypoints in a simulated sky, much faster than real time, to test routes, sector design and rules for controllers. Question it answers: How much extra traffic can a new sector layout or route structure carry safely? Leaves out: Controller workload and judgement are represented by simple rules, so a busy sector's real limit may be lower. Runs on: about 10^9 FLOPS rough minutes to hours on a workstation per day of traffic. Since: 1964 Price's queueing theory in the fast-time simulation of air traffic control, in Navigation. [source](https://doi.org/10.1002/j.2161-4296.1964.tb02094.x) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ## Queues and logistics ### Supply chains Goods moving from suppliers through factories, warehouses and shops, with delays and shortages that echo back up the chain. Question it answers: Why does a small change in demand produce a large swing in production at the factory? Leaves out: Assumes rational reordering; panic buying and hoarding break the model. Runs on: about 10^13 FLOPS rough a company server, minutes per scenario Since: 1958 Jay Forrester's industrial dynamics models of supply-chain swings [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### Manufacturing lines Machines, workers, buffers and breakdowns on a production line. Question it answers: Where is the bottleneck, and is the new machine worth buying? Leaves out: Rare breakdowns and human factors are approximated from averages. Runs on: about 10^12 FLOPS rough a factory planning desktop, minutes per run Since: 1961 Geoffrey Gordon's early discrete-event simulation language [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Bodies ### Queues and service systems Customers or passengers arriving, waiting and being served: airports, call centres, ports. Question it answers: How many desks do we need to keep the wait under ten minutes? Leaves out: Assumes people line up and behave predictably; real queue-jumping and abandonment vary. Runs on: about 10^12 FLOPS rough a desktop, minutes per scenario Since: 1961 by 1961, general discrete-event simulation tools begin modelling queues [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Bodies ### Hospital patient flow Patients moving through emergency departments, wards, theatres and discharge. Question it answers: Where do patients wait, and what would free up beds? Leaves out: Rare surges, like mass-casualty events, sit outside its normal patterns. Runs on: about 10^12 FLOPS rough a hospital's desktop, minutes per scenario Since: 1965 by 1965, early discrete-event simulations of hospital clinics [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Warehouse and distribution centre simulation Robots, conveyors, pickers and storage racks moving goods through a warehouse. Question it answers: Can this warehouse pick and ship orders fast enough at peak demand? Leaves out: Assumes equipment works as specified; real jams and breakdowns are harder to fully predict. Runs on: about 10^13 FLOPS rough a logistics company's server, minutes per scenario Since: 1988 by 1988, early discrete-event simulations of automated warehouses [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Last-mile delivery routing Delivery vehicles and couriers routed through city streets to drop off many parcels in the least time. Question it answers: What is the best order and route to deliver everything today? Leaves out: Real traffic, weather and missed deliveries change the plan more than the model assumes. Runs on: about 10^13 FLOPS rough a delivery company's server, minutes per day's routes Since: 1964 early computer solutions to the vehicle routing problem [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Project schedule risk simulation Task durations drawn at random across a project network to give the spread of completion dates, instead of one critical-path estimate. Question it answers: How likely is a project to finish by its deadline? Leaves out: Task durations are assumed independent, though real delays are correlated. Runs on: about 10^6 FLOPS rough tens of thousands of schedule draws, cheap. Since: 1963 Van Slyke's Monte Carlo methods and the PERT problem. [source](https://doi.org/10.1287/opre.11.5.839) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Warehouse robot fleet coordination Hundreds of mobile robots carry shelves to pickers, and their routes, traffic jams and charging are simulated to size a fleet before it is built. Question it answers: How many robots and what routing rules does a warehouse need to ship its peak orders? Leaves out: Real robots break, humans work unevenly and orders arrive in bursts that are hard to predict. Runs on: about 10^10 FLOPS rough hours on a workstation per layout and day of orders. Since: 2008 D'Andrea's account of coordinating hundreds of autonomous vehicles in distribution facilities. [source](https://doi.org/10.1109/tepra.2008.4686677) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Supply chain digital twins A live model of a company's suppliers, factories, stock and shipping, kept in step with its data, used to test what a disruption would do. Question it answers: If a port or supplier fails tomorrow, how long until shelves run empty and what is the cheapest fix? Leaves out: Data from suppliers beyond the first tier is usually missing, so hidden dependencies stay hidden. Runs on: about 10^11 FLOPS rough hours to days on a cloud cluster for many disruption scenarios. Since: 2020 Ivanov and Dolgui's digital supply chain twin for managing disruption risks and resilience. [source](https://doi.org/10.1080/09537287.2020.1768450) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Container terminal simulation Ships, cranes, trucks and yard stacks in a port, with random arrivals and service times, to find where containers queue and how many cranes are needed. Question it answers: Where does this terminal jam, and how much would one more crane or gate help? Leaves out: Ship arrival times slip with weather and upstream ports in ways that are hard to model, and yard stacking decisions are simplified. Runs on: about 10^8 FLOPS rough minutes to hours on a workstation. Since: 1975 Borovits and Ein-Dor's computer simulation of a seaport container terminal. [source](https://doi.org/10.1177/003754977502500204) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Construction process simulation Crews and machines such as trucks, excavators and cranes working through repeating cycles on a site, with random durations, to find bottlenecks and cost. Question it answers: How many trucks per excavator will finish this earthwork fastest? Leaves out: Weather, breakdowns and human variation are hard to put in, so the schedule is usually too optimistic. Runs on: about 10^6 FLOPS rough seconds to minutes on a laptop. Since: 1977 Halpin's CYCLONE method for modelling job-site processes. [source](https://doi.org/10.1061/jcceaz.0000712) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ## Infrastructure ### Power grids Generation, lines and demand balanced second by second, including how failures cascade. Question it answers: Can the grid take more wind and solar, and could one failure black out a region? Leaves out: Rare cascading failures across many linked grids are hard to fully anticipate. Runs on: about 10^14 FLOPS rough a grid operator's control-centre server, seconds per scenario Since: 1956 by 1956, early digital load-flow programs replace physical network analysers [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Water and drainage networks Water flowing through pipes, pumps, sewers and drains. Question it answers: Will the drains cope with a heavier storm? Leaves out: Ageing pipes and leaks are hard to know exactly, so results depend on assumed condition. Runs on: about 10^12 FLOPS rough a water utility's desktop, minutes per scenario Since: 1968 by 1968, early digital hydraulic models of water distribution networks [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Building energy and daylight Heat, air and light through a building across a whole year of weather. Question it answers: How much energy will this design use, and is it comfortable inside? Leaves out: Real occupant behaviour rarely matches the assumed schedules. Runs on: about 10^13 FLOPS rough a design office desktop, minutes to hours per building Since: 1977 early US building energy programs following the 1973 oil crisis [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Infrastructure interdependence Power, water, communications and transport linked, so that a failure in one spreads to the others. Question it answers: What fails next when the power goes out? Leaves out: Needs detailed data on every linked system, which is rarely all available at once. Runs on: about 10^14 FLOPS rough a research cluster, minutes per scenario Since: 2001 Rinaldi, Peerenboom and Kelly's framework for interdependent infrastructures [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Waste collection and treatment simulation Waste and recyclables collected by trucks on routes, then sorted and processed at treatment plants. Question it answers: Can we collect all the waste on time, and where should the next treatment plant go? Leaves out: Assumes households sort waste correctly, which they do not always do. Runs on: about 10^12 FLOPS rough a city council's desktop, minutes per scenario Since: 1974 by 1974, early computer models of municipal waste collection routes [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### District heating and cooling networks Hot or chilled water piped from a central plant to heat and cool many buildings at once. Question it answers: Can the network deliver enough heat on the coldest day of the year? Leaves out: Assumes pipes and pumps perform as designed; real networks leak and silt up over decades. Runs on: about 10^12 FLOPS rough a utility engineer's desktop, minutes per scenario Since: 1979 by 1979, early hydraulic and thermal models of district heating networks [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Power-system electromagnetic transients Fast voltage and current surges in a grid, from lightning, switching and faults, followed microsecond by microsecond to protect equipment. Question it answers: What happens to a grid in the first milliseconds of a fault or lightning strike? Leaves out: Lines and equipment are modelled with frequency-dependent approximations, and component data are often incomplete. Runs on: about 10^10 FLOPS rough time-stepped network solves on sub-microsecond steps. Since: 1969 Dommel's digital computer solution of electromagnetic transients in single- and multiphase networks. [source](https://doi.org/10.1109/tpas.1969.292459) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Fields ### Energy-system capacity-planning models The choice of power plants, fuels and networks over decades found by minimising cost under demand and emission limits. Question it answers: What mix of energy technologies meets demand cheapest under a carbon limit? Leaves out: Perfect foresight and fixed demand assumptions give tidy but unrealistic transitions. Runs on: about 10^10 FLOPS rough large linear programs over decades and regions. Since: 1981 Fishbone and Abilock's linear-programming model for energy systems analysis. [source](https://doi.org/10.1002/er.4440050406) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Rules ### Agent-based electricity markets Power generators as adaptive agents bidding into an auction, to find how pricing rules, strategies and market power shape prices. Question it answers: Do generators learn to raise prices in an electricity auction? Leaves out: Agent learning rules are assumed, and human traders are not so simple. Runs on: about 10^9 FLOPS rough many agent-learning runs. Since: 2001 Bower and Bunn's experimental analysis of uniform-price versus discriminatory auctions in the England and Wales electricity market. [source](https://doi.org/10.1016/s0165-1889%2800%2900036-1) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Populations ### Cascading-blackout models Power lines tripping one after another as load shifts onto the rest, simulated to find how small faults grow into regional outages. Question it answers: How does a small failure in a grid grow into a blackout? Leaves out: Operator response and protection settings are simplified, and rare cascades need huge sampling. Runs on: about 10^9 FLOPS rough many Monte Carlo cascades on a grid model. Since: 2002 Carreras and colleagues' critical points and transitions in a power transmission model for cascading failure blackouts. [source](https://doi.org/10.1063/1.1505810) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ### Smart-grid co-simulation The power network, houses, batteries, solar panels and their controllers are each simulated separately and run together, to test how the whole system behaves under different strategies. Question it answers: How does a control scheme for thousands of home batteries affect the local grid? Leaves out: Household behaviour is represented by synthetic load profiles, which miss rare patterns of use that stress the grid. Runs on: about 10^10 FLOPS rough hours on a workstation for a day of a district. Since: 2011 Schütte and colleagues' mosaik framework for modular simulation of active components in smart grids. [source](https://doi.org/10.1109/sgms.2011.6089027) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Gas pipeline network transients Pressure and flow waves in a network of pipes, compressors and valves as demand changes, so operators can schedule supply and keep gas moving without leaks or shortfalls. Question it answers: How will the pressure in a gas network respond when a large user switches off or the gas mix changes? Leaves out: Demand is uncertain and the pipes are treated as one-dimensional, so local effects at joints are simplified. Runs on: about 10^9 FLOPS rough minutes to hours on a workstation. Since: 1970 Distefano's Pipetran program for simulating gas pipeline network dynamics. [source](https://doi.org/10.55274/r0010038) [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Fields ## Telecommunications and the internet ### Mobile network planning Radio signals from phone masts spreading across a city or region, mapped against how many calls and data connections each mast must carry. Question it answers: Where should the next mast go, and will callers get a signal there? Leaves out: Real buildings and weather scatter radio signals more unpredictably than the terrain model assumes. Runs on: about 10^13 FLOPS rough a carrier's planning server, minutes per area Since: 1978 by 1978, early cellular network coverage and capacity planning tools [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Internet backbone and cable resilience Data routes across the internet's backbone links and undersea cables, tested against breaks and outages. Question it answers: If this cable or exchange point fails, whose connection goes down? Leaves out: Real routing decisions during an outage depend on business deals the model does not see. Runs on: about 10^12 FLOPS rough a research or carrier server, minutes per scenario Since: 1995 by 1995, early studies of internet routing failures and resilience [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Data centre facility simulation Servers, cooling systems and power feeds inside a data centre, balanced against the computing jobs they run. Question it answers: Will this data centre stay cool and powered as we add more servers? Leaves out: Real equipment ages and fails in ways average models smooth over. Runs on: about 10^13 FLOPS rough an operator's own server, minutes per scenario Since: 1999 by 1999, early computational fluid dynamics models of data centre cooling [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Fields ### Satellite broadband constellation simulation Hundreds or thousands of satellites moving in orbit, handing signals between each other and down to ground users. Question it answers: Can this constellation give everyone on the ground a fast, steady connection? Leaves out: Real weather, ground terrain and interference cut into the coverage the geometry alone predicts. Runs on: about 10^13 FLOPS rough an operator's planning cluster, hours per scenario Since: 1997 by 1997, early orbital and coverage simulations for satellite phone networks [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Telecom traffic engineering Calls and data connections arriving at random, sized against the lines and equipment available to carry them. Question it answers: How many circuits or channels do we need before callers start getting busy signals? Leaves out: Assumes arrivals are random and independent, which breaks down during a big shared event. Runs on: about 10^11 FLOPS rough a carrier's desktop, seconds per scenario Since: 1917 Agner Krarup Erlang's traffic theory for telephone exchanges [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Smart-city sensor network simulation Thousands of small sensors across a city reporting traffic, air quality, water or lighting data over a wireless network. Question it answers: Will enough sensor readings get through, and how long will the batteries last? Leaves out: Real sensors drift, fail without notice and drop off the network more often than the model assumes. Runs on: about 10^12 FLOPS rough a city IT department's server, minutes per scenario Since: 2010 by 2010, early simulation studies of city-scale wireless sensor networks [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Internet worm propagation models Simulated hosts on a network are infected by self-spreading code, using measured scanning strategies and bandwidth limits. Question it answers: How fast could a worm infect the vulnerable internet? Leaves out: Defences and patching speed are assumed. Runs on: about 10^10 FLOPS rough Cheap epidemic-style runs Since: 2002 How to 0wn the Internet in your spare time (2002) [source](https://www.usenix.org/legacy/events/sec02/full%5Fpapers/staniford/staniford.pdf) [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Vehicular network simulation Cars exchanging messages while a road-traffic simulator moves them, to test collision warning and platooning over radio. Question it answers: Will cars exchange warnings reliably while driving? Leaves out: Radio shadowing by other vehicles and buildings is only approximated. Runs on: about 10^10 FLOPS rough coupled traffic and packet simulators. Since: 2011 Sommer, German and Dressler's bidirectionally coupled network and road-traffic simulation. [source](https://doi.org/10.1109/tmc.2010.133) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations [◂ Engineering and technology](https://simulation-hypothesis.com/simulations/engineering)[Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation) --- title: "Minds, brains and artificial worlds · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/minds-computation description: "Neurons, brains, artificial life, and the simulated worlds in which machines learn. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 11 of 18 # Minds, brains and artificial worlds Neurons, brains, artificial life, and the simulated worlds in which machines learn. Simulations of brains, and of worlds built for artificial agents to live in and learn from. In one limited way, the simulation hypothesis is already real here: we've built simulated worlds with learning agents inside them. ## Brains ### Detailed neuron models A single neuron as a branching electrical cable with ion channels, following Hodgkin and Huxley. Question it answers: How does this neuron’s shape change what it computes? Leaves out: One neuron's fine chemistry is still simplified into a handful of currents. Runs on: about 10^12 FLOPS rough a laptop, real time for one neuron Since: 1952 Huxley integrated the Hodgkin–Huxley equations by hand on a mechanical calculator, about three weeks per action potential; computers took over later [source](https://www.physoc.org/about-us/history-archives/historicalhighlights/hodgkin-and-huxleys-modelling-of-the-action-potential/) In the simulations tree: [Hodgkin–Huxley by hand](https://simulation-hypothesis.com/trees/simulations?n=min-hh) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Large-scale brain circuits Millions of spiking neurons wired into a circuit resembling a patch of cortex. Question it answers: Can we reproduce brain rhythms and responses from wiring alone? Leaves out: Wiring is often statistical, not the animal's actual measured connections. Runs on: about 10^15 FLOPS rough a university cluster, hours for a cortical patch Since: 2006 by 2006, early large-scale simulations of a cortical column In the simulations tree: [Neocortical microcircuit](https://simulation-hypothesis.com/trees/simulations?n=min-markram) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ### Whole-brain network models Brain regions as nodes connected by measured wiring, fitted to scans. Question it answers: How does damage in one region change activity across the brain? Leaves out: Regions are treated as single points, missing all detail inside them. Runs on: about 10^14 FLOPS rough a university cluster, minutes per simulated scenario Since: 2008 by 2008, early whole-brain network models fitted to diffusion MRI wiring Models: [Human](https://simulation-hypothesis.com/entities/human) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Simulated small organisms A tiny animal’s complete nervous system, such as a roundworm’s 302 neurons, connected to a simulated body in a virtual dish. Question it answers: Is the wiring diagram enough to produce the behaviour? Leaves out: The wiring diagram alone still does not fully explain the animal's behaviour. Runs on: about 10^12 FLOPS rough a laptop, real time for the whole nervous system Since: 1997 by 1997, early simulations built on the roundworm's 1986 connectome map In the simulations tree: [OpenWorm](https://simulation-hypothesis.com/trees/simulations?n=min-openworm) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Cells ### Neuromorphic hardware simulation Chips built with circuits that behave like neurons and synapses directly in hardware, instead of calculating the equations step by step in software. Question it answers: Can neuromorphic hardware compute the same things a brain does, using far less power? Leaves out: Real neurons have far richer chemistry than a circuit built to mimic their spikes. Runs on: about 10^13 FLOPS rough a neuromorphic research chip, real time Since: 1989 Carver Mead's early silicon neuron and retina circuits [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Brain disease and seizure spread Abnormal electrical activity or misfolded proteins spreading through a simulated brain network, as in epilepsy or dementia. Question it answers: Where does a seizure start, and how far will it spread? Leaves out: Every real brain's disease path is different; the model shows a pattern, not a prediction for one patient. Runs on: about 10^13 FLOPS rough a hospital or university cluster, minutes per patient model Since: 1997 by 1997, early network models of seizure spread through the brain [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Connectome-constrained whole-brain models A neural simulation uses the full measured wiring of an insect brain with simple neuron models to predict how stimuli produce behaviour. Question it answers: Does wiring alone predict how the brain turns senses into action? Leaves out: Synapse strengths and neuron dynamics are assumed from simple rules. Runs on: about 10^12 FLOPS rough Spiking network of about 130,000 neurons Since: 2024 A Drosophila computational brain model reveals sensorimotor processing (2024) [source](https://doi.org/10.1038/s41586-024-07763-9) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Neural mass and field models A population of neurons reduced to one or two average activity variables, giving the rhythms and waves of whole regions. Question it answers: What collective rhythms can excitation and inhibition produce between populations? Leaves out: Individual neurons vanish into an average. Runs on: about 10^9 FLOPS rough a laptop, seconds Since: 1972 by 1972, Wilson and Cowan, Excitatory and inhibitory interactions in localized populations of model neurons [source](https://doi.org/10.1016/s0006-3495%2872%2986068-5) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Cells ### Functional spiking brain models A network of spiking model neurons built to carry out cognitive tasks such as recall, counting and copying a drawn digit. Question it answers: Can a model made of neurons carry out tasks a brain handles? Leaves out: Its task set is small and wiring is designed, not measured. Runs on: about 10^15 FLOPS rough a university cluster, hours Since: 2012 by 2012, Eliasmith and others, A large-scale model of the functioning brain (Spaun) [source](https://doi.org/10.1126/science.1225266) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Attractor memory networks A network of simple units whose connections store patterns as stable states, so a partial cue settles into the full memory. Question it answers: How can a network recall a whole memory from a fragment? Leaves out: Capacity is small and real neurons are far more complex. Runs on: about 10^8 FLOPS rough a laptop, seconds Since: 1982 by 1982, Hopfield, Neural networks and physical systems with emergent collective computational abilities [source](https://en.wikipedia.org/wiki/Hopfield%5Fnetwork) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Connectome-based insect brain models A whole fly brain simulated from its measured wiring diagram, with each neuron and synapse taken from the reconstruction. Question it answers: Which behaviours follow from wiring alone, once every connection is known? Leaves out: Synapse strengths and neuron chemistry are inferred, not measured. Runs on: about 10^14 FLOPS rough a workstation, minutes per simulated second Since: 2024 by 2024, Dorkenwald and others, the adult fly brain wiring diagram, and Shiu and others, a computational model built on it [source](https://doi.org/10.1038/s41586-024-07763-9) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ## Artificial life and complexity ### Cellular automata Grids of cells following simple rules, such as John Conway’s Life, which grow gliders, replicators and even working computers. Question it answers: How much complexity can grow from how simple a rule? Leaves out: Simple rules rarely map cleanly onto real physical or biological systems. Runs on: about 10^12 FLOPS rough a laptop, huge grids in seconds Since: 1970 John Conway's Game of Life In the simulations tree: [Life, played by hand](https://simulation-hypothesis.com/trees/simulations?n=life-life) [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-life) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Digital evolution Self-copying computer programs mutating and competing for processor time in a simulated machine. Question it answers: Can evolution invent complex features we can watch step by step? Leaves out: Programs evolve in an artificial computer world, not real biochemistry. Runs on: about 10^12 FLOPS rough a desktop, millions of generations overnight Since: 1953 Barricelli’s numerical evolution experiments on the Institute for Advanced Study computer [source](https://www.ias.edu/ideas/2012/george-dyson-ecp) [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ### Evolved virtual creatures Bodies and brains evolved together in a physics simulation, learning to swim, walk or jump. Question it answers: What bodies and behaviours does evolution invent when we are not steering it? Leaves out: Evolved gaits often look very different from biological ones, because the simulated physics differs subtly from the real world. Runs on: about 10^13 FLOPS rough a desktop or small cluster, hours to evolve a population Since: 1994 Karl Sims evolved creatures that swim and walk in a physics simulation [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Self-organised criticality Grains added one at a time to a sandpile until avalanches of every size appear. Question it answers: Why do earthquakes, fires and extinctions follow the same statistics? Leaves out: Real earthquakes and fires have specific physics a sandpile only caricatures. Runs on: about 10^11 FLOPS rough a laptop, seconds for a large sandpile Since: 1987 Bak, Tang and Wiesenfeld's sandpile model [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-sandpile) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Bodies ### Swarm intelligence algorithms Simple virtual agents that leave trails or copy their neighbours, borrowed from ants and birds to solve abstract problems like routing and scheduling. Question it answers: Can simple copying and trail-following solve a hard optimisation problem? Leaves out: Works well on the well-posed problems it was tested on. Real, irregular problems need more tuning. Runs on: about 10^11 FLOPS rough a laptop, seconds to minutes per run Since: 1992 Marco Dorigo's ant colony optimisation algorithm [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-flock) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ### Random Boolean networks Switches wired together at random, each turning on or off based on a handful of others, studied for when the whole network settles down or churns forever. Question it answers: How much wiring does it take before a network of switches turns chaotic? Leaves out: Random wiring is a crude stand-in for the carefully evolved wiring of a real cell or brain. Runs on: about 10^11 FLOPS rough a laptop, seconds per network Since: 1969 Stuart Kauffman's random networks of genetic switches [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Continuous cellular automata Cellular automata whose cell states, space and time are continuous, producing smooth self-organising creatures. Question it answers: What life-like patterns appear in a continuous cellular automaton? Leaves out: The rules are artificial and do not model real chemistry. Runs on: about 10^11 FLOPS rough GPU grid updates Since: 2018 Lenia: biology of artificial life (2018) [source](https://arxiv.org/abs/1812.05433) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Neural cellular automata Each cell holds a small neural network that learns the local rule so a grid grows and repairs a target pattern. Question it answers: Can a local learned rule make a global pattern grow and self-repair? Leaves out: Target patterns are small, and rules are trained, not discovered. Runs on: about 10^11 FLOPS rough Small differentiable training Since: 2020 Growing Neural Cellular Automata (2020) [source](https://distill.pub/2020/growing-ca/) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Self-replicating program soups A pool of random programs interacts by chance until self-copying ones emerge from the mix. Question it answers: Can replicators appear without being designed in? Leaves out: Language choice sets the result, and it is far from chemistry. Runs on: about 10^10 FLOPS rough Millions of tiny program interactions Since: 2024 Computational Life: how well-formed, self-replicating programs emerge from simple interaction (2024) [source](https://arxiv.org/abs/2406.19108) [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Artificial chemistry A pool of abstract molecules that react by rules, so self-maintaining structures can appear without any real chemistry. Question it answers: Can self-sustaining chemical organisation arise from simple reaction rules? Leaves out: The molecules are symbols; real bond energies and geometry are absent. Runs on: about 10^9 FLOPS rough a laptop, hours Since: 1991 by 1991, Fontana's AlChemy, presented at the Second Artificial Life Conference [source](https://en.wikipedia.org/wiki/Artificial%5Fchemistry) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Molecules ### Evolutionary robotics Controllers or bodies of simulated robots are evolved over many generations by selecting for task performance. Question it answers: Can a robot's brain and body be bred instead of designed? Leaves out: Controllers evolved in simulation often fail on real hardware. Runs on: about 10^14 FLOPS rough a university cluster, days Since: 1993 by 1993, Cliff, Husbands and Harvey, Evolving visually guided robots [source](https://doi.org/10.7551/mitpress/3116.003.0051) [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Continuous artificial life A cellular automaton with continuous states, space and time that produces moving, self-organising lifelike patterns. Question it answers: What lifelike forms appear when the rules are smooth rather than discrete? Leaves out: The patterns resemble organisms but follow no real biology. Runs on: about 10^11 FLOPS rough a gaming PC, real time Since: 2018 by 2018, Chan, Lenia: Biology of Artificial Life (arXiv 1812.05433) [source](https://arxiv.org/abs/1812.05433) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Rules ### Artificial immune models Populations of interacting antibody-like agents that learn to recognise patterns by selection and network effects. Question it answers: How does a recognition system adapt using only local interactions? Leaves out: It borrows ideas from immunology for computing, not a calibrated model of a real immune response. Runs on: about 10^8 FLOPS rough a laptop, hours Since: 1986 by 1986, Farmer, Packard and Perelson, The immune system, adaptation, and machine learning [source](https://doi.org/10.1016/0167-2789%2886%2990240-x) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Cells ### Core War battles Programs written in a tiny assembly language fight for control of a shared simulated memory, overwriting each other. Question it answers: Which self-copying program survives when all of memory is a battlefield? Leaves out: The machine is an invented instruction set, so lessons do not map to real malware. Runs on: about 10^7 FLOPS rough a laptop, seconds per battle Since: 1984 by 1984, Core War by Jones and Dewdney, in Scientific American [source](https://en.wikipedia.org/wiki/Core%5FWar) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ## Worlds for artificial minds ### Reinforcement learning environments Simulated worlds where an artificial agent acts, is rewarded and improves over millions of attempts. Question it answers: Can an agent learn this skill from trial and error alone? Leaves out: Skills learned in a simplified world do not always transfer to the complexity of reality. Runs on: about 10^15 FLOPS rough a cluster of GPUs, days of simulated experience Since: 1992 by 1992, TD-Gammon learned backgammon strategy through self-play [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Multi-agent AI societies Many AI agents sharing a world, with their own goals, memories and conversations. Question it answers: What social behaviour appears when many artificial agents live together? Leaves out: Behaviours that look social can be narrow tricks tuned to the training setup. Runs on: about 10^15 FLOPS rough a cluster of GPUs, running many agents in parallel Since: 2017 by 2017, early experiments with many learning agents sharing one world [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Synthetic training data Photorealistic scenes rendered in endless variations to train vision systems. Question it answers: Can a system trained only on rendered images see the real world? Leaves out: Rendered scenes are cleaner than reality, so trained systems can be misled by real-world noise. Runs on: about 10^14 FLOPS rough a render farm or GPU cluster, hours for a dataset Since: 2016 by 2016, early rendered datasets train image recognition systems [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Learned world models A neural network that predicts what happens next in a world, well enough to generate playable scenes of it. Question it answers: Can a network learn to simulate a world just by watching it? Leaves out: Long-term predictions drift away from anything physically consistent. Runs on: about 10^15 FLOPS rough a large GPU cluster, days of training Since: 2018 Ha and Schmidhuber trained a network to predict and dream game-like scenes [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Fields ### Self-play strategy training An artificial agent playing repeated matches against copies of itself in an abstract strategy game, improving with every round. Question it answers: How strong can a strategy get with no teacher but its own past self? Leaves out: Strategies tuned against a copy of the same agent can have blind spots that a different opponent would exploit. Runs on: about 10^16 FLOPS rough a large GPU cluster, days of self-play Since: 1959 Arthur Samuel's checkers program learned by playing itself [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### AI safety red-teaming environments A simulated setting built to tempt an artificial agent into unwanted behaviour, so the failure can be found before deployment. Question it answers: Under what conditions does this system exhibit behaviour that it should not? Leaves out: Only tests for the failures the red team thought to look for. Runs on: about 10^14 FLOPS rough a research team's GPU server, hours per test suite Since: 2016 by 2016, early adversarial testing environments for reinforcement learning agents [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Embodied household simulators 3D virtual homes where an agent sees, moves and manipulates objects, used to train and test embodied AI. Question it answers: Can an agent learn tasks in a virtual home that transfer to real ones? Leaves out: Object physics and scene variety are limited. Runs on: about 10^12 FLOPS rough Real-time rendering, many parallel instances Since: 2017 AI2-THOR: an interactive 3D environment for visual AI (2017) [source](https://arxiv.org/abs/1712.05474) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Open-ended environment generation Training worlds are created and mutated automatically as agents learn so challenges keep growing in difficulty and variety. Question it answers: Can an environment generator keep producing useful new challenges? Leaves out: The search is limited by what the environment family can express. Runs on: about 10^15 FLOPS rough Population of environments and agents Since: 2019 Paired Open-Ended Trailblazer (POET) (2019) [source](https://arxiv.org/abs/1901.01753) [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Simulated web environments for agents Self-hosted copies of real websites where a language-model agent completes tasks, scored by checking the final state. Question it answers: Can an agent complete multi-step tasks on realistic websites? Leaves out: Sites are static copies, and task variety is limited. Runs on: about 10^13 FLOPS rough Environment resets and many model calls Since: 2023 WebArena (2023) [source](https://arxiv.org/abs/2307.13854) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Recommender-system simulators A configurable simulated user population and item catalogue used to train and test recommendation algorithms. Question it answers: How would a recommendation algorithm behave over many interactions with users? Leaves out: User behaviour is assumed, not measured. Runs on: about 10^10 FLOPS rough Cheap parallel runs Since: 2019 RecSim: a configurable simulation platform for recommender systems (2019) [source](https://arxiv.org/abs/1909.04847) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Neural game engines A diffusion model trained on gameplay recordings generates the next frame from the player's actions, replacing the game's own engine. Question it answers: Can a neural network run an interactive game at playable speed? Leaves out: Memory is short, and details drift over long play. Runs on: about 10^15 FLOPS rough Heavy training; real-time inference on one accelerator Since: 2024 Diffusion models are real-time game engines (2024) [source](https://arxiv.org/abs/2408.14837) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Interactive generative worlds A model learns from unlabelled video to create controllable worlds in which a user can act frame by frame. Question it answers: Can a playable world be generated from images alone? Leaves out: Consistency and frame rate are limited, and physics are not guaranteed. Runs on: about 10^17 FLOPS rough Large-scale video training Since: 2024 Genie: generative interactive environments (2024) [source](https://arxiv.org/abs/2402.15391) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Learned real-world interactive simulators A video model conditioned on actions predicts what a robot or agent would see after each command, replacing a hand-built simulator. Question it answers: Can a learned model simulate the real-world results of actions? Leaves out: Long rollouts hallucinate, and physical accuracy is not verified. Runs on: about 10^17 FLOPS rough Training on large video and action datasets Since: 2023 Learning interactive real-world simulators (2023) [source](https://arxiv.org/abs/2310.06114) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Generative driving world models A video model conditioned on speed and steering generates plausible future scenes from a car's view for training and testing autonomy. Question it answers: What traffic scenes could follow from a given driving action? Leaves out: Generated scenes may violate physics or rare-case behaviour. Runs on: about 10^17 FLOPS rough Large video model training Since: 2023 GAIA-1: a generative world model for autonomous driving (2023) [source](https://arxiv.org/abs/2309.17080) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Simulated robot soccer Two teams of software players, each seeing only part of the pitch through noisy senses, play football in a simulated stadium to test cooperation and strategy. Question it answers: Can independent software players coordinate well enough to beat a rival team? Leaves out: The pitch, ball and robot bodies are idealised, so success shows tactics rather than skill with real hardware. Runs on: about 10^9 FLOPS rough real time on a workstation for a match. Since: 1998 Noda and colleagues' Soccer Server, a tool for research on multi-agent systems. [source](https://doi.org/10.1080/088395198117848) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Populations ### Software engineering agent sandboxes An agent is given a real code project and a problem report, edits files and runs tests in a sandbox, and is scored on whether the fix passes. Question it answers: Can an AI agent fix real bugs in real software projects without help? Leaves out: Tests passing is not the same as a correct fix, and the projects are a small slice of all software. Runs on: about 10^15 FLOPS rough thousands of model runs, each with many calls and test runs. Since: 2023 Jimenez and colleagues' SWE-bench of real GitHub issues for language models. [source](https://arxiv.org/abs/2310.06770) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Desktop computer agent environments A full virtual computer with real programs is given to an agent that sees the screen and clicks and types, and is scored on whether the task was done. Question it answers: Can an AI agent carry out tasks on a computer the way a person does? Leaves out: The tasks are fixed and scripted, while real work is open-ended, interrupted and shared with other people. Runs on: about 10^15 FLOPS rough thousands of runs, each running a virtual machine and many model calls. Since: 2024 Xie and colleagues' OSWorld, benchmarking agents in real computer environments. [source](https://doi.org/10.52202/079017-1650) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules [◂ Cities, infrastructure and operations](https://simulation-hypothesis.com/simulations/cities-operations)[Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation) --- title: "Mathematics and computation · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/mathematics-computation description: "Numbers, proofs, graphs and machines, investigated by computation as well as by deduction. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 12 of 18 # Mathematics and computation Numbers, proofs, graphs and machines, investigated by computation as well as by deduction. Mathematics and computer science now test their own ideas by simulation. They generate millions of random graphs to see what's typical. They run a machine to see what an algorithm actually does. They attack a cipher over and over to learn how it fails. None of this describes the physical world. It explores the space of numbers, structures and computations themselves. The practice runs from experimental mathematics done by hand over centuries to modern verification tools that check a design against every reachable state before it's built. ## Pure mathematics by computer ### Random matrix experiments Large matrices filled with random numbers, diagonalised repeatedly to study the statistics of their eigenvalues. Question it answers: What pattern do the eigenvalues of a random matrix settle into, and does it match other areas of mathematics and physics? Leaves out: Only ever samples a tiny corner of an infinite space of possible matrices. Runs on: about 10^12 FLOPS rough a university cluster generating and diagonalising many large matrices Since: 1955 Wigner's early work on random matrix eigenvalue statistics [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Random graph experiments Graphs generated by a random rule, node by node or edge by edge, to see which properties, such as connectivity or clustering, appear typically. Question it answers: What does a 'typical' network look like under this rule for adding nodes and edges? Leaves out: Real-world networks are rarely as clean as the rule that generates the model. Runs on: about 10^10 FLOPS rough runs on a desktop for graphs up to millions of nodes Since: 1959 Erdos and Renyi's random graph model [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Percolation simulation A lattice or network with sites or bonds opened at random, watched for the point at which a connected path suddenly spans the whole system. Question it answers: At what density does a random network suddenly become connected end to end? Leaves out: Idealised lattices behave more cleanly than any real porous material or network. Runs on: about 10^10 FLOPS rough a desktop machine for large lattice sweeps Since: 1957 Broadbent and Hammersley's introduction of percolation theory [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Experimental mathematics searches Brute-force numerical search for patterns, counterexamples or exact relationships among numbers, run far beyond what could be checked by hand. Question it answers: Is this conjecture true for every case anyone can afford to check, and does a pattern emerge? Leaves out: No amount of checked cases is a proof, however many are found to hold. Runs on: about 10^11 FLOPS rough a university cluster running for days on one search Since: 1963 by 1963, computer searches for integer relations and prime patterns [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Monte Carlo estimation of constants Random sampling used to estimate a mathematical constant or integral, such as scattering points to estimate an area, as an exercise rather than for a physical model. Question it answers: How accurately can blind random sampling alone pin down an exact mathematical quantity? Leaves out: Converges far more slowly than almost any more sophisticated numerical method. Runs on: about 10^9 FLOPS rough runs on a laptop in seconds to minutes Since: 1946 Ulam’s idea of 1946; von Neumann proposed an electronic-computer version in March 1947, and the method was first published in 1949 [source](https://mcnp-green.lanl.gov/pdf%5Ffiles/Article%5F1987%5FLAS%5FEckhardt%5F131--141.pdf) In the simulations tree: [Monte Carlo method](https://simulation-hypothesis.com/trees/simulations?n=m-montecarlo) [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-pi) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Computational number theory searches Large numbers tested for primality, factored, or searched for special properties such as perfect numbers, using algorithms run at scale rather than by hand. Question it answers: Does this huge number have the property we are looking for, and how far can the search push the record? Leaves out: Record-breaking searches say little about numbers nobody has thought to check yet. Runs on: about 10^13 FLOPS rough a distributed volunteer computing project across many donated machines Since: 1951 Lucas's hand test for Mersenne primes, first run by computer in 1951 [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Chaotic-attractor numerics A small set of nonlinear equations integrated step by step to reveal sensitive dependence on initial conditions and a fractal attractor. Question it answers: Why does a simple deterministic system become unpredictable? Leaves out: Numerical rounding means a long trajectory is not a true orbit, only one that stays close to one. Runs on: about 10^3 FLOPS rough a few equations, seconds on a laptop. Since: 1963 Lorenz's deterministic nonperiodic flow, a convection model run on a computer. [source](https://doi.org/10.1175/1520-0469%281963%29020<0130:dnf>2.0.co;2) In the simulations tree: [Lorenz’s chaotic convection](https://simulation-hypothesis.com/trees/simulations?n=p-lorenz) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Nonlinear lattice experiments A chain of masses with nonlinear springs started in one mode and followed to see whether the energy spreads evenly, as thermodynamics would suggest. Question it answers: Does a nonlinear chain share its energy evenly among all its motions? Leaves out: Results depend on the chosen chain and initial state. Runs on: about 10^3 FLOPS rough tiny by modern standards; the original used a few dozen masses. Since: 1955 Fermi, Pasta and Ulam's studies of nonlinear problems on an early digital computer. [source](https://doi.org/10.2172/4376203) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Rules ### Soliton numerical experiments A nonlinear wave equation solved on a grid to watch pulses pass through each other and keep their shape, which linear waves do not. Question it answers: Why do some nonlinear waves pass through each other unchanged? Leaves out: It shows one family of equations, not the general behaviour of nonlinear waves. Runs on: about 10^4 FLOPS rough a one-dimensional grid, trivial today. Since: 1965 Zabusky and Kruskal's interaction of solitons in a collisionless plasma and the recurrence of initial states. [source](https://doi.org/10.1103/physrevlett.15.240) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Rules ### Fractal-set rendering A simple iterated formula tested at each location in the complex plane to see whether it escapes, drawing the boundary of the set of stable points. Question it answers: What is the shape of the set where a simple iteration stays bounded? Leaves out: Escape tests only suggest membership, and the picture is a finite-resolution sampling of an infinitely detailed set. Runs on: about 10^9 FLOPS rough deep zooms need extended-precision iteration at millions of points. Since: 1980 Mandelbrot's fractal aspects of the iteration of z to lambda z(1-z), first computer images of the Mandelbrot set. [source](https://doi.org/10.1111/j.1749-6632.1980.tb29690.x) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Sandpile self-organised criticality Grains dropped on a grid that topple when too steep, giving avalanches of every size without tuning, as a model of how systems reach a critical state. Question it answers: Why do avalanches of every size appear without any tuning? Leaves out: Whether real systems share the same scaling is contested. Runs on: about 10^9 FLOPS rough long runs on large grids to see scaling. Since: 1987 Bak, Tang and Wiesenfeld's self-organised criticality: an explanation of 1/f noise. [source](https://doi.org/10.1103/physrevlett.59.381) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Riemann zeta zero computation The values of the zeta function along its critical line are calculated to locate and count its zeros, checking they lie where the hypothesis says. Question it answers: Do all the non-trivial zeros of the zeta function lie on one line? Leaves out: A finite check, however long, cannot prove that no zero off the line exists beyond it. Runs on: about 10^18 FLOPS rough decades of CPU time at the largest searches. Since: 1953 Turing's calculations of the Riemann zeta function. [source](https://doi.org/10.1112/plms/s3-3.1.99) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ### Digits of pi by computer Series for pi are summed to enormous numbers of digits with exact arithmetic, testing both the number and the machine. Question it answers: Do the digits of pi look random, and can the machine be trusted at this scale? Leaves out: The digits do not answer any open question, and checks catch hardware errors only if the method is independent. Runs on: about 10^17 FLOPS rough months on a server for hundreds of trillions of digits. Since: 1950 Reitwiesner's ENIAC determination of pi and e to more than 2000 decimal places (published 1950, reprinted in Pi: A Source Book). [source](https://doi.org/10.1007/978-1-4757-3240-5%5F34) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ### AI-guided conjecture discovery Machine learning on large tables of mathematical objects finds which properties are linked, to suggest a conjecture that mathematicians then try to prove. Question it answers: Which unseen relationship between these mathematical quantities is worth proving? Leaves out: It only suggests patterns and proves nothing itself, and some regularities in the data may be artefacts of how the data were made. Runs on: about 10^15 FLOPS rough days on a few GPUs per dataset. Since: 2021 Davies and colleagues' advancing mathematics by guiding human intuition with AI. [source](https://doi.org/10.1038/s41586-021-04086-x) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Learned algorithm and construction search A game-playing or language-model system searches for new procedures or mathematical objects, with a computer checking each candidate for correctness. Question it answers: Can a program discover a faster algorithm or a larger example than people have found? Leaves out: Each result is a single new example, and the search covers only the kinds of objects its designers framed as a game. Runs on: about 10^17 FLOPS rough days to weeks on accelerator clusters. Since: 2022 Fawzi and colleagues' AlphaTensor, discovering faster matrix multiplication algorithms with reinforcement learning. [source](https://doi.org/10.1038/s41586-022-05172-4) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ## Proof, logic and security ### Model checking Every reachable state of a finite system, such as a protocol or a circuit design, enumerated by computer to check that a property holds in all of them. Question it answers: Is there any reachable state where this design breaks its own rules? Leaves out: State spaces explode past what can be checked, so real designs are simplified first. Runs on: about 10^12 FLOPS rough a university cluster exhausting a large but bounded state space Since: 1981 Clarke and Emerson's introduction of model checking [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Automated theorem proving search A search through chains of logical inference, computer-generated step by step, looking for a proof or disproof of a mathematical statement. Question it answers: Does a valid chain of logical steps exist from the axioms to this statement? Leaves out: Finds proofs no human would choose, and sometimes none at all within reach. Runs on: about 10^11 FLOPS rough a university cluster searching for hours to days Since: 1956 the Logic Theorist, an early automated proof search program [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### SAT and constraint solving Millions of combinations of true or false values searched systematically to satisfy a large set of logical constraints, used to schedule, route or verify designs. Question it answers: Is there any assignment of values that satisfies every one of these constraints at once? Leaves out: Some instances are hard enough that no solver, however good, finishes in time. Runs on: about 10^11 FLOPS rough a workstation to a cluster, depending on problem size Since: 1962 the Davis-Putnam procedure for satisfiability search [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Cryptographic attack modelling A code or key-exchange scheme attacked millions of times in simulation, by brute force, statistical bias or a modelled weakness, to measure how much effort breaking it really takes. Question it answers: How many operations would it actually take to break this, and is that number still safely large? Leaves out: Only tests the attacks the analyst thought to model, not the one nobody has found yet. Runs on: about 10^14 FLOPS rough a distributed cluster of many machines running attack trials Since: 1976 by 1976, computational analysis of cipher and key-exchange strength [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Side-channel leakage simulation The power draw, timing or electromagnetic emission of a device modelled while it runs a cryptographic operation, to see what a listener outside could learn from it. Question it answers: How much of the secret key leaks out through the physical behaviour of the device, not the maths? Leaves out: Lab conditions catch cleaner signals than a noisy real device usually gives away. Runs on: about 10^10 FLOPS rough a workstation modelling one device's power or timing trace Since: 1996 Kocher's demonstration of timing attacks on cryptographic implementations [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Security protocol verification Every message an attacker could send, replay or forge in a communication protocol, enumerated by computer to check whether a secret or an identity can be forced out of it. Question it answers: Can any sequence of messages trick this protocol into leaking a secret or accepting a fake identity? Leaves out: Verifies the protocol as specified, not the shortcuts a real implementation takes. Runs on: about 10^11 FLOPS rough a workstation to a cluster checking one protocol's message space Since: 1989 the Dolev-Yao model, a foundational basis for protocol verification [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Computer-assisted proof by exhaustive case checking A theorem reduced to a finite list of cases, each verified by program, because no human could check them all. Question it answers: Can a proof be completed by a machine checking every case? Leaves out: Trust moves to the program, the hardware and the case-reduction argument. Runs on: about 10^9 FLOPS rough about a thousand hours on a mainframe for the original; far less now. Since: 1977 Appel and Haken's proof that every planar map is four-colourable, using computer-checked reducibility. [source](https://doi.org/10.1215/ijm/1256049011) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Validated numerics Computations carried out with guaranteed bounds, so a numerical result proves a mathematical statement, such as the existence of a chaotic attractor. Question it answers: Can a computed answer be proved correct, not just probably accurate? Leaves out: Bounds can blow up over long times, limiting proofs to short or well-behaved problems. Runs on: about 10^9 FLOPS rough interval arithmetic multiplies cost by a modest factor. Since: 2002 Tucker's rigorous ODE solver and Smale's 14th problem, proving the Lorenz attractor exists. [source](https://doi.org/10.1007/s002080010018) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Turing-machine enumeration Every small program of a minimal machine run to see which halt and which run forever, to find the longest-running halting one of each size. Question it answers: How long can a tiny program run before it stops? Leaves out: Undecidability means some machines can never be classified, no matter how long they run. Runs on: about 10^15 FLOPS rough billions of machines, with proofs for the non-halting ones. Since: 1965 Lin and Rado's computer studies of Turing-machine problems. [source](https://doi.org/10.1145/321264.321270) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Statistical model checking A system with random behaviour simulated many times to estimate with confidence how likely it is to violate a property. Question it answers: How likely is a random system to break a safety rule? Leaves out: Statistical runs give a probability with a confidence level, not a proof, and rare failures need importance sampling. Runs on: about 10^9 FLOPS rough thousands to millions of sampled executions. Since: 2002 Younes and Simmons's probabilistic verification of discrete event systems using acceptance sampling. [source](https://doi.org/10.1007/3-540-45657-0%5F17) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Fuzz testing A program is fed huge numbers of random or mutated inputs to find those that make it crash, in effect simulating a hostile or careless world. Question it answers: What input will make this software fail? Leaves out: It finds only failures that random inputs reach, and a program can pass for years while hiding a bug behind a rare case. Runs on: about 10^14 FLOPS rough machine-years of CPU time for a major code base. Since: 1990 Miller, Fredriksen and So's empirical study of the reliability of UNIX utilities. [source](https://doi.org/10.1145/96267.96279) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)floor: Rules ### Symbolic execution A program is run with unknown inputs written as symbols, collecting the conditions on each path, then a solver finds values that take each branch. Question it answers: Which inputs make each path of this program run, and does any reach a bug? Leaves out: The number of paths grows exponentially with program size, so large ones are covered only in part. Runs on: about 10^12 FLOPS rough hours of solver time per program, growing steeply with path count. Since: 1976 King's symbolic execution and program testing. [source](https://doi.org/10.1145/360248.360252) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ### Abstract interpretation A program is run on sets of possible values, such as ranges, instead of single values, to prove properties that hold for every input. Question it answers: Can this program ever divide by zero or overflow, for any input? Leaves out: Safe approximation raises false alarms, so people must still check each warning. Runs on: about 10^11 FLOPS rough hours on a workstation for a large avionics code base. Since: 1977 Cousot and Cousot's abstract interpretation, a unified lattice model for static analysis of programs. [source](https://doi.org/10.1145/512950.512973) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ### Bounded model checking The behaviour of a design up to a fixed number of steps is written as a logic formula and handed to a satisfiability solver to find any short path to a bug. Question it answers: Can this circuit or program reach an error state within a given number of steps? Leaves out: It proves nothing beyond the step bound unless a separate argument shows it is enough. Runs on: about 10^13 FLOPS rough hours on a server per property. Since: 1999 Biere, Cimatti, Clarke and Zhu's symbolic model checking without BDDs. [source](https://doi.org/10.21236/ada360973) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ### Property-based random testing A rule that should always hold is stated, and the computer generates many random cases and shrinks any failure to a small counterexample. Question it answers: Does this code obey its own specification on a wide range of inputs? Leaves out: Random cases may never reach a rare condition, and the property written down may not be the one that matters. Runs on: about 10^9 FLOPS rough minutes on a laptop for thousands of cases. Since: 2000 Claessen and Hughes' QuickCheck, a lightweight tool for random testing of Haskell programs. [source](https://doi.org/10.1145/351240.351266) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Neural network verification Constraint solvers prove that for every input in a region, a neural network's output stays within bounds, instead of testing samples. Question it answers: Can a small change to an input ever make the network give a wrong answer? Leaves out: Proofs scale only to small networks, and the set of perturbations that can be checked is narrow. Runs on: about 10^13 FLOPS rough hours to days on a server for a small network. Since: 2017 Katz and colleagues' Reluplex, an SMT solver for verifying deep neural networks. [source](https://doi.org/10.1007/978-3-319-63387-9%5F5) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[First principles](https://simulation-hypothesis.com/simulations/methods#m-first-principles)floor: Rules ## Systems and machines ### Computer architecture simulation A proposed processor's pipeline, caches and branch predictor modelled instruction by instruction, to estimate the speed of a chip before it is built. Question it answers: How fast would this processor design run real programs, before any silicon is cut? Leaves out: Simplifies enough of the real chip that final silicon always differs a little from the model. Runs on: about 10^11 FLOPS rough a university cluster running benchmark programs through the model Since: 1990 by 1990, cycle-accurate processor simulators for architecture research [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Distributed systems and consensus simulation Many computers modelled sending messages to each other with delays, drops and failures, to test whether a distributed algorithm still agrees on the right answer. Question it answers: Does this algorithm still reach the correct agreement when messages are lost, delayed or nodes crash? Leaves out: Injected failures are those the designer anticipated, not those that arise unexpectedly in production. Runs on: about 10^10 FLOPS rough a cluster simulating hundreds of virtual nodes Since: 1978 Lamport's early work on ordering and failure in distributed systems [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Rules ### Storage systems simulation Disks, drives and file systems modelled for how they lay out data, fail and recover, to test a storage design before real drives are bought and filled. Question it answers: How does this storage design perform and survive failure, at a scale too expensive to test for real first? Leaves out: Real drives fail in messier, more correlated ways than the model's random failure rate. Runs on: about 10^10 FLOPS rough a workstation to a small cluster modelling a storage array Since: 1988 by 1988, simulation models of disk array reliability [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Operating system scheduler simulation A stream of computing tasks modelled arriving and competing for a processor, run against different scheduling rules to see which one is fairest or fastest. Question it answers: Which way of ordering the queue of tasks gets the most work done, or is fairest to every task? Leaves out: Synthetic workloads rarely match the irregular mix of tasks a real machine encounters. Runs on: about 10^9 FLOPS rough runs on a laptop or workstation in seconds to minutes Since: 1968 by 1968, simulation studies of processor scheduling policies [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Compiler and program optimisation search Enormous numbers of small variations of a piece of code tried and measured, searching for the fastest or shortest version that still does the same job. Question it answers: Out of every equivalent way to write this small piece of code, which one is actually fastest? Leaves out: Programs found are sometimes so unusual that no explanation of why they work is available. Runs on: about 10^10 FLOPS rough a cluster searching a large space of code variants Since: 2006 by 2006, superoptimisation search over short instruction sequences [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Empirical algorithm performance testing An algorithm run thousands of times over randomly generated or real-world inputs of increasing size, measuring how its running time actually grows rather than proving it on paper. Question it answers: How does this algorithm's running time actually grow in practice, on the inputs it will really see? Leaves out: A worst case absent from the test inputs remains undetected until it occurs. Runs on: about 10^9 FLOPS rough runs on a workstation across many generated test inputs Since: 1970 by 1970, systematic empirical testing of algorithm running times [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Language-model program execution A language model writes out step-by-step intermediate states as it traces what a program would compute. Question it answers: Can a language model emulate running code? Leaves out: Output is not guaranteed correct, and long programs fail. Runs on: about 10^14 FLOPS rough Per-query inference Since: 2021 Show your work: scratchpads for intermediate computation with language models (2021) [source](https://arxiv.org/abs/2112.00114) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Blockchain consensus simulation A network of nodes producing and sharing blocks under delays, to test how block size, timing and attackers affect security and throughput. Question it answers: How secure and fast is a blockchain under network delay and attack? Leaves out: Real node behaviour and network topologies are only partly measured. Runs on: about 10^8 FLOPS rough event-driven runs of thousands of nodes. Since: 2016 Gervais and colleagues' security and performance analysis of proof-of-work blockchains with a simulator. [source](https://doi.org/10.1145/2976749.2978341) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Parallel discrete-event simulation A simulation of events in time is split across many processors that each advance their own clock and roll back if one arrives late. Question it answers: How can a huge event-driven simulation, such as a network or battlefield, run fast on many machines? Leaves out: Rollbacks can cascade, and the speed-up depends heavily on how tightly the events are coupled. Runs on: about 10^14 FLOPS rough hours on a supercomputer for billions of events. Since: 1985 Jefferson's virtual time, the Time Warp mechanism for optimistic synchronisation. [source](https://doi.org/10.1145/3916.3988) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Graphics processor architecture simulation A graphics processor's cores, warps and memory are modelled cycle by cycle, running real programs to evaluate a design before building it. Question it answers: How would a design change affect the speed of parallel programs on a graphics chip? Leaves out: Details of real chips are secret or unknown, so the model matches the numbers of existing designs only roughly. Runs on: about 10^12 FLOPS rough hours to days of host time per second of simulated execution. Since: 2009 Bakhoda and colleagues' analysis of CUDA workloads using a detailed GPU simulator. [source](https://doi.org/10.1109/ispass.2009.4919648) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### FPGA-accelerated system simulation A chip design is loaded onto many reconfigurable circuits that run it cycle-exactly at megahertz speeds, simulating whole servers and networks of them. Question it answers: How will this processor and its cluster behave running real software, before it is made? Leaves out: It is far slower than the real chip, and a design that does not fit on the circuits cannot be run. Runs on: about 10^15 FLOPS rough days on a cloud of hundreds of reconfigurable circuits. Since: 2018 Karandikar and colleagues' FireSim, FPGA-accelerated cycle-exact scale-out system simulation in the public cloud. [source](https://doi.org/10.1109/isca.2018.00014) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Full-system simulation An entire computer, with processors, memory, disks and network cards, is simulated well enough to boot an unmodified operating system and run its programs. Question it answers: How does real software behave on a machine that does not yet exist, or can be paused and replayed at will? Leaves out: Timing is approximated for speed, so it cannot give exact performance, only the functional behaviour. Runs on: about 10^11 FLOPS rough near real time on a server per simulated machine. Since: 2002 Magnusson and colleagues' Simics, a full-system simulation platform. [source](https://doi.org/10.1109/2.982916) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Lightweight network emulation Dozens or hundreds of virtual hosts and switches run real network software on one laptop, linked by emulated cables with set speed and delay. Question it answers: Will this network control program work on a whole topology before it is deployed? Leaves out: The host's own processor is shared by all the virtual nodes, so fast links get slowed down. Runs on: about 10^10 FLOPS rough real time on one workstation. Since: 2010 Lantz, Heller and McKeown's 'A network in a laptop', rapid prototyping for software-defined networks. [source](https://doi.org/10.1145/1868447.1868466) [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Simulated annealing A computer cools a model of atoms or a design slowly, accepting worse arrangements sometimes, to find a good solution to a hard optimisation problem. Question it answers: What is a near-best layout or schedule among astronomically many possibilities? Leaves out: It gives no guarantee of the best answer, and results depend on the cooling schedule. Runs on: about 10^12 FLOPS rough hours on a workstation for a chip placement. Since: 1983 Kirkpatrick, Gelatt and Vecchi's optimisation by simulated annealing. [source](https://doi.org/10.1126/science.220.4598.671) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Approximate Bayesian computation A simulator is run with many trial parameter values, and those that produce data close to the observed data are kept, giving a picture of which values are plausible. Question it answers: Which settings of a complicated model could have produced the data we observe? Leaves out: The result depends on which summaries of the data are used and how close a match must be to count. Runs on: about 10^13 FLOPS rough millions of simulator runs on a cluster. Since: 1997 Tavaré and colleagues' inference of coalescence times from DNA sequence data using simulation. [source](https://doi.org/10.1093/genetics/145.2.505) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules [◂ Minds, brains and artificial worlds](https://simulation-hypothesis.com/simulations/minds-computation)[Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations) --- title: "Minds as simulators · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/mind-simulations description: "The simulations that brains run: dreaming, imagining, modelling other minds, play, and modelling the body and the world." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 13 of 18 # Minds as simulators The simulations that brains run: dreaming, imagining, modelling other minds, play, and building models of the body and the world. Many accounts in psychology and neuroscience say brains don't just register the world. They simulate it. Dreaming replays and recombines the day's experience, and none of it is real. Rehearsing a movement before making it, working out what another person thinks, and a child feeding a toy dinner all do the same thing. Each runs a model forward and reads off the result before acting, or instead of acting. Predictive accounts go further. They describe perception, memory and social thinking as simulation: always predicting what comes next and correcting for what arrives. Enactive and ecological accounts reject that picture of perception. This section covers the simulations documented in humans and other animals, not the computers built to imitate them. ## Sleep and dreaming ### REM dreaming The vivid, narrative dreams of rapid-eye-movement sleep, built from memory fragments and emotion with little conscious control. Question it answers: What does the sleeping brain construct once it is cut off from the senses? Leaves out: Physical consistency: flying, dead relatives and rooms that rearrange themselves pass without complaint. Runs on: about 10^16 FLOPS wild guess a sleeping human brain; Sandberg and Bostrom-style estimate Documented since: 1953 Aserinsky and Kleitman's discovery of REM sleep In the simulations tree: [Dreams](https://simulation-hypothesis.com/trees/simulations?n=w-dreams) Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Lucid dreaming Knowing you are dreaming while the dream continues, sometimes with enough control left over to steer what happens next. Question it answers: Can a dreamer recognise, from inside it, that it is a dream? Leaves out: Awakening, which commonly interrupts the episode just as it becomes absorbing. Runs on: about 10^16 FLOPS wild guess a sleeping human brain; Sandberg and Bostrom-style estimate Documented since: 1913 Frederik van Eeden coined the term from his dream diaries Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Hippocampal replay in rats Place-cell firing sequences recorded while a rat runs a maze, then replayed in the same order during rest and sleep. Question it answers: Does the brain rerun a route it has already travelled? Leaves out: Anything the animal has not just experienced: replay only reruns the recent past. Runs on: about 10^16 FLOPS wild guess a rat brain; Sandberg and Bostrom-style estimate Documented since: 1994 Wilson and McNaughton's report of hippocampal reactivation during sleep In the simulations tree: [Hippocampal replay](https://simulation-hypothesis.com/trees/simulations?n=min-replay) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ### Threat-simulation theory of dreams The idea that dreams exist to rehearse dangerous encounters, tested by counting threat content across many recorded dreams. Question it answers: Do dreams train the brain to handle threats it has not yet met? Leaves out: Explaining why so many dreams concern mundane failures, such as missing a bus, rather than threats. Runs on: about 10^16 FLOPS wild guess a sleeping human brain; Sandberg and Bostrom-style estimate Documented since: 2000 Antti Revonsuo's threat-simulation theory of dreaming Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Sleep-dependent memory consolidation Skills and facts learned before sleep, tested again afterwards to see what the brain reprocessed and strengthened overnight. Question it answers: What does the brain rehearse and strengthen while the body is unconscious? Leaves out: It doesn't say which memories get picked, or why those and not others. Runs on: about 10^16 FLOPS wild guess a sleeping human brain; Sandberg and Bostrom-style estimate Documented since: 1924 Jenkins and Dallenbach's nonsense-syllable retention study Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Hypnagogic imagery Vivid, fragmentary perceptual images that appear as the brain disengages from the senses while falling asleep. Question it answers: What does the brain generate when input from the world is fading but consciousness has not yet switched off? Leaves out: Coherence: hypnagogic images rarely add up to a story. Runs on: about 10^16 FLOPS wild guess a drowsy human brain; Sandberg and Bostrom-style estimate Documented since: 1848 Alfred Maury's description of hypnagogic hallucinations Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Hippocampal preplay Place cells fire in sequences for places never yet visited, as if the brain rehearsed paths in advance. Question it answers: Does the brain simulate journeys before it takes them? Leaves out: Later work questions how much of preplay is truly predictive. Runs on: no computer. the brain, no computation counted Documented since: 2011 by 2011, Dragoi and Tonegawa, Preplay of future place cell sequences [source](https://doi.org/10.1038/nature09633) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ## Imagination and planning ### Mental rehearsal in athletes Athletes running through a routine or shot in their head, activating much of the same motor circuitry as performing it for real. Question it answers: Can practising a movement only in imagination improve performance of the real thing? Leaves out: Fatigue, anxiety and the genuine risk of failure. Runs on: about 10^16 FLOPS wild guess an athlete's brain; Sandberg and Bostrom-style estimate Documented since: 1932 Edmund Jacobson recorded muscle activity during imagined movement Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Episodic future thinking Constructing a detailed personal scene of a specific future event, using much of the same machinery used to recall the past. Question it answers: What will a particular future moment be like, in enough detail to plan for it? Leaves out: Accuracy: imagined futures borrow freely from memory and are often wrong in the details. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 2001 Atance and O'Neill named episodic future thinking Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Counterfactual thinking Replaying a past event with one detail changed, to see how differently things would have turned out. Question it answers: What would have happened had the agent acted otherwise? Leaves out: Ever running the real alternative to check the answer. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1982 Kahneman and Tversky's simulation heuristic paper Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Mental rotation Rotating an imagined three-dimensional object in the mind's eye to decide whether it matches another view of the same shape. Question it answers: Is this the same object, seen from a different angle? Leaves out: The object entirely: nothing physical actually turns. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1971 Shepard and Metzler's mental rotation experiment Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Mental navigation Picturing a route through a familiar place before walking or driving it, using the same spatial map the brain keeps for real navigation. Question it answers: Which route reaches the destination, before any movement is made? Leaves out: Traffic, weather and any changes to the place since it was last visited. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1948 Tolman's cognitive-map studies in rats and men Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Mind-wandering and daydreaming Spontaneous, self-generated trains of thought about hypothetical people, places and events, running whenever attention is not needed elsewhere. Question it answers: What does the brain simulate when it has nothing else to do? Leaves out: Staying on topic. Runs on: about 10^16 FLOPS wild guess an idle human brain; Sandberg and Bostrom-style estimate Documented since: 1966 Singer's systematic study of daydreaming Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Constructive episodic simulation Remembering is a rebuilding of past events from stored pieces, the same system that imagines what might happen. Question it answers: Is recalling the past the same act as imagining the future? Leaves out: It is a hypothesis about memory, not a mechanism with parameters. Runs on: no computer. the brain, no computation counted Documented since: 2007 Schacter and Addis’s account of remembering and imagining as one constructive system [source](https://doi.org/10.1098/rstb.2007.2087) In the simulations tree: [Imagining the future](https://simulation-hypothesis.com/trees/simulations?n=min-episodic) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Motor imagery Imagining a movement without doing it, which engages much of the same neural machinery as performing it. Question it answers: Does imagining a movement run the brain's motor program? Leaves out: Imagery can be vague or absent, and its timing varies among people. Runs on: no computer. the brain, no computation counted Documented since: 1994 by 1994, Jeannerod, The representing brain: neural correlates of motor intention and imagery [source](https://doi.org/10.1017/s0140525x00034026) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Visual mental imagery Pictures in the mind's eye that can be scanned, zoomed and inspected, with effort rising with distance. Question it answers: Is a mental image like a picture that can be scanned? Leaves out: Whether images are pictorial or descriptive remains disputed. Runs on: no computer. the brain, no computation counted Documented since: 1973 by 1973, Kosslyn, Scanning visual images: some structural implications [source](https://doi.org/10.3758/bf03198621) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Affective forecasting People simulate how they will feel in a future event and mispredict its intensity and duration. Question it answers: How well can people predict their own future feelings? Leaves out: The forecast is of a few feelings, not of a full life. Runs on: no computer. the brain, no computation counted Documented since: 1998 by 1998, Gilbert and others, Immune neglect [source](https://doi.org/10.1037/0022-3514.75.3.617) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Mental models of reasoning The mind holds a small-scale model of how things work and uses it to try out actions before taking them. Question it answers: Does reasoning work by running a small model of the world? Leaves out: Craik gave an idea, not a testable theory of how models are built. Runs on: no computer. the brain, no computation counted Documented since: 1943 by 1943, Craik, The Nature of Explanation [source](https://en.wikipedia.org/wiki/Kenneth%5FCraik) In the simulations tree: [Craik’s model in the head](https://simulation-hypothesis.com/trees/simulations?n=min-craik) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Vicarious trial and error A rat pauses at a choice point and looks back and forth between options as if trying each in turn. Question it answers: Does a rat deliberate by sampling the outcomes of paths? Leaves out: Behaviour shows deliberation, but not what is in the animal's mind. Runs on: no computer. the brain, no computation counted Documented since: 1938 by 1938, Tolman, The determiners of behavior at a choice point [source](https://doi.org/10.1037/h0062733) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Future planning in animals A bird caches food in the place where it expects to be hungry, acting on a simulated future need. Question it answers: Can an animal plan for a need it does not feel now? Leaves out: Simpler learning rules can explain some of these results. Runs on: no computer. the brain, no computation counted Documented since: 2007 by 2007, Raby and others, Planning for the future by western scrub-jays [source](https://doi.org/10.1038/nature05575) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Other minds ### Theory of mind Modelling what another person knows, wants or believes, including cases where that differs from what is actually true. Question it answers: What does this other person think is going on? Leaves out: Ever checking the model directly against what they actually think. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1978 Premack and Woodruff coined theory of mind Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Empathy as simulation theory Feeling something of another person's state by running a version of their situation through one's own emotional and bodily systems. Question it answers: What would the observer feel in the other person's position? Leaves out: The difference between self and other, which is where empathy most often fails. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1986 Gordon's simulation theory of folk psychology In the simulations tree: [Simulating other minds](https://simulation-hypothesis.com/trees/simulations?n=soc-gordon) Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Mirror systems Neurons that fire both when an action is performed and when it is watched in someone else. Question it answers: Can understanding another's action be simulating it in one's own motor system? Leaves out: Explaining understanding that has no matching action, such as watching a fish swim. Runs on: about 10^16 FLOPS wild guess a macaque brain; Sandberg and Bostrom-style estimate Documented since: 1992 Di Pellegrino, Fadiga and colleagues report mirror neurons Models: [Human](https://simulation-hypothesis.com/entities/human) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Cells ### Audience design Predicting what a listener already knows and needs explained, before choosing how to say something. Question it answers: What must the speaker simulate on the listener's behalf? Leaves out: Directly querying the listener. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1987 Isaacs and Clark on references between experts and novices Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Visual perspective-taking Working out what another person can see from where they are standing, by mentally moving to their point of view. Question it answers: What does the scene look like from the other person's position rather than the observer's own? Leaves out: The step in toddlers, who assume that everyone sees what they see. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1948 Piaget and Inhelder's three mountains task Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Joint attention Following another person's gaze or point to work out what they are looking at, then checking back to confirm the target is shared. Question it answers: What is currently capturing their attention? Leaves out: The underlying thought, tracking only the target of it. Runs on: about 10^16 FLOPS wild guess an infant's brain; Sandberg and Bostrom-style estimate Documented since: 1975 Scaife and Bruner on joint visual attention in infants Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Fiction as social simulation Reading stories runs a model of social life, strengthening the reader's grasp of other people's minds. Question it answers: Does fiction train the mind to simulate other people? Leaves out: Evidence for a lasting gain in social skill is mixed. Runs on: no computer. the brain, no computation counted Documented since: 2008 by 2008, Mar and Oatley, The function of fiction is the abstraction and simulation of social experience [source](https://doi.org/10.1111/j.1745-6924.2008.00073.x) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Play and pretence ### Children's pretend play A child treating a banana as a telephone, or an empty cup as full of tea, running an invented layer of meaning over the real objects. Question it answers: What would happen if this object were something else? Leaves out: Any objection when the pretend layer contradicts the real one. Runs on: about 10^16 FLOPS wild guess a child's brain; Sandberg and Bostrom-style estimate Documented since: 1945 Piaget's study of symbolic play in children In the simulations tree: [Children’s pretend play](https://simulation-hypothesis.com/trees/simulations?n=w-pretend) Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Animal play as practice Young mammals wrestling, chasing and stalking without consequence, using movements drawn from real hunting and fighting. Question it answers: Does harmless play rehearse skills the animal will need for real later? Leaves out: Establishing whether play is merely intrinsically rewarding. Runs on: about 10^16 FLOPS wild guess a young mammal's brain; Sandberg and Bostrom-style estimate Documented since: 1898 Groos's practice theory of animal play [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Imaginary companions A sustained, named, invented character that a child talks to and negotiates with over weeks or years. Question it answers: Can a fully invented other mind still be useful to think with? Leaves out: Continuity: for most children the companion fades by about age seven. Runs on: about 10^16 FLOPS wild guess a child's brain; Sandberg and Bostrom-style estimate Documented since: 1934 Svendsen's early study of children's imaginary companions Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Sociodramatic play Groups of children jointly acting out invented roles and scenes, negotiating the rules of the pretend world as they go. Question it answers: Can several separate imaginations run the same simulated scene together? Leaves out: Sustained maintenance of character. Runs on: about 10^16 FLOPS wild guess several children's brains; Sandberg and Bostrom-style estimate Documented since: 1933 Vygotsky's lecture on play and child development Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Rules ### Paracosms An elaborate invented world, with its own geography, history and rules, built and maintained in the imagination over months or years. Question it answers: How much internal consistency can an invented world sustain? Leaves out: Any requirement that others share the belief. Runs on: about 10^16 FLOPS wild guess a child's or adult's brain; Sandberg and Bostrom-style estimate Documented since: 1826 the Brontë children’s Glass Town, from 1826; Silvey’s survey of childhood paracosms followed in 1976 [source](https://en.wikipedia.org/wiki/Glass%5FTown) In the simulations tree: [Glass Town](https://simulation-hypothesis.com/trees/simulations?n=w-bronte) Models: [Human](https://simulation-hypothesis.com/entities/human) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Object play in primates Wild chimpanzees carrying and cradling a stick the way they would hold an infant, well past the age of ordinary play. Question it answers: Can play stand in for a skill an animal has not yet had a chance to practise? Leaves out: Knowing whether the chimpanzee is pretending in any human sense. Runs on: about 10^16 FLOPS wild guess a chimpanzee's brain; Sandberg and Bostrom-style estimate Documented since: 2010 Kahlenberg and Wrangham on stick-carrying in wild chimpanzees [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## The brain's world model ### Predictive processing The brain generating a running prediction of its own sensory input, and updating only on the mismatch with what arrives. Question it answers: What does the world probably look like right now, before the senses even report it? Leaves out: Explaining where the very first prediction ever came from. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1999 Rao and Ballard's predictive coding model of visual cortex Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Motor forward models A copy of a movement command run forward to predict its sensory consequences, ready before the real feedback arrives. Question it answers: What will this movement feel and look like, before it has finished? Leaves out: The actual movement, which occasionally disagrees with the prediction. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1995 Wolpert, Ghahramani and Jordan's internal-model paper Models: [Human](https://simulation-hypothesis.com/entities/human) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### The body schema A running model of where the body's own parts are and how large they are, updated by touch, sight and movement, and susceptible to manipulation, as in the rubber-hand illusion. Question it answers: Where are the body's parts, and where does the body end? Leaves out: Frequent obvious error, which makes illusions striking when it does occur. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1911 Head and Holmes introduced the body schema Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Hallucination as uncontrolled prediction Perception with the balance tipped too far towards prediction and away from incoming evidence, so the model is experienced as though it were the world. Question it answers: What happens to perception when prediction stops being corrected by evidence? Leaves out: Explaining every kind of hallucination equally well. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 2009 Fletcher and Frith's Bayesian account of hallucination Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Blind-spot filling-in The visual system generating plausible content for the small blind spot in each eye's field of view, matched to the surrounding pattern. Question it answers: What is probably there, in the one place the eye cannot see? Leaves out: Any verification of the inferred content, since nothing appears obviously missing. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 1992 Ramachandran's studies of blind-spot filling-in Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Interoception A running prediction of the body's internal state, heartbeat, breathing, hunger and gut, checked against the actual signals arriving from inside. Question it answers: What is the current internal state of the body? Leaves out: Conscious access: most people can report on it only rarely. Runs on: about 10^16 FLOPS wild guess a human brain; Sandberg and Bostrom-style estimate Documented since: 2013 Seth's predictive account of interoceptive inference Models: [Human](https://simulation-hypothesis.com/entities/human) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Thought as simulated action Thinking is covert action and perception: the brain runs its own motor and sensory systems offline to rehearse outcomes. Question it answers: Is conscious thought the brain simulating its own behaviour and perception? Leaves out: Competing accounts explain the same results with symbols. Runs on: no computer. the brain, no computation counted Documented since: 2002 by 2002, Hesslow, Conscious thought as simulation of behaviour and perception [source](https://doi.org/10.1016/s1364-6613%2802%2901913-7) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Grounded cognition Concepts are reactivations of sensory and motor states stored from experience, not abstract symbols. Question it answers: Does understanding a concept re-run the experience of it? Leaves out: Abstract concepts are hard to explain by sensory reenactment. Runs on: no computer. the brain, no computation counted Documented since: 1999 by 1999, Barsalou, Perceptual symbol systems [source](https://doi.org/10.1017/s0140525x99002149) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### The phenomenal self-model The sense of being a self is a model the brain builds of its own body and state and cannot see as a model. Question it answers: Is the self a simulation that the brain does not recognise as one? Leaves out: It is a philosophical framework, not an experimentally tested mechanism. Runs on: no computer. the brain, no computation counted Documented since: 2003 by 2003, Metzinger, Being No One [source](https://doi.org/10.7551/mitpress/1551.001.0001) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Body ownership illusions Brushing a hidden hand and a visible rubber hand together makes the rubber hand feel like one's own. Question it answers: How does the brain decide which body is yours? Leaves out: Strength of the illusion varies widely among people. Runs on: no computer. the brain, no computation counted Documented since: 1998 by 1998, Botvinick and Cohen, the rubber hand illusion [source](https://en.wikipedia.org/wiki/Rubber%5Fhand%5Fillusion) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Embodied language simulation Understanding a sentence involves mentally simulating the scene it describes, including shapes and orientations. Question it answers: Do readers build a mental scene while reading? Leaves out: Some replications give weak effects. Runs on: no computer. the brain, no computation counted Documented since: 2001 by 2001, Stanfield and Zwaan, implied orientation and picture recognition [source](https://doi.org/10.1111/1467-9280.00326) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### The intuitive physics engine The brain predicts how objects will fall, collide and stack by running approximate physical simulations in the head. Question it answers: Does judging a falling tower use an internal physics simulation? Leaves out: The model fits some judgements, and fails on others. Runs on: about 10^9 FLOPS rough a laptop, seconds per judgement Documented since: 2013 by 2013, Battaglia, Hamrick and Tenenbaum, Simulation as an engine of physical scene understanding [source](https://doi.org/10.1073/pnas.1306572110) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies [◂ Mathematics and computation](https://simulation-hypothesis.com/simulations/mathematics-computation)[Training simulators ▸](https://simulation-hypothesis.com/simulations/training) --- title: "Training simulators · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/training description: "Simulations with a person in the loop: cockpits, operating theatres, control rooms and bridges. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 14 of 18 # Training simulators Simulations with a person in the loop: cockpits, operating theatres, control rooms and bridges. These are simulations with a human operator in the loop. The point isn't to predict the world. It's practice: letting people rehearse rare, costly and dangerous situations before they meet them for real. ## Vehicles ### Full-flight simulators A replica cockpit on a motion platform with the aircraft’s flight model, systems and failures, good enough that pilots qualify on new types in them. Question it answers: Can the crew handle an engine failure on take-off? Leaves out: Motion platforms approximate acceleration; sustained acceleration cannot be reproduced. Runs on: about 10^13 FLOPS rough a simulator's dedicated computer, real time Since: 1929 Edwin Link's pneumatic pilot trainer In the simulations tree: [Link Trainer](https://simulation-hypothesis.com/trees/simulations?n=w-linktrainer) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Driving and rail simulators A car or train cab with a projected world, used for research and teaching. Question it answers: How do fatigue, distraction or a new display change how people drive? Leaves out: Drivers know the environment is not real, so risk-taking does not fully match that on the road. Runs on: about 10^13 FLOPS rough a dedicated simulator computer, real time Since: 1970 by 1970, early university driving simulators for road safety research [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Ship bridge simulators A full ship’s bridge with realistic handling, weather and harbour traffic. Question it answers: Can the pilot bring this ship into a narrow harbour in a crosswind? Leaves out: Rare mechanical failures and true sea conditions are hard to fully replicate. Runs on: about 10^13 FLOPS rough a dedicated simulator computer, real time Since: 1972 by 1972, early full-mission ship bridge simulators for officer training [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Spaceflight and mission control Spacecraft and mission-control simulators running every phase of a flight, with failures injected on purpose. Question it answers: Can the crew and the ground team handle what goes wrong? Leaves out: Only failures the designers expected are injected. Real missions throw up ones they didn't. Runs on: about 10^13 FLOPS rough mission-control simulator computers, real time Since: 1959 early NASA simulators trained the first astronauts and ground teams [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Heavy equipment simulators Cranes, excavators and mining trucks with realistic controls and loads, for training operators away from a real site. Question it answers: Can the operator handle this load or this ground safely? Leaves out: Real ground conditions and machine wear are harder to replicate than the model assumes. Runs on: about 10^12 FLOPS rough the simulator's own computer, real time Since: 1990 by 1990, early crane and mining equipment simulators for operator training [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Diving and submersible simulators Underwater conditions, buoyancy and vehicle handling for divers and crewed submersible pilots. Question it answers: Can the diver or pilot handle an emergency at depth? Leaves out: Real water pressure and cold on the body are things a simulator on land cannot recreate. Runs on: about 10^12 FLOPS rough the simulator's own computer, real time Since: 1978 by 1978, early submersible pilot training simulators [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ## Medicine ### Surgical simulators Virtual tissue and instruments with force feedback, for practising procedures. Question it answers: Is this trainee ready to operate on a real patient? Leaves out: Virtual tissue does not bleed, tear or smell as the real thing does. Runs on: about 10^12 FLOPS rough a desktop with haptic hardware, real time Since: 1993 by 1993, early virtual-reality simulators for laparoscopic surgery [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Patient simulators Manikins that breathe, bleed, talk and respond to drugs, for emergency and team training. Question it answers: Does the team recognise the problem and act in time? Leaves out: Physiology is scripted to the scenario; unscripted complications do not emerge on their own. Runs on: about 10^10 FLOPS rough an embedded computer inside the manikin, real time Since: 1969 the first anaesthesia training manikin, built in Los Angeles [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Dental simulators Virtual teeth and gums with force feedback, for practising drilling, fillings and extractions. Question it answers: Is this trainee's hand steady and careful enough for a real patient's mouth? Leaves out: Virtual tooth and gum tissue still feels more uniform than a real patient's mouth. Runs on: about 10^11 FLOPS rough a dental school workstation, real time Since: 1997 by 1997, early haptic dental training simulators [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Childbirth simulators A birthing manikin with a model baby, for practising normal delivery and rare emergencies like a stuck shoulder. Question it answers: Does the team recognise and manage a birth emergency quickly enough? Leaves out: The manikin's fixed set of complications does not cover every real birth emergency. Runs on: about 10^9 FLOPS rough an embedded controller inside the manikin, real time Since: 1996 by 1996, early computerised birthing manikins for obstetric training [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Anaesthesia simulators A virtual patient's breathing, heart and drug response, controlled by a trainee giving anaesthetic drugs. Question it answers: Does the trainee dose correctly and catch a complication before it becomes dangerous? Leaves out: The model's drug responses are typical ones; real patients react more variably. Runs on: about 10^11 FLOPS rough a training centre desktop, real time Since: 1967 Sim One, an early anaesthesia training manikin with simulated physiology [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Paramedic and mass-casualty triage training Simulated casualties with different injuries, used to practise sorting patients by urgency under time pressure. Question it answers: Does the trainee sort patients correctly when there are more casualties than hands to help? Leaves out: Actors and manikins cannot fully convey the disorder of a real mass-casualty scene. Runs on: about 10^10 FLOPS rough a training exercise's basic equipment, little computing Since: 1988 by 1988, early computer-assisted mass-casualty triage exercises [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Virtual human patients Animated characters respond to a trainee's questions with scripted or generated dialogue to practise clinical skills. Question it answers: How well can a trainee interview a patient who is not real? Leaves out: Dialogue range is limited, and nonverbal cues are shallow. Runs on: about 10^9 FLOPS rough Real-time rendering and dialogue Since: 2007 Virtual patients for clinical therapist skills training (2007) [source](https://doi.org/10.1007/978-3-540-74997-4%5F19) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Agent hospitals A simulated hospital in which language-model doctors, nurses and patients carry out the care process and improve with experience. Question it answers: Can agents practise treatment in a virtual hospital and improve? Leaves out: Patients and diseases are generated, so realism of outcomes is unproven. Runs on: about 10^14 FLOPS rough Many model calls per simulated case Since: 2024 Agent Hospital: a simulacrum of hospital with evolvable medical agents (2024) [source](https://arxiv.org/abs/2405.02957) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Catheter and endovascular simulators A haptic device mimics a catheter and a virtual X-ray image of the vessels so trainees can practise cardiac or vascular procedures. Question it answers: Can a trainee thread the catheter without damaging the vessel? Leaves out: The feel of tissue is approximate and unusual anatomy is limited. Runs on: about 10^10 FLOPS rough real-time physics and haptics on a workstation. Since: 2000 Dawson and colleagues, designing a computer-based simulator for interventional cardiology training. [source](https://doi.org/10.1002/1522-726x%28200012%2951:4<522::aid-ccd30>3.0.co;2-7) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Structured clinical examinations Trainees move through a series of stations with trained actors playing patients and are scored against a checklist. Question it answers: Can this trainee take a history and examine a patient to the standard? Leaves out: An actor cannot produce real physical signs such as a heart murmur or an enlarged liver. Runs on: no computer. no computation, a human role-play exercise. Since: 1975 Harden and colleagues, assessment of clinical competence using an objective structured examination. [source](https://doi.org/10.1136/bmj.1.5955.447) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Ultrasound training simulators A dummy body and a probe, with a computer showing the ultrasound image for that position, drawn from stored scans of real patients. Question it answers: Can a trainee learn to find and read ultrasound views without a patient? Leaves out: A limited library of stored cases cannot show the variety of real bodies or the feel of pressing the probe. Runs on: about 10^9 FLOPS rough real time on a workstation. Since: 2004 Maul and colleagues' experience with SonoTrainer and comparative review of other ultrasound simulators. [source](https://doi.org/10.1002/uog.1119) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Robotic surgery simulators A virtual copy of a surgical robot's console in which trainees practise moving instruments, cutting and suturing in simulated tissue, with scores for skill. Question it answers: Is a surgeon safe to operate with the robot, as shown by practice in virtual tissue? Leaves out: Virtual tissue is simpler than the real thing, so bleeding and complications are not well trained. Runs on: about 10^9 FLOPS rough real time on a workstation. Since: 2009 Kenney and colleagues' face, content and construct validity study of the dV-Trainer virtual reality robotic simulator. [source](https://doi.org/10.1016/j.urology.2008.12.044) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Eye surgery simulators A model eye viewed through a real microscope with virtual instruments inside it, to practise steps such as removing a cataract, with feedback on errors. Question it answers: Can a trainee learn delicate eye surgery before touching a patient? Leaves out: The eye's tissue is modelled coarsely, so rare complications are not rehearsed. Runs on: about 10^9 FLOPS rough real time on a workstation. Since: 2009 Feudner and colleagues' randomised trial showing virtual reality training improves wet-lab performance of capsulorhexis. [source](https://doi.org/10.1007/s00417-008-1029-7) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Endoscopy simulators A real scope is passed into a model of the gut that displays a computer-drawn view of the lining and responds to turning and pushing. Question it answers: Can a trainee learn to steer a scope and spot disease without a patient? Leaves out: The gut's stretch and the patient's discomfort are poorly reproduced, so the feel of real procedures is missing. Runs on: about 10^9 FLOPS rough real time on a workstation. Since: 1992 Beer-Gabel and colleagues' computer-assisted training in endoscopy, from a simulator to a learning station. [source](https://doi.org/10.1055/s-2007-1010538) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Language-model simulated students Language-model characters play confused or struggling learners so that trainee teachers can practise explaining and giving feedback. Question it answers: Can new teachers practise responding to learners before meeting real ones? Leaves out: The model's students are more polite and consistent than real ones and make mistakes real ones would not. Runs on: about 10^14 FLOPS rough a few model calls per turn of dialogue. Since: 2023 Markel and colleagues' GPTeach, interactive teaching-assistant training with GPT-based students. [source](https://doi.org/10.1145/3573051.3593393) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ## Control and crisis ### Control-room simulators Exact copies of the control rooms of power stations, chemical plants and grids, driven by a model of the process. Question it answers: Can the operators bring the plant back safely after an upset? Leaves out: The model cannot include every valve and failure the real thing has. Runs on: about 10^13 FLOPS rough the simulator's own dedicated computer, real time Since: 1958 by 1958, early full-scope simulators for nuclear power plant operators [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Emergency exercises A scripted disaster worked through by the people who would respond to it, around a table or across a real city. Question it answers: Where does the plan break down? Leaves out: Participants know it is an exercise, so real panic and confusion are underplayed. Runs on: no computer. paper and people; sometimes a simple computer to track events Since: 1954 by 1954, civil defence tabletop exercises rehearse disaster response [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Business simulations Teams running a simulated company or market over several rounds, taught in business schools. Question it answers: Can the team read the market and manage the company through it? Leaves out: Simplified market rules can reward exploitation of the model, not necessarily sound management. Runs on: about 10^10 FLOPS rough a modest computer; most of the exercise is discussion Since: 1956 the American Management Association ran the Top Management Decision Game, an early computer-based business game [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ### Air traffic control simulators A simulated sky full of aircraft, radar screens and radio calls, for training and testing controllers. Question it answers: Can the controller keep enough aircraft safely apart as traffic gets busier? Leaves out: Simulated pilots follow instructions more predictably than real ones under pressure. Runs on: about 10^12 FLOPS rough an air navigation service provider's server, real time Since: 1966 by 1966, early computer-driven air traffic control training simulators [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Bodies ### Negotiation and diplomacy training simulations Trainee diplomats, mediators or executives role-playing a dispute against instructors or each other, practising how to read the other side and reach a deal. Question it answers: Did the trainee find a workable deal, and where did their approach go wrong? Leaves out: Role-players usually compromise more readily than real counterparts under real domestic pressure. Runs on: about 10^10 FLOPS rough little computing; mostly people, rules and a scorer's desktop Since: 1963 by 1963, early simulated negotiation exercises for diplomatic training [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Emergency incident command simulators A live, timed exercise where commanders and staff receive escalating, unscripted updates about an unfolding emergency over real radios and screens. Question it answers: Can the command team make good decisions in real time, not just with hindsight? Leaves out: However realistic, everyone involved still knows no one will really get hurt. Runs on: about 10^11 FLOPS rough a training centre's server, real time Since: 1974 by 1974, early functional emergency-management exercises with live radio traffic [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Language-model conflict rehearsal A language-model counterpart plays a difficult person so a trainee can rehearse a conflict and get feedback. Question it answers: How can a hard conversation be practised safely? Leaves out: The partner's responses are not those of a real person. Runs on: about 10^13 FLOPS rough Model calls per session Since: 2023 Rehearsal: simulating conflict to teach conflict resolution (2023) [source](https://arxiv.org/abs/2309.12309) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Rules ### Mass-casualty exercises Actors or manikins stand for many victims, and hospitals, ambulances and teams go through a staged disaster to test triage and capacity. Question it answers: Would a hospital cope if dozens of seriously injured people arrived at once? Leaves out: Staff know it is an exercise, so fear, fatigue and chaos of a real event are absent. Runs on: no computer. no computation; a day of staff, actors and observers. Since: 1989 Simon and colleagues' simulated mass casualty evaluation at Beilinson Hospital. [source](https://doi.org/10.1017/s1049023x00029885) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Populations [◂ Minds as simulators](https://simulation-hypothesis.com/simulations/mind-simulations)[Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers) --- title: "Before computers · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/before-computers description: "Simulation before the transistor: gears, water, sand and rehearsal as stand-ins for the real system. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 15 of 18 # Before computers Simulation before the transistor: gears, water, sand and rehearsal as stand-ins for the real system. Long before electronic computers, people built devices, models and rehearsals to stand in for systems that were too big, slow, expensive or dangerous to test directly. Gears were turned to trace planetary motion. Scale models of ships, rivers and dams were run with real water. Mechanical linkages solved equations by moving instead of calculating. Officers, midwives and children acted out scenarios with counters, sand, wax and each other. None of it was digital, and some of it is still used alongside the computer. All of it counts as simulation: a stand-in system, built to answer a question about the real one. ## Models of the heavens ### Orrery A geared mechanical model of the Sun, Earth, Moon and planets, turned by hand or clockwork to show their relative motion. Question it answers: Where will the planets and moons be relative to each other? Leaves out: Scale completely: the planets are always represented far too close together and far too large. Runs on: no computer. a geared mechanical model; a physical device, no digital computing at all Since: 1704 George Graham's geared planetary model, made for the Earl of Orrery [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Astrolabe A hand-held disc instrument that models the rotating sky, used to find the time, latitude and the positions of stars. Question it answers: What time is it, and where in the sky is that star, right now? Leaves out: Anything not on its engraved plates: a new star needs a new astrolabe. Runs on: no computer. an engraved brass hand instrument; a physical device, no digital computing at all Since: 800 by 800, Islamic astronomers refining earlier Greek instrument designs [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### The Antikythera mechanism A geared bronze device that modelled the Sun, Moon and calendar cycles well enough to predict eclipses. Question it answers: When will the Moon eclipse the Sun next? Leaves out: It reproduces observed cycles with gear trains and has no account of why the bodies move. Runs on: no computer. a hand-cranked bronze gear train; a physical device, no digital computing at all Since: 150 BCE the Antikythera shipwreck device, Greece In the simulations tree: [Antikythera mechanism](https://simulation-hypothesis.com/trees/simulations?n=p-antikythera) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Optical planetarium A projector inside a domed theatre casting the whole night sky, including its motion over time, onto the ceiling. Question it answers: What will the sky over this city look like on a given night? Leaves out: Weather and light pollution, so the stars are always visible. Runs on: no computer. an optical star projector; a physical device, no digital computing at all Since: 1923 the first optical projection planetarium opened, Munich [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Armillary sphere Nested rings representing the celestial equator, ecliptic and horizon, built to model and measure the sky's apparent rotation. Question it answers: Where does a given star cross the horizon, and when? Leaves out: The planets' individual wandering, treating the sky as one rotating shell. Runs on: no computer. a nested-ring metal or wooden instrument; a physical device, no digital computing at all Since: 117 by 117 CE, Zhang Heng's water-driven armillary sphere, China (earlier ring instruments are credited to Eratosthenes, Geng Shouchang and others but are not securely documented as nested-ring spheres) [source](https://en.wikisource.org/wiki/1911%5FEncyclop%C3%A6dia%5FBritannica/Armilla) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Equatorium A geometric instrument with rotating plates that gives a planet's position by construction, without any arithmetic. Question it answers: Where is this planet on the zodiac tonight, read straight off a dial? Leaves out: Precision: it is only as good as the engraving and the eye reading it. Runs on: no computer. a graduated brass or wooden instrument; a physical device, no digital computing at all Since: 1080 by 1080, al-Zarqali's equatorium, Islamic Spain [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Terrestrial globe A sphere carrying a map of the world, used to show distances, routes and the sizes of lands. Question it answers: How do the continents sit relative to each other on a sphere? Leaves out: Globes show shape and place, not the processes on the surface. Runs on: no computer. a hand-turned model, no computation Since: 150 BCE by about 150 BCE, Crates of Mallus's globe at Pergamon, known from Strabo; Martin Behaim's 1492 Erdapfel is the oldest surviving globe [source](https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.01.0239:book=2:chapter=5:section=10) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Astronomical clock A clock that also shows the positions of sun, moon and stars, driven by gears and an escapement. Question it answers: Where are the sun and moon in the sky right now? Leaves out: It reproduces fixed cycles and cannot predict anything not built into its gears. Runs on: no computer. a gear train, no computation Since: 1092 by 1092, Su Song's water-driven clock tower, described in the Xinyi Xiangfayao [source](https://en.wikipedia.org/wiki/Su%5FSong) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ## Scale models and tanks ### Ship-model towing tank A small-scale hull towed down a long tank of still water, its resistance measured and scaled up to the full-size ship. Question it answers: How much power will the real ship need to reach a given speed? Leaves out: Waves and weather unless the tank is built to add them. Runs on: no computer. a towed scale hull in a water tank; a physical device, no digital computing at all Since: 1871 William Froude’s ship-model towing tank at Torquay, funded in 1870, built 1871, first test March 1872 [source](https://rina.org.uk/industry-news/maritime-history-and-heritage/william-froude-the-father-of-hydrodynamics) In the simulations tree: [Froude’s towing tank](https://simulation-hypothesis.com/trees/simulations?n=mat-froude) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Physical river basin model A large outdoor scale model of an entire river system, complete with tributaries, built to run real water over real contours. Question it answers: Where will the water go if this much rain falls, or this levee breaks? Leaves out: Groundwater and most of the fine sediment detail. Runs on: no computer. an outdoor concrete terrain model with running water; a physical device, no digital computing at all Since: 1943 the US Army Corps of Engineers' Mississippi basin model begun [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Harbour and estuary model A scale model of a port or estuary with a working tide, used to see how currents, silt and waves will move once it is built. Question it answers: Will this new breakwater silt up the channel it is meant to protect? Leaves out: Storms rarer than the ones the operators choose to run. Runs on: no computer. a scale basin with a mechanical tide; a physical device, no digital computing at all Since: 1935 by 1935, European hydraulics laboratories building tidal harbour models [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Dam and spillway model A small physical replica of a dam and its spillway, run with real water to check that the design carries a flood without failing. Question it answers: Does the spillway pass the largest flood it is ever likely to see? Leaves out: The very largest, rarest floods, which are usually just extrapolated. Runs on: no computer. a scale concrete model with running water; a physical device, no digital computing at all Since: 1928 US Bureau of Reclamation hydraulic model tests before a major dam [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Structural scale model A small loaded replica of a bridge or building, sometimes made from stress-revealing plastic, to see where and how it will fail first. Question it answers: Where does this structure crack first, and under how much load? Leaves out: Fatigue over decades, which no short test can show. Runs on: no computer. a loaded scale replica, sometimes photoelastic plastic; a physical device, no digital computing at all Since: 1901 Coker and Filon's early photoelastic stress models [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Architectural acoustic scale model A small physical replica of a hall or theatre, tested with sound pitched up to match the model's size, to hear how the real room will perform. Question it answers: Will the back row hear the stage clearly in this hall? Leaves out: The audience, whose clothes and bodies change the room's real absorption. Runs on: no computer. a scale room model with shifted-frequency sound; a physical device, no digital computing at all Since: 1934 Spandöck's scaled room-acoustic model experiments, Germany [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Fields ### Hele-Shaw cell Fluid squeezed between two close plates, so flow around obstacles is seen as a flat picture of streamlines. Question it answers: How does fluid flow around this shape, drawn as a flat picture? Leaves out: It represents only slow two-dimensional flow. Runs on: no computer. a bench apparatus, no computation Since: 1898 by 1898, Hele-Shaw's study of flow between parallel plates [source](https://en.wikipedia.org/wiki/Hele-Shaw%5Fflow) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Hanging-chain arch model A chain or string hung from fixed points takes a shape that, inverted, is the ideal line of a masonry arch. Question it answers: What shape lets an arch stand using only compression? Leaves out: It solves one load case at a time. Runs on: no computer. a hung model, no computation Since: 1675 by 1675, Hooke's anagram on the arch, later used by designers [source](https://en.wikipedia.org/wiki/Catenary) In the simulations tree: [Hooke’s hanging chain](https://simulation-hypothesis.com/trees/simulations?n=mat-hooke) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Soap film minimal-surface models A wire frame dipped in soap solution forms a film whose surface settles to the smallest area. Question it answers: What surface of least area spans this boundary? Leaves out: Films find one surface and cannot show competing ones. Runs on: no computer. a bench apparatus, no computation Since: 1873 by 1873, Plateau, Statique expérimentale et théorique des liquides [source](https://en.wikipedia.org/wiki/Joseph%5FPlateau) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ## Analogue computers ### Mechanical differential analyser Spinning wheel-and-disc integrators linked by rods and gears, set up by hand to solve a particular set of differential equations. Question it answers: How does this system evolve over time, given the equation that governs it? Leaves out: Being reusable without rebuilding the linkage for the next problem. Runs on: no computer. a room-sized mechanical linkage of wheels and discs; a physical device, no digital computing at all Since: 1931 Vannevar Bush's mechanical differential analyser, MIT [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Populations ### Tide-predicting machine Pulleys and gears summing dozens of known tidal cycles by hand-cranked mechanism, to print out a year of predicted tide heights. Question it answers: How high will the tide be in this port, on a given day next year? Leaves out: Storm surge and anything not already in its measured tidal cycles. Runs on: no computer. a hand-cranked pulley-and-gear machine; a physical device, no digital computing at all Since: 1872 Kelvin and Roberts's harmonic tide-predicting machine In the simulations tree: [Kelvin’s tide predictor](https://simulation-hypothesis.com/trees/simulations?n=p-tide) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Populations ### Hydraulic economy model Coloured water pumped through tanks, valves and pipes standing for income, tax, savings and spending in a national economy. Question it answers: What happens to spending and stock levels if this tax rate changes? Leaves out: Expectations and behaviour: the water does not anticipate the next valve turn. Runs on: no computer. a room-sized network of tanks and pipes; a physical device, no digital computing at all Since: 1949 Bill Phillips's hydraulic model of the economy, London School of Economics In the simulations tree: [Phillips’s hydraulic economy](https://simulation-hypothesis.com/trees/simulations?n=soc-moniac) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Populations ### Electrical network analyser A room-sized array of scaled resistors, capacitors and transformers wired to mimic a power grid, dialled to test a fault or a new line. Question it answers: What happens to voltage and current across the grid if this line trips? Leaves out: Anything on the real grid that was not patched into the model that day. Runs on: no computer. a wired room of scaled electrical components; a physical device, no digital computing at all Since: 1925 MIT's alternating-current network analyser for power-grid studies [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Populations ### Mechanical harmonic analyser A geared instrument that traces a curve, such as recorded tide or wave data, and reads off the strength of its underlying cycles. Question it answers: What regular cycles is this messy, real-world curve actually made of? Leaves out: Anything in the data that is not a clean repeating cycle. Runs on: no computer. a traced-curve mechanical instrument; a physical device, no digital computing at all Since: 1876 Kelvin's mechanical harmonic analyser [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Populations ### Analogue fire-control computer Gears and cams combining a ship's own course and speed with a target's bearing to point guns at where it will be, not where it is. Question it answers: Where should the gun point now, to hit a moving target later? Leaves out: Any manoeuvre the target has not yet begun. Runs on: no computer. a mechanical gear-and-cam calculator; a physical device, no digital computing at all Since: 1912 the Dreyer table mechanical fire-control computer, Royal Navy [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Galton board Balls drop through rows of pegs and pile into a bell-shaped curve, showing how many small chances add up. Question it answers: What spread results when many small random steps combine? Leaves out: It shows one distribution and cannot change its rules. Runs on: no computer. a bench apparatus, no computation Since: 1874 by 1874, Galton's quincunx shown at the Royal Institution [source](https://en.wikipedia.org/wiki/Galton%5Fboard) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Buffon's needle Dropping a needle on ruled lines and counting how often it crosses gives an estimate of pi, a hand-run Monte Carlo experiment. Question it answers: Can random throws estimate a number? Leaves out: It is inefficient: the estimate improves only slowly with more throws. Runs on: no computer. hand throwing, no computation Since: 1777 by 1777, Buffon's needle problem in his Essai d'arithmetique morale [source](https://en.wikipedia.org/wiki/Buffon's%5Fneedle%5Fproblem) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Iron wire nerve model A passive iron wire in acid carries a travelling surface change that fires, recovers and can be re-triggered like a nerve impulse. Question it answers: Can a nerve impulse be reproduced by a non-living system? Leaves out: It copies the pattern, not the ion channels that cause it. Runs on: no computer. a bench apparatus, no computation Since: 1920 by 1920, Lillie, iron wire as a model of recovery processes in living protoplasm [source](https://doi.org/10.1085/jgp.3.2.129) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Cells ### Cybernetic tortoises Small wheeled robots with a few valve circuits that seek light, avoid obstacles and return to a charger. Question it answers: Can a few parts produce lifelike behaviour? Leaves out: The behaviours are few and cannot learn beyond simple conditioning. Runs on: no computer. a two-valve circuit, no computation Since: 1948 by 1948, Grey Walter's Machina speculatrix, Elmer and Elsie [source](https://en.wikipedia.org/wiki/William%5FGrey%5FWalter) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Tables, boards and rehearsals ### Sand table A shallow tray of sand shaped into the hills, rivers and roads of a real or imagined battlefield, used to brief and plan around. Question it answers: How does the ground itself shape what is possible here? Leaves out: The weather, the enemy's plan, and anything below the scale of the sand grains. Runs on: no computer. a shaped tray of sand; a physical device, no digital computing at all Since: 32 by 32 CE, Ma Yuan modelled mountains and valleys in rice for Emperor Guangwu (Book of the Later Han); Reisswitz's damp-sand table followed in 1811 [source](https://zh.wikisource.org/wiki/%E5%BE%8C%E6%BC%A2%E6%9B%B8/%E5%8D%B724) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Staff ride Officers walking the actual ground of a historical battle, working through the decisions the original commanders faced at each spot. Question it answers: Given what is visible from this position, what would have been ordered? Leaves out: The fear, fatigue and confusion the original commanders actually felt. Runs on: no computer. a real battlefield walked on foot; a physical device, no digital computing at all Since: 1906 Eben Swift's staff rides at the US Army's Fort Leavenworth [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Dress rehearsal A full run-through of a performance, ceremony or launch, in costume or full procedure, with everything except the real audience or stakes. Question it answers: Does the whole procedure function, from start to finish, under realistic conditions? Leaves out: The nerves and the unrepeatable feeling of the real occasion. Runs on: no computer. a full run-through with real people and props; a physical device, no digital computing at all Since: 1828 by 1828, the term recorded for a full theatrical run-through [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Fire and evacuation drills Everyone in a building or ship actually leaving by the planned routes when an alarm sounds, timed and watched for bottlenecks. Question it answers: Can all occupants evacuate in time by the planned routes? Leaves out: Smoke, panic and blocked exits, which are precisely what distinguish real fires. Runs on: no computer. a real building or ship, evacuated for practice; a physical device, no digital computing at all Since: 1912 by 1912, mandatory lifeboat and fire drills on passenger ships [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Mock trial A rehearsed courtroom proceeding, argued by real or trainee lawyers in front of a judge and jury, to test a case before it counts. Question it answers: How will this argument, and this witness, actually play in front of a jury? Leaves out: The real verdict's consequences, for everyone involved. Runs on: no computer. a rehearsed courtroom with real people; a physical device, no digital computing at all Since: 1400 by 1400, moots held at London's Inns of Court [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Military field exercises Real troops manoeuvring against each other on real terrain, using blank ammunition or safety equipment in place of live weapons. Question it answers: Can this unit actually execute the plan against people trying to stop it? Leaves out: Real casualties and the worst of real terrain and weather, by agreement. Runs on: no computer. real troops on real terrain; a physical device, no digital computing at all Since: 100 by 100 CE, Josephus's account of Roman training manoeuvres In the simulations tree: [Roman drill as rehearsal](https://simulation-hypothesis.com/trees/simulations?n=soc-josephus) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ## Bodies and manikins ### Anatomical models Detailed wax, wood or papier-mache replicas of the body's organs and layers, built for teaching anatomy without a real cadaver. Question it answers: What does the inside of a body actually look like, layer by layer? Leaves out: Individual variation: every model shows one idealised body, not the one on the table. Runs on: no computer. a hand-built wax or wood replica; a physical device, no digital computing at all Since: 1780 Clemente Susini's wax anatomical models, Florence [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Obstetric phantom A life-sized pelvis and infant model used to teach midwives to handle a difficult birth by feel, before ever attending a real one. Question it answers: Can this trainee deliver a baby safely when something goes wrong? Leaves out: The mother's condition and any complication not built into the model. Runs on: no computer. a stitched fabric and leather training mannequin; a physical device, no digital computing at all Since: 1756 Angelique du Coudray's obstetric training mannequin, France In the simulations tree: [Du Coudray’s birth mannequin](https://simulation-hypothesis.com/trees/simulations?n=life-coudray) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Early resuscitation manikins A simple mannequin chest and airway that a trainee breathes into and presses on, giving basic feedback on technique. Question it answers: Is this person pressing hard enough and giving enough breaths to keep someone alive? Leaves out: Almost everything about a real emergency except the two actions being drilled. Runs on: no computer. a simple mechanical training mannequin; a physical device, no digital computing at all Since: 1960 the first mass-produced CPR training manikin, Norway [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Crash-test dummies Instrumented mannequins with human-like mass and joints, strapped into a real vehicle and driven into a real barrier. Question it answers: How hard would a real body be hit in this exact crash? Leaves out: The variation between real bodies: one dummy design stands in for everyone. Runs on: no computer. an instrumented mannequin in a real vehicle; a physical device, no digital computing at all Since: 1949 the first anthropomorphic test dummy, for US aviation ejection-seat testing [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Moulage Realistic wounds, burns and rashes painted or moulded onto actors or manikins, used to train medics and triage teams to recognise conditions fast. Question it answers: Can this responder correctly read and prioritise what they are looking at? Leaves out: The patient's actual physiology underneath the painted surface. Runs on: no computer. painted wax or makeup on a person or manikin; a physical device, no digital computing at all Since: 1867 Jules Baretta's dermatological wax moulages, Paris [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Ballistic gelatin blocks Blocks of gelatin calibrated to match the density of muscle tissue, shot to study how a bullet or fragment behaves once inside a body. Question it answers: How far does this round travel, and what shape of path does it leave, in tissue? Leaves out: Bone, skin and clothing unless layered in on purpose. Runs on: no computer. a calibrated gelatin block; a physical device, no digital computing at all Since: 1945 wartime wound-ballistics researchers testing rounds in gelatin blocks [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)floor: Bodies ### Automata Mechanical figures of people and animals that move, play instruments or mimic life, driven by weights, cams or gears. Question it answers: Can a machine imitate a living body? Leaves out: They replay a fixed routine and cannot respond to the world. Runs on: no computer. a clockwork, no computation Since: 50 by the mid-1st century CE, Hero of Alexandria's Automata describes self-moving figures and theatres; the earliest instrument-playing machine is the Banū Mūsā's flute player (9th century, Baghdad) [source](https://theses.gla.ac.uk/76774/) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Motion platforms A moving seat or cabin that tilts and shifts so the occupant feels the movements of a vehicle. Question it answers: What does the occupant feel when the vehicle moves? Leaves out: Platforms can only hint at sustained acceleration. Runs on: no computer. a mechanical rig, no computation Since: 1910 by 1910, the Sanders Teacher, a model aircraft joined to the ground by a universal joint [source](https://en.wikipedia.org/wiki/Motion%5Fsimulator) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies [◂ Training simulators](https://simulation-hypothesis.com/simulations/training)[Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict) --- title: "Defence and conflict · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/defence-conflict description: "War games, combat models, military trainers and weapons physics: the origin of many of the methods in this taxonomy." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 16 of 18 # Defence and conflict War games, combat models, military trainers and weapons physics: the origin of many of the methods in this taxonomy. Militaries were among the earliest and biggest users of simulation, and much of the toolkit here started with them. Monte Carlo was developed for weapons physics, operations research for wartime logistics, and flight simulators for pilot training. War gaming is older still. Officers have trained on tabletop games since the early nineteenth century. Defence ministries, universities and research institutes now use the same methods to study strategy, escalation and the human cost of war. ## War games and analysis ### Professional war games Officers and analysts playing opposing sides of a scenario, move by move, with umpires deciding outcomes. They are used to test plans, not to predict results. Question it answers: Where does the plan break when a thinking opponent pushes back? Leaves out: A skilled umpire's judgement replaces missing physics, to the advantage or detriment of validity. Runs on: no computer. umpires, maps and people; computers only assist scoring Since: 1812 Kriegsspiel, from the elder Reisswitz’s war-game table (1811–12); his son’s rules of 1824 were taken up by Prussian officers [source](https://en.wikipedia.org/wiki/Kriegsspiel) In the simulations tree: [Kriegsspiel](https://simulation-hypothesis.com/trees/simulations?n=soc-kriegs) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Political–military crisis games Teams playing governments through an escalating international crisis, run by universities and research institutes as well as ministries. Question it answers: How do crises escalate, and what lets leaders step back? Leaves out: Players usually behave more rationally than real leaders under real pressure. Runs on: about 10^9 FLOPS rough people role-playing governments; little or no computing Since: 1958 by 1958, early political-military games run by defence research institutes [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Historical war games Past battles and campaigns refought under their original conditions, used by historians and military academies. Question it answers: Was the outcome likely, or could it easily have gone the other way? Leaves out: Refighting a battle under known conditions still cannot test truly novel decisions. Runs on: about 10^11 FLOPS rough a hobbyist or academic desktop, seconds to minutes per run Since: 1913 H. G. Wells published Little Wars, rules for refighting battles with toy soldiers [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Combat and campaign models Forces worn down against each other over time, from Lanchester’s attrition equations to large statistical campaign models. Question it answers: How does the balance of forces change the course and cost of a campaign? Leaves out: Real combat effectiveness depends on morale and leadership that the equations do not capture. Runs on: about 10^12 FLOPS rough a desktop, seconds per run of the equations Since: 1916 Frederick Lanchester published his combat attrition equations [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Agent-based combat models Individual units with their own sensors, orders and decisions, interacting on simulated terrain. Question it answers: How much do communication, morale and local decisions change the outcome? Leaves out: Simple decision rules for each unit rarely capture real soldiers' judgement. Runs on: about 10^14 FLOPS rough a research cluster, minutes per battle run Since: 1997 by 1997, early agent-based combat models built for military research institutes [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Military logistics Fuel, food, ammunition, spare parts and transport moving through a theatre of operations. Question it answers: Can the force be supplied, and where will it run short first? Leaves out: Real-world friction, weather and breakdowns are only partly represented. Runs on: about 10^13 FLOPS rough a logistics command's server, minutes per scenario Since: 1955 by 1955, early operations-research studies of military supply chains [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### Deterrence and arms races Rival states building and cutting arms in response to each other, as feedback equations or repeated games. Question it answers: When is an arms race stable, and when does it spiral? Leaves out: Assumes rational, simplified state behaviour. Real politics is messier. Runs on: about 10^11 FLOPS rough a desktop, seconds to run the equations or games Since: 1939 Lewis Fry Richardson's mathematical model of arms races [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Models of civil conflict Social science models of how grievance, legitimacy and policing interact to produce unrest or civil war. Question it answers: Why does violence break out in some places and not in others? Leaves out: Grievance and legitimacy are hard to quantify, so results are sensitive to assumptions. Runs on: about 10^13 FLOPS rough a research cluster, minutes per run Since: 2002 Joshua Epstein's agent-based models of civil violence [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Language-model wargame agents Language models play national leaders in a turn-based crisis game, choosing diplomatic and military actions. Question it answers: How do model agents escalate or de-escalate in a simulated crisis? Leaves out: Model choices depend on prompts and do not match real leaders. Runs on: about 10^13 FLOPS rough Many model calls per game Since: 2024 Escalation risks from language models in military and diplomatic decision-making (2024) [source](https://arxiv.org/abs/2401.03408) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Swarm combat simulation Many simple unmanned aircraft or boats with local rules attack or defend, and the simulation tests how a swarm fares against a protected target. Question it answers: Can a swarm overwhelm a defended target? Leaves out: Communications, jamming and the rules of engagement are simplified. Runs on: about 10^9 FLOPS rough thousands of agents on a workstation. Since: 2002 Lin and colleagues, simulation of a swarm of unmanned combat air vehicles. [source](https://doi.org/10.21236/ada403633) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Populations ### Computer virus and malware epidemics Computers are nodes that infect their neighbours with a program, with antivirus cures, so that the spread follows epidemic models. Question it answers: How fast does malware spread, and what patching rate stops it? Leaves out: Attacker adaptation and real network topologies are simplified. Runs on: about 10^5 FLOPS rough epidemic equations or network simulations on a laptop. Since: 1991 Kephart and White, directed-graph epidemiological models of computer viruses. [source](https://doi.org/10.1109/risp.1991.130801) [Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Search and rescue drift planning Thousands of possible drift paths of a lost object or person are simulated with currents and winds to find where to search. Question it answers: Where is the most likely place to search first? Leaves out: Currents and wind are uncertain and the object may behave differently from the model. Runs on: about 10^8 FLOPS rough Monte Carlo drift of many particles on a workstation. Since: 1980 Richardson and Discenza, the Coast Guard computer-assisted search planning system. [source](https://doi.org/10.1002/nav.3800270413) [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Naval salvo exchange models Missile salvos between ships are modelled by simple equations of offensive power and defensive shot-down capacity, to see which side survives. Question it answers: Which fleet design wins a missile exchange? Leaves out: Treats ships as identical units and ignores sensors and tactics. Runs on: about 10^3 FLOPS rough closed-form equations on a laptop. Since: 1995 Hughes, a salvo model of warships in missile combat used to evaluate their staying power. [source](https://doi.org/10.1002/1520-6750%28199503%2942:2<267::aid-nav3220420209>3.0.co;2-y) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Rules ### Anti-submarine search theory The chance of finding a hidden submarine is worked out from the paths of searchers, the target's speed and the range at which it can be detected. Question it answers: Where and how should ships and aircraft search to find a submarine soonest? Leaves out: Detection range depends on ocean conditions and noise that are not known well, and the target may evade. Runs on: about 10^6 FLOPS rough seconds to minutes on a laptop. Since: 1956 Koopman's theory of search, kinematic bases, in Operations Research. [source](https://doi.org/10.1287/opre.4.3.324) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations ## Military training ### Military flight and mission simulators Networked cockpits in which crews fly missions together against computer-generated opponents. Question it answers: Can the crews work together under pressure in a mission too costly or risky to rehearse for real? Leaves out: Computer-generated adversaries fight predictably compared to real opponents. Runs on: about 10^13 FLOPS rough networked simulator computers, real time Since: 1985 by 1985, SIMNET, a DARPA programme that networked combat simulators [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Vehicle and crew trainers Replica tank turrets, ship operations rooms, submarine control rooms and helicopter cabs. Question it answers: Does every crew member know their role when failures occur? Leaves out: Confined mock-ups cannot fully replicate real vehicle motion and stress. Runs on: about 10^12 FLOPS rough the simulator's own computer, real time Since: 1954 by 1954, early gunnery trainers for armoured vehicle crews [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Networked training exercises Real units, crewed simulators and computer-generated forces joined into one shared exercise across many sites. Question it answers: Can large formations coordinate across services and countries? Leaves out: Network delays and simplifications mean not every unit behaves as it would live. Runs on: about 10^14 FLOPS rough many linked simulator and computer nodes, real time Since: 1983 SIMNET, a 1980s defence programme that first linked simulators over a network for joint exercises [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Marksmanship and use-of-force trainers Screen- and laser-based ranges with branching scenarios, used by armed forces and police, including practice in de-escalation. Question it answers: Does the trainee make the right decision, including the choice not to shoot? Leaves out: Actors on screen react on a script, not with a real person's unpredictability. Runs on: about 10^12 FLOPS rough a desktop with projection and sensors, real time Since: 1985 by 1985, early branching-scenario trainers for police and military decisions [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Cyber ranges Whole simulated computer networks where defenders practise detecting and stopping attacks. Question it answers: Can the team spot and contain an intrusion in time? Leaves out: Scripted attacks in a range are less severe than those of a determined real adversary. Runs on: about 10^13 FLOPS rough a cluster of virtual machines, real time Since: 2009 by 2009, early dedicated ranges for rehearsing cyber attack and defence [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Combat medic trainers Manikins that bleed, breathe and respond to battlefield first aid, for practising trauma care under simulated fire. Question it answers: Can the medic stop the bleeding and keep the casualty alive under pressure? Leaves out: Real fear and exhaustion in combat are hard to recreate in a training exercise. Runs on: about 10^10 FLOPS rough an embedded controller inside the manikin, real time Since: 1997 by 1997, early high-fidelity trauma manikins for combat medic training [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Autonomous cyber-defence gyms A simulated network where learning attack and defence agents act and are scored. Question it answers: Can agents learn to defend a network against an attacker? Leaves out: Network topology and attacks are far simpler than real ones. Runs on: about 10^11 FLOPS rough Cheap many-episode training Since: 2021 CybORG: a gym for the development of autonomous cyber agents (2021) [source](https://arxiv.org/abs/2108.09118) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ## Weapons physics and protection ### Nuclear stockpile simulation Since nuclear test bans, ageing warheads are assessed by simulating their physics instead of testing them. This work built some of the world’s largest supercomputers. Question it answers: Is the stockpile still safe and reliable without explosive testing? Leaves out: Simulating ageing materials without real tests still leaves some physics uncertain. Runs on: about 10^18 FLOPS textbook one of the world's largest supercomputers, a large fraction, for weeks Since: 1995 the US Stockpile Stewardship Program begins after the test moratorium [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Ballistics Projectiles through the barrel, the air and the target, as three separate problems. Question it answers: Where will the projectile land, and what occurs on impact? Leaves out: Wind and manufacturing variation still make individual shots harder to predict than the average. Runs on: about 10^12 FLOPS rough a desktop, seconds per shot simulated Since: 1945 ENIAC, one of the first electronic computers, whose first job computed artillery firing tables [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Blast and impact protection Shock waves and impacts hitting buildings, vehicles and body armour, used to design protection. Question it answers: Will the structure, and the people inside it, survive? Leaves out: Fine details of fracture and fragmentation are still hard to capture exactly. Runs on: about 10^15 FLOPS rough a university or defence lab cluster, hours per case Since: 1961 by 1961, early hydrocodes at national laboratories model blast waves [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Radar and sensor performance Radar, sonar and infrared signals travelling through the environment and bouncing off targets. Question it answers: What can the sensor detect, at what range, in this weather? Leaves out: Real weather and terrain clutter are harder to fully capture than the model assumes. Runs on: about 10^14 FLOPS rough a defence contractor's cluster, minutes per scenario Since: 1963 by 1963, early computer models of radar propagation and clutter [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Fields ### Directed energy weapon simulation A laser or high-power microwave beam travelling through the air and heating or disabling a target. Question it answers: How much power reaches the target, and how long before it has an effect? Leaves out: Real atmospheric turbulence and dust scatter the beam more unpredictably than the model assumes. Runs on: about 10^14 FLOPS rough a defence laboratory cluster, hours per scenario Since: 1974 by 1974, early beam propagation models for high-energy laser weapons [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Torpedo and underwater weapon simulation A torpedo or naval mine's path, guidance and explosion through water, and the sound it makes doing it. Question it answers: Will it find, reach and disable the target? Leaves out: Real ocean noise and layered water temperatures confuse guidance more than the clean model assumes. Runs on: about 10^14 FLOPS rough a naval research cluster, hours per scenario Since: 1960 by 1960, early digital torpedo guidance and hydrodynamics models [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Chemical, biological and radiological hazard plumes The release of a hazardous agent is carried by wind and turbulence in a puff model to predict the footprint and dose. Question it answers: Who is exposed after a release and where should they evacuate? Leaves out: Urban terrain and uncertain wind conditions limit accuracy. Runs on: about 10^9 FLOPS rough puff models run in seconds to minutes on a workstation. Since: 1996 Sykes and colleagues, SCIPUFF, a generalised dispersion model. [source](https://doi.org/10.1007/978-1-4615-5841-5%5F45) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ## Consequences of war ### Climate effects of nuclear war Climate models given the smoke from burning cities, to trace the cooling and crop failures that would result. Question it answers: How many people would a nuclear war harm far from where it was fought? Leaves out: How much smoke actually reaches the stratosphere is still debated. Runs on: about 10^16 FLOPS rough a national climate-modelling supercomputer, a share of it for weeks Since: 1983 the TTAPS study modelled smoke from burning cities cooling the climate [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Displacement and refugee flows People fleeing conflict, choosing routes and destinations, used by humanitarian agencies to plan aid. Question it answers: Where will people go, and where should help be waiting? Leaves out: People's real decisions about where to flee are harder to predict than the model assumes. Runs on: about 10^13 FLOPS rough a humanitarian agency's server, minutes per scenario Since: 2015 by 2015, early agent-based models forecast wartime refugee movement Models: [Human](https://simulation-hypothesis.com/entities/human) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Bodies ### Casualty and humanitarian response Injured people, medical teams, supplies and evacuation routes after a conflict or disaster. Question it answers: How can the greatest number of lives be saved with the resources available? Leaves out: Assumes that supplies and transport arrive as planned, which is rarely the case in practice. Runs on: about 10^12 FLOPS rough a hospital or military planning desktop, minutes per scenario Since: 1996 by 1996, early discrete-event simulations of mass-casualty triage and evacuation [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Landmine and unexploded ordnance clearance planning Suspected minefields mapped and scheduled for clearance, balancing safety, cost and the land people need back. Question it answers: Which fields should be cleared first, and how long will it take? Leaves out: Real records of where mines were laid are often incomplete or wrong. Runs on: about 10^10 FLOPS rough a humanitarian demining charity's laptop, minutes per scenario Since: 1994 by 1994, early planning models for humanitarian minefield clearance [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Populations ### War economic and reconstruction modelling A country's economy after conflict, tracking damaged infrastructure, lost workers and the aid and investment needed to rebuild. Question it answers: How long will recovery take, and where should reconstruction money go first? Leaves out: Real reconstruction depends on political stability that the economic model cannot foresee. Runs on: about 10^11 FLOPS rough a development agency's desktop, minutes per scenario Since: 1993 by 1993, early post-conflict reconstruction economic models [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Populations ### Sanctions and economic warfare modelling A blockaded or sanctioned country's trade, currency and supplies, tracking how much economic pressure builds and who it actually hurts. Question it answers: How much economic pain will these sanctions cause, and how long can the target hold out? Leaves out: Real sanctions leak through smuggling and third countries more than the clean model assumes. Runs on: about 10^11 FLOPS rough a research institute's desktop, minutes per scenario Since: 1985 by 1985, early economic models of trade sanctions and blockades [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)floor: Populations ### Biological attack response models How a disease spreads after a deliberate release, with vaccination, isolation and hospital capacity added, so response plans can be compared. Question it answers: Is mass vaccination or targeted tracing better after a release? Leaves out: Assumes the pathogen's properties and the delay before detection. Runs on: about 10^7 FLOPS rough epidemic simulations on a laptop. Since: 2002 Kaplan, Craft and Wein, emergency response to a smallpox attack: the case for mass vaccination. [source](https://doi.org/10.1073/pnas.162282799) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Populations [◂ Before computers](https://simulation-hypothesis.com/simulations/before-computers)[Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art) --- title: "Film, media and art · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/media-art description: "Cloth, smoke, crowds and light, generated from physical models rather than animated by hand. Part of a taxonomy of the simulations people actually run." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 17 of 18 # Film, media and art Cloth, smoke, crowds and light, generated from physical models rather than animated by hand. Before computers, film and animation approximated physics with wire rigs, miniatures and hand-drawn frames. Now simulation supplies the physics directly: draping cloth, moving hair, crowds that don't repeat, and light that travels the way it does in the real world. The methods of engineering and science are pointed at a story instead of a bridge or a reactor. They're tuned to look believable, not to be physically exact, and they often run offline, frame by frame, instead of in real time. Music and image share one idea: set up the underlying process and let the result emerge. ## Simulated physical media ### Cloth simulation Fabric represented as a mesh of points and springs, draping, folding and tearing under gravity and movement. Question it answers: How does this garment move on a moving body without an animator posing every fold? Leaves out: Real fabric has a memory of its folds that most cloth solvers ignore. Runs on: about 10^12 FLOPS rough a render farm node for one shot's cloth pass Since: 1987 by 1987, early mass-spring cloth models for computer animation [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Hair and fur simulation Tens of thousands of individual strands, each obeying its own bending and collision rules, moved by wind, gravity and the body beneath. Question it answers: How does a full head of hair or a coat of fur move believably, strand by strand? Leaves out: Strand-to-strand friction is approximated. Otherwise each simulation would take longer than a production schedule allows. Runs on: about 10^12 FLOPS rough a render farm node for one character's hair pass Since: 1989 by 1989, early strand-based hair animation research [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Fluid and smoke simulation for effects Fire, smoke, water, dust and explosions computed as a fluid on a grid or in particles, styled for how they should look rather than for scientific accuracy. Question it answers: How does this explosion, wave or smoke plume move and look on screen? Leaves out: Directed to look good in frame, not to conserve energy or mass exactly. Runs on: about 10^13 FLOPS rough a render farm allocation for one effects-heavy shot Since: 1982 by 1982, early computer-generated fluid and particle effects for film [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Destruction and debris simulation Buildings, vehicles and objects fractured into pieces and thrown apart by rigid-body physics, tuned so the collapse looks dramatic rather than merely correct. Question it answers: How does this structure break apart, and where do the pieces land? Leaves out: Real materials fail unpredictably; these fracture patterns are pre-planned to look good. Runs on: about 10^12 FLOPS rough a render farm node for one destruction shot Since: 1995 by 1995, rigid-body fracture simulation used in film effects [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Muscle and skin deformation A digital body's skin and soft tissue sliding, bulging and wrinkling over an animated skeleton and muscles underneath. Question it answers: Does the body of this creature or character move as though it had real soft tissue? Leaves out: Skin sliding over bone is still mostly approximated, not properly simulated tissue. Runs on: about 10^12 FLOPS rough a render farm node for one character's body pass Since: 1999 by 1999, muscle-based deformation rigs for computer-animated characters [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Rigid body dynamics for animation Solid objects that collide, stack, roll and settle under gravity and friction, used to animate props and secondary motion without hand-keying every bounce. Question it answers: How does this pile of objects tumble and settle once it is disturbed? Leaves out: Objects occasionally interpenetrate or jitter in ways no real thing would. Runs on: about 10^11 FLOPS rough a workstation for one shot's prop simulation Since: 1988 by 1988, rigid-body physics used for computer animation [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Position-based dynamics Objects such as cloth and soft bodies move by directly adjusting point positions to meet constraints, which is fast and stable. Question it answers: How can deformable objects be simulated fast enough for interactive use? Leaves out: Not physically exact and stiffness depends on step count. Runs on: about 10^9 FLOPS rough Real-time on one CPU or GPU Since: 2007 Position based dynamics (2007) [source](https://doi.org/10.1016/j.jvcir.2007.01.005) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Ocean surface synthesis A water surface generated from a spectrum of waves, used to render open sea with swell and foam. Question it answers: What does a sea of given wind and depth look like? Leaves out: It models surface shape, not the full flow below or the breaking of large waves. Runs on: about 10^12 FLOPS rough a workstation, minutes per frame Since: 1986 by 1986, Fournier and Reeves, A simple model of ocean waves [source](https://doi.org/10.1145/15922.15894) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Particle system effects Fire, sparks, smoke and spray drawn as thousands of short-lived points, each with its own motion and appearance. Question it answers: How can a fuzzy event be shown as a cloud of independently moving points? Leaves out: Points do not push on each other, so true fluid behaviour is absent. Runs on: about 10^10 FLOPS rough a laptop, real time Since: 1983 by 1983, Reeves, Particle systems (used in a wall of fire effect) [source](https://doi.org/10.1145/964967.801167) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Fields ### Snow and granular material simulation Snow, sand and similar materials simulated as points that carry stress, so they pile, break and clump like the real material. Question it answers: How does snow pack, fracture and flow when pushed? Leaves out: Grain-scale ice physics is replaced by an averaged material law. Runs on: about 10^14 FLOPS rough a render farm, hours per shot Since: 2013 by 2013, Stomakhin and others, A material point method for snow simulation [source](https://doi.org/10.1145/2461912.2461948) [Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ## Populated and built worlds ### Digital crowd simulation Thousands of individual figures, each with simple movement and avoidance rules, filling a stadium, battlefield or street without being animated one by one. Question it answers: How does a crowd this size move, flee or fight as a mass? Leaves out: Every figure in the back rows tends to move a little too similarly. Runs on: about 10^12 FLOPS rough a render farm allocation for one crowd shot Since: 1997 by 1997, agent-based crowd systems used in feature film battle scenes [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Digital humans and faces A face's muscles, skin and micro-expressions modelled well enough to animate a synthetic performance that reads as a real person's. Question it answers: Can this synthetic face convey emotion as convincingly as the real one it is based on? Leaves out: The eyes and the corners of the mouth remain the most difficult regions to reproduce convincingly. Runs on: about 10^13 FLOPS rough a render farm allocation for one hero character's face Since: 2001 by 2001, high-resolution facial capture and simulation for film [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Procedural cities and landscapes Streets, buildings, terrain and vegetation generated by rules and randomness from a small set of parameters, instead of being placed by hand. Question it answers: How can an entire city or continent be populated with detail that cannot practicably be placed by hand? Leaves out: Generated cities tend to be statistically plausible but lack any specific history. Runs on: about 10^12 FLOPS rough a workstation or render farm node for one environment build Since: 1982 by 1982, fractal terrain generation used in computer graphics [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Virtual production sets A computer-generated environment displayed live on large screens behind actors and filmed in camera, with the scene reacting to how the lens moves. Question it answers: Can the background react to the camera in real time so it does not have to be added afterwards? Leaves out: The lighting match between the real actor and the screen behind them remains imperfect. Runs on: about 10^13 FLOPS rough a cluster of gaming GPUs driving the stage screens live Since: 2019 by 2019, large LED-volume virtual production stages in wide use [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Fields ### Digital ecosystems and vegetation Forests, grasslands and animal populations generated and animated together, with plants competing for light and animals moving through the result. Question it answers: How does a whole simulated landscape of plants and creatures look and move together? Leaves out: Simulated ecosystems are tuned to look lush, not to balance the way real ones do. Runs on: about 10^12 FLOPS rough a render farm node for one environment's ecosystem pass Since: 2000 by 2000, procedural vegetation and ecosystem tools for film environments [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Atmospheric and sky simulation Clouds, fog, rain and sky colour generated from physical models of light scattering and moisture, for a scene's weather rather than the real thing. Question it answers: What should the sky and weather in this shot look like, without shooting on the right day? Leaves out: Tuned for how a sky should look, not for genuine atmospheric physics. Runs on: about 10^12 FLOPS rough a render farm node for one environment's sky pass Since: 1986 by 1986, physically based sky and cloud rendering models [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Fields ### Neural avatars A neural network trained on multi-camera captures of a person renders a lifelike, animatable face or body. Question it answers: Can a virtual person be rendered indistinguishably from the real one? Leaves out: Needs capture of each subject, and behaviour is not generated. Runs on: about 10^13 FLOPS rough Per-person training Since: 2018 Deep appearance models for face rendering (2018) [source](https://arxiv.org/abs/1808.00362) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Virtual idols and influencers A fictional performer rendered in computer graphics and managed as a celebrity, appearing in media and social feeds. Question it answers: Does an audience attach to a performer who has no body? Leaves out: The persona is written by a team; no autonomous inner life is modelled. Runs on: about 10^11 FLOPS rough a workstation, rendering in near real time Since: 1996 by 1996, Kyoko Date, a 3D CG idol debuted by Horipro [source](https://en.wikipedia.org/wiki/Kyoko%5FDate) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Virtual concerts A live performance staged in a shared virtual world or game engine, with avatars, stage effects and a remote audience. Question it answers: Can a concert be shared by an audience that is only present as avatars? Leaves out: Audience reaction and crowd presence are thin compared with a real venue. Runs on: about 10^12 FLOPS rough a data centre, real time for thousands of viewers Since: 2006 by 2006, Duran Duran performed in Second Life [source](https://en.wikipedia.org/wiki/Virtual%5Fconcert) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### Digital de-ageing A performer's face is rebuilt in 3D and retargeted to a younger or older age, driven by the actor's own acting. Question it answers: Can a face be shown at another age while keeping the actor's expression? Leaves out: The result is an appearance model; no ageing biology is simulated. Runs on: about 10^13 FLOPS rough a render farm, hours per shot Since: 2008 by 2008, The Curious Case of Benjamin Button, with Digital Domain effects [source](https://en.wikipedia.org/wiki/The%5FCurious%5FCase%5Fof%5FBenjamin%5FButton%5F%28film%29) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)floor: Bodies ### Performance-captured digital characters A computer-generated character animated by an actor's recorded body and facial movement, composited into live footage. Question it answers: Can an actor's movement drive a creature that looks nothing like a person? Leaves out: Muscle and thought are not modelled, only the captured motion. Runs on: about 10^11 FLOPS rough a workstation, hours per shot Since: 2002 by 2002, Gollum in The Lord of the Rings: The Two Towers [source](https://en.wikipedia.org/wiki/Motion%5Fcapture) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### L-system plant modelling Plant shapes grown by repeatedly rewriting a string of symbols into branching structure, then drawn as trees and leaves. Question it answers: What simple rewriting rules produce a given branching shape? Leaves out: The rules fit shapes; the chemistry and light competition that drive real growth are absent. Runs on: about 10^8 FLOPS rough a laptop, seconds Since: 1968 by 1968, Lindenmayer, Mathematical models for cellular interactions in development [source](https://doi.org/10.1016/0022-5193%2868%2990079-9) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Cells ### Machinima Films shot by directing characters and cameras inside a real-time game engine instead of a physical camera or an offline renderer. Question it answers: What can be filmed in a world that exists only in a game engine? Leaves out: The engine decides what can be shown; acting is limited to what its controls allow. Runs on: about 10^11 FLOPS rough a gaming PC, real time Since: 1996 by 1996, Diary of a Camper, a short made in the Quake engine [source](https://en.wikipedia.org/wiki/Machinima) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Animatronic figures Mechanical, motor-driven figures of people and animals that perform scripted movement and speech. Question it answers: How convincingly can a machine act like a living creature? Leaves out: Motion is replayed from a recording; there is no sensing or decision. Runs on: no computer. a mechanical controller, no computation Since: 1963 by 1963, Disney's Audio-Animatronics, the Enchanted Tiki Birds [source](https://en.wikipedia.org/wiki/Animatronics) [Physical analogue](https://simulation-hypothesis.com/simulations/methods#m-analogue)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Physics-based character control A virtual body with joints and muscles is trained to move, jump or fight by reinforcement learning in a physics engine, copying motion-capture clips. Question it answers: Can a character balance and move naturally, reacting to pushes, without hand-made animation? Leaves out: Style comes only from the clips it copies, and rare motions and fine hand-work are poorly handled. Runs on: about 10^15 FLOPS rough days on a GPU workstation per skill. Since: 2018 Peng and colleagues' DeepMimic, example-guided deep reinforcement learning of physics-based character skills. [source](https://doi.org/10.1145/3197517.3201311) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ## Light and sound ### Physically based light transport Light rays traced backward from the camera, bouncing off and through every surface, to compute a physically consistent image. Question it answers: How does light behave in this scene, bounce by bounce, rather than being approximated? Leaves out: Converges slowly, so noise is still suppressed by heuristics rather than by taking more samples. Runs on: about 10^14 FLOPS rough a render farm allocation across many nodes for one frame Since: 1986 Kajiya's 1986 path tracing algorithm [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Sound propagation and acoustics Sound waves traced or modelled as they reflect, absorb and diffract through a virtual room, city street or battlefield, for film and game audio. Question it answers: How should this space actually sound, given its shape and the materials in it? Leaves out: Real ears and rooms have idiosyncrasies that acoustic models routinely idealise. Runs on: about 10^11 FLOPS rough a workstation for one scene's acoustic pass Since: 1968 by 1968, ray-based room acoustics modelling [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Fields ### Physical modelling synthesis of instruments A string, reed, drum skin or pipe modelled as a vibrating physical object, computed directly to produce its sound rather than recording or sampling it. Question it answers: What would this instrument sound like, computed from its physics rather than recorded? Leaves out: Captures the physics of the instrument, not the decades of a player's technique. Runs on: about 10^10 FLOPS rough runs in real time on a laptop or synthesiser Since: 1983 by 1983, digital waveguide models of vibrating strings [Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Generative art systems Rules, randomness or simple agents run forward to make an image, pattern or composition. The rules alone didn't fully spell out the result in advance. Question it answers: What shape does this process take if it is simply allowed to run? Leaves out: The artist chooses which random runs to keep, so 'generative' work still involves substantial curation. Runs on: about 10^9 FLOPS rough runs on a laptop in seconds to minutes Since: 1965 by 1965, early computer-generated art from algorithmic rules [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Procedural and generative music Musical rules, Markov chains or simple agents run forward to generate a melody, harmony or an evolving soundtrack that reacts to what is happening on screen. Question it answers: What music does this set of rules produce if it keeps generating without a composer choosing every note? Leaves out: Tends to sound competent and rarely surprising, which is exactly what the rules allow. Runs on: about 10^9 FLOPS rough runs on a laptop in real time Since: 1957 the Illiac Suite, an early rule-based computer composition [Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Procedural texture and material generation Surface patterns such as wood grain, rust, skin pores or rock strata generated from noise and simple physical rules, instead of painted by hand or photographed. Question it answers: What should this surface look like close up, generated rather than photographed? Leaves out: Noise-based textures can look uniform at a scale a real surface never would. Runs on: about 10^10 FLOPS rough a workstation generating textures for one asset Since: 1985 by 1985, Perlin-style procedural noise textures in computer graphics [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Rules ### Physically based sound effects Impact, rolling and scraping sounds synthesised from the shape, material and contact of the simulated objects instead of played from recordings. Question it answers: Which sound does an object of this material make when it hits that surface? Leaves out: Mode models are tuned by ear and omit radiation into a real room. Runs on: about 10^9 FLOPS rough a laptop, real time Since: 2001 by 2001, van den Doel, Kry and Pai, FoleyAutomatic [source](https://doi.org/10.1145/383259.383322) [Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Fields ### Live-coded music and visuals Performers write and change running code in front of an audience, so sound or image evolves as the program is edited. Question it answers: How does music change when its rules are rewritten while playing? Leaves out: The simulation is the program itself; nothing physical is modelled. Runs on: about 10^8 FLOPS rough a laptop, real time Since: 2004 by 2004, the TOPLAP group formed to unite live coding communities [source](https://en.wikipedia.org/wiki/Live%5Fcoding) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Neural scene rendering A neural network fitted to a set of photographs stores a scene's light and density so that new views can be rendered from any camera position. Question it answers: What would this place look like from where nobody took a photograph? Leaves out: It interpolates between photographs and invents detail where none were taken, so views far from the originals are unreliable. Runs on: about 10^15 FLOPS rough hours on a GPU for a scene, and a day for a large one. Since: 2020 Mildenhall and colleagues' NeRF, representing scenes as neural radiance fields for view synthesis. [source](https://doi.org/10.1007/978-3-030-58452-8%5F24) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields [◂ Defence and conflict](https://simulation-hypothesis.com/simulations/defence-conflict)[Video games ▸](https://simulation-hypothesis.com/simulations/video-games) --- title: "Video games · Simulations · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/video-games description: "Every video game simulates something; the genres here are sorted by what they model and what they omit." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- [Simulations](https://simulation-hypothesis.com/simulations)domain 18 of 18 # Video games Every video game simulates something. The genres here are sorted by what they model and what they leave out. Every video game is a simulation: a world with rules, stepped forward many times a second, with a person inside it. Genres differ in what they model carefully and what they approximate or leave out. By a wide margin, games are the most-run simulations in existence. They're also a working answer to the Sandbox's observation dial, since almost all of them draw only what the player can perceive. ## Vehicles and machines ### Flight simulation Aircraft with detailed aerodynamics, instruments and procedures, often over a model of the whole planet. The player’s question: Can the aircraft be landed in a night crosswind? Leaves out: Failure carries no consequence, and the atmosphere is simplified far below the resolution of a research model. Runs on: about 10^13.5 FLOPS rough a gaming desktop's CPU and GPU rendering aerodynamics and instruments Since: 1980 subLOGIC’s Flight Simulator, a home-computer game modelling single-engine flight physics [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)floor: Bodies ### Spaceflight simulation Rockets and flight paths under real orbital mechanics, sometimes with user-designed vehicles. The player’s question: Can a vehicle reach orbit and return? Leaves out: Gravity usually comes from one body at a time rather than from every body acting on every other. Runs on: about 10^13 FLOPS rough a home desktop CPU; orbital mechanics is cheap to solve Since: 1969 by 1969, Jim Storer’s text game Lunar, written on a PDP-8 minicomputer [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Racing simulation Cars with detailed tyre, suspension and engine models on laser-scanned tracks. The player’s question: How close to the grip limit can the car be driven through a corner? Leaves out: Wear, weather and damage are milder than in reality, or can be disabled. Runs on: about 10^13.5 FLOPS rough a gaming console or desktop GPU rendering tyre and suspension models Since: 1989 by 1989, Indianapolis 500: The Simulation, a home-computer game modelling suspension and tyre grip [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Arcade racing Fast cars with forgiving physics, tuned for speed and spectacle. The player’s question: Can a race be won while sustaining drifts through every corner? Leaves out: Most of the vehicle dynamics, by design. Runs on: about 10^13 FLOPS rough an arcade cabinet or console GPU, physics kept deliberately cheap Since: 1974 Gran Trak 10, an arcade cabinet with a scrolling road and a car sprite to steer [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Driving and transport simulation Trucks, buses and trains over long routes, with schedules, cargo and road rules. The player’s question: Can the cargo be delivered on schedule and undamaged? Leaves out: Distances are compressed and durations shortened. Runs on: about 10^13 FLOPS rough a desktop CPU rendering long routes, cargo and traffic Since: 2001 Microsoft Train Simulator, a home-computer train-driving game simulating routes and signalling [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Naval and submarine simulation Ships and submarines with sonar, weather and ship handling, sometimes with a full crew to manage. The player’s question: Can the contact be located before the player's vessel is? Leaves out: Months at sea are compressed into a single session. Runs on: about 10^13.5 FLOPS rough a desktop CPU modelling sonar, weather and ship handling Since: 1984 a home-computer submarine simulation with sonar and torpedo modelling [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Job and machinery simulation Real trades and machines: farming equipment, construction, cleaning, repair. The player’s question: Can the work be done correctly while the business grows? Leaves out: Fatigue, weather and administration. Runs on: about 10^13 FLOPS rough a desktop or console GPU rendering machinery and terrain Since: 2008 by 2008, Farming Simulator, a home-computer farming-machinery game with real equipment routines [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Open-city driving Free driving through a large streamed city with traffic and pedestrians, with no fixed track. The player’s question: What does a city feel like when it is driven rather than looked at? Leaves out: Roads and traffic are simplified; vehicle physics is usually arcade-grade. Runs on: about 10^12 FLOPS rough a gaming PC, real time Since: 1999 by 1999, Midtown Madness (Chicago, released May 1999) [source](https://en.wikipedia.org/wiki/Midtown%5FMadness) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Fields ### Flight simulation over streamed Earth A flight simulator that draws the whole planet from streamed satellite imagery, elevation and live weather rather than hand-built scenery. The player’s question: Can a flight over any real place be rendered from survey data on demand? Leaves out: Buildings and vegetation are generated from imagery and are only approximately right. Runs on: about 10^13 FLOPS rough a gaming PC, real time with a data connection Since: 2020 by 2020, Microsoft Flight Simulator (2020) using streamed mapping imagery [source](https://en.wikipedia.org/wiki/Microsoft%5FFlight%5FSimulator%5F%282020%5Fvideo%5Fgame%29) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Continuum fields](https://simulation-hypothesis.com/simulations/methods#m-continuum)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Fields ### Soft-body vehicle crash simulation Vehicles modelled as networks of beams and nodes that bend, tear and crumple in collisions at interactive speed. The player’s question: How does a car deform and break in a crash, in real time? Leaves out: The beam lattice is coarse and fracture is not resolved at material scale. Runs on: about 10^12 FLOPS rough a gaming PC, real time Since: 2013 by 2013, the BeamNG.drive tech demo (3 August 2013) [source](https://en.wikipedia.org/wiki/BeamNG.drive) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Mech combat simulation A cockpit simulation of a walking war machine, with heat, armour sections, weapon groups and a limited-view controls panel. The player’s question: What is it like to pilot a walking fighting machine whose damage and heat are tracked by part? Leaves out: No real machine exists, so the physics is invented and tuned for play. Runs on: about 10^10 FLOPS rough a laptop, real time Since: 1989 by 1989, MechWarrior, the first BattleTech cockpit simulator [source](https://en.wikipedia.org/wiki/MechWarrior%5F%281989%5Fvideo%5Fgame%29) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Life and people ### Life simulation Simulated people with needs, moods, relationships and careers, living in homes the player builds. The player’s question: Can every household member's needs be kept satisfied? Leaves out: Inner lives are reduced to a handful of meters, which is the Sandbox’s “functional minds” setting in practice. Runs on: about 10^13 FLOPS rough a desktop or console CPU running many simulated households' needs Since: 2000 The Sims, a home-computer game simulating households of characters with need meters [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Virtual pets A creature with hunger, happiness and health that change over real time. The player’s question: Will the creature's needs be met at the required intervals? Leaves out: Everything except the needs. Runs on: about 10^6 FLOPS rough a handheld toy's simple microcontroller; needs are trivial to track Since: 1996 Tamagotchi, a handheld digital pet toy with hunger and mood counters [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Farming and village life Crops, seasons, animals and a small community of neighbours. The player’s question: Can a sustainable livelihood be built in a single small valley? Leaves out: Soil science, crop failure and the physical labour involved. Runs on: about 10^13 FLOPS rough a console or desktop CPU tracking crops, seasons and neighbours Since: 1996 Harvest Moon, a home-console farming and village-life game with seasonal crops [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Relationship simulation Characters whose affect towards the player changes with the player's choices of speech and action. The player’s question: Which responses maximise the character's regard? Leaves out: The other party is a branching script. Runs on: about 10^12.5 FLOPS rough a phone or desktop CPU running branching dialogue and affection scores Since: 1994 a home-computer dating-simulation program with branching affection scores [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Social hangout worlds Avatar-based spaces whose main activity is conversation, dress and social display, with no set goal. The player’s question: How do users choose to present themselves to others? Leaves out: There is no game to play, only interaction between people. Runs on: about 10^13 FLOPS rough a desktop or phone GPU rendering avatars and chat Since: 1995 by 1995, a graphical online world for chatting through customisable avatars [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Dating simulation A single point-of-view character choosing whom to court through scheduled meetings, gifts and conversation. The player’s question: Does the sequence of choices produce acceptance? Leaves out: Each suitor has a fixed, fully knowable preference function. Runs on: about 10^12 FLOPS rough a desktop or handheld CPU tracking scheduling and favour stats Since: 1994 Tokimeki Memorial, a dating game scheduling dates and tracking a suitor's favour [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Parenting and family life Raising simulated children or a household through school, chores and milestones over many years. The player’s question: Does the child reach adulthood with the intended outcomes? Leaves out: A childhood compressed into a few dozen hours. Runs on: about 10^12.5 FLOPS rough a desktop or console CPU tracking a child's growth stats Since: 2001 by 2001, a home-computer program raising a simulated child through milestones [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### Surgery and medical games Operations and emergency care played as time-pressed tasks on a virtual patient, with tools, vital signs and complications. The player’s question: How well can a patient be treated under time pressure on a simulated body? Leaves out: Tissue is a set of scripted wounds, not a mechanical or physiological model. Runs on: about 10^9 FLOPS rough a handheld console, real time Since: 2005 by 2005, Trauma Center: Under the Knife (Japan, 16 June 2005) [source](https://en.wikipedia.org/wiki/Trauma%5FCenter:%5FUnder%5Fthe%5FKnife) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Systems and societies ### City building Zoning, roads, utilities, budgets and a simulated population that immigrates, commutes and places demands on services. The player’s question: Can a city grow without congestion exceeding its road capacity? Leaves out: Most citizens exist only as aggregate quantities until the camera is directed at them. Runs on: about 10^13.5 FLOPS rough a desktop CPU simulating thousands of virtual citizens Since: 1989 SimCity, a home-computer city-building game with simulated traffic and zoning [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### Colony simulation A small group of characters, or a colony of ants or other creatures, surviving through work, needs and chance events. The player’s question: Can the colony survive the winter, and its own internal conflicts? Leaves out: Much of real biology and psychology, with dramatic events exaggerated. Runs on: about 10^13 FLOPS rough a desktop CPU running dozens of characters' needs and pathing Since: 1991 by 1991, SimAnt, a home-computer ant-colony game with foraging and pheromone trails [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Management and tycoon A business such as a theme park, hospital, railway or zoo, with customers, staff and money. The player’s question: Can the enterprise remain profitable without losing its customers? Leaves out: Customers are modelled as a few needs and a budget. Runs on: about 10^13 FLOPS rough a desktop CPU tracking customers, staff and money Since: 1990 Railroad Tycoon, a home-computer transport-management game with simulated freight economics [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Bodies ### God games A world and its inhabitants guided from above, through miracles, terrain and indirect influence. The player’s question: How does a population respond to indirect, sustained intervention? Leaves out: The inhabitants never learn of the intervening agent, which is the simulation hypothesis seen from the other side. Runs on: about 10^13 FLOPS rough a desktop CPU simulating a population responding to indirect guidance Since: 1989 Populous, a home-computer game of guiding a tribe through terrain and miracles [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Ecosystem and evolution games Creatures, food chains and species that change over generations. The player’s question: Which lineage dominates under the imposed selection pressures? Leaves out: Real evolutionary timescales, and the absence of any goal in the process. Runs on: about 10^13 FLOPS rough a desktop CPU running generations of simple creature genomes Since: 1996 Creatures, a home-computer game evolving simple creatures over simulated generations [Evolutionary](https://simulation-hypothesis.com/simulations/methods#m-evolutionary)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Automation and factory building Mines, conveyor belts, assembly machines and logistics networks, growing ever larger. The player’s question: Can a production system be made self-expanding? Leaves out: Pollution, labour and the cost of failures. Runs on: about 10^13.5 FLOPS rough a desktop CPU stepping thousands of factory events per second Since: 2012 by 2012, a home-computer conveyor-and-factory building program [Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Idle and incremental An economy of numbers that grows exponentially while the player is absent. The player’s question: How large can the quantity grow? Leaves out: Everything except compound growth. Runs on: about 10^9 FLOPS rough a phone browser tab; the maths is trivial exponential growth Since: 2013 a browser page incrementing a counter exponentially while idle [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)floor: Populations ### Social deduction games Players hold hidden roles and must infer who is lying through talk, voting and elimination, with an informed minority hiding among an uninformed majority. The player’s question: Can a hidden minority survive when the majority reasons about who is lying? Leaves out: The deception is among real players; the simulation only enforces roles, votes and information limits. Runs on: about 10^8 FLOPS rough a phone, real time for a lobby of about ten players Since: 1986 by 1986, the tabletop party game Mafia; video versions followed from 2003 [source](https://en.wikipedia.org/wiki/Social%5Fdeduction%5Fgame) [Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ### Station systems simulation A crewed space station modelled as coupled systems such as air, power, medical and atmospheric flow, which players maintain or break. The player’s question: What failures cascade through a crewed habitat when systems are coupled? Leaves out: Gas flow is a coarse grid model and the other systems are rule-based. Runs on: about 10^10 FLOPS rough a laptop, real time for a server Since: 2003 by 2003, Space Station 13, begun as an atmospheric simulation program [source](https://en.wikipedia.org/wiki/Space%5FStation%5F13) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Fields ## Strategy ### Grand strategy Whole nations across centuries: economy, diplomacy, population, religion and war. The player’s question: Can a state be steered through centuries of history? Leaves out: Individuals are represented as counts within provinces. Runs on: about 10^13.5 FLOPS rough a desktop CPU tracking provinces, population and diplomacy for centuries Since: 1991 a home-computer program simulating a nation's economy and wars across centuries [System dynamics](https://simulation-hypothesis.com/simulations/methods#m-system-dynamics)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ### 4X strategy A civilisation that explores, expands, exploits and competes, turn by turn, from the stone age to space. The player’s question: Does the player's civilisation outlast its competitors? Leaves out: Millennia elapse within a single turn. Runs on: about 10^13 FLOPS rough a desktop CPU computing turn-based civilisation growth Since: 1991 Sid Meier’s Civilization, a home-computer turn-based civilisation game from stone age to space [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ### Real-time strategy Resource gathering, base building and many units commanded at once, in real time. The player’s question: Can planning and resource management outpace an opponent under time pressure? Leaves out: Logistics and morale, largely. Runs on: about 10^13.5 FLOPS rough a desktop CPU pathing hundreds of units in real time Since: 1992 Dune II, a home-computer game with real-time unit orders and base building [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Hex-and-counter war games Digital versions of board war games: historical campaigns on hex maps, with detailed supply, terrain and orders. The player’s question: Could the historical outcome have been improved upon? Leaves out: Units are counters, and soldiers are the numbers printed on them. Runs on: about 10^12.5 FLOPS rough a phone or desktop CPU running turn-based hex-map calculations Since: 1980 a home-computer adaptation of a hex-and-counter board war game [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Populations ### Tactics A small squad on a grid, taking turns, with cover, chance and positioning. The player’s question: Can the engagement be won without losses? Leaves out: Everything outside the battle map. Runs on: about 10^12.5 FLOPS rough a desktop or console CPU resolving grid-based turns Since: 1990 Fire Emblem, a home-console squad tactics game fought on a grid map [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Tower defence Waves of enemies following a path, and defences placed along it. The player’s question: Where must defences be placed to withstand every wave? Leaves out: The enemies' motivation. Runs on: about 10^12 FLOPS rough a phone or browser tab tracking pathing enemies and towers Since: 2003 by 2003, a strategy-map modification with enemies following a fixed path [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Auto-battlers Players assemble a team from a shared random pool between rounds, then the teams fight automatically by rules with no direct control. The player’s question: Which team compositions win once all fighting is automatic? Leaves out: Combat is deterministic rules over stat values, not a model of fighting. Runs on: about 10^9 FLOPS rough a phone, real time for eight players Since: 2019 by 2019, the community mod Dota Auto Chess (January 2019) [source](https://en.wikipedia.org/wiki/Auto%5Fbattler) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Populations ## Worlds and sandboxes ### Block and voxel sandboxes A world made of blocks that can all be mined, moved and built with, generated without end. The player’s question: What can be constructed from the available blocks? Leaves out: Matter is quantised into one-metre cubes, the coarsest matter floor in any shipped simulation. Runs on: about 10^13.5 FLOPS rough a desktop or console CPU simulating an endless block world Since: 2009 Minecraft, a home-computer game generating an endless world of mineable blocks [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Bodies ### Survival and crafting Hunger, cold, shelter and tools in a hostile open world. The player’s question: Can the character survive the first night? Leaves out: The skill, time and chance that real survival requires. Runs on: about 10^13.5 FLOPS rough a desktop or console CPU tracking hunger, cold and crafting Since: 2006 by 2006, a home-computer open-world survival program with hunger and crafting [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Physics sandboxes and building Bridges, machines and vehicles built from parts and tested under simulated physics. The player’s question: Will the structure bear its load? Leaves out: Materials and joints are idealised. Runs on: about 10^13.5 FLOPS rough a desktop GPU running real-time rigid-body physics Since: 2004 Garry’s Mod, a home-computer building game driven by a real-time physics engine [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Falling-sand games Every pixel a particle of sand, water, fire or gas, reacting with its neighbours. The player’s question: What happens when one material is combined with another? Leaves out: Chemistry is reduced to a lookup table. Runs on: about 10^12 FLOPS rough a phone or browser tab updating a grid of particle cells Since: 2005 the Falling Sand Game, a browser game simulating falling sand, water and fire pixel by pixel [Run the interactive model](https://simulation-hypothesis.com/simulations/run#toy-sand) [Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Fields ### Space exploration and trading Star systems, economies and ships to fly, trade and fight between. The player’s question: Can a living be made trading between star systems? Leaves out: Most of space is empty, and the game omits it. Runs on: about 10^13 FLOPS rough a desktop CPU simulating star systems and trade economies Since: 1984 Elite, a home-computer space-trading game with simulated star systems and markets [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Level and world creation tools General-purpose building tools for terrain, logic and objects, used to make entire games inside the game. The player’s question: What can be built from these components? Leaves out: Nothing is simulated until a player assembles it. Runs on: about 10^13 FLOPS rough a desktop or console CPU running whatever the player has built Since: 1983 a home-computer level-editing program letting players build and share stages [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Terrarium and habitat sandboxes A sealed environment such as an aquarium, terrarium or garden, stocked and watched rather than directed. The player’s question: What equilibrium will the habitat reach? Leaves out: The chemistry of water and soil, reduced to a few parameters. Runs on: about 10^12 FLOPS rough a desktop or phone CPU running a small closed ecosystem Since: 1985 a home-computer aquarium program modelling fish, feeding and water quality [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Bodies ### Agent-based game playtesting Learning agents play a game thousands of times to find bugs and test balance. The player’s question: Is this level or rule balanced? Leaves out: Agents do not play like people and miss fun. Runs on: about 10^12 FLOPS rough Many parallel game instances Since: 2019 Winning isn't everything: enhancing game development with intelligent agents (2019) [source](https://arxiv.org/abs/1903.10545) [Learned emulators](https://simulation-hypothesis.com/simulations/methods#m-learned)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Rules ### User-generated game platforms A hosted engine where players build and publish their own games and worlds, with shared physics, avatars and an in-world economy. The player’s question: What do millions of amateur designers build when the engine and audience are provided? Leaves out: Each world is a small rule set; the platform simulates no particular real system. Runs on: about 10^12 FLOPS rough a data centre, real time for a server of a few dozen players Since: 2006 by 2006, the public release of Roblox (developed from 2004) [source](https://en.wikipedia.org/wiki/Roblox) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Populations ## Role-playing and story ### Role-playing games A character with statistics, skills and choices in a world that reacts, descended from tabletop rules. The player’s question: What character does the player develop? Leaves out: Personality is reduced to a set of numbers. Runs on: about 10^13 FLOPS rough a desktop or console CPU resolving dice-based rules and dialogue Since: 1975 a mainframe dungeon-crawling program adapting tabletop role-playing rules [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Bodies ### Massively multiplayer worlds One persistent world shared by thousands of players at once, with its own economy and social life. The player’s question: How do players behave in a world shared with thousands of others? Leaves out: The world resets and repeats, so no individual's actions change it for long. Runs on: about 10^16 FLOPS rough a server farm, a slice per shard, for thousands of concurrent players Since: 1978 MUD1, a university mainframe text world shared by many users at once (1978, on Bartle’s account) [source](https://mud.co.uk/richard/mudhist.htm) In the simulations tree: [MUD1](https://simulation-hypothesis.com/trees/simulations?n=w-mud1) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Immersive simulation Worlds built from consistent systems (physics, sound, light, guards, doors) that can be combined in ways the designers did not plan. The player’s question: Is there a route through that the designers never specified? Leaves out: Less than any other genre, by design. Runs on: about 10^13.5 FLOPS rough a desktop CPU running interacting physics, AI and sound systems Since: 1994 a home-computer program combining physics, guard AI and sound in one world [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Open-world adventure A large continuous world with its own traffic, weather and daily routines, free to roam. The player’s question: What lies beyond the next hill? Leaves out: Characters distant from the player are paused or thinned out. Runs on: about 10^13.5 FLOPS rough a desktop or console GPU rendering a continuous large world Since: 1997 by 1997, Grand Theft Auto, a home-computer and console game with a large continuous city to roam freely [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Roguelikes A new world generated for every attempt, and death is permanent. The player’s question: How far can a single attempt progress? Leaves out: The world is procedurally generated and not intended to persist. Runs on: about 10^11 FLOPS rough a university terminal or phone; procedural generation is cheap Since: 1980 a university mainframe dungeon-crawl generating a new maze each run with permanent death [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)floor: Rules ### Interactive fiction A world described in text, which responds to typed commands or choices. The player’s question: What action follows from the described situation? Leaves out: Everything is text, so nothing needs to be rendered. Runs on: about 10^9 FLOPS rough a terminal or phone parsing typed text commands Since: 1975 Crowther’s mainframe cave program (1975), released with Woods’s expansion in 1976 [source](https://www.raphkoster.com/gaming/book/3a.html) In the simulations tree: [Colossal Cave Adventure](https://simulation-hypothesis.com/trees/simulations?n=w-colossal) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Visual novels and narrative games A story told in scenes, with choices that branch it. The player’s question: Which branch of the narrative will the choices select? Leaves out: Only the paths written by the authors exist. Runs on: about 10^9 FLOPS rough a phone or desktop CPU displaying branching text and images Since: 1983 The Portopia Serial Murder Case, a home-computer branching-story game told through text and static scenes [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Exploration and walking A place to move through and discover, with story told by the environment. The player’s question: What happened in this place? Leaves out: Nearly all interaction; the world is scenery. Runs on: about 10^13 FLOPS rough a desktop or console GPU rendering an environment to walk through Since: 2012 by 2012, a home-console walking program telling its story through the environment [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Adventure and point-and-click Scenes, objects and characters, with puzzles solved by using the right thing in the right place. The player’s question: Which object belongs with which? Leaves out: Only the listed objects can be used. Runs on: about 10^12 FLOPS rough a desktop CPU tracking a small set of usable objects Since: 1987 Maniac Mansion, a home-computer game where a mouse click combined objects to solve puzzles [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Alternate reality games A story told across real websites, phone calls and physical places that players treat as true, solving clues collaboratively. The player’s question: How does a crowd investigate a fiction presented as if it were real? Leaves out: Little is simulated by machine; the world is the real internet with scripted additions. Runs on: no computer. mostly human effort, no large computation Since: 2001 by 2001, The Beast, a campaign for the film A.I. Artificial Intelligence [source](https://en.wikipedia.org/wiki/Alternate%5Freality%5Fgame) [Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Populations ## Action and skill ### Platformers A character running and jumping through levels with carefully tuned physics. The player’s question: Can the jump be completed? Leaves out: Real momentum: characters can change direction in mid-air. Runs on: about 10^12 FLOPS rough an arcade cabinet or console CPU tracking simple jump physics Since: 1981 Donkey Kong, an arcade cabinet with a character climbing platforms and jumping gaps [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Action adventure Exploration, combat and puzzles in a world opened up bit by bit. The player’s question: Can the obstacle guarding the next area be overcome? Leaves out: Pain, fatigue and most consequences. Runs on: about 10^13 FLOPS rough a console or desktop CPU handling combat, puzzles and exploration Since: 1986 The Legend of Zelda, a home-console game combining exploration, combat and item puzzles [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Shooters Fast movement and aiming, with projectiles, cover and team play, usually against other players. The player’s question: Which player reacts first and holds the better position? Leaves out: Nearly everything except line of sight and reaction time. Runs on: about 10^13.5 FLOPS rough a desktop or console GPU rendering fast first-person movement Since: 1974 by 1974, Maze War at NASA Ames, where players hunted each other through a maze [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Fighting games Two characters with precisely timed moves, frame by frame. The player’s question: Can the opponent's next move be predicted? Leaves out: Anatomy and injury, entirely. Runs on: about 10^12.5 FLOPS rough an arcade cabinet or console CPU resolving frame-by-frame moves Since: 1976 Heavyweight Champ, an arcade cabinet with two fighters exchanging timed blows [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Tactical military simulation Realistic squads, ballistics, radio and command structure, usually on large maps with many players. The player’s question: Can a squad operate as a coordinated unit? Leaves out: Fear, exhaustion and consequences. Runs on: about 10^14 FLOPS rough a desktop CPU modelling ballistics and radio for many players Since: 1999 by 1999, a home-computer tactical shooter modelling real ballistics and squad radio [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Stealth Guards with models of sight, hearing and suspicion, and light and sound that reveal the player. The player’s question: Can the objective be reached without detection? Leaves out: Guards forget far faster than people do. Runs on: about 10^13 FLOPS rough a console or desktop CPU tracking guards' sight and hearing Since: 1998 Metal Gear Solid, a home-console game giving guards simulated sight and hearing cones [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Team arena games Two teams of heroes with distinct abilities competing over a symmetric map. The player’s question: Which team coordinates more effectively? Leaves out: The world outside a single map. Runs on: about 10^13.5 FLOPS rough a desktop or console GPU running two teams on a shared map Since: 1999 a home-computer team-based arena shooter with distinct character roles [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Rhythm games Actions timed to music, often with a real or simulated instrument. The player’s question: Can the actions be kept in time with the music? Leaves out: Everything but timing. Runs on: about 10^11 FLOPS rough an arcade cabinet or console tracking simple beat timing Since: 1997 Beatmania, an arcade cabinet with buttons timed to a musical beat [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ### Battle royale Many players dropped into one shrinking map, scavenging equipment until one player or team remains. The player’s question: Which player or team remains when the play area has closed? Leaves out: Most of the map, most of the time; each player observes only a small part of it. Runs on: about 10^14 FLOPS rough a desktop or console plus a game server coordinating up to about a hundred players Since: 2013 by 2013, a large-map multiplayer mode where the play area shrank until one survivor remained [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Extraction shooters A persistent raid in which players and computer-controlled enemies compete for loot and must reach an exit alive, losing carried gear on death. The player’s question: How does risking carried loot change how players trade off greed and survival? Leaves out: Ballistics and injury are simplified and the economy is a designed loop, not a market. Runs on: about 10^12 FLOPS rough a gaming PC, real time per raid Since: 2016 by 2016, the closed alpha of Escape from Tarkov (4 August 2016) [source](https://en.wikipedia.org/wiki/Extraction%5Fshooter) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ## Sports ### Sports simulation Team and individual sports with animated players, tactics and ball physics. The player’s question: Can a championship be won? Leaves out: Fatigue and injury are reduced or abstracted. Runs on: about 10^13.5 FLOPS rough a console or desktop GPU animating players and ball physics Since: 1983 a home-computer program simulating a team sport with player statistics and tactics [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Sports management A club’s squad, tactics, transfers and finances across many seasons, with matches simulated from player statistics. The player’s question: Can a winning team be assembled within the budget? Leaves out: Players are represented by hundreds of numbers each, more detail than most games give any entity. Runs on: about 10^12.5 FLOPS rough a desktop CPU simulating seasons of matches from statistics Since: 1982 Football Manager, a home-computer game simulating a league season from team statistics [Monte Carlo](https://simulation-hypothesis.com/simulations/methods#m-monte-carlo)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Fitness and motion games The player's own body as the controller, tracked by camera, motion sensors or a balance board. The player’s question: Can the required movement be sustained? Leaves out: The world; the setting is a gym with scenery. Runs on: about 10^12.5 FLOPS rough a console with a camera or balance-board sensor, light processing Since: 1987 Stadium Events, a home-console game controlled by a pressure-sensitive floor mat [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Extreme and action sports Skating, snowboarding, surfing or similar disciplines with trick systems and momentum-based physics. The player’s question: Can a trick sequence be completed without a fall? Leaves out: Injury. Runs on: about 10^13 FLOPS rough a console or desktop GPU running trick physics and momentum Since: 1987 Skate or Die!, a home-computer skateboarding game with trick combos and momentum [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Golf simulation A golf swing modelled from club, ball spin and wind, on a course built hole by hole. The player’s question: How do green slope and wind affect the putt? Leaves out: Nerves, and the interval between shots. Runs on: about 10^12.5 FLOPS rough a desktop or console CPU modelling ball flight and green slope Since: 1984 an arcade cabinet modelling swing timing, spin and wind on a golf shot [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Combat sports simulation Boxing, wrestling or martial arts matches with stamina, striking and grappling systems. The player’s question: Can the player outlast the opponent's stamina? Leaves out: Real damage accumulation, softened for playability. Runs on: about 10^12.5 FLOPS rough an arcade cabinet or console CPU resolving stamina and strikes Since: 1980 an arcade cabinet simulating a boxing match with a stamina meter [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Racket and ball sports Tennis, table tennis or similar disciplines with timing-based swings and ball physics. The player’s question: Can the swing be timed to the ball's arrival? Leaves out: Wind and spin are simplified to a couple of variables. Runs on: about 10^12 FLOPS rough a console or phone CPU modelling ball trajectory and swing timing Since: 1958 an analogue computer displaying a two-player tennis match on an oscilloscope [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Differential equations](https://simulation-hypothesis.com/simulations/methods#m-equations)floor: Bodies ### Fishing simulation Casting, hooking and reeling in virtual fish, with water depth, bait, line tension and fish behaviour. The player’s question: What does it take to land a fish given depth, bait and line tension? Leaves out: Fish behaviour is a few scripted states rather than ecology. Runs on: about 10^8 FLOPS rough a phone, real time Since: 1980 by 1980, Fishing Derby for the Atari 2600 [source](https://en.wikipedia.org/wiki/Fishing%5FDerby) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Stochastic processes](https://simulation-hypothesis.com/simulations/methods#m-stochastic)floor: Bodies ### Hunting simulation Stalking animals across a landscape, with wind, noise, scent and shot placement deciding the outcome. The player’s question: How do an animal's senses and a hunter's approach decide an encounter? Leaves out: Animals use simple alert-and-flee rules, not behavioural models. Runs on: about 10^10 FLOPS rough a laptop, real time Since: 1997 by 1997, Deer Hunter (November 1997) [source](https://en.wikipedia.org/wiki/Deer%5FHunter%5F%28video%5Fgame%29) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ## Puzzle and abstract ### Physics puzzles Objects to launch, stack, roll or connect under simulated physics. The player’s question: Which single arrangement satisfies the constraints? Leaves out: Friction, mass and materials are simplified. Runs on: about 10^13 FLOPS rough a desktop or phone CPU running a simple real-time physics engine Since: 2009 Angry Birds, a phone game launching objects under a simple physics engine [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Particles and N-body](https://simulation-hypothesis.com/simulations/methods#m-particles)floor: Bodies ### Logic and falling-block puzzles Grids, blocks and rules to reason within, often against a clock. The player’s question: Can the pattern be identified in time? Leaves out: There is no world at all, only rules. Runs on: about 10^10 FLOPS rough a simple CPU; falling-block logic is a trivial calculation Since: 1984 Tetris, a home-computer game dropping shaped blocks into a grid to clear lines [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Board and card game adaptations Traditional and modern tabletop games with the rules enforced by the computer and an opponent built in. The player’s question: Can the built-in opponent be defeated? Leaves out: The table and the other players. Runs on: about 10^11 FLOPS rough a phone or desktop CPU enforcing rules and running a built-in opponent Since: 1977 Microchess, a home-computer adaptation of chess with a built-in opponent [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)floor: Rules ### Word and letter puzzles Letters to arrange or guess against a dictionary, with a limited number of tries. The player’s question: Which word satisfies the feedback received so far? Leaves out: Meaning; only spelling is evaluated. Runs on: about 10^9 FLOPS rough a phone CPU checking guesses against a dictionary Since: 1972 a mainframe program guessing a hidden word one letter at a time [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Match-three and tile-swap puzzles A grid of tiles swapped to line up three or more of a kind, clearing them for points and chain reactions. The player’s question: Which swap produces the next chain? Leaves out: Everything beyond the grid; the theme is surface decoration. Runs on: about 10^9 FLOPS rough a phone or browser tab evaluating a small grid Since: 1994 Shariki, a home-computer game where swapping adjacent tiles clears rows of three [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Cellular automata](https://simulation-hypothesis.com/simulations/methods#m-cellular-automata)floor: Rules ### Hidden-object and spot-the-difference A cluttered scene searched for listed items or subtle differences from a reference image. The player’s question: Which items are concealed in the scene? Leaves out: The scene is static unless the player finds the element that changes it. Runs on: about 10^9 FLOPS rough a phone or desktop CPU checking click coordinates against a list Since: 1993 a home-computer program searching a cluttered scene for listed items [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Number and grid logic puzzles Digits or symbols placed under strict constraints, such as one of each in every row, column and block. The player’s question: Which value is forced in each cell, and by what deduction? Leaves out: Chance; a solved grid is provable, not guessed. Runs on: about 10^9 FLOPS rough a phone app checking a filled grid against constraint rules Since: 1979 Number Place (later Sudoku), a printed number-grid puzzle, later adapted onto computers [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Escape-room puzzles A locked space with a chain of puzzles that unlock the next, usually against a countdown. The player’s question: Can the puzzle chain be completed before the countdown ends? Leaves out: The stress of a real locked room. Runs on: about 10^9 FLOPS rough a phone or desktop CPU tracking a small state machine of clues Since: 2004 Crimson Room, a browser game locking progress behind a chain of solved puzzles [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Rules ### Programming battle games Players write programs that control a robot or process, then watch them fight each other without further input. The player’s question: Which program wins when no one can intervene during the fight? Leaves out: The arena is a toy world, so strategies rarely carry over to real robots. Runs on: about 10^7 FLOPS rough a laptop, seconds per battle Since: 1981 by 1981, RobotWar for the Apple II (Muse Software); see also Core War in minds-computation [source](https://en.wikipedia.org/wiki/RobotWar) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Game theory](https://simulation-hypothesis.com/simulations/methods#m-game-theory)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules ### Hacking simulation A stylised model of intruding into networked computers through commands, passwords and files, played under time or trace limits. The player’s question: How does an intruder move through a network before being traced? Leaves out: Real exploits are replaced by puzzles, and network behaviour is invented. Runs on: about 10^7 FLOPS rough a laptop, real time Since: 1985 by 1985, Hacker for home computers (Activision) [source](https://en.wikipedia.org/wiki/Hacker%5F%28video%5Fgame%29) [Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)[Network models](https://simulation-hypothesis.com/simulations/methods#m-network)[Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Rules ## Immersive hardware ### Virtual reality Worlds rendered stereoscopically to both eyes and tracked to head and hands, so that the user's body is the camera. The player’s question: Does the perceptual illusion of presence hold? Leaves out: Touch, weight, smell and temperature, where the illusion breaks down. Runs on: about 10^13.5 FLOPS rough a headset's onboard GPU or a tethered desktop GPU Since: 1991 Virtuality, a coin-operated cabinet with a stereoscopic head-mounted display [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Augmented and location-based Game objects laid over the real world through a phone or headset, often tied to real places. The player’s question: Which virtual objects are anchored to which real places? Leaves out: The real world supplies the rendering. Runs on: about 10^12 FLOPS rough a phone's CPU and GPU overlaying graphics on its camera feed Since: 2000 by 2000, a GPS-enabled handheld program placing virtual objects at real locations [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Motion-controller games Full-body or hand gestures tracked by a camera or wand and mapped directly onto in-game actions. The player’s question: Does the player's gesture match the on-screen action? Leaves out: Fine technique; broad gestures score the same as precise ones. Runs on: about 10^13 FLOPS rough a console CPU processing a camera or wand's tracked motion Since: 2006 the Wii Remote, a home-console wand tracked by motion sensors to control on-screen actions [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Haptic and force-feedback games Vibration, resistance or force fed back through a controller, wheel or vest to stand in for touch. The player’s question: Can an impact be conveyed through touch alone? Leaves out: Every texture is one of a handful of vibration patterns. Runs on: about 10^13 FLOPS rough a desktop or console CPU driving a force-feedback wheel or vest Since: 1997 a home-console controller with a motor that vibrated in step with on-screen impacts [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Location-based and arcade VR Virtual reality experienced by walking through a tracked physical room or riding a motion platform, shared with other people nearby. The player’s question: Does proprioception remain consistent with vision? Leaves out: The real walls, which remain present. Runs on: about 10^14 FLOPS rough a venue's networked computers tracking a whole room of headsets Since: 2016 by 2016, The VOID, a warehouse attraction tracking several players walking through a room in headsets [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Cockpit and rig simulation A physical seat, wheel, pedals or flight stick that moves or resists in step with the simulated vehicle. The player’s question: Is the vestibular cue convincing enough to sustain the illusion? Leaves out: Real g-forces; the rig can tilt the user but cannot sustain acceleration. Runs on: about 10^13.5 FLOPS rough a desktop CPU driving a motorised seat or force-feedback wheel Since: 1988 an arcade cabinet with a hydraulic motion seat synced to a racing or flight program [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)floor: Bodies ### Biometric-adaptive games Heart rate, skin conductance or breath measured live and fed back into the game's difficulty or story. The player’s question: Can the game infer arousal before the player is aware of it? Leaves out: It reads arousal, not its cause. Runs on: about 10^13 FLOPS rough a desktop CPU reading a heart-rate or skin sensor in real time Since: 2010 a home-computer horror program that sped up threats when a heart-rate sensor sensed fear [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Virtual reality social worlds Persistent shared rooms entered in a headset, where users appear as tracked avatars with body language, voice and user-made spaces. The player’s question: How do people behave and bond when meeting as avatars in embodied space? Leaves out: Avatars carry only head and hand tracking; faces and bodies are largely animated by rule. Runs on: about 10^12 FLOPS rough a gaming PC with a headset, real time for a room of tens of users Since: 2014 by 2014, VRChat first released on the Oculus Rift DK1 (16 January 2014) [source](https://en.wikipedia.org/wiki/VRChat) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Agent-based](https://simulation-hypothesis.com/simulations/methods#m-agent-based)floor: Bodies ### Augmented reality pets A virtual animal is drawn over the live camera view of the player's room, and reacts to hands, sounds and objects. The player’s question: Does a virtual creature feel present when it shares the player's real room? Leaves out: The pet follows scripted behaviour and responds to a few detected gestures. Runs on: about 10^11 FLOPS rough a console with a camera, real time Since: 2009 by 2009, EyePet for PlayStation 3 using a camera feed [source](https://en.wikipedia.org/wiki/EyePet) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Rules and states](https://simulation-hypothesis.com/simulations/methods#m-rules)floor: Bodies ### Cloud-streamed games A game's simulation and rendering run on a remote server, and only the video is sent to the player, whose controls are sent back. The player’s question: Can a game with demanding graphics be played on a weak device through the network? Leaves out: Network delay between pressing a button and seeing the result limits fast action games. Runs on: about 10^14 FLOPS rough a server-class graphics processor per player, running continuously. Since: 2013 Shea and colleagues' 'Cloud gaming: architecture and performance'. [source](https://doi.org/10.1109/mnet.2013.6574660) [Real time](https://simulation-hypothesis.com/simulations/methods#m-real-time)[Discrete event](https://simulation-hypothesis.com/simulations/methods#m-discrete-event)floor: Rules [◂ Film, media and art](https://simulation-hypothesis.com/simulations/media-art)[Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics) --- title: "Simulations by floor · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/floors description: "Every simulation sorted by the smallest entity it tracks, from quarks up to pure rules." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations by floor · 941 simulations The smallest thing each simulation keeps track of, from quarks up to pure rules. It’s the same ladder as the Sandbox’s matter-floor dial. The lower the floor, the more of reality has to be computed. Expand all Collapse all floor Subatomic 28 Quarks, gluons, nucleons, neutrinos, photons. domain Fundamental physics 25 Lattice QCD Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Collider event generation Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collider-events) Detector response Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#detector-response) Cosmic-ray air showers Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#air-showers) Accelerator beam dynamics Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Neutrino detector simulation Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neutrino-detectors) Generative calorimeter shower models Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#calorimeter-shower-generators) Flow-based sampling for lattice field theory Particles and fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Nuclear structure Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Reactor core physics Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Radiation transport Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#radiation-transport) Nuclear criticality safety Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#criticality-safety) Radioactivation and decay chains Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Fusion breeding blanket neutronics Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-blanket) Nuclear lattice effective field theory Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Time-dependent nuclear mean-field dynamics Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Neutron-star crust pasta dynamics Nuclei and radiation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) One-component plasma simulation Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) Quantum many-body systems Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Quantum computer emulation Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-circuit-emulation) Quantum error correction Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Topological quantum matter Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Digital quantum simulation on hardware Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#digital-quantum-simulation) Lattice gauge theory on quantum hardware Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) Neural-network quantum states Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) domain Astronomy and cosmology 3 Big Bang nucleosynthesis The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#nucleosynthesis) Early-universe lattice field dynamics The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) Supernova neutrino flavour evolution Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) floor Atoms 40 Individual atoms, often with their electrons. domain Fundamental physics 4 Laser wakefield acceleration Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Analogue quantum simulation Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#analogue-quantum) Ultracold atomic gas dynamics Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#cold-atom-bec) Path-integral Monte Carlo of quantum fluids Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) domain Chemistry and materials 28 Electronic structure Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#electronic-structure) Reaction dynamics Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Computational materials screening Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Excited states and photochemistry Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#excited-states-photochemistry) Spectroscopy prediction Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#spectroscopy-prediction) Solvation free energy Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#solvation-free-energy) Machine-learned interatomic potentials Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Universal interatomic potentials Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#universal-interatomic-potentials) Ab initio molecular dynamics Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Path-integral molecular dynamics Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Real-time electron dynamics Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Transition-state and reaction-path search Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Quantum Monte Carlo for electrons Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Learned density functionals Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Neural-network wavefunctions for molecules Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Reactive force-field dynamics Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reactive-force-field-dynamics) Metadynamics and enhanced sampling Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Kinetic Monte Carlo Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Enhanced-sampling free-energy methods Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Magnetism and phase transitions Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) Fracture and defects Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fracture) Dislocation dynamics Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Thin film growth Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#thin-film-growth) Radiation-damage cascades in materials Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) Alloy cluster expansion Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Lattice thermal-conductivity calculation Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Generative models of crystals Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) Catalysis Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#catalysis) domain Life and medicine 6 Protein folding and dynamics Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#protein-dynamics) Molecular docking and drug binding Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) Membranes and ion channels Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#membranes) Whole virus particles Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virus-particles) Enzyme catalysis Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) Vaccine antigen design Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) domain Engineering and technology 2 Semiconductor device simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Semiconductor process simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) floor Molecules 36 Whole molecules, or beads standing for groups of atoms. domain Fundamental physics 2 Industrial plasma processing Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Dusty plasma and Yukawa-system simulation Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) domain Astronomy and cosmology 2 Astrochemical reaction networks Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) Exoplanet atmosphere retrieval Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) domain Chemistry and materials 17 Quantum chemistry on quantum computers Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-chemistry-on-quantum-computers) Quantum wavepacket dynamics Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Automated reaction-mechanism generation Electrons and bonds [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) Liquids and solutions Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#liquids-solutions) Polymers and soft matter Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Colloids and nanoparticle assembly Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Glass formation Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#glass-formation) Molten salts and ionic liquids Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ionic-liquids-electrolytes) Learned equilibrium samplers Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Coarse-grained molecular dynamics Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Dissipative particle dynamics Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Adsorption in porous materials Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#grand-canonical-adsorption) Polymer self-consistent field theory Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Chain-growth Monte Carlo for polymers Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chain-growth-monte-carlo) Organic semiconductor charge transport Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Crystallisation Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) Polymerisation kinetics Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) domain Life and medicine 12 RNA folding and structure Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) Coarse-grained DNA and RNA models Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coarse-grained-nucleic-acids) Learned protein structure prediction Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#learned-structure-prediction) Generative protein ensembles Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#generative-protein-ensembles) Volunteer-computed molecular dynamics Molecules of life [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#volunteer-computing-molecular-dynamics) Stochastic biochemistry Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#stochastic-biochemistry) Gene regulatory networks Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Metabolic networks Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#metabolism) Whole-cell models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Predictive toxicology Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) Drug repurposing network models Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-repurposing-networks) Drug formulation and delivery modelling Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) domain Ecology, evolution and animal behaviour 1 Origin of life Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) domain Engineering and technology 1 Rarefied-gas direct simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) domain Minds, brains and artificial worlds 1 Artificial chemistry Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) floor Cells 33 Individual living cells, or neurons. domain Life and medicine 15 Pattern formation Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Tissue and tumour growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Cell perturbation-response models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#perturbation-response-models) Tumour evolution agent-based models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Microbial community metabolic models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Tumour growth and therapy response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Tumour microenvironment evolution Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Tumour-induced blood vessel growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Cancer drug response and resistance dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Blood cell production dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#haematopoiesis-dynamics) Bacterial colony growth and biofilms Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) Immune response Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Neural predictive models of sensory brain areas Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#neural-predictive-digital-twins) Gut microbiome community models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Within-host virus dynamics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#within-host-viral-dynamics) domain Ecology, evolution and animal behaviour 2 Slime mould aggregation Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Bacterial swarming and quorum sensing Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) domain Agriculture and food 1 Predictive food microbiology Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) domain Minds, brains and artificial worlds 10 Detailed neuron models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#detailed-neurons) Large-scale brain circuits Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Simulated small organisms Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Neuromorphic hardware simulation Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Connectome-constrained whole-brain models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Neural mass and field models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Functional spiking brain models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Attractor memory networks Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Connectome-based insect brain models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) Artificial immune models Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) domain Minds as simulators 3 Hippocampal replay in rats Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-replay) Hippocampal preplay Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-preplay) Mirror systems Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mirror-systems) domain Before computers 1 Iron wire nerve model Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) domain Film, media and art 1 L-system plant modelling Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) floor Bodies 254 Whole objects as units: organisms, people, vehicles, stars, grains. domain Fundamental physics 1 Particle-in-cell plasma Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) domain Astronomy and cosmology 5 Cosmological N-body The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-n-body) Planet formation Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Orbital dynamics Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Impact cratering Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Exoplanet detection and characterisation Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) domain Chemistry and materials 1 Granular materials Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#granular) domain Life and medicine 24 Musculoskeletal biomechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#biomechanics) In silico clinical trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Cardiac digital twins Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Brain-stimulation field models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Virtual-population drug exposure models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Surgical planning with patient-specific models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Heart valve fluid-structure interaction Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Bone adaptation and implant remodelling Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Musculoskeletal models for surgery Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#musculoskeletal-surgery-models) Radiotherapy dose calculation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Virtual anatomical phantoms for imaging Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Magnetic resonance image simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Fracture healing simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Coronary flow reserve from scans Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Cochlear mechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Whole-body integrative physiology Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Bioheat transfer and hyperthermia Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Kidney nephron transport models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Vocal fold and voice production models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Circadian clock models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) Agent-based epidemics Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Virtual imaging trials Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Cancer screening microsimulation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Closed-loop diabetes control in silico Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) domain Ecology, evolution and animal behaviour 11 Ant colony foraging Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) Honeybee colonies Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Flocking and schooling Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) Termite mound building Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Movement and foraging Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) Migration and navigation Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#migration) Evolution of behaviour Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Dynamic energy budget modelling Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#dynamic-energy-budget) Forest dynamics Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forest-dynamics) Wildlife disease Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) Reintroduction and translocation planning Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) domain Agriculture and food 3 Plant architecture growth models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Precision livestock monitoring Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Digestion and gastric flow simulation Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) domain Human behaviour and society 22 Residential sorting Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) Opinion dynamics Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Cooperation and norms Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Diffusion of ideas Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Social network formation Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#network-formation) Language evolution Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#language-evolution) Pedestrian and crowd dynamics Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) Crowd emotion and behavioural contagion Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Protest mobilisation network models Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Mass gathering disease risk modelling Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) Agent-based economies Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#agent-economies) Financial markets Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Market and auction design Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) Artificial societies Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#artificial-societies) Reconstructed ancient societies Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#archaeological-abm) Hunter-gatherer economies Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#hunter-gatherers) Ancient trade and exchange Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Demographic microsimulation Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#demographic-microsimulation) Monument construction and engineering reconstruction Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) Tax and benefit microsimulation Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) Organisations and teams Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#organisations) Policing and patrol deployment simulation Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) domain Engineering and technology 20 Multibody dynamics Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multibody) Robot simulation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Autonomous vehicle testing Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) Swarm robotics Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#swarm-robotics) Digital twins Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) Planetary rover mobility Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Exoskeleton and prosthetic control Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) GPU-parallel robot learning environments Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Domain-randomised sim-to-real training Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Differentiable physics simulation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Adversarial driving-scenario generation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) Open driving simulators with sensor models Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) Learned legged locomotion Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned humanoid locomotion Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Drone flight simulation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Learned drone racing Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Soft robot simulation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Tactile sensor simulation Robotics and autonomy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) Spacecraft trajectories Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#trajectory-design) Spacecraft thermal and power simulation Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#spacecraft-thermal) domain Cities, infrastructure and operations 14 Traffic flow Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Transport and land use Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Evacuation and emergency response Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#evacuation) Public transit network simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Ride-hailing and dispatch simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Supply chains Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Manufacturing lines Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#manufacturing) Queues and service systems Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#service-queues) Hospital patient flow Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Warehouse and distribution centre simulation Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Last-mile delivery routing Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Infrastructure interdependence Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Waste collection and treatment simulation Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) Satellite broadband constellation simulation Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) domain Minds, brains and artificial worlds 7 Evolved virtual creatures Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Self-organised criticality Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) Evolutionary robotics Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Reinforcement learning environments Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Multi-agent AI societies Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) Synthetic training data Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#synthetic-data) Embodied household simulators Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) domain Minds as simulators 21 Mental rehearsal in athletes Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rehearsal-athletes) Constructive episodic simulation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#constructive-episodic-simulation) Motor imagery Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-imagery) Visual mental imagery Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#visual-mental-imagery) Affective forecasting Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#affective-forecasting) Mental models of reasoning Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Vicarious trial and error Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#vicarious-trial-and-error) Future planning in animals Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-future-planning) Empathy as simulation theory Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#empathy-simulation-theory) Fiction as social simulation Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#fiction-as-social-simulation) Animal play as practice Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-play-practice) Object play in primates Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#primate-object-play) Motor forward models The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-forward-models) The body schema The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-schema) Interoception The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#interoception) Thought as simulated action The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) Grounded cognition The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#grounded-cognition) The phenomenal self-model The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#phenomenal-self-model) Body ownership illusions The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-ownership-illusions) Embodied language simulation The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#embodied-language-simulation) The intuitive physics engine The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) domain Training simulators 18 Full-flight simulators Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#flight-simulators) Driving and rail simulators Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#driving-simulators) Ship bridge simulators Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ship-bridge) Spaceflight and mission control Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) Heavy equipment simulators Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#heavy-equipment-simulators) Diving and submersible simulators Vehicles [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) Patient simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Childbirth simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) Anaesthesia simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Paramedic and mass-casualty triage training Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Virtual human patients Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Catheter and endovascular simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Ultrasound training simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Robotic surgery simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Endoscopy simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Air traffic control simulators Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) Emergency incident command simulators Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) domain Before computers 22 Orrery Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#orrery) Astrolabe Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astrolabe) The Antikythera mechanism Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#antikythera-mechanism) Optical planetarium Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#planetarium) Armillary sphere Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#armillary-sphere) Equatorium Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#equatorium) Structural scale model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#structural-scale-model) Analogue fire-control computer Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#analogue-fire-control-computer) Cybernetic tortoises Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) Sand table Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#sand-table) Staff ride Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#staff-ride) Dress rehearsal Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#dress-rehearsal) Fire and evacuation drills Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#fire-drills) Military field exercises Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#field-exercises) Anatomical models Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#anatomical-models) Obstetric phantom Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#obstetric-phantom) Early resuscitation manikins Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#resuscitation-manikins) Crash-test dummies Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#crash-test-dummies) Moulage Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#moulage) Ballistic gelatin blocks Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#ballistic-gelatin) Automata Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) Motion platforms Bodies and manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) domain Defence and conflict 12 Historical war games War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Agent-based combat models War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#agent-combat) Military logistics War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) Models of civil conflict War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Military flight and mission simulators Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Vehicle and crew trainers Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crew-trainers) Networked training exercises Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Marksmanship and use-of-force trainers Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) Combat medic trainers Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) Ballistics Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Displacement and refugee flows Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Casualty and humanitarian response Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) domain Film, media and art 11 Destruction and debris simulation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Rigid body dynamics for animation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Position-based dynamics Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Digital crowd simulation Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-crowds) Digital ecosystems and vegetation Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Neural avatars Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-avatars) Virtual idols and influencers Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Digital de-ageing Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Performance-captured digital characters Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) Animatronic figures Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) Physics-based character control Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) domain Video games 62 Flight simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Spaceflight simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) Racing simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Arcade racing Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arcade-racing) Driving and transport simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Naval and submarine simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) Job and machinery simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Soft-body vehicle crash simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Mech combat simulation Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) Life simulation Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Virtual pets Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#virtual-pets) Farming and village life Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Social hangout worlds Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) Parenting and family life Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) Surgery and medical games Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) City building Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Colony simulation Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) Management and tycoon Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) God games Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) Ecosystem and evolution games Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) Automation and factory building Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Real-time strategy Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Tactics Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Tower defence Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tower-defence) Block and voxel sandboxes Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Survival and crafting Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) Physics sandboxes and building Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Space exploration and trading Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) Terrarium and habitat sandboxes Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Role-playing games Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Massively multiplayer worlds Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) Immersive simulation Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Open-world adventure Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Exploration and walking Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#exploration) Platformers Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#platformers) Action adventure Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Shooters Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#shooters) Fighting games Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Tactical military simulation Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Stealth Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Team arena games Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) Battle royale Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Extraction shooters Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Sports simulation Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Sports management Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) Fitness and motion games Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fitness-games) Extreme and action sports Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Golf simulation Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Combat sports simulation Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) Racket and ball sports Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) Fishing simulation Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Hunting simulation Sports [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Physics puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) Virtual reality Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr) Augmented and location-based Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#augmented-reality) Motion-controller games Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#motion-controller-games) Haptic and force-feedback games Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#haptic-feedback-games) Location-based and arcade VR Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#large-scale-vr) Cockpit and rig simulation Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cockpit-sim-rigs) Biometric-adaptive games Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Virtual reality social worlds Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) Augmented reality pets Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) floor Fields 227 A continuous medium cut into grid cells: air, water, rock, plasma, ice. domain Fundamental physics 10 Fusion plasma turbulence Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Plasma equilibrium and stability Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Inertial confinement implosion Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#inertial-confinement-fusion) Magnetic reconnection Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Stellarator configuration optimisation Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Tokamak edge pedestal and ELM modelling Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Tokamak whole-device modelling Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Collisionless shock simulation Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) Learned plasma control in simulation Plasma [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) Superconducting vortex dynamics Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) domain Astronomy and cosmology 48 Galaxy formation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Cosmic microwave background The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Cosmic reionization The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Intergalactic medium and the Lyman-alpha forest The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Wave dark matter simulations The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Constrained simulations of the local universe The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Cosmological emulators The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Semi-analytic galaxy formation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Self-interacting dark matter simulation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#self-interacting-dark-matter) Massive-neutrino cosmological simulation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Weak-lensing ray tracing through simulated universes The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Cosmic string network evolution The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Galactic cosmic-ray propagation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Differentiable cosmological simulation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Synthetic sky survey catalogues and images The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Galaxy collision and merger simulation The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) Stellar evolution Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-evolution) Core-collapse supernovae Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Star formation Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Stellar oscillations Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-interiors-seismology) Binary star evolution Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-star-evolution) Stellar atmospheres and spectra Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Stellar surface convection simulation Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Common-envelope evolution Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Binary population synthesis Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Collapsar and gamma-ray burst jets Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Interstellar magnetised turbulence Stars [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) Planetary and exoplanet atmospheres Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-atmospheres) Planetary interiors and dynamos Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-interiors) Giant-impact simulations Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Planet population synthesis Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Habitable-zone climate modelling Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Planetesimal formation by streaming instability Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Planet-disk interaction and migration Planets and orbits [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) Black hole mergers Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#numerical-relativity) Accretion discs and jets Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#accretion) Space weather Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Neutron star mergers Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#neutron-star-mergers) Pulsar magnetospheres Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Solar interior and dynamo Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#solar-dynamo) Gravitational-wave template banks from numerical relativity Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Magnetar magnetosphere and flare simulation Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Black-hole shadow and image rendering Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Tidal disruption of stars by black holes Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) Kilonova radiative transfer Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) Radiation belt modelling Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) Neural inference for gravitational waves Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) domain Earth and climate 58 Earth system models Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system) Palaeoclimate Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Ice sheets and sea level Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ice-sheets) Regional climate downscaling Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#regional-climate-downscaling) Solar geoengineering Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geoengineering-modelling) World-Earth models Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Global cloud-resolving models Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Superparameterisation Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Extreme-event attribution Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Volunteer-computed perturbed-physics ensembles Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Initial-condition large ensembles Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Learned climate emulators Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-climate-emulators) Earth-system digital twins Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Radiative-convective climate model Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Dynamic global vegetation and carbon-cycle modelling Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Coupled carbon-cycle and climate simulation Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Ocean ecosystem and biogeochemistry modelling Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Learned subgrid parameterisation Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) Numerical weather prediction Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Machine-learned weather Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-weather) Tropical cyclones Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tropical-cyclones) Air quality and dispersion Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Seasonal forecasting Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Severe convective storms Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#severe-storms) Generative ensemble weather forecasting Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) Ensemble weather forecasting Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Atmospheric reanalysis Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Atmospheric boundary-layer large-eddy simulation Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Global storm-resolving simulation Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Mineral dust emission and transport Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Urban surface energy-balance modelling Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Thermosphere and ionosphere modelling Weather and air [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) Ocean circulation Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-circulation) Tsunamis and storm surge Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tsunami-surge) Rivers and floods Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) Groundwater Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#groundwater) Sea ice Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#sea-ice-dynamics) Ocean wave forecasting Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-wave-forecasting) Flood inundation modelling Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Coastal and estuarine circulation modelling Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Marine debris and Lagrangian drift modelling Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Petroleum and gas reservoir simulation Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Glacial isostatic adjustment and sea-level fingerprints Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Geological carbon-dioxide storage simulation Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Reactive transport in the subsurface Water [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) Mantle convection and plate tectonics Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mantle-convection) Earthquakes and seismic waves Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquakes) Volcanic eruptions and lava flows Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landscape evolution Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Wildfire spread Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) Landslides and debris flows Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) Physics-based seismic hazard Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Geodynamo simulation Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Full-waveform seismic inversion Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Spectral-element seismic wave propagation Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Earthquake-cycle simulation Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Land-surface model Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Coupled fire and atmosphere models Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) domain Chemistry and materials 9 Combustion Molecules in motion [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#combustion) Microstructure Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Crystal plasticity finite-element modelling Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Micromagnetic simulation Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Battery and electrochemical cell modelling Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Corrosion Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Chemical reactor engineering Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chemical-reactor-engineering) Fuel-cell membrane and transport modelling Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) Pore-network modelling Reactions, catalysis and electrochemistry [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) domain Life and medicine 4 The heart Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Blood flow Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#blood-flow) Breathing and airways Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#lungs) Indoor airborne transmission simulation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) domain Ecology, evolution and animal behaviour 3 Animal locomotion Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) Pollination service across landscapes Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) Wind seed and pollen dispersal models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) domain Agriculture and food 11 Soil water and nutrient transport Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Soil erosion and land degradation Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Precision agriculture optimisation Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Multi-model crop ensembles Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Soil organic carbon turnover Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Agricultural catchment pollution models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Global gridded crop model ensembles Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Agrivoltaic light-sharing models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Greenhouse climate models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) Grazing and pasture management Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Baking and thermal food processing Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) domain Engineering and technology 36 Aerodynamics Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#aerodynamics) Turbulence Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#turbulence) Physical scale models Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#scale-models) Cavitation simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#cavitation) Multiphase and pipeline flow Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multiphase-flow) Ice accretion simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#icing) Physics-informed neural networks Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Neural operators Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Graph-network learned simulators Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Learned fluid solvers Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Lattice Boltzmann flow simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) Wind-farm large-eddy simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Fluid-structure interaction Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Fire dynamics large-eddy simulation Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) Structural analysis Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#structural-analysis) Crash simulation Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#crash) Acoustics and vibration Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#acoustics) Fatigue and crack growth Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#durability-fatigue) Tribology and contact mechanics Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tribology-contact) Topology optimisation Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Peridynamic fracture modelling Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Electromagnetics Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#electromagnetics) Optical lithography simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Processor thermal modelling Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Photonic-crystal band-structure calculation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Stacked chip thermal modelling Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) Atmospheric entry Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#reentry) Batteries and fuel cells Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) Rocket engine simulation Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rocket-propulsion) Solar and wind farm yield simulation Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Metal casting and solidification Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-casting) Welding simulation Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#welding-simulation) Additive manufacturing simulation Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#additive-manufacturing) Metal forming and stamping Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-forming) Machining simulation Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#machining-simulation) Injection moulding simulation Manufacturing and materials processing [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#injection-moulding) domain Cities, infrastructure and operations 8 Urban growth Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#urban-growth) Water and drainage networks Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Building energy and daylight Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) District heating and cooling networks Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Power-system electromagnetic transients Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Gas pipeline network transients Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Mobile network planning Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Data centre facility simulation Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) domain Minds, brains and artificial worlds 1 Learned world models Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learned-world-models) domain Training simulators 2 Surgical simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) Dental simulators Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) domain Before computers 10 Terrestrial globe Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#terrestrial-globe) Astronomical clock Models of the heavens [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astronomical-clock) Ship-model towing tank Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#towing-tank) Physical river basin model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#river-basin-model) Harbour and estuary model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harbour-model) Dam and spillway model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#spillway-model) Architectural acoustic scale model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#acoustic-scale-model) Hele-Shaw cell Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) Hanging-chain arch model Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Soap film minimal-surface models Scale models and tanks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) domain Defence and conflict 8 Search and rescue drift planning War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) Nuclear stockpile simulation Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) Blast and impact protection Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#blast-protection) Radar and sensor performance Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Directed energy weapon simulation Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Torpedo and underwater weapon simulation Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) Chemical, biological and radiological hazard plumes Weapons physics and protection [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) Climate effects of nuclear war Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#nuclear-winter) domain Film, media and art 15 Cloth simulation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Hair and fur simulation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Fluid and smoke simulation for effects Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Muscle and skin deformation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Ocean surface synthesis Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Particle system effects Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Snow and granular material simulation Simulated physical media [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) Digital humans and faces Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Virtual production sets Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Atmospheric and sky simulation Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Physically based light transport Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) Sound propagation and acoustics Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) Physical modelling synthesis of instruments Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) Physically based sound effects Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Neural scene rendering Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) domain Video games 4 Open-city driving Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Flight simulation over streamed Earth Vehicles and machines [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Station systems simulation Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Falling-sand games Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) floor Populations 139 Aggregate counts and totals: number infected, mass of carbon, quantity of money. domain Earth and climate 1 Integrated assessment models Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) domain Life and medicine 22 Pharmacokinetics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacokinetics) Compartment epidemic models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#compartment-epidemics) Pathogen evolution Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) Disease burden and health economic modelling Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Outbreak genomic epidemiology Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Environmental and chemical exposure risk assessment Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Mobility-network epidemic models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Individual-based malaria models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Scenario modelling hubs Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Digital contact-tracing models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Antimicrobial resistance spread Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Malaria transmission and intervention models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Tobacco-control policy simulation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Vaccine allocation optimisation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-allocation-optimisation) Epidemics on contact networks Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Mosquito population dynamics Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Obesity and diet agent-based models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) Organ allocation policy simulation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Ambulance and fire station deployment models Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) Synthetic patient record generation Public health [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) Pharmacodynamic modelling Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacodynamics) Clinical trial design simulation Drug discovery and pharmacology [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#trial-design-simulation) domain Ecology, evolution and animal behaviour 31 Locust marching bands Collective behaviour [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) Predator–prey dynamics Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) Food webs Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Fisheries and wildlife management Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Species ranges Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) General ecosystem models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Metapopulation dynamics Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Individual-based ecological models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Coral reef resilience models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Spatial host-parasitoid and pest lattices Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) Fisheries management strategy evaluation Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Trophic mass-balance ecosystem models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Plankton ecosystem models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Lake eutrophication models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Marine larval dispersal and connectivity Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Honeybee colony and landscape models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Near-term ecological forecasting Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Size-spectrum ecosystem models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) Neutral community models Populations and ecosystems [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Population genetics Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Coalescent and phylogenetic simulation Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coalescent) Host-parasite coevolution Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Speciation and macroevolution models Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Sexual selection and mate choice evolution Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Gene drive population models Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Forward-time genome simulation Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Animal contest strategies Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) Population viability analysis Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Reserve and corridor design Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) Invasive species spread Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) Rewilding and trophic cascade modelling Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) domain Agriculture and food 20 Crop growth and yield models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Pest and plant disease spread Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Irrigation scheduling Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Crop breeding simulation Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Farm agent-based models of land use and adoption Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#farm-agent-based-adoption) Pesticide resistance management models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Degree-day pest phenology models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Sterile insect release models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Land-use change agent models Crops and soil [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) Livestock herd and feed models Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Aquaculture and fish farming Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Livestock disease outbreak models Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Livestock breeding and genetics Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) Aquaculture pond bioenergetics Livestock and aquaculture [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) Food supply chain simulation Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) Famine early warning models Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) Fermentation process modelling Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Cold chain and spoilage modelling Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Food safety and traceability simulation Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) Quantitative microbial risk assessment Food systems and processing [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) domain Human behaviour and society 20 Cultural evolution Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Misinformation and rumour spread Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Migration under climate stress Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#climate-migration-abm) Human mobility and migration models Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Synthetic population generation Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) Macroeconomic models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Financial risk Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#risk) Housing market agent-based models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#housing-market-abm) Insurance catastrophe models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Electricity market agent-based models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Coupled epidemic and economy models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#epidemic-economy-coupled) Flash-crash market models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Algorithmic pricing collusion Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Language-model macroeconomic agents Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) Human dispersal Anthropology and archaeology [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) World models Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#world-models) Computable general equilibrium modelling Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#computable-general-equilibrium) Policy diffusion network models Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) Opioid epidemic system dynamics Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opioid-system-dynamics) Crime hotspot dynamics Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) domain Engineering and technology 1 Circuit simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#circuit-simulation) domain Cities, infrastructure and operations 14 Aircraft boarding simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Airport airside simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Elevator traffic simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Shared autonomous vehicle fleets Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Airspace fast-time simulation Movement [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Warehouse robot fleet coordination Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Supply chain digital twins Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Container terminal simulation Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Construction process simulation Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) Power grids Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Agent-based electricity markets Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) Cascading-blackout models Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Smart-grid co-simulation Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Vehicular network simulation Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) domain Minds, brains and artificial worlds 3 Whole-brain network models Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Brain disease and seizure spread Brains [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Simulated robot soccer Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) domain Mathematics and computation 1 Blockchain consensus simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) domain Training simulators 3 Control-room simulators Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) Business simulations Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) Mass-casualty exercises Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) domain Before computers 5 Mechanical differential analyser Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#differential-analyser) Tide-predicting machine Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#tide-predicting-machine) Hydraulic economy model Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hydraulic-economy-model) Electrical network analyser Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#electrical-network-analyser) Mechanical harmonic analyser Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harmonic-analyser) domain Defence and conflict 9 Combat and campaign models War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Deterrence and arms races War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) Swarm combat simulation War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Computer virus and malware epidemics War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Anti-submarine search theory War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Landmine and unexploded ordnance clearance planning Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) War economic and reconstruction modelling Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Sanctions and economic warfare modelling Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) Biological attack response models Consequences of war [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) domain Film, media and art 1 Virtual concerts Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) domain Video games 8 Idle and incremental Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#idle-games) Social deduction games Systems and societies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Grand strategy Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) 4X strategy Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#four-x) Hex-and-counter war games Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Auto-battlers Strategy [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) User-generated game platforms Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Alternate reality games Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) floor Rules 184 Symbols, states and turns, with no physical scale at all. domain Fundamental physics 3 Stabilizer circuit simulation Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Learned error-correction decoders Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) Quantum network simulation Quantum matter and computers [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) domain Astronomy and cosmology 3 Stellar population synthesis The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Galactic chemical evolution The universe as a whole [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Gravitational-wave mock data challenges Extreme gravity and space plasma [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) domain Earth and climate 2 Energy-balance climate model Climate [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Stochastic earthquake-catalogue models Solid Earth and landscape [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) domain Chemistry and materials 1 Diffusion-limited aggregation Solids [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) domain Ecology, evolution and animal behaviour 3 Birdsong and vocal learning models Individual animals [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) Adaptive dynamics of coevolution Evolution [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Poaching and anti-poaching patrol games Conservation and reserve design [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#poaching-patrol-games) domain Human behaviour and society 31 Cognitive architectures Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cognitive-architectures) Models of decision-making Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#decision-models) Models of learning Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Social cognition and theory-of-mind models Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Emotion and affect modelling Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Choice under risk and uncertainty modelling Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Language-model survey respondents Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-survey-respondents) Language-model behavioural experiments Minds and decisions [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-behavioural-experiments) Language-model agent societies Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) Populated social-system prototypes Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Language-model social platform simulation Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Recommender feedback-loop simulation Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Language-model user simulation for recommenders Social dynamics [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) Collective action and tipping-point models Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Collective estimation and crowd wisdom Crowds [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) AI-designed economic policy simulation Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Agent-based exchange simulators Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Dynamic stochastic general equilibrium models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Financial contagion in interbank networks Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Kinetic wealth exchange models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) Disaster economic ripple models Economies and markets [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Institutional corruption and integrity modelling Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Language-model agent organisations Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Language-grounded negotiation agents Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Exploratory modelling under deep uncertainty Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Supply-chain dynamics and the bullwhip effect Policy and organisations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) Electoral and voting system simulation Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Court and case-flow simulation Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Sentencing and recidivism risk modelling Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) Legislative bargaining and coalition simulation Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) Jury decision-making simulation Law, justice and elections [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) domain Engineering and technology 9 Lattice-gas automata for fluid flow Flow [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) Orbital-debris and satellite-collision modelling Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Co-simulation of linked models Structures and machines [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Chip logic simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Computer network simulation Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-simulation) Emulation and virtual machines Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#emulation) Network digital twins Electronics and computers [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) Mega-constellation collision risk Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) Conjunction collision probability Spaceflight and energy [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) domain Cities, infrastructure and operations 6 Project schedule risk simulation Queues and logistics [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Energy-system capacity-planning models Infrastructure [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) Internet backbone and cable resilience Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Telecom traffic engineering Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) Smart-city sensor network simulation Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Internet worm propagation models Telecommunications and the internet [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) domain Minds, brains and artificial worlds 20 Cellular automata Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) Digital evolution Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#digital-evolution) Swarm intelligence algorithms Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Random Boolean networks Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Continuous cellular automata Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-cellular-automata) Neural cellular automata Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Self-replicating program soups Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Continuous artificial life Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) Core War battles Artificial life and complexity [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) Self-play strategy training Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) AI safety red-teaming environments Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Open-ended environment generation Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) Simulated web environments for agents Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Recommender-system simulators Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) Neural game engines Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Interactive generative worlds Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#interactive-generative-worlds) Learned real-world interactive simulators Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#real-world-interactive-simulators) Generative driving world models Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#driving-world-models) Software engineering agent sandboxes Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments Worlds for artificial minds [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) domain Mathematics and computation 45 Random matrix experiments Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-matrix-experiments) Random graph experiments Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Percolation simulation Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Experimental mathematics searches Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Monte Carlo estimation of constants Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) Computational number theory searches Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Chaotic-attractor numerics Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#chaotic-attractor-numerics) Nonlinear lattice experiments Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) Soliton numerical experiments Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) Fractal-set rendering Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fractal-set-rendering) Sandpile self-organised criticality Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) Riemann zeta zero computation Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Digits of pi by computer Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) AI-guided conjecture discovery Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#ai-guided-conjecture-discovery) Learned algorithm and construction search Pure mathematics by computer [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) Model checking Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#model-checking) Automated theorem proving search Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) SAT and constraint solving Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Cryptographic attack modelling Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Side-channel leakage simulation Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Security protocol verification Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Computer-assisted proof by exhaustive case checking Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Validated numerics Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#validated-numerics) Turing-machine enumeration Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) Statistical model checking Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Fuzz testing Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Symbolic execution Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Abstract interpretation Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Bounded model checking Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Property-based random testing Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Neural network verification Proof, logic and security [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) Computer architecture simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Distributed systems and consensus simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Storage systems simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Operating system scheduler simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#os-scheduler-simulation) Compiler and program optimisation search Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Empirical algorithm performance testing Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) Language-model program execution Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#llm-program-execution) Parallel discrete-event simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#parallel-discrete-event-simulation) Graphics processor architecture simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) FPGA-accelerated system simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Full-system simulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Lightweight network emulation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) Simulated annealing Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Approximate Bayesian computation Systems and machines [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) domain Minds as simulators 21 REM dreaming Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#rem-dreaming) Lucid dreaming Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#lucid-dreaming) Threat-simulation theory of dreams Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#threat-simulation-theory) Sleep-dependent memory consolidation Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#memory-consolidation-sleep) Hypnagogic imagery Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hypnagogic-imagery) Episodic future thinking Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#episodic-future-thinking) Counterfactual thinking Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#counterfactual-thinking) Mental rotation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rotation) Mental navigation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-navigation) Mind-wandering and daydreaming Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mind-wandering) Theory of mind Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#theory-of-mind) Audience design Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#audience-design) Visual perspective-taking Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#perspective-taking) Joint attention Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#joint-attention) Children's pretend play Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#pretend-play-children) Imaginary companions Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#imaginary-companions) Sociodramatic play Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) Paracosms Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#paracosms) Predictive processing The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#predictive-processing) Hallucination as uncontrolled prediction The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hallucination-uncontrolled-prediction) Blind-spot filling-in The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#blind-spot-filling-in) domain Training simulators 6 Agent hospitals Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Structured clinical examinations Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#clinical-examination-standardised-patients) Language-model simulated students Medicine [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) Emergency exercises Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#tabletop-exercises) Negotiation and diplomacy training simulations Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) Language-model conflict rehearsal Control and crisis [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-conflict-rehearsal) domain Before computers 3 Galton board Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Buffon's needle Analogue computers [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) Mock trial Tables, boards and rehearsals [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) domain Defence and conflict 6 Professional war games War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#professional-wargames) Political–military crisis games War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Language-model wargame agents War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) Naval salvo exchange models War games and analysis [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#naval-salvo-models) Cyber ranges Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) Autonomous cyber-defence gyms Military training [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) domain Film, media and art 6 Procedural cities and landscapes Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Machinima Populated and built worlds [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Generative art systems Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) Procedural and generative music Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Procedural texture and material generation Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) Live-coded music and visuals Light and sound [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) domain Video games 19 Relationship simulation Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#relationship-sims) Dating simulation Life and people [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Level and world creation tools Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) Agent-based game playtesting Worlds and sandboxes [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) Roguelikes Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Interactive fiction Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#interactive-fiction) Visual novels and narrative games Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#visual-novels) Adventure and point-and-click Role-playing and story [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#puzzle-adventure) Rhythm games Action and skill [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rhythm) Logic and falling-block puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#logic-puzzles) Board and card game adaptations Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Word and letter puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#word-puzzles) Match-three and tile-swap puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) Hidden-object and spot-the-difference Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hidden-object) Number and grid logic puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#number-logic-puzzles) Escape-room puzzles Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#escape-room-games) Programming battle games Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Hacking simulation Puzzle and abstract [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) Cloud-streamed games Immersive hardware [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) --- title: "Simulations by method · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/methods description: "The same taxonomy sorted by computational method, from Monte Carlo to agent-based to real-time." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations by method · 941 simulations How the computing gets done. Most simulations mix two or three methods, so they show up under each. Expand all Collapse all method First principles 34 Solve the quantum equations for the electrons directly, with no parameters fitted to experiment beyond the fundamental constants (density functional theory, coupled cluster). domain Fundamental physics 7 Nuclear structure Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Time-dependent nuclear mean-field dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Quantum many-body systems Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Topological quantum matter Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Digital quantum simulation on hardware Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#digital-quantum-simulation) Lattice gauge theory on quantum hardware Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) Path-integral Monte Carlo of quantum fluids Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) domain Chemistry and materials 18 Electronic structure Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#electronic-structure) Reaction dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Computational materials screening Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Excited states and photochemistry Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#excited-states-photochemistry) Spectroscopy prediction Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#spectroscopy-prediction) Solvation free energy Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#solvation-free-energy) Quantum chemistry on quantum computers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-chemistry-on-quantum-computers) Ab initio molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Real-time electron dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Quantum wavepacket dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Transition-state and reaction-path search Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Quantum Monte Carlo for electrons Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Learned density functionals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Neural-network wavefunctions for molecules Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Alloy cluster expansion Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Lattice thermal-conductivity calculation Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Generative models of crystals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) Catalysis Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#catalysis) domain Life and medicine 1 Enzyme catalysis Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) domain Engineering and technology 2 Semiconductor device simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Batteries and fuel cells Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) domain Mathematics and computation 6 Riemann zeta zero computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Digits of pi by computer Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) Symbolic execution Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Abstract interpretation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Bounded model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Neural network verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) method Lattice field theory 8 Discretise spacetime as a four-dimensional grid and place the quantum fields on its sites. domain Fundamental physics 4 Lattice QCD Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Flow-based sampling for lattice field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Nuclear lattice effective field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Lattice gauge theory on quantum hardware Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) domain Astronomy and cosmology 1 Early-universe lattice field dynamics Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) domain Chemistry and materials 1 Alloy cluster expansion Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) domain Ecology, evolution and animal behaviour 1 Spatial host-parasitoid and pest lattices Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) domain Engineering and technology 1 Lattice Boltzmann flow simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) method Molecular dynamics 27 Integrate Newton’s equations of motion for every atom in steps of about a femtosecond, using a force field for the interatomic interactions. domain Fundamental physics 3 Neutron-star crust pasta dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) Dusty plasma and Yukawa-system simulation Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) One-component plasma simulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) domain Chemistry and materials 16 Reaction dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Machine-learned interatomic potentials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Ab initio molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Path-integral molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Liquids and solutions Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#liquids-solutions) Polymers and soft matter Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Colloids and nanoparticle assembly Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Glass formation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#glass-formation) Molten salts and ionic liquids Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ionic-liquids-electrolytes) Reactive force-field dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reactive-force-field-dynamics) Metadynamics and enhanced sampling Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Learned equilibrium samplers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Coarse-grained molecular dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Enhanced-sampling free-energy methods Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Fracture and defects Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fracture) Radiation-damage cascades in materials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) domain Life and medicine 8 Protein folding and dynamics Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#protein-dynamics) Molecular docking and drug binding Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) Membranes and ion channels Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#membranes) Whole virus particles Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virus-particles) Enzyme catalysis Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) Coarse-grained DNA and RNA models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coarse-grained-nucleic-acids) Volunteer-computed molecular dynamics Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#volunteer-computing-molecular-dynamics) Vaccine antigen design Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) method Monte Carlo 128 Repeated sampling: run the process many times with random choices and estimate the quantity of interest from the statistics. domain Fundamental physics 22 Lattice QCD Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Collider event generation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collider-events) Detector response Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#detector-response) Cosmic-ray air showers Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#air-showers) Neutrino detector simulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neutrino-detectors) Flow-based sampling for lattice field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Nuclear structure Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Reactor core physics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Radiation transport Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#radiation-transport) Nuclear criticality safety Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#criticality-safety) Radioactivation and decay chains Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Fusion breeding blanket neutronics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-blanket) Nuclear lattice effective field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Dusty plasma and Yukawa-system simulation Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) One-component plasma simulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) Quantum many-body systems Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Quantum error correction Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Topological quantum matter Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Neural-network quantum states Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) Path-integral Monte Carlo of quantum fluids Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) Stabilizer circuit simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Learned error-correction decoders Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) domain Astronomy and cosmology 8 Cosmic microwave background Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Synthetic sky survey catalogues and images Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Core-collapse supernovae Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Binary population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Exoplanet detection and characterisation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) Exoplanet atmosphere retrieval Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) Kilonova radiative transfer Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) Neural inference for gravitational waves Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) domain Earth and climate 4 Numerical weather prediction Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Seasonal forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Stochastic earthquake-catalogue models Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) domain Chemistry and materials 18 Path-integral molecular dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Quantum Monte Carlo for electrons Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Neural-network wavefunctions for molecules Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Polymers and soft matter Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Colloids and nanoparticle assembly Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Metadynamics and enhanced sampling Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Kinetic Monte Carlo Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Enhanced-sampling free-energy methods Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Adsorption in porous materials Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#grand-canonical-adsorption) Chain-growth Monte Carlo for polymers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chain-growth-monte-carlo) Magnetism and phase transitions Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) Microstructure Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Thin film growth Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#thin-film-growth) Alloy cluster expansion Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Organic semiconductor charge transport Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Diffusion-limited aggregation Rules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) Corrosion Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Crystallisation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) domain Life and medicine 11 Molecular docking and drug binding Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) RNA folding and structure Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) In silico clinical trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Radiotherapy dose calculation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Virtual anatomical phantoms for imaging Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Disease burden and health economic modelling Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Environmental and chemical exposure risk assessment Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Virtual imaging trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Predictive toxicology Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) Clinical trial design simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#trial-design-simulation) Vaccine antigen design Atoms [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) domain Ecology, evolution and animal behaviour 9 Fisheries and wildlife management Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Species ranges Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) Fisheries management strategy evaluation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Near-term ecological forecasting Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Neutral community models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Population genetics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Speciation and macroevolution models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Population viability analysis Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Reserve and corridor design Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) domain Agriculture and food 1 Quantitative microbial risk assessment Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) domain Human behaviour and society 13 Choice under risk and uncertainty modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Synthetic population generation Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) Collective estimation and crowd wisdom Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) Macroeconomic models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Financial risk Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#risk) Insurance catastrophe models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Kinetic wealth exchange models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) Demographic microsimulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#demographic-microsimulation) Tax and benefit microsimulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) Exploratory modelling under deep uncertainty Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Electoral and voting system simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Court and case-flow simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Sentencing and recidivism risk modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) domain Engineering and technology 3 Rarefied-gas direct simulation Molecules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) Mega-constellation collision risk Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) Conjunction collision probability Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) domain Cities, infrastructure and operations 6 Transport and land use Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Last-mile delivery routing Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Project schedule risk simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Mobile network planning Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Internet backbone and cable resilience Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Telecom traffic engineering Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) domain Mathematics and computation 17 Random matrix experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-matrix-experiments) Random graph experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Percolation simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Experimental mathematics searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Monte Carlo estimation of constants Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) Computational number theory searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Automated theorem proving search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) SAT and constraint solving Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Cryptographic attack modelling Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Side-channel leakage simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Statistical model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Fuzz testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Property-based random testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Compiler and program optimisation search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Empirical algorithm performance testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) Simulated annealing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Approximate Bayesian computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) domain Before computers 1 Buffon's needle Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) domain Defence and conflict 8 Historical war games Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Combat and campaign models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Models of civil conflict Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Search and rescue drift planning Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) Anti-submarine search theory Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Nuclear stockpile simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) Radar and sensor performance Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Landmine and unexploded ordnance clearance planning Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) domain Film, media and art 1 Physically based light transport Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) domain Video games 6 Dating simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Hex-and-counter war games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Tactics Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Role-playing games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Roguelikes Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Sports management Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) method Particles and N-body 67 Track many discrete bodies and the forces between them: stars, dark-matter clumps, grains of sand, plasma charges. domain Fundamental physics 8 Accelerator beam dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Neutron-star crust pasta dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) Fusion plasma turbulence Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Particle-in-cell plasma Bodies [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) Magnetic reconnection Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Industrial plasma processing Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Laser wakefield acceleration Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Collisionless shock simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) domain Astronomy and cosmology 22 Cosmological N-body Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-n-body) Galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Cosmic reionization Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Intergalactic medium and the Lyman-alpha forest Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Constrained simulations of the local universe Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Cosmological emulators Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Self-interacting dark matter simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#self-interacting-dark-matter) Massive-neutrino cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Weak-lensing ray tracing through simulated universes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Differentiable cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Galaxy collision and merger simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) Star formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Common-envelope evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Planet formation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Orbital dynamics Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Impact cratering Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Giant-impact simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Planetesimal formation by streaming instability Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Space weather Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Pulsar magnetospheres Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Tidal disruption of stars by black holes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) domain Earth and climate 3 Air quality and dispersion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Marine debris and Lagrangian drift modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Landslides and debris flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) domain Chemistry and materials 5 Coarse-grained molecular dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Dissipative particle dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Granular materials Bodies [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#granular) Dislocation dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Radiation-damage cascades in materials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) domain Life and medicine 2 Radiotherapy dose calculation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Indoor airborne transmission simulation Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) domain Ecology, evolution and animal behaviour 2 Locust marching bands Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) Marine larval dispersal and connectivity Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) domain Human behaviour and society 1 Kinetic wealth exchange models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) domain Engineering and technology 6 Graph-network learned simulators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Lattice-gas automata for fluid flow Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) Rarefied-gas direct simulation Molecules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) Peridynamic fracture modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Orbital-debris and satellite-collision modelling Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Mega-constellation collision risk Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) domain Mathematics and computation 1 Nonlinear lattice experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) domain Minds as simulators 1 The intuitive physics engine Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) domain Defence and conflict 3 Swarm combat simulation Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Search and rescue drift planning Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) Chemical, biological and radiological hazard plumes Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) domain Film, media and art 8 Fluid and smoke simulation for effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Destruction and debris simulation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Rigid body dynamics for animation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Position-based dynamics Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Particle system effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Snow and granular material simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) Physically based light transport Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) Sound propagation and acoustics Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) domain Video games 5 Soft-body vehicle crash simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Physics sandboxes and building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Tactical military simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Extreme and action sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Physics puzzles Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) method Continuum fields 221 Treat matter as a continuous fluid or solid, express it as partial differential equations, and solve them on a mesh (finite element, finite volume, spectral). domain Fundamental physics 13 Reactor core physics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Time-dependent nuclear mean-field dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Fusion plasma turbulence Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Particle-in-cell plasma Bodies [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) Plasma equilibrium and stability Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Inertial confinement implosion Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#inertial-confinement-fusion) Magnetic reconnection Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Industrial plasma processing Molecules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Stellarator configuration optimisation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Tokamak edge pedestal and ELM modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Tokamak whole-device modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Collisionless shock simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) Superconducting vortex dynamics Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) domain Astronomy and cosmology 37 Galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Cosmic reionization Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Intergalactic medium and the Lyman-alpha forest Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Wave dark matter simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Constrained simulations of the local universe Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Massive-neutrino cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Cosmic string network evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Galactic cosmic-ray propagation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Core-collapse supernovae Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Star formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Stellar atmospheres and spectra Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Supernova neutrino flavour evolution Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) Stellar surface convection simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Common-envelope evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Collapsar and gamma-ray burst jets Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Interstellar magnetised turbulence Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) Planet formation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Planetary and exoplanet atmospheres Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-atmospheres) Planetary interiors and dynamos Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-interiors) Impact cratering Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Giant-impact simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Habitable-zone climate modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Planetesimal formation by streaming instability Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Planet-disk interaction and migration Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) Black hole mergers Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#numerical-relativity) Accretion discs and jets Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#accretion) Space weather Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Neutron star mergers Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#neutron-star-mergers) Pulsar magnetospheres Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Solar interior and dynamo Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#solar-dynamo) Gravitational-wave template banks from numerical relativity Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Magnetar magnetosphere and flare simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Black-hole shadow and image rendering Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Tidal disruption of stars by black holes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) Kilonova radiative transfer Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) Radiation belt modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) domain Earth and climate 48 Earth system models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system) Palaeoclimate Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Ice sheets and sea level Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ice-sheets) Regional climate downscaling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#regional-climate-downscaling) Solar geoengineering Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geoengineering-modelling) Global cloud-resolving models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Superparameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Radiative-convective climate model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Coupled carbon-cycle and climate simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Learned subgrid parameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) Numerical weather prediction Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Tropical cyclones Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tropical-cyclones) Air quality and dispersion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Seasonal forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Severe convective storms Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#severe-storms) Ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Atmospheric reanalysis Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Atmospheric boundary-layer large-eddy simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Global storm-resolving simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Mineral dust emission and transport Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Urban surface energy-balance modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Thermosphere and ionosphere modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) Ocean circulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-circulation) Tsunamis and storm surge Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tsunami-surge) Rivers and floods Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) Groundwater Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#groundwater) Sea ice Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#sea-ice-dynamics) Ocean wave forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-wave-forecasting) Flood inundation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Coastal and estuarine circulation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Marine debris and Lagrangian drift modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Petroleum and gas reservoir simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Glacial isostatic adjustment and sea-level fingerprints Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Geological carbon-dioxide storage simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Reactive transport in the subsurface Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) Mantle convection and plate tectonics Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mantle-convection) Earthquakes and seismic waves Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquakes) Volcanic eruptions and lava flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landscape evolution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Wildfire spread Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) Landslides and debris flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) Physics-based seismic hazard Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Geodynamo simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Full-waveform seismic inversion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Spectral-element seismic wave propagation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Earthquake-cycle simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Land-surface model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Coupled fire and atmosphere models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) domain Chemistry and materials 12 Real-time electron dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Combustion Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#combustion) Polymer self-consistent field theory Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Microstructure Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Dislocation dynamics Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Crystal plasticity finite-element modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Micromagnetic simulation Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Battery and electrochemical cell modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Corrosion Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Crystallisation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) Chemical reactor engineering Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chemical-reactor-engineering) Fuel-cell membrane and transport modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) domain Life and medicine 21 Pattern formation Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Tumour growth and therapy response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Tumour-induced blood vessel growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Bacterial colony growth and biofilms Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) The heart Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Blood flow Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#blood-flow) Breathing and airways Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#lungs) Cardiac digital twins Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Brain-stimulation field models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Surgical planning with patient-specific models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Heart valve fluid-structure interaction Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Bone adaptation and implant remodelling Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Magnetic resonance image simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Fracture healing simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Coronary flow reserve from scans Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Cochlear mechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Bioheat transfer and hyperthermia Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Kidney nephron transport models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Vocal fold and voice production models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Indoor airborne transmission simulation Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) Drug formulation and delivery modelling Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) domain Ecology, evolution and animal behaviour 7 Termite mound building Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Bacterial swarming and quorum sensing Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) Animal locomotion Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) Marine larval dispersal and connectivity Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Pollination service across landscapes Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) Wind seed and pollen dispersal models Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) Size-spectrum ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) domain Agriculture and food 6 Soil water and nutrient transport Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Soil erosion and land degradation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Agricultural catchment pollution models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Agrivoltaic light-sharing models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Baking and thermal food processing Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) Digestion and gastric flow simulation Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) domain Human behaviour and society 1 Pedestrian and crowd dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) domain Engineering and technology 37 Aerodynamics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#aerodynamics) Turbulence Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#turbulence) Cavitation simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#cavitation) Multiphase and pipeline flow Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multiphase-flow) Ice accretion simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#icing) Learned fluid solvers Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Lattice Boltzmann flow simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) Wind-farm large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Fluid-structure interaction Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Fire dynamics large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) Structural analysis Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#structural-analysis) Crash simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#crash) Acoustics and vibration Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#acoustics) Fatigue and crack growth Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#durability-fatigue) Tribology and contact mechanics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tribology-contact) Topology optimisation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Peridynamic fracture modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Electromagnetics Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#electromagnetics) Semiconductor device simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Optical lithography simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Semiconductor process simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) Processor thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Photonic-crystal band-structure calculation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Stacked chip thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) Digital twins Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) Planetary rover mobility Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Soft robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Atmospheric entry Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#reentry) Batteries and fuel cells Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) Rocket engine simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rocket-propulsion) Solar and wind farm yield simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Metal casting and solidification Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-casting) Welding simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#welding-simulation) Additive manufacturing simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#additive-manufacturing) Metal forming and stamping Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-forming) Machining simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#machining-simulation) Injection moulding simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#injection-moulding) domain Cities, infrastructure and operations 7 Traffic flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Water and drainage networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Building energy and daylight Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) District heating and cooling networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Gas pipeline network transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Mobile network planning Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Data centre facility simulation Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) domain Minds, brains and artificial worlds 2 Neural mass and field models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Continuous artificial life Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) domain Mathematics and computation 1 Soliton numerical experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) domain Training simulators 5 Surgical simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) Dental simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) Catheter and endovascular simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Robotic surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) domain Before computers 2 Hele-Shaw cell Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) Soap film minimal-surface models Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) domain Defence and conflict 8 Nuclear stockpile simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) Ballistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Blast and impact protection Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#blast-protection) Radar and sensor performance Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Directed energy weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Torpedo and underwater weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) Chemical, biological and radiological hazard plumes Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) Climate effects of nuclear war Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#nuclear-winter) domain Film, media and art 12 Cloth simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Hair and fur simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Fluid and smoke simulation for effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Muscle and skin deformation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Ocean surface synthesis Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Snow and granular material simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) Digital humans and faces Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Virtual production sets Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Atmospheric and sky simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Digital de-ageing Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Sound propagation and acoustics Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) Physical modelling synthesis of instruments Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) domain Video games 2 Flight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Flight simulation over streamed Earth Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) method Differential equations 269 A small number of time-dependent quantities, written as coupled equations and integrated forward (compartment models, circuits, orbits). domain Fundamental physics 10 Accelerator beam dynamics Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Radioactivation and decay chains Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Plasma equilibrium and stability Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Laser wakefield acceleration Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Stellarator configuration optimisation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Tokamak edge pedestal and ELM modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Tokamak whole-device modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Learned plasma control in simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) Ultracold atomic gas dynamics Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#cold-atom-bec) Superconducting vortex dynamics Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) domain Astronomy and cosmology 32 Big Bang nucleosynthesis Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#nucleosynthesis) Cosmic microwave background Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Wave dark matter simulations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Stellar population synthesis Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Galactic chemical evolution Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Semi-analytic galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Weak-lensing ray tracing through simulated universes Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Cosmic string network evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Early-universe lattice field dynamics Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) Galactic cosmic-ray propagation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Differentiable cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Galaxy collision and merger simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) Stellar evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-evolution) Stellar oscillations Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-interiors-seismology) Binary star evolution Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-star-evolution) Stellar atmospheres and spectra Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Supernova neutrino flavour evolution Subatomic [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) Stellar surface convection simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Collapsar and gamma-ray burst jets Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Astrochemical reaction networks Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) Interstellar magnetised turbulence Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) Orbital dynamics Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Exoplanet detection and characterisation Bodies [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) Planet population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Exoplanet atmosphere retrieval Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) Habitable-zone climate modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Planet-disk interaction and migration Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) Gravitational-wave template banks from numerical relativity Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Gravitational-wave mock data challenges Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) Magnetar magnetosphere and flare simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Black-hole shadow and image rendering Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Radiation belt modelling Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) domain Earth and climate 33 Palaeoclimate Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Integrated assessment models Populations [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) World-Earth models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Global cloud-resolving models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Superparameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Extreme-event attribution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Volunteer-computed perturbed-physics ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Initial-condition large ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Earth-system digital twins Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Radiative-convective climate model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Energy-balance climate model Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Dynamic global vegetation and carbon-cycle modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Coupled carbon-cycle and climate simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Ocean ecosystem and biogeochemistry modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Atmospheric reanalysis Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Atmospheric boundary-layer large-eddy simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Global storm-resolving simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Mineral dust emission and transport Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Urban surface energy-balance modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Thermosphere and ionosphere modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) Flood inundation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Coastal and estuarine circulation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Petroleum and gas reservoir simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Glacial isostatic adjustment and sea-level fingerprints Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Geological carbon-dioxide storage simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Reactive transport in the subsurface Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) Physics-based seismic hazard Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Geodynamo simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Full-waveform seismic inversion Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Spectral-element seismic wave propagation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Earthquake-cycle simulation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Land-surface model Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Coupled fire and atmosphere models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) domain Chemistry and materials 11 Quantum wavepacket dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Transition-state and reaction-path search Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Automated reaction-mechanism generation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) Polymer self-consistent field theory Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Crystal plasticity finite-element modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Micromagnetic simulation Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Lattice thermal-conductivity calculation Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Battery and electrochemical cell modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Polymerisation kinetics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) Fuel-cell membrane and transport modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) Pore-network modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) domain Life and medicine 40 RNA folding and structure Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) Gene regulatory networks Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Whole-cell models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Tumour growth and therapy response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Cancer drug response and resistance dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Blood cell production dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#haematopoiesis-dynamics) The heart Fields [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Musculoskeletal biomechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#biomechanics) Immune response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Pharmacokinetics Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacokinetics) In silico clinical trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Cardiac digital twins Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Brain-stimulation field models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Gut microbiome community models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Surgical planning with patient-specific models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Heart valve fluid-structure interaction Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Bone adaptation and implant remodelling Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Musculoskeletal models for surgery Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#musculoskeletal-surgery-models) Virtual anatomical phantoms for imaging Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Magnetic resonance image simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Fracture healing simulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Within-host virus dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#within-host-viral-dynamics) Coronary flow reserve from scans Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Cochlear mechanics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Whole-body integrative physiology Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Bioheat transfer and hyperthermia Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Kidney nephron transport models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Vocal fold and voice production models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Circadian clock models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) Compartment epidemic models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#compartment-epidemics) Disease burden and health economic modelling Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Environmental and chemical exposure risk assessment Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Antimicrobial resistance spread Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Tobacco-control policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Vaccine allocation optimisation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-allocation-optimisation) Virtual imaging trials Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Mosquito population dynamics Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Pharmacodynamic modelling Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacodynamics) Drug formulation and delivery modelling Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) Closed-loop diabetes control in silico Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) domain Ecology, evolution and animal behaviour 17 Honeybee colonies Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Animal locomotion Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) Birdsong and vocal learning models Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) Dynamic energy budget modelling Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#dynamic-energy-budget) Predator–prey dynamics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) Food webs Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Fisheries and wildlife management Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Metapopulation dynamics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Coral reef resilience models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Fisheries management strategy evaluation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Trophic mass-balance ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Plankton ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Lake eutrophication models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Size-spectrum ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) Adaptive dynamics of coevolution Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Gene drive population models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Rewilding and trophic cascade modelling Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) domain Agriculture and food 22 Crop growth and yield models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Soil water and nutrient transport Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Irrigation scheduling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Soil erosion and land degradation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Precision agriculture optimisation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Soil organic carbon turnover Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Agricultural catchment pollution models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Global gridded crop model ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Pesticide resistance management models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Agrivoltaic light-sharing models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Degree-day pest phenology models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Sterile insect release models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Greenhouse climate models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) Livestock herd and feed models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Grazing and pasture management Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Aquaculture and fish farming Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Aquaculture pond bioenergetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) Fermentation process modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Baking and thermal food processing Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) Cold chain and spoilage modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Predictive food microbiology Cells [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) Digestion and gastric flow simulation Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) domain Human behaviour and society 13 Models of learning Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Emotion and affect modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Choice under risk and uncertainty modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Human mobility and migration models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Macroeconomic models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Dynamic stochastic general equilibrium models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Financial contagion in interbank networks Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Disaster economic ripple models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Coupled epidemic and economy models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#epidemic-economy-coupled) Monument construction and engineering reconstruction Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) Computable general equilibrium modelling Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#computable-general-equilibrium) Exploratory modelling under deep uncertainty Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Crime hotspot dynamics Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) domain Engineering and technology 25 Physics-informed neural networks Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Neural operators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Wind-farm large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Fluid-structure interaction Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Fire dynamics large-eddy simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) Multibody dynamics Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multibody) Topology optimisation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Co-simulation of linked models Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Circuit simulation Populations [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#circuit-simulation) Optical lithography simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Semiconductor process simulation Atoms [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) Processor thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Photonic-crystal band-structure calculation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Stacked chip thermal modelling Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) Exoskeleton and prosthetic control Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) Differentiable physics simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Learned legged locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned humanoid locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Drone flight simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Learned drone racing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Soft robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Tactile sensor simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) Spacecraft trajectories Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#trajectory-design) Spacecraft thermal and power simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#spacecraft-thermal) Conjunction collision probability Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) domain Cities, infrastructure and operations 7 Power grids Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Building energy and daylight Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) Power-system electromagnetic transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Energy-system capacity-planning models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) Smart-grid co-simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Gas pipeline network transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Satellite broadband constellation simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) domain Minds, brains and artificial worlds 12 Detailed neuron models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#detailed-neurons) Large-scale brain circuits Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Whole-brain network models Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Simulated small organisms Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Neuromorphic hardware simulation Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Brain disease and seizure spread Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Connectome-constrained whole-brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Neural mass and field models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Functional spiking brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Attractor memory networks Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Connectome-based insect brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) Evolutionary robotics Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) domain Mathematics and computation 10 Chaotic-attractor numerics Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#chaotic-attractor-numerics) Nonlinear lattice experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) Soliton numerical experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) Fractal-set rendering Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fractal-set-rendering) Riemann zeta zero computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Digits of pi by computer Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) Side-channel leakage simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Computer-assisted proof by exhaustive case checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Validated numerics Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#validated-numerics) Turing-machine enumeration Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) domain Minds as simulators 1 Motor forward models Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-forward-models) domain Training simulators 5 Diving and submersible simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) Patient simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Childbirth simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) Anaesthesia simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Control-room simulators Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) domain Before computers 2 Hanging-chain arch model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Iron wire nerve model Cells [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) domain Defence and conflict 11 Combat and campaign models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Deterrence and arms races Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) Computer virus and malware epidemics Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Naval salvo exchange models Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#naval-salvo-models) Anti-submarine search theory Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Combat medic trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) Ballistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Directed energy weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Torpedo and underwater weapon simulation Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) War economic and reconstruction modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Biological attack response models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) domain Film, media and art 11 Cloth simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Hair and fur simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Destruction and debris simulation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Muscle and skin deformation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Rigid body dynamics for animation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Ocean surface synthesis Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Digital humans and faces Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Physics-based character control Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) Physical modelling synthesis of instruments Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) Physically based sound effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Neural scene rendering Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) domain Video games 7 Spaceflight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) Racing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Naval and submarine simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) Flight simulation over streamed Earth Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Soft-body vehicle crash simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Golf simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Racket and ball sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) method Stochastic processes 123 Events that occur at random with known rates, one reaction or one birth at a time (Gillespie, Markov chains, random walks). domain Fundamental physics 2 Stabilizer circuit simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Quantum network simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) domain Astronomy and cosmology 4 Synthetic sky survey catalogues and images Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Binary population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Planet population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Gravitational-wave mock data challenges Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) domain Earth and climate 5 Extreme-event attribution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Volunteer-computed perturbed-physics ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Initial-condition large ensembles Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Generative ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) Stochastic earthquake-catalogue models Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) domain Chemistry and materials 5 Kinetic Monte Carlo Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Dissipative particle dynamics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Organic semiconductor charge transport Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Diffusion-limited aggregation Rules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) Polymerisation kinetics Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) domain Life and medicine 22 Stochastic biochemistry Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#stochastic-biochemistry) Whole-cell models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Tumour-induced blood vessel growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Cancer drug response and resistance dynamics Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Virtual-population drug exposure models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Gut microbiome community models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Circadian clock models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) Pathogen evolution Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) Outbreak genomic epidemiology Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Mobility-network epidemic models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Individual-based malaria models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Scenario modelling hubs Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Digital contact-tracing models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Antimicrobial resistance spread Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Malaria transmission and intervention models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Epidemics on contact networks Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Mosquito population dynamics Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Cancer screening microsimulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Organ allocation policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Ambulance and fire station deployment models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) Synthetic patient record generation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) Closed-loop diabetes control in silico Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) domain Ecology, evolution and animal behaviour 19 Movement and foraging Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) General ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Metapopulation dynamics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Individual-based ecological models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Fisheries management strategy evaluation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Marine larval dispersal and connectivity Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Honeybee colony and landscape models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Wind seed and pollen dispersal models Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) Near-term ecological forecasting Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Neutral community models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Population genetics Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Coalescent and phylogenetic simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coalescent) Origin of life Molecules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) Speciation and macroevolution models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Adaptive dynamics of coevolution Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Gene drive population models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Forward-time genome simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Population viability analysis Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Reintroduction and translocation planning Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) domain Agriculture and food 14 Pest and plant disease spread Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Crop breeding simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Multi-model crop ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Plant architecture growth models Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Sterile insect release models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Livestock disease outbreak models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Livestock breeding and genetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) Precision livestock monitoring Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Famine early warning models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) Fermentation process modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Cold chain and spoilage modelling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Food safety and traceability simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) Predictive food microbiology Cells [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) Quantitative microbial risk assessment Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) domain Human behaviour and society 14 Models of decision-making Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#decision-models) Models of learning Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Recommender feedback-loop simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Human mobility and migration models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Synthetic population generation Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) Collective action and tipping-point models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Collective estimation and crowd wisdom Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) Mass gathering disease risk modelling Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) Financial markets Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Dynamic stochastic general equilibrium models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Insurance catastrophe models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Flash-crash market models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Policing and patrol deployment simulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) Jury decision-making simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) domain Engineering and technology 5 Orbital-debris and satellite-collision modelling Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Domain-randomised sim-to-real training Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Adversarial driving-scenario generation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) Solar and wind farm yield simulation Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Mega-constellation collision risk Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) domain Cities, infrastructure and operations 9 Airport airside simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Elevator traffic simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Airspace fast-time simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Project schedule risk simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Container terminal simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Construction process simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) Cascading-blackout models Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Telecom traffic engineering Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) Internet worm propagation models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) domain Minds, brains and artificial worlds 3 Self-replicating program soups Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Artificial chemistry Molecules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Recommender-system simulators Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) domain Mathematics and computation 7 Sandpile self-organised criticality Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) Statistical model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Fuzz testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Storage systems simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Empirical algorithm performance testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) Simulated annealing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Approximate Bayesian computation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) domain Minds as simulators 1 The intuitive physics engine Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) domain Before computers 2 Galton board Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Buffon's needle Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) domain Defence and conflict 3 Anti-submarine search theory Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Chemical, biological and radiological hazard plumes Fields [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) Biological attack response models Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) domain Film, media and art 6 Ocean surface synthesis Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Particle system effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Procedural cities and landscapes Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Generative art systems Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) Procedural and generative music Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Procedural texture and material generation Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) domain Video games 2 Auto-battlers Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Fishing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) method Agent-based 159 Each individual has its own rules and state; the individuals interact, and collective behaviour emerges that no individual intends. domain Earth and climate 1 World-Earth models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) domain Life and medicine 14 Pattern formation Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Tissue and tumour growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Tumour evolution agent-based models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Tumour microenvironment evolution Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Tumour-induced blood vessel growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Bacterial colony growth and biofilms Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) Immune response Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Agent-based epidemics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Individual-based malaria models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Scenario modelling hubs Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Malaria transmission and intervention models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Cancer screening microsimulation Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Obesity and diet agent-based models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) Synthetic patient record generation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) domain Ecology, evolution and animal behaviour 24 Ant colony foraging Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) Honeybee colonies Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Flocking and schooling Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) Termite mound building Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Slime mould aggregation Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Bacterial swarming and quorum sensing Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) Locust marching bands Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) Movement and foraging Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) Migration and navigation Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#migration) Forest dynamics Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forest-dynamics) Wildlife disease Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) General ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Individual-based ecological models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Coral reef resilience models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Honeybee colony and landscape models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Neutral community models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Host-parasite coevolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Sexual selection and mate choice evolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Gene drive population models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Forward-time genome simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Animal contest strategies Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) Reintroduction and translocation planning Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) Invasive species spread Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) Rewilding and trophic cascade modelling Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) domain Agriculture and food 5 Precision agriculture optimisation Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Farm agent-based models of land use and adoption Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#farm-agent-based-adoption) Land-use change agent models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) Precision livestock monitoring Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Aquaculture pond bioenergetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) domain Human behaviour and society 42 Social cognition and theory-of-mind models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Residential sorting Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) Opinion dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Cooperation and norms Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Diffusion of ideas Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Language evolution Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#language-evolution) Cultural evolution Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Language-model agent societies Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) Populated social-system prototypes Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Language-model social platform simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Recommender feedback-loop simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Language-model user simulation for recommenders Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) Misinformation and rumour spread Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Migration under climate stress Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#climate-migration-abm) Pedestrian and crowd dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) Crowd emotion and behavioural contagion Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Collective action and tipping-point models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Protest mobilisation network models Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Mass gathering disease risk modelling Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) Agent-based economies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#agent-economies) Financial markets Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Market and auction design Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) Artificial societies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#artificial-societies) AI-designed economic policy simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Agent-based exchange simulators Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Housing market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#housing-market-abm) Electricity market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Flash-crash market models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Algorithmic pricing collusion Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Language-model macroeconomic agents Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) Reconstructed ancient societies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#archaeological-abm) Human dispersal Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) Hunter-gatherer economies Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#hunter-gatherers) Ancient trade and exchange Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Monument construction and engineering reconstruction Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) Organisations and teams Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#organisations) Institutional corruption and integrity modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Policy diffusion network models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) Language-model agent organisations Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Legislative bargaining and coalition simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) Jury decision-making simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) Crime hotspot dynamics Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) domain Engineering and technology 2 Autonomous vehicle testing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) Swarm robotics Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#swarm-robotics) domain Cities, infrastructure and operations 19 Traffic flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Transport and land use Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Evacuation and emergency response Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#evacuation) Public transit network simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Ride-hailing and dispatch simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Aircraft boarding simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Airport airside simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Elevator traffic simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Shared autonomous vehicle fleets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Airspace fast-time simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Hospital patient flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Warehouse and distribution centre simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Warehouse robot fleet coordination Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Supply chain digital twins Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Container terminal simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Infrastructure interdependence Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Agent-based electricity markets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) Smart-grid co-simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Vehicular network simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) domain Minds, brains and artificial worlds 7 Swarm intelligence algorithms Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Artificial chemistry Molecules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Artificial immune models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) Multi-agent AI societies Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) AI safety red-teaming environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Recommender-system simulators Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) Simulated robot soccer Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) domain Mathematics and computation 1 Blockchain consensus simulation Populations [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) domain Minds as simulators 1 Sociodramatic play Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) domain Training simulators 3 Paramedic and mass-casualty triage training Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Agent hospitals Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Mass-casualty exercises Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) domain Defence and conflict 9 Agent-based combat models Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#agent-combat) Models of civil conflict Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Language-model wargame agents Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) Swarm combat simulation Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Military flight and mission simulators Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Networked training exercises Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Autonomous cyber-defence gyms Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) Displacement and refugee flows Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Casualty and humanitarian response Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) domain Film, media and art 3 Digital crowd simulation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-crowds) Digital ecosystems and vegetation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Virtual concerts Populations [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) domain Video games 28 Open-city driving Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Life simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Farming and village life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Social hangout worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) City building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Colony simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) Management and tycoon Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) God games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) Ecosystem and evolution games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) Social deduction games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Grand strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) Real-time strategy Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Auto-battlers Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Space exploration and trading Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) Terrarium and habitat sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Agent-based game playtesting Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) User-generated game platforms Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Massively multiplayer worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) Immersive simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Open-world adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Alternate reality games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) Stealth Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Battle royale Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Extraction shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Sports management Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) Hunting simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Virtual reality social worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) method Cellular automata 33 A grid of cells, each updating from its neighbours by a simple local rule. domain Earth and climate 4 Flood inundation modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Volcanic eruptions and lava flows Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landscape evolution Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Wildfire spread Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) domain Life and medicine 3 Tissue and tumour growth Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Tumour evolution agent-based models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Tumour microenvironment evolution Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) domain Ecology, evolution and animal behaviour 4 Slime mould aggregation Cells [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Species ranges Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) Spatial host-parasitoid and pest lattices Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) Invasive species spread Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) domain Agriculture and food 1 Land-use change agent models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) domain Human behaviour and society 2 Residential sorting Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) Human dispersal Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) domain Engineering and technology 1 Lattice-gas automata for fluid flow Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) domain Cities, infrastructure and operations 2 Traffic flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Urban growth Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#urban-growth) domain Minds, brains and artificial worlds 6 Cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) Self-organised criticality Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) Random Boolean networks Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Continuous cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-cellular-automata) Neural cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Continuous artificial life Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) domain Mathematics and computation 2 Percolation simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Sandpile self-organised criticality Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) domain Film, media and art 1 L-system plant modelling Cells [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) domain Video games 7 City building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Station systems simulation Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Block and voxel sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Falling-sand games Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) Level and world creation tools Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) Terrarium and habitat sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Match-three and tile-swap puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) method System dynamics 49 Stocks, flows and feedback loops: the quantity held in each stock and the rate at which it flows into the next. domain Astronomy and cosmology 2 Galactic chemical evolution Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Astrochemical reaction networks Molecules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) domain Earth and climate 6 Integrated assessment models Populations [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) World-Earth models Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Energy-balance climate model Rules [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Dynamic global vegetation and carbon-cycle modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Ocean ecosystem and biogeochemistry modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Rivers and floods Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) domain Life and medicine 7 Microbial community metabolic models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Virtual-population drug exposure models Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Whole-body integrative physiology Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Scenario modelling hubs Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Antimicrobial resistance spread Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Tobacco-control policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Obesity and diet agent-based models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) domain Ecology, evolution and animal behaviour 6 Trophic mass-balance ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Plankton ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Lake eutrophication models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Honeybee colony and landscape models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Near-term ecological forecasting Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Size-spectrum ecosystem models Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) domain Agriculture and food 12 Crop growth and yield models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Irrigation scheduling Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Multi-model crop ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Soil organic carbon turnover Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Global gridded crop model ensembles Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Sterile insect release models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Greenhouse climate models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) Livestock herd and feed models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Grazing and pasture management Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Aquaculture and fish farming Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Aquaculture pond bioenergetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) Famine early warning models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) domain Human behaviour and society 3 World models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#world-models) Opioid epidemic system dynamics Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opioid-system-dynamics) Supply-chain dynamics and the bullwhip effect Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) domain Engineering and technology 1 Orbital-debris and satellite-collision modelling Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) domain Cities, infrastructure and operations 3 Supply chains Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Supply chain digital twins Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Energy-system capacity-planning models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) domain Training simulators 1 Business simulations Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) domain Defence and conflict 3 Military logistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) War economic and reconstruction modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Sanctions and economic warfare modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) domain Video games 5 Parenting and family life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) City building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Management and tycoon Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) Idle and incremental Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#idle-games) Grand strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) method Discrete event 56 Advance from one event to the next (an arrival, a breakdown, a packet), skipping the intervals in which nothing happens. domain Fundamental physics 1 Quantum network simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) domain Life and medicine 2 Organ allocation policy simulation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Ambulance and fire station deployment models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) domain Agriculture and food 1 Food supply chain simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) domain Human behaviour and society 5 Agent-based exchange simulators Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Flash-crash market models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Supply-chain dynamics and the bullwhip effect Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) Court and case-flow simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Policing and patrol deployment simulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) domain Engineering and technology 5 Co-simulation of linked models Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Chip logic simulation Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Computer network simulation Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-simulation) Network digital twins Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) Digital twins Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) domain Cities, infrastructure and operations 23 Public transit network simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Ride-hailing and dispatch simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Aircraft boarding simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Airport airside simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Elevator traffic simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Shared autonomous vehicle fleets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Airspace fast-time simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Supply chains Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Manufacturing lines Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#manufacturing) Queues and service systems Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#service-queues) Hospital patient flow Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Warehouse and distribution centre simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Last-mile delivery routing Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Warehouse robot fleet coordination Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Supply chain digital twins Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Container terminal simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Construction process simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) Waste collection and treatment simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) Power-system electromagnetic transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Smart-grid co-simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Data centre facility simulation Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) Smart-city sensor network simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Vehicular network simulation Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) domain Minds, brains and artificial worlds 1 Core War battles Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) domain Mathematics and computation 10 Computer architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Distributed systems and consensus simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Storage systems simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Operating system scheduler simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#os-scheduler-simulation) Blockchain consensus simulation Populations [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) Parallel discrete-event simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#parallel-discrete-event-simulation) Graphics processor architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) FPGA-accelerated system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Full-system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Lightweight network emulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) domain Training simulators 1 Air traffic control simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) domain Defence and conflict 4 Military logistics Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) Cyber ranges Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) Casualty and humanitarian response Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) Landmine and unexploded ordnance clearance planning Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) domain Video games 3 Automation and factory building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Programming battle games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Cloud-streamed games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) method Network models 66 Nodes and links: the connectivity of the system, and what spreads or flows along the connections. domain Fundamental physics 1 Quantum network simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) domain Chemistry and materials 1 Pore-network modelling Fields [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) domain Life and medicine 10 Gene regulatory networks Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Metabolic networks Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#metabolism) Microbial community metabolic models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Gut microbiome community models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Agent-based epidemics Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Outbreak genomic epidemiology Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Mobility-network epidemic models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Digital contact-tracing models Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Epidemics on contact networks Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Drug repurposing network models Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-repurposing-networks) domain Ecology, evolution and animal behaviour 4 Food webs Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Wildlife disease Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) Origin of life Molecules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) Reserve and corridor design Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) domain Agriculture and food 4 Pest and plant disease spread Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Livestock disease outbreak models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Food supply chain simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) Food safety and traceability simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) domain Human behaviour and society 11 Opinion dynamics Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Diffusion of ideas Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Social network formation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#network-formation) Language-model social platform simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Misinformation and rumour spread Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Crowd emotion and behavioural contagion Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Protest mobilisation network models Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Financial contagion in interbank networks Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Disaster economic ripple models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Ancient trade and exchange Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Policy diffusion network models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) domain Cities, infrastructure and operations 14 Project schedule risk simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Warehouse robot fleet coordination Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Supply chain digital twins Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Power grids Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Water and drainage networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Infrastructure interdependence Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Waste collection and treatment simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) District heating and cooling networks Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Cascading-blackout models Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Gas pipeline network transients Fields [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Internet backbone and cable resilience Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Satellite broadband constellation simulation Bodies [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) Smart-city sensor network simulation Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Internet worm propagation models Rules [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) domain Minds, brains and artificial worlds 9 Large-scale brain circuits Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Whole-brain network models Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Brain disease and seizure spread Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Connectome-constrained whole-brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Functional spiking brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Attractor memory networks Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Connectome-based insect brain models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) Random Boolean networks Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Artificial immune models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) domain Mathematics and computation 5 Random graph experiments Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Security protocol verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Distributed systems and consensus simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Blockchain consensus simulation Populations [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) Lightweight network emulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) domain Minds as simulators 3 Hippocampal replay in rats Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-replay) Hippocampal preplay Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-preplay) Mirror systems Cells [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mirror-systems) domain Defence and conflict 3 Computer virus and malware epidemics Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Displacement and refugee flows Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Sanctions and economic warfare modelling Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) domain Video games 1 Hacking simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) method Game theory 24 Players with strategies and payoffs, interacting repeatedly to determine which strategies persist. domain Ecology, evolution and animal behaviour 3 Evolution of behaviour Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Animal contest strategies Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) Poaching and anti-poaching patrol games Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#poaching-patrol-games) domain Human behaviour and society 9 Cooperation and norms Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Market and auction design Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) AI-designed economic policy simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Electricity market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Algorithmic pricing collusion Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Institutional corruption and integrity modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Language-grounded negotiation agents Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Electoral and voting system simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Legislative bargaining and coalition simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) domain Cities, infrastructure and operations 1 Agent-based electricity markets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) domain Minds, brains and artificial worlds 2 Self-play strategy training Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) Simulated robot soccer Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) domain Training simulators 1 Negotiation and diplomacy training simulations Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) domain Defence and conflict 4 Political–military crisis games Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Deterrence and arms races Populations [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) Language-model wargame agents Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) Autonomous cyber-defence gyms Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) domain Video games 4 Social deduction games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Auto-battlers Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Board and card game adaptations Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Programming battle games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) method Evolutionary 26 Variation, selection and inheritance implemented computationally, on genomes, programs or virtual bodies. domain Fundamental physics 1 Stellarator configuration optimisation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) domain Life and medicine 2 Tumour microenvironment evolution Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Pathogen evolution Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) domain Ecology, evolution and animal behaviour 6 Evolution of behaviour Bodies [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Host-parasite coevolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Sexual selection and mate choice evolution Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Adaptive dynamics of coevolution Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Forward-time genome simulation Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Animal contest strategies Populations [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) domain Agriculture and food 3 Crop breeding simulation Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Pesticide resistance management models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Livestock breeding and genetics Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) domain Human behaviour and society 2 Cultural evolution Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Electricity market agent-based models Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) domain Cities, infrastructure and operations 1 Agent-based electricity markets Populations [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) domain Minds, brains and artificial worlds 8 Digital evolution Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#digital-evolution) Evolved virtual creatures Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Swarm intelligence algorithms Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Self-replicating program soups Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Evolutionary robotics Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Artificial immune models Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) Core War battles Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) Open-ended environment generation Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) domain Mathematics and computation 2 Learned algorithm and construction search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) Fuzz testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) domain Video games 1 Ecosystem and evolution games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) method Learned emulators 101 A neural network trained on data or on a slower simulation, substituting for the physics at a fraction of the cost. domain Fundamental physics 5 Generative calorimeter shower models Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#calorimeter-shower-generators) Flow-based sampling for lattice field theory Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Learned plasma control in simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) Neural-network quantum states Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) Learned error-correction decoders Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) domain Astronomy and cosmology 3 Cosmological emulators Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Differentiable cosmological simulation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Neural inference for gravitational waves Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) domain Earth and climate 5 Learned climate emulators Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-climate-emulators) Earth-system digital twins Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Learned subgrid parameterisation Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) Machine-learned weather Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-weather) Generative ensemble weather forecasting Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) domain Chemistry and materials 7 Computational materials screening Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Machine-learned interatomic potentials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Universal interatomic potentials Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#universal-interatomic-potentials) Learned density functionals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Neural-network wavefunctions for molecules Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Learned equilibrium samplers Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Generative models of crystals Atoms [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) domain Life and medicine 6 Learned protein structure prediction Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#learned-structure-prediction) Generative protein ensembles Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#generative-protein-ensembles) Cell perturbation-response models Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#perturbation-response-models) Cardiac digital twins Bodies [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Neural predictive models of sensory brain areas Cells [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#neural-predictive-digital-twins) Predictive toxicology Molecules [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) domain Ecology, evolution and animal behaviour 1 Birdsong and vocal learning models Rules [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) domain Human behaviour and society 12 Language-model survey respondents Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-survey-respondents) Language-model behavioural experiments Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-behavioural-experiments) Language-model agent societies Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) Populated social-system prototypes Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Language-model social platform simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Language-model user simulation for recommenders Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) AI-designed economic policy simulation Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Algorithmic pricing collusion Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Language-model macroeconomic agents Populations [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) Language-model agent organisations Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Language-grounded negotiation agents Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Sentencing and recidivism risk modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) domain Engineering and technology 15 Physics-informed neural networks Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Neural operators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Graph-network learned simulators Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Learned fluid solvers Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Network digital twins Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) Robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Digital twins Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) GPU-parallel robot learning environments Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Domain-randomised sim-to-real training Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Differentiable physics simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Adversarial driving-scenario generation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) Learned legged locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned humanoid locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Learned drone racing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Tactile sensor simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) domain Minds, brains and artificial worlds 14 Neural cellular automata Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Reinforcement learning environments Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Multi-agent AI societies Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) Learned world models Fields [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learned-world-models) Self-play strategy training Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) AI safety red-teaming environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Open-ended environment generation Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) Simulated web environments for agents Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Neural game engines Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Interactive generative worlds Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#interactive-generative-worlds) Learned real-world interactive simulators Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#real-world-interactive-simulators) Generative driving world models Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#driving-world-models) Software engineering agent sandboxes Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) domain Mathematics and computation 3 AI-guided conjecture discovery Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#ai-guided-conjecture-discovery) Learned algorithm and construction search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) Language-model program execution Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#llm-program-execution) domain Minds as simulators 21 REM dreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#rem-dreaming) Lucid dreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#lucid-dreaming) Threat-simulation theory of dreams Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#threat-simulation-theory) Sleep-dependent memory consolidation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#memory-consolidation-sleep) Hypnagogic imagery Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hypnagogic-imagery) Mental rehearsal in athletes Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rehearsal-athletes) Episodic future thinking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#episodic-future-thinking) Counterfactual thinking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#counterfactual-thinking) Mental rotation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rotation) Mental navigation Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-navigation) Mind-wandering and daydreaming Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mind-wandering) Theory of mind Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#theory-of-mind) Empathy as simulation theory Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#empathy-simulation-theory) Audience design Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#audience-design) Visual perspective-taking Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#perspective-taking) Joint attention Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#joint-attention) Predictive processing Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#predictive-processing) The body schema Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-schema) Hallucination as uncontrolled prediction Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hallucination-uncontrolled-prediction) Blind-spot filling-in Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#blind-spot-filling-in) Interoception Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#interoception) domain Training simulators 3 Agent hospitals Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Language-model simulated students Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) Language-model conflict rehearsal Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-conflict-rehearsal) domain Defence and conflict 1 Language-model wargame agents Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) domain Film, media and art 4 Neural avatars Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-avatars) Digital de-ageing Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Physics-based character control Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) Neural scene rendering Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) domain Video games 1 Agent-based game playtesting Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) method Real time 122 Fast enough to keep pace with a wall clock, usually because a person or a machine is in the loop and responding. domain Fundamental physics 2 Tokamak whole-device modelling Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Learned plasma control in simulation Fields [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) domain Earth and climate 1 Earth-system digital twins Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) domain Engineering and technology 13 Co-simulation of linked models Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Autonomous vehicle testing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) Planetary rover mobility Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Exoskeleton and prosthetic control Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) GPU-parallel robot learning environments Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Open driving simulators with sensor models Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) Learned legged locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned humanoid locomotion Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Drone flight simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Learned drone racing Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Soft robot simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Tactile sensor simulation Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) domain Minds, brains and artificial worlds 11 Simulated small organisms Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Neuromorphic hardware simulation Cells [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Evolved virtual creatures Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Evolutionary robotics Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Reinforcement learning environments Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Synthetic training data Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#synthetic-data) Embodied household simulators Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) Neural game engines Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Simulated robot soccer Populations [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) Software engineering agent sandboxes Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) domain Mathematics and computation 3 FPGA-accelerated system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Full-system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Lightweight network emulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) domain Minds as simulators 1 The intuitive physics engine Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) domain Training simulators 20 Full-flight simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#flight-simulators) Driving and rail simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#driving-simulators) Ship bridge simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ship-bridge) Spaceflight and mission control Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) Heavy equipment simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#heavy-equipment-simulators) Diving and submersible simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) Surgical simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) Dental simulators Fields [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) Anaesthesia simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Virtual human patients Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Catheter and endovascular simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Ultrasound training simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Robotic surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Endoscopy simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Language-model simulated students Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) Control-room simulators Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) Air traffic control simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) Emergency incident command simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) Mass-casualty exercises Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) domain Before computers 5 Dress rehearsal Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#dress-rehearsal) Fire and evacuation drills Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#fire-drills) Mock trial Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) Military field exercises Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#field-exercises) Motion platforms Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) domain Defence and conflict 4 Military flight and mission simulators Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Vehicle and crew trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crew-trainers) Networked training exercises Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Marksmanship and use-of-force trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) domain Film, media and art 10 Position-based dynamics Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Virtual production sets Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Virtual idols and influencers Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Virtual concerts Populations [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) Digital de-ageing Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Performance-captured digital characters Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) Machinima Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Physics-based character control Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) Physically based sound effects Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Live-coded music and visuals Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) domain Video games 52 Flight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Spaceflight simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) Racing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Arcade racing Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arcade-racing) Driving and transport simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Naval and submarine simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) Job and machinery simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Open-city driving Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Flight simulation over streamed Earth Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Soft-body vehicle crash simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Mech combat simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) Surgery and medical games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) Station systems simulation Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Real-time strategy Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Survival and crafting Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) Physics sandboxes and building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Space exploration and trading Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) User-generated game platforms Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Massively multiplayer worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) Immersive simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Open-world adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Exploration and walking Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#exploration) Platformers Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#platformers) Action adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#shooters) Fighting games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Tactical military simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Stealth Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Team arena games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) Rhythm games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rhythm) Battle royale Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Extraction shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Fitness and motion games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fitness-games) Extreme and action sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Golf simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Combat sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) Racket and ball sports Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) Fishing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Hunting simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Physics puzzles Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) Hacking simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) Virtual reality Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr) Augmented and location-based Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#augmented-reality) Motion-controller games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#motion-controller-games) Haptic and force-feedback games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#haptic-feedback-games) Location-based and arcade VR Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#large-scale-vr) Cockpit and rig simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cockpit-sim-rigs) Biometric-adaptive games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Virtual reality social worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) Augmented reality pets Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) Cloud-streamed games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) method Rules and states 150 A system defined by discrete rules: logic gates, game rules, symbols, turns. Nothing is continuous unless the rules specify it. domain Fundamental physics 3 Quantum computer emulation Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-circuit-emulation) Quantum error correction Subatomic [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Stabilizer circuit simulation Rules [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) domain Astronomy and cosmology 3 Stellar population synthesis Rules [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Semi-analytic galaxy formation Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Binary population synthesis Fields [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) domain Earth and climate 1 Dynamic global vegetation and carbon-cycle modelling Fields [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) domain Chemistry and materials 1 Automated reaction-mechanism generation Molecules [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) domain Life and medicine 1 Synthetic patient record generation Populations [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) domain Ecology, evolution and animal behaviour 1 Pollination service across landscapes Fields [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) domain Agriculture and food 4 Agrivoltaic light-sharing models Fields [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Plant architecture growth models Bodies [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Degree-day pest phenology models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Land-use change agent models Populations [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) domain Human behaviour and society 4 Cognitive architectures Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cognitive-architectures) Social cognition and theory-of-mind models Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Emotion and affect modelling Rules [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Tax and benefit microsimulation Bodies [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) domain Engineering and technology 3 Chip logic simulation Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Emulation and virtual machines Rules [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#emulation) Open driving simulators with sensor models Bodies [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) domain Minds, brains and artificial worlds 6 Artificial chemistry Molecules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Core War battles Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) Embodied household simulators Bodies [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) Simulated web environments for agents Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Software engineering agent sandboxes Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments Rules [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) domain Mathematics and computation 19 Experimental mathematics searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Computational number theory searches Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#model-checking) Automated theorem proving search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) SAT and constraint solving Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Cryptographic attack modelling Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Security protocol verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Computer-assisted proof by exhaustive case checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Turing-machine enumeration Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) Symbolic execution Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Abstract interpretation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Bounded model checking Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Property-based random testing Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Neural network verification Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) Computer architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Compiler and program optimisation search Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Graphics processor architecture simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) FPGA-accelerated system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Full-system simulation Rules [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) domain Minds as simulators 19 Constructive episodic simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#constructive-episodic-simulation) Motor imagery Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-imagery) Visual mental imagery Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#visual-mental-imagery) Affective forecasting Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#affective-forecasting) Mental models of reasoning Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Vicarious trial and error Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#vicarious-trial-and-error) Future planning in animals Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-future-planning) Fiction as social simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#fiction-as-social-simulation) Children's pretend play Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#pretend-play-children) Animal play as practice Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-play-practice) Imaginary companions Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#imaginary-companions) Sociodramatic play Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) Paracosms Rules [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#paracosms) Object play in primates Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#primate-object-play) Thought as simulated action Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) Grounded cognition Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#grounded-cognition) The phenomenal self-model Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#phenomenal-self-model) Body ownership illusions Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-ownership-illusions) Embodied language simulation Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#embodied-language-simulation) domain Training simulators 13 Spaceflight and mission control Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) Paramedic and mass-casualty triage training Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Virtual human patients Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Structured clinical examinations Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#clinical-examination-standardised-patients) Ultrasound training simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Robotic surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Endoscopy simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Emergency exercises Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#tabletop-exercises) Business simulations Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) Negotiation and diplomacy training simulations Rules [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) Emergency incident command simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) Mass-casualty exercises Populations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) domain Before computers 3 Cybernetic tortoises Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) Mock trial Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) Automata Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) domain Defence and conflict 5 Professional war games Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#professional-wargames) Political–military crisis games Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Historical war games Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Marksmanship and use-of-force trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) Cyber ranges Rules [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) domain Film, media and art 12 Procedural cities and landscapes Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Digital ecosystems and vegetation Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Atmospheric and sky simulation Fields [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Virtual idols and influencers Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Performance-captured digital characters Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) L-system plant modelling Cells [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) Machinima Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Animatronic figures Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) Generative art systems Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) Procedural and generative music Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Procedural texture and material generation Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) Live-coded music and visuals Rules [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) domain Video games 52 Driving and transport simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Job and machinery simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Open-city driving Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Mech combat simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) Life simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Virtual pets Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#virtual-pets) Farming and village life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Relationship simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#relationship-sims) Social hangout worlds Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) Dating simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Parenting and family life Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) Surgery and medical games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) Colony simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) God games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) Automation and factory building Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Social deduction games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Station systems simulation Fields [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Grand strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) 4X strategy Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#four-x) Hex-and-counter war games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Tactics Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Tower defence Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tower-defence) Auto-battlers Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Block and voxel sandboxes Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Survival and crafting Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) Level and world creation tools Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) User-generated game platforms Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Role-playing games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Immersive simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Roguelikes Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Interactive fiction Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#interactive-fiction) Visual novels and narrative games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#visual-novels) Adventure and point-and-click Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#puzzle-adventure) Alternate reality games Populations [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) Action adventure Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Fighting games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Team arena games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) Extraction shooters Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Combat sports simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) Fishing simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Hunting simulation Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Logic and falling-block puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#logic-puzzles) Board and card game adaptations Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Word and letter puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#word-puzzles) Match-three and tile-swap puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) Hidden-object and spot-the-difference Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hidden-object) Number and grid logic puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#number-logic-puzzles) Escape-room puzzles Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#escape-room-games) Programming battle games Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Hacking simulation Rules [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) Biometric-adaptive games Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Augmented reality pets Bodies [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) method Physical analogue 45 One physical system standing in for another: a scale model in a wind tunnel, cold atoms emulating electrons, a manikin with a pulse. domain Fundamental physics 1 Analogue quantum simulation Atoms [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#analogue-quantum) domain Engineering and technology 1 Physical scale models Fields [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#scale-models) domain Minds as simulators 2 Mental models of reasoning Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Thought as simulated action Bodies [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) domain Training simulators 2 Patient simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Childbirth simulators Bodies [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) domain Before computers 37 Orrery Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#orrery) Astrolabe Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astrolabe) The Antikythera mechanism Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#antikythera-mechanism) Optical planetarium Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#planetarium) Armillary sphere Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#armillary-sphere) Equatorium Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#equatorium) Terrestrial globe Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#terrestrial-globe) Astronomical clock Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astronomical-clock) Ship-model towing tank Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#towing-tank) Physical river basin model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#river-basin-model) Harbour and estuary model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harbour-model) Dam and spillway model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#spillway-model) Structural scale model Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#structural-scale-model) Architectural acoustic scale model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#acoustic-scale-model) Hele-Shaw cell Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) Hanging-chain arch model Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Soap film minimal-surface models Fields [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) Mechanical differential analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#differential-analyser) Tide-predicting machine Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#tide-predicting-machine) Hydraulic economy model Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hydraulic-economy-model) Electrical network analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#electrical-network-analyser) Mechanical harmonic analyser Populations [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harmonic-analyser) Analogue fire-control computer Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#analogue-fire-control-computer) Galton board Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Buffon's needle Rules [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) Iron wire nerve model Cells [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) Cybernetic tortoises Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) Sand table Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#sand-table) Staff ride Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#staff-ride) Anatomical models Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#anatomical-models) Obstetric phantom Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#obstetric-phantom) Early resuscitation manikins Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#resuscitation-manikins) Crash-test dummies Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#crash-test-dummies) Moulage Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#moulage) Ballistic gelatin blocks Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#ballistic-gelatin) Automata Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) Motion platforms Bodies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) domain Defence and conflict 1 Combat medic trainers Bodies [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) domain Film, media and art 1 Animatronic figures Bodies [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) --- title: "Simulations by era · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/eras description: "When the first simulation of each kind ran, from orreries and war games to the present." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations by era · 941 simulations When the first simulation of each kind ran, oldest first. Dates are the earliest well-documented case, not always the very first. Expand all Collapse all era Always 45 The simulations that brains run: dreaming, imagining, pretending, modelling other minds. They predate every other entry here. The year given for each is when science first documented it. REM dreaming Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#rem-dreaming) Lucid dreaming Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#lucid-dreaming) Hippocampal replay in rats Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-replay) Threat-simulation theory of dreams Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#threat-simulation-theory) Sleep-dependent memory consolidation Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#memory-consolidation-sleep) Hypnagogic imagery Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hypnagogic-imagery) Hippocampal preplay Sleep and dreaming [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-preplay) Mental rehearsal in athletes Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rehearsal-athletes) Episodic future thinking Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#episodic-future-thinking) Counterfactual thinking Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#counterfactual-thinking) Mental rotation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rotation) Mental navigation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-navigation) Mind-wandering and daydreaming Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mind-wandering) Constructive episodic simulation Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#constructive-episodic-simulation) Motor imagery Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-imagery) Visual mental imagery Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#visual-mental-imagery) Affective forecasting Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#affective-forecasting) Mental models of reasoning Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Vicarious trial and error Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#vicarious-trial-and-error) Future planning in animals Imagination and planning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-future-planning) Theory of mind Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#theory-of-mind) Empathy as simulation theory Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#empathy-simulation-theory) Mirror systems Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mirror-systems) Audience design Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#audience-design) Visual perspective-taking Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#perspective-taking) Joint attention Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#joint-attention) Fiction as social simulation Other minds [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#fiction-as-social-simulation) Children's pretend play Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#pretend-play-children) Animal play as practice Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-play-practice) Imaginary companions Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#imaginary-companions) Sociodramatic play Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) Paracosms Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#paracosms) Object play in primates Play and pretence [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#primate-object-play) Predictive processing The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#predictive-processing) Motor forward models The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-forward-models) The body schema The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-schema) Hallucination as uncontrolled prediction The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hallucination-uncontrolled-prediction) Blind-spot filling-in The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#blind-spot-filling-in) Interoception The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#interoception) Thought as simulated action The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) Grounded cognition The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#grounded-cognition) The phenomenal self-model The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#phenomenal-self-model) Body ownership illusions The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-ownership-illusions) Embodied language simulation The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#embodied-language-simulation) The intuitive physics engine The brain's world model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) era Before 1500 10 Models of the heavens, sand tables, rehearsal and play: simulation long before machines. The Antikythera mechanism 150 BCE [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#antikythera-mechanism) Terrestrial globe 150 BCE [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#terrestrial-globe) Sand table 32 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#sand-table) Automata 50 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) Military field exercises 100 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#field-exercises) Armillary sphere 117 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#armillary-sphere) Astrolabe 800 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astrolabe) Equatorium 1080 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#equatorium) Astronomical clock 1092 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astronomical-clock) Mock trial 1400 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) era 1500 to 1799 5 Clockwork, orreries and anatomical models. Hanging-chain arch model 1675 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Orrery 1704 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#orrery) Obstetric phantom 1756 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#obstetric-phantom) Buffon's needle 1777 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) Anatomical models 1780 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#anatomical-models) era 1800 to 1899 10 War games, towing tanks and the first tide-predicting machines. Professional war games 1812 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#professional-wargames) Dress rehearsal 1828 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#dress-rehearsal) Moulage 1867 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#moulage) Physical scale models 1871 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#scale-models) Ship-model towing tank 1871 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#towing-tank) Tide-predicting machine 1872 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#tide-predicting-machine) Soap film minimal-surface models 1873 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) Galton board 1874 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Mechanical harmonic analyser 1876 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harmonic-analyser) Hele-Shaw cell 1898 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) era 1900 to 1939 22 Wind tunnels, differential analysers and flight trainers. Structural scale model 1901 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#structural-scale-model) Staff ride 1906 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#staff-ride) Collective estimation and crowd wisdom 1907 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) Motion platforms 1910 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) Analogue fire-control computer 1912 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#analogue-fire-control-computer) Fire and evacuation drills 1912 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#fire-drills) Historical war games 1913 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Combat and campaign models 1916 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Telecom traffic engineering 1917 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) Iron wire nerve model 1920 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) Optical planetarium 1923 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#planetarium) Predator–prey dynamics 1925 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) Electrical network analyser 1925 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#electrical-network-analyser) Compartment epidemic models 1927 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#compartment-epidemics) Sentencing and recidivism risk modelling 1928 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) Dam and spillway model 1928 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#spillway-model) Full-flight simulators 1929 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#flight-simulators) Mechanical differential analyser 1931 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#differential-analyser) Architectural acoustic scale model 1934 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#acoustic-scale-model) Harbour and estuary model 1935 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harbour-model) Pharmacokinetics 1937 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacokinetics) Deterrence and arms races 1939 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) era 1940s 9 The first electronic computers, and with them Monte Carlo methods. Physical river basin model 1943 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#river-basin-model) Ballistic gelatin blocks 1945 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#ballistic-gelatin) Ballistics 1945 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Monte Carlo estimation of constants 1946 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) Reactor core physics 1948 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Bioheat transfer and hyperthermia 1948 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Cybernetic tortoises 1948 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) Hydraulic economy model 1949 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hydraulic-economy-model) Crash-test dummies 1949 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#crash-test-dummies) era 1950s 47 Numerical weather prediction 1950 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Digits of pi by computer 1950 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) Invasive species spread 1951 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) Computational number theory searches 1951 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Pattern formation 1952 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Detailed neuron models 1952 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#detailed-neurons) Electronic structure 1953 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#electronic-structure) Magnetism and phase transitions 1953 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) Digital evolution 1953 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#digital-evolution) Riemann zeta zero computation 1953 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Emergency exercises 1954 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#tabletop-exercises) Vehicle and crew trainers 1954 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crew-trainers) Stellar evolution 1955 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-evolution) Petroleum and gas reservoir simulation 1955 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Combustion 1955 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#combustion) Chain-growth Monte Carlo for polymers 1955 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chain-growth-monte-carlo) Sterile insect release models 1955 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Macroeconomic models 1955 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Traffic flow 1955 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Random matrix experiments 1955 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-matrix-experiments) Nonlinear lattice experiments 1955 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) Military logistics 1955 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) Ocean wave forecasting 1956 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-wave-forecasting) Pore-network modelling 1956 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) Structural analysis 1956 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#structural-analysis) Power grids 1956 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Automated theorem proving search 1956 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) Business simulations 1956 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) Anti-submarine search theory 1956 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Nuclear criticality safety 1957 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#criticality-safety) Fisheries and wildlife management 1957 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Demographic microsimulation 1957 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#demographic-microsimulation) Percolation simulation 1957 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Procedural and generative music 1957 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Plasma equilibrium and stability 1958 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Supply-chain dynamics and the bullwhip effect 1958 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) Atmospheric entry 1958 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#reentry) Supply chains 1958 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Control-room simulators 1958 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) Political–military crisis games 1958 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Racket and ball sports 1958 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) Accelerator beam dynamics 1959 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Particle-in-cell plasma 1959 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) Spacecraft trajectories 1959 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#trajectory-design) Self-play strategy training 1959 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) Random graph experiments 1959 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Spaceflight and mission control 1959 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) era 1960s 82 Radiation-damage cascades in materials 1960 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) The heart 1960 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Early resuscitation manikins 1960 [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#resuscitation-manikins) Torpedo and underwater weapon simulation 1960 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) Cosmic-ray air showers 1961 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#air-showers) Drug formulation and delivery modelling 1961 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) Market and auction design 1961 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) Manufacturing lines 1961 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#manufacturing) Queues and service systems 1961 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#service-queues) Blast and impact protection 1961 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#blast-protection) Radioactivation and decay chains 1962 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Polymers and soft matter 1962 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Aerodynamics 1962 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#aerodynamics) SAT and constraint solving 1962 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Magnetic reconnection 1963 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Organisations and teams 1963 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#organisations) Rarefied-gas direct simulation 1963 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) Emulation and virtual machines 1963 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#emulation) Project schedule risk simulation 1963 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Experimental mathematics searches 1963 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Chaotic-attractor numerics 1963 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#chaotic-attractor-numerics) Negotiation and diplomacy training simulations 1963 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) Radar and sensor performance 1963 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Animatronic figures 1963 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) Black hole mergers 1964 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#numerical-relativity) Liquids and solutions 1964 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#liquids-solutions) Population genetics 1964 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Computer network simulation 1964 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-simulation) Semiconductor device simulation 1964 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Transport and land use 1964 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Airspace fast-time simulation 1964 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Last-mile delivery routing 1964 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Nuclear structure 1965 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Polymer self-consistent field theory 1965 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Crop growth and yield models 1965 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Soil erosion and land degradation 1965 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Chip logic simulation 1965 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Spacecraft thermal and power simulation 1965 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#spacecraft-thermal) Hospital patient flow 1965 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Soliton numerical experiments 1965 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) Turing-machine enumeration 1965 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) Generative art systems 1965 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) One-component plasma simulation 1966 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) Core-collapse supernovae 1966 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Rivers and floods 1966 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) Thin film growth 1966 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#thin-film-growth) Kidney nephron transport models 1966 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Electromagnetics 1966 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#electromagnetics) Air traffic control simulators 1966 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) Big Bang nucleosynthesis 1967 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#nucleosynthesis) Binary star evolution 1967 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-star-evolution) Stellar atmospheres and spectra 1967 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Radiative-convective climate model 1967 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Anaesthesia simulators 1967 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Radiation transport 1968 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#radiation-transport) Galactic chemical evolution 1968 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Groundwater 1968 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#groundwater) Earthquakes and seismic waves 1968 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquakes) Polymerisation kinetics 1968 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) Pharmacodynamic modelling 1968 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacodynamics) Acoustics and vibration 1968 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#acoustics) Fatigue and crack growth 1968 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#durability-fatigue) Rocket engine simulation 1968 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rocket-propulsion) Water and drainage networks 1968 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Operating system scheduler simulation 1968 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#os-scheduler-simulation) L-system plant modelling 1968 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) Sound propagation and acoustics 1968 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) Star formation 1969 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Planetary and exoplanet atmospheres 1969 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-atmospheres) Earth system models 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system) Energy-balance climate model 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Tropical cyclones 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tropical-cyclones) Ocean circulation 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-circulation) Tsunamis and storm surge 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tsunami-surge) Sea ice 1969 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#sea-ice-dynamics) Gene regulatory networks 1969 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Speciation and macroevolution models 1969 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Diffusion of ideas 1969 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Power-system electromagnetic transients 1969 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Random Boolean networks 1969 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Patient simulators 1969 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Spaceflight simulation 1969 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) era 1970s 111 Cosmological N-body 1970 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-n-body) Air quality and dispersion 1970 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Corrosion 1970 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Chemical reactor engineering 1970 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chemical-reactor-engineering) Slime mould aggregation 1970 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Forest dynamics 1970 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forest-dynamics) Livestock herd and feed models 1970 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Baking and thermal food processing 1970 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) Tribology and contact mechanics 1970 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tribology-contact) Public transit network simulation 1970 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Gas pipeline network transients 1970 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Cellular automata 1970 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) Empirical algorithm performance testing 1970 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) Driving and rail simulators 1970 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#driving-simulators) Origin of life 1971 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) Residential sorting 1971 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) World models 1971 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#world-models) Multibody dynamics 1971 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multibody) Inertial confinement implosion 1972 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#inertial-confinement-fusion) Galaxy collision and merger simulation 1972 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) Atmospheric boundary-layer large-eddy simulation 1972 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Wildfire spread 1972 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) Tumour growth and therapy response 1972 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Heart valve fluid-structure interaction 1972 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Whole-body integrative physiology 1972 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Vocal fold and voice production models 1972 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Food webs 1972 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Soil water and nutrient transport 1972 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Models of learning 1972 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Insurance catastrophe models 1972 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Computable general equilibrium modelling 1972 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#computable-general-equilibrium) Policing and patrol deployment simulation 1972 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) Turbulence 1972 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#turbulence) Neural mass and field models 1972 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Ship bridge simulators 1972 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ship-bridge) Word and letter puzzles 1972 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#word-puzzles) Astrochemical reaction networks 1973 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) Animal contest strategies 1973 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) Grazing and pasture management 1973 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Circuit simulation 1973 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#circuit-simulation) Detector response 1974 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#detector-response) Ensemble weather forecasting 1974 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Mantle convection and plate tectonics 1974 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mantle-convection) Spectroscopy prediction 1974 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#spectroscopy-prediction) Ambulance and fire station deployment models 1974 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) Opinion dynamics 1974 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Fluid-structure interaction 1974 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Waste collection and treatment simulation 1974 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) Emergency incident command simulators 1974 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) Directed energy weapon simulation 1974 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Arcade racing 1974 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arcade-racing) Shooters 1974 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#shooters) Stellar oscillations 1975 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-interiors-seismology) Severe convective storms 1975 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#severe-storms) Kinetic Monte Carlo 1975 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Adsorption in porous materials 1975 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#grand-canonical-adsorption) Battery and electrochemical cell modelling 1975 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Irrigation scheduling 1975 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Fermentation process modelling 1975 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Electoral and voting system simulation 1975 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Optical lithography simulation 1975 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Welding simulation 1975 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#welding-simulation) Container terminal simulation 1975 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Structured clinical examinations 1975 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#clinical-examination-standardised-patients) Role-playing games 1975 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Interactive fiction 1975 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#interactive-fiction) Time-dependent nuclear mean-field dynamics 1976 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Ice sheets and sea level 1976 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ice-sheets) Glacial isostatic adjustment and sea-level fingerprints 1976 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Reaction dynamics 1976 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Glass formation 1976 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#glass-formation) Fracture and defects 1976 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fracture) Enzyme catalysis 1976 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) Neutral community models 1976 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Degree-day pest phenology models 1976 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Tax and benefit microsimulation 1976 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) Court and case-flow simulation 1976 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Injection moulding simulation 1976 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#injection-moulding) Cryptographic attack modelling 1976 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Symbolic execution 1976 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Fighting games 1976 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Palaeoclimate 1977 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Protein folding and dynamics 1977 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#protein-dynamics) Stochastic biochemistry 1977 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#stochastic-biochemistry) Soil organic carbon turnover 1977 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Pesticide resistance management models 1977 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Construction process simulation 1977 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) Building energy and daylight 1977 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) Computer-assisted proof by exhaustive case checking 1977 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Abstract interpretation 1977 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Board and card game adaptations 1977 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Planet formation 1978 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Space weather 1978 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Blood cell production dynamics 1978 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#haematopoiesis-dynamics) Size-spectrum ecosystem models 1978 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) Models of decision-making 1978 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#decision-models) Social cognition and theory-of-mind models 1978 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Collective action and tipping-point models 1978 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Orbital-debris and satellite-collision modelling 1978 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Mobile network planning 1978 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Distributed systems and consensus simulation 1978 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Diving and submersible simulators 1978 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) Massively multiplayer worlds 1978 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) Lattice QCD 1979 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Granular materials 1979 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#granular) Multiphase and pipeline flow 1979 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multiphase-flow) Crash simulation 1979 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#crash) Semiconductor process simulation 1979 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) Urban growth 1979 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#urban-growth) District heating and cooling networks 1979 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Number and grid logic puzzles 1979 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#number-logic-puzzles) era 1980s 148 Fusion breeding blanket neutronics 1980 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-blanket) Quantum many-body systems 1980 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Impact cratering 1980 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Volcanic eruptions and lava flows 1980 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landslides and debris flows 1980 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) Quantum Monte Carlo for electrons 1980 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Population viability analysis 1980 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Pest and plant disease spread 1980 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Cooperation and norms 1980 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Legislative bargaining and coalition simulation 1980 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) Metal forming and stamping 1980 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-forming) Fractal-set rendering 1980 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fractal-set-rendering) Search and rescue drift planning 1980 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) Flight simulation 1980 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Hex-and-counter war games 1980 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Roguelikes 1980 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Combat sports simulation 1980 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) Fishing simulation 1980 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Solvation free energy 1981 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#solvation-free-energy) Diffusion-limited aggregation 1981 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) RNA folding and structure 1981 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) Cochlear mechanics 1981 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Evolution of behaviour 1981 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Sexual selection and mate choice evolution 1981 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Cultural evolution 1981 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Solar and wind farm yield simulation 1981 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Airport airside simulation 1981 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Energy-system capacity-planning models 1981 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) Model checking 1981 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#model-checking) Platformers 1981 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#platformers) Programming battle games 1981 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Collider event generation 1982 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collider-events) Crystal plasticity finite-element modelling 1982 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Molecular docking and drug binding 1982 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) Membranes and ion channels 1982 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#membranes) Circadian clock models 1982 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) Dynamic stochastic general equilibrium models 1982 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Machining simulation 1982 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#machining-simulation) Attractor memory networks 1982 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Fluid and smoke simulation for effects 1982 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Procedural cities and landscapes 1982 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Sports management 1982 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) Fusion plasma turbulence 1983 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Stellar population synthesis 1983 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Solar interior and dynamo 1983 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#solar-dynamo) Molten salts and ionic liquids 1983 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ionic-liquids-electrolytes) Environmental and chemical exposure risk assessment 1983 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Coalescent and phylogenetic simulation 1983 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coalescent) Cognitive architectures 1983 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cognitive-architectures) Jury decision-making simulation 1983 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) Robot simulation 1983 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Simulated annealing 1983 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Networked training exercises 1983 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Climate effects of nuclear war 1983 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#nuclear-winter) Particle system effects 1983 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Physical modelling synthesis of instruments 1983 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) Level and world creation tools 1983 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) Visual novels and narrative games 1983 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#visual-novels) Sports simulation 1983 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Path-integral Monte Carlo of quantum fluids 1984 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) Exoplanet detection and characterisation 1984 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) Full-waveform seismic inversion 1984 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Excited states and photochemistry 1984 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#excited-states-photochemistry) Path-integral molecular dynamics 1984 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Alloy cluster expansion 1984 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Core War battles 1984 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) Naval and submarine simulation 1984 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) Space exploration and trading 1984 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) Golf simulation 1984 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Logic and falling-block puzzles 1984 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#logic-puzzles) Industrial plasma processing 1985 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Collisionless shock simulation 1985 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) Cosmic string network evolution 1985 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Reactive transport in the subsurface 1985 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) Ab initio molecular dynamics 1985 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Cancer screening microsimulation 1985 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Greenhouse climate models 1985 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) Aquaculture and fish farming 1985 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Aquaculture pond bioenergetics 1985 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) Food supply chain simulation 1985 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) Famine early warning models 1985 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) Metal casting and solidification 1985 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-casting) Parallel discrete-event simulation 1985 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#parallel-discrete-event-simulation) Military flight and mission simulators 1985 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Marksmanship and use-of-force trainers 1985 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) Sanctions and economic warfare modelling 1985 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) Procedural texture and material generation 1985 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) Terrarium and habitat sandboxes 1985 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Hacking simulation 1985 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) Seasonal forecasting 1986 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Earthquake-cycle simulation 1986 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Land-surface model 1986 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Colloids and nanoparticle assembly 1986 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Metabolic networks 1986 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#metabolism) Dynamic energy budget modelling 1986 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#dynamic-energy-budget) Species ranges 1986 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) Lattice-gas automata for fluid flow 1986 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) Artificial immune models 1986 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) Ocean surface synthesis 1986 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Atmospheric and sky simulation 1986 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Physically based light transport 1986 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) Social deduction games 1986 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Action adventure 1986 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Neutrino detector simulation 1987 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neutrino-detectors) Coastal and estuarine circulation modelling 1987 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Bone adaptation and implant remodelling 1987 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Flocking and schooling 1987 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) Mass gathering disease risk modelling 1987 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) Self-organised criticality 1987 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) Sandpile self-organised criticality 1987 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) Cloth simulation 1987 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Adventure and point-and-click 1987 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#puzzle-adventure) Fitness and motion games 1987 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fitness-games) Extreme and action sports 1987 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Stellarator configuration optimisation 1988 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Topological quantum matter 1988 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Orbital dynamics 1988 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Thermosphere and ionosphere modelling 1988 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) Stochastic earthquake-catalogue models 1988 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) Micromagnetic simulation 1988 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Crystallisation 1988 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) Radiotherapy dose calculation 1988 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Individual-based ecological models 1988 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Reserve and corridor design 1988 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) Plant architecture growth models 1988 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Emotion and affect modelling 1988 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Cavitation simulation 1988 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#cavitation) Ice accretion simulation 1988 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#icing) Lattice Boltzmann flow simulation 1988 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) Topology optimisation 1988 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Warehouse and distribution centre simulation 1988 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Storage systems simulation 1988 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Paramedic and mass-casualty triage training 1988 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Rigid body dynamics for animation 1988 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Cockpit and rig simulation 1988 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cockpit-sim-rigs) Tidal disruption of stars by black holes 1989 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) Regional climate downscaling 1989 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#regional-climate-downscaling) Blood flow 1989 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#blood-flow) Wind seed and pollen dispersal models 1989 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) Swarm robotics 1989 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#swarm-robotics) Neuromorphic hardware simulation 1989 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Security protocol verification 1989 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Mass-casualty exercises 1989 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) Hair and fur simulation 1989 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Racing simulation 1989 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Mech combat simulation 1989 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) City building 1989 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) God games 1989 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) era 1990s 163 Neutron star mergers 1990 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#neutron-star-mergers) Ocean ecosystem and biogeochemistry modelling 1990 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Quantum wavepacket dynamics 1990 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Dislocation dynamics 1990 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Musculoskeletal biomechanics 1990 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#biomechanics) Musculoskeletal models for surgery 1990 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#musculoskeletal-surgery-models) Pathogen evolution 1990 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) Ant colony foraging 1990 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) Plankton ecosystem models 1990 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Host-parasite coevolution 1990 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Reintroduction and translocation planning 1990 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) Crop breeding simulation 1990 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Livestock breeding and genetics 1990 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) Cold chain and spoilage modelling 1990 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Policy diffusion network models 1990 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) Photonic-crystal band-structure calculation 1990 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Exoskeleton and prosthetic control 1990 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) Fuzz testing 1990 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Computer architecture simulation 1990 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Heavy equipment simulators 1990 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#heavy-equipment-simulators) Management and tycoon 1990 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) Tactics 1990 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Accretion discs and jets 1991 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#accretion) Landscape evolution 1991 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Microstructure 1991 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Fuel-cell membrane and transport modelling 1991 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) Wildlife disease 1991 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) Spatial host-parasitoid and pest lattices 1991 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) Artificial chemistry 1991 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Computer virus and malware epidemics 1991 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Colony simulation 1991 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) Grand strategy 1991 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) 4X strategy 1991 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#four-x) Virtual reality 1991 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr) Galaxy formation 1992 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Integrated assessment models 1992 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) Solar geoengineering 1992 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geoengineering-modelling) Dissipative particle dynamics 1992 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Immune response 1992 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Choice under risk and uncertainty modelling 1992 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Swarm intelligence algorithms 1992 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Reinforcement learning environments 1992 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Endoscopy simulators 1992 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Real-time strategy 1992 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Semi-analytic galaxy formation 1993 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Habitable-zone climate modelling 1993 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Organic semiconductor charge transport 1993 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Tissue and tumour growth 1993 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Breathing and airways 1993 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#lungs) Disease burden and health economic modelling 1993 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Mosquito population dynamics 1993 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Agent-based economies 1993 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#agent-economies) Exploratory modelling under deep uncertainty 1993 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Batteries and fuel cells 1993 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) Elevator traffic simulation 1993 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Evolutionary robotics 1993 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Surgical simulators 1993 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) War economic and reconstruction modelling 1993 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Hidden-object and spot-the-difference 1993 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hidden-object) Dusty plasma and Yukawa-system simulation 1994 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) Intergalactic medium and the Lyman-alpha forest 1994 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Mineral dust emission and transport 1994 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Automated reaction-mechanism generation 1994 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) Clinical trial design simulation 1994 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#trial-design-simulation) Bacterial swarming and quorum sensing 1994 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) Animal locomotion 1994 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) Metapopulation dynamics 1994 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Predictive food microbiology 1994 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) Financial markets 1994 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Financial risk 1994 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#risk) Hunter-gatherer economies 1994 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#hunter-gatherers) Evolved virtual creatures 1994 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Landmine and unexploded ordnance clearance planning 1994 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) Relationship simulation 1994 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#relationship-sims) Dating simulation 1994 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Immersive simulation 1994 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Match-three and tile-swap puzzles 1994 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) Ultracold atomic gas dynamics 1995 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#cold-atom-bec) Planetary interiors and dynamos 1995 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-interiors) Radiation belt modelling 1995 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) Geodynamo simulation 1995 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Catalysis 1995 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#catalysis) Lake eutrophication models 1995 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Rewilding and trophic cascade modelling 1995 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) Precision agriculture optimisation 1995 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Food safety and traceability simulation 1995 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) Language evolution 1995 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#language-evolution) Pedestrian and crowd dynamics 1995 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) Additive manufacturing simulation 1995 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#additive-manufacturing) Evacuation and emergency response 1995 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#evacuation) Internet backbone and cable resilience 1995 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Naval salvo exchange models 1995 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#naval-salvo-models) Nuclear stockpile simulation 1995 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) Destruction and debris simulation 1995 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Social hangout worlds 1995 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) Quantum computer emulation 1996 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-circuit-emulation) Quantum error correction 1996 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Superconducting vortex dynamics 1996 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) Cosmic microwave background 1996 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Early-universe lattice field dynamics 1996 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) Common-envelope evolution 1996 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Dynamic global vegetation and carbon-cycle modelling 1996 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Atmospheric reanalysis 1996 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Coupled fire and atmosphere models 1996 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) Real-time electron dynamics 1996 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Within-host virus dynamics 1996 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#within-host-viral-dynamics) Movement and foraging 1996 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) Migration and navigation 1996 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#migration) Adaptive dynamics of coevolution 1996 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Synthetic population generation 1996 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) Artificial societies 1996 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#artificial-societies) Side-channel leakage simulation 1996 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Childbirth simulators 1996 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) Chemical, biological and radiological hazard plumes 1996 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) Casualty and humanitarian response 1996 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) Virtual idols and influencers 1996 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Machinima 1996 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Virtual pets 1996 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#virtual-pets) Farming and village life 1996 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Ecosystem and evolution games 1996 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) Antimicrobial resistance spread 1997 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Trophic mass-balance ecosystem models 1997 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Protest mobilisation network models 1997 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Monument construction and engineering reconstruction 1997 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) Planetary rover mobility 1997 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Satellite broadband constellation simulation 1997 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) Simulated small organisms 1997 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Brain disease and seizure spread 1997 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Approximate Bayesian computation 1997 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) Dental simulators 1997 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) Agent-based combat models 1997 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#agent-combat) Combat medic trainers 1997 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) Digital crowd simulation 1997 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-crowds) Open-world adventure 1997 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Rhythm games 1997 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rhythm) Hunting simulation 1997 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Haptic and force-feedback games 1997 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#haptic-feedback-games) Galactic cosmic-ray propagation 1998 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Stellar surface convection simulation 1998 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Interstellar magnetised turbulence 1998 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) Spectral-element seismic wave propagation 1998 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Transition-state and reaction-path search 1998 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Tumour-induced blood vessel growth 1998 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Bacterial colony growth and biofilms 1998 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) Agricultural catchment pollution models 1998 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Quantitative microbial risk assessment 1998 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) Simulated robot soccer 1998 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) Stealth 1998 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Cosmic reionization 1999 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Collapsar and gamma-ray burst jets 1999 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Pulsar magnetospheres 1999 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Surgical planning with patient-specific models 1999 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Fracture healing simulation 1999 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Termite mound building 1999 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Fisheries management strategy evaluation 1999 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Social network formation 1999 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#network-formation) Conjunction collision probability 1999 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) Data centre facility simulation 1999 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) Bounded model checking 1999 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Muscle and skin deformation 1999 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Open-city driving 1999 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Tactical military simulation 1999 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Team arena games 1999 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) era 2000s 130 Self-interacting dark matter simulation 2000 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#self-interacting-dark-matter) Weak-lensing ray tracing through simulated universes 2000 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Planet-disk interaction and migration 2000 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) Black-hole shadow and image rendering 2000 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Coupled carbon-cycle and climate simulation 2000 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Urban surface energy-balance modelling 2000 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Flood inundation modelling 2000 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Volunteer-computed molecular dynamics 2000 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#volunteer-computing-molecular-dynamics) Tobacco-control policy simulation 2000 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Organ allocation policy simulation 2000 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Predictive toxicology 2000 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) Crowd emotion and behavioural contagion 2000 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Kinetic wealth exchange models 2000 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) Fire dynamics large-eddy simulation 2000 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) Peridynamic fracture modelling 2000 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Ride-hailing and dispatch simulation 2000 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Property-based random testing 2000 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Catheter and endovascular simulators 2000 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Digital ecosystems and vegetation 2000 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Life simulation 2000 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Augmented and location-based 2000 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#augmented-reality) Giant-impact simulations 2001 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Superparameterisation 2001 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Reactive force-field dynamics 2001 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reactive-force-field-dynamics) Epidemics on contact networks 2001 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Farm agent-based models of land use and adoption 2001 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#farm-agent-based-adoption) Livestock disease outbreak models 2001 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Financial contagion in interbank networks 2001 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Electricity market agent-based models 2001 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Infrastructure interdependence 2001 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Agent-based electricity markets 2001 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) Digital humans and faces 2001 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Physically based sound effects 2001 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Driving and transport simulation 2001 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Parenting and family life 2001 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) Alternate reality games 2001 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) Laser wakefield acceleration 2002 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Tokamak edge pedestal and ELM modelling 2002 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Analogue quantum simulation 2002 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#analogue-quantum) Binary population synthesis 2002 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Geological carbon-dioxide storage simulation 2002 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Metadynamics and enhanced sampling 2002 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Enhanced-sampling free-energy methods 2002 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Birdsong and vocal learning models 2002 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) Reconstructed ancient societies 2002 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#archaeological-abm) Institutional corruption and integrity modelling 2002 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Digital twins 2002 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) Aircraft boarding simulation 2002 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Cascading-blackout models 2002 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Internet worm propagation models 2002 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) Validated numerics 2002 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#validated-numerics) Statistical model checking 2002 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Full-system simulation 2002 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Models of civil conflict 2002 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Swarm combat simulation 2002 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Biological attack response models 2002 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) Performance-captured digital characters 2002 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) Honeybee colonies 2003 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Gene drive population models 2003 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Land-use change agent models 2003 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) Processor thermal modelling 2003 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Station systems simulation 2003 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Tower defence 2003 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tower-defence) Neutron-star crust pasta dynamics 2004 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) Stabilizer circuit simulation 2004 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Planet population synthesis 2004 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Extreme-event attribution 2004 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Autonomous vehicle testing 2004 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) Ultrasound training simulators 2004 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Live-coded music and visuals 2004 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) Physics sandboxes and building 2004 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Escape-room puzzles 2004 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#escape-room-games) Volunteer-computed perturbed-physics ensembles 2005 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Cancer drug response and resistance dynamics 2005 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Magnetic resonance image simulation 2005 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Agent-based epidemics 2005 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Precision livestock monitoring 2005 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Surgery and medical games 2005 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) Falling-sand games 2005 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) Supernova neutrino flavour evolution 2006 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) Gravitational-wave mock data challenges 2006 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) Computational materials screening 2006 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Whole virus particles 2006 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virus-particles) Tumour evolution agent-based models 2006 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Tumour microenvironment evolution 2006 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Locust marching bands 2006 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) Marine larval dispersal and connectivity 2006 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Large-scale brain circuits 2006 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Compiler and program optimisation search 2006 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Virtual concerts 2006 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) Survival and crafting 2006 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) User-generated game platforms 2006 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Motion-controller games 2006 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#motion-controller-games) Planetesimal formation by streaming instability 2007 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Global cloud-resolving models 2007 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Machine-learned interatomic potentials 2007 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Coarse-grained molecular dynamics 2007 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Lattice thermal-conductivity calculation 2007 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Microbial community metabolic models 2007 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Obesity and diet agent-based models 2007 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) Coral reef resilience models 2007 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Ancient trade and exchange 2007 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Virtual human patients 2007 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Position-based dynamics 2007 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Massive-neutrino cosmological simulation 2008 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation 2008 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Global storm-resolving simulation 2008 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Individual-based malaria models 2008 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Malaria transmission and intervention models 2008 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Disaster economic ripple models 2008 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Human dispersal 2008 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) Crime hotspot dynamics 2008 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) Warehouse robot fleet coordination 2008 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Whole-brain network models 2008 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Digital de-ageing 2008 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Job and machinery simulation 2008 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Exoplanet atmosphere retrieval 2009 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) Brain-stimulation field models 2009 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Virtual-population drug exposure models 2009 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Mobility-network epidemic models 2009 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Vaccine allocation optimisation 2009 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-allocation-optimisation) Closed-loop diabetes control in silico 2009 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) Pollination service across landscapes 2009 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) Graphics processor architecture simulation 2009 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) Robotic surgery simulators 2009 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators 2009 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Cyber ranges 2009 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) Block and voxel sandboxes 2009 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Physics puzzles 2009 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) Augmented reality pets 2009 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) era 2010s 103 Constrained simulations of the local universe 2010 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Cosmological emulators 2010 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Kilonova radiative transfer 2010 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) Physics-based seismic hazard 2010 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Virtual anatomical phantoms for imaging 2010 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Synthetic patient record generation 2010 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) Digestion and gastric flow simulation 2010 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) Wind-farm large-eddy simulation 2010 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Stacked chip thermal modelling 2010 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) Smart-city sensor network simulation 2010 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Lightweight network emulation 2010 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) Biometric-adaptive games 2010 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Nuclear lattice effective field theory 2011 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Digital quantum simulation on hardware 2011 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#digital-quantum-simulation) Coarse-grained DNA and RNA models 2011 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coarse-grained-nucleic-acids) In silico clinical trials 2011 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Drug repurposing network models 2011 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-repurposing-networks) Agrivoltaic light-sharing models 2011 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Migration under climate stress 2011 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#climate-migration-abm) Co-simulation of linked models 2011 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Smart-grid co-simulation 2011 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Vehicular network simulation 2011 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) Magnetar magnetosphere and flare simulation 2012 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Marine debris and Lagrangian drift modelling 2012 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Learned density functionals 2012 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Whole-cell models 2012 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Human mobility and migration models 2012 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Housing market agent-based models 2012 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#housing-market-abm) Flash-crash market models 2012 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Functional spiking brain models 2012 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Automation and factory building 2012 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Exploration and walking 2012 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#exploration) Gravitational-wave template banks from numerical relativity 2013 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Gut microbiome community models 2013 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Coronary flow reserve from scans 2013 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Outbreak genomic epidemiology 2013 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Vaccine antigen design 2013 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) Forward-time genome simulation 2013 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Multi-model crop ensembles 2013 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Global gridded crop model ensembles 2013 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Opioid epidemic system dynamics 2013 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opioid-system-dynamics) Soft robot simulation 2013 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Snow and granular material simulation 2013 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) Soft-body vehicle crash simulation 2013 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Idle and incremental 2013 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#idle-games) Battle royale 2013 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Cloud-streamed games 2013 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) Wave dark matter simulations 2014 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Quantum chemistry on quantum computers 2014 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-chemistry-on-quantum-computers) General ecosystem models 2014 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Honeybee colony and landscape models 2014 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Poaching and anti-poaching patrol games 2014 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#poaching-patrol-games) Shared autonomous vehicle fleets 2014 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Virtual reality social worlds 2014 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) Tokamak whole-device modelling 2015 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Initial-condition large ensembles 2015 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Displacement and refugee flows 2015 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Lattice gauge theory on quantum hardware 2016 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) Neural-network quantum states 2016 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) Learned error-correction decoders 2016 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) Learned fluid solvers 2016 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Differentiable physics simulation 2016 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Synthetic training data 2016 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#synthetic-data) AI safety red-teaming environments 2016 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Blockchain consensus simulation 2016 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) Extraction shooters 2016 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Location-based and arcade VR 2016 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#large-scale-vr) Generative calorimeter shower models 2017 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#calorimeter-shower-generators) Recommender feedback-loop simulation 2017 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Physics-informed neural networks 2017 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Domain-randomised sim-to-real training 2017 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Open driving simulators with sensor models 2017 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) Drone flight simulation 2017 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Mega-constellation collision risk 2017 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) Multi-agent AI societies 2017 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) Embodied household simulators 2017 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) Neural network verification 2017 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) World-Earth models 2018 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Learned subgrid parameterisation 2018 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) Learned equilibrium samplers 2018 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Learned protein structure prediction 2018 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#learned-structure-prediction) Virtual imaging trials 2018 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Near-term ecological forecasting 2018 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Misinformation and rumour spread 2018 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Learned legged locomotion 2018 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Continuous cellular automata 2018 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-cellular-automata) Continuous artificial life 2018 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) Learned world models 2018 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learned-world-models) FPGA-accelerated system simulation 2018 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Neural avatars 2018 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-avatars) Physics-based character control 2018 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) Flow-based sampling for lattice field theory 2019 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Neural-network wavefunctions for molecules 2019 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Cell perturbation-response models 2019 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#perturbation-response-models) Neural predictive models of sensory brain areas 2019 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#neural-predictive-digital-twins) Agent-based exchange simulators 2019 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Algorithmic pricing collusion 2019 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Neural operators 2019 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Open-ended environment generation 2019 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) Recommender-system simulators 2019 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) Virtual production sets 2019 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Auto-battlers 2019 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Agent-based game playtesting 2019 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) era 2020s 56 Differentiable cosmological simulation 2020 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Cardiac digital twins 2020 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Scenario modelling hubs 2020 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Digital contact-tracing models 2020 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Indoor airborne transmission simulation 2020 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) AI-designed economic policy simulation 2020 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Coupled epidemic and economy models 2020 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#epidemic-economy-coupled) Graph-network learned simulators 2020 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Tactile sensor simulation 2020 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) Supply chain digital twins 2020 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Neural cellular automata 2020 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Neural scene rendering 2020 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) Flight simulation over streamed Earth 2020 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Quantum network simulation 2021 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) Synthetic sky survey catalogues and images 2021 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Neural inference for gravitational waves 2021 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) Earth-system digital twins 2021 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Generative models of crystals 2021 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) Network digital twins 2021 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) GPU-parallel robot learning environments 2021 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Adversarial driving-scenario generation 2021 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) AI-guided conjecture discovery 2021 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#ai-guided-conjecture-discovery) Language-model program execution 2021 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#llm-program-execution) Autonomous cyber-defence gyms 2021 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) Learned plasma control in simulation 2022 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) Machine-learned weather 2022 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-weather) Universal interatomic potentials 2022 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#universal-interatomic-potentials) Language-model survey respondents 2022 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-survey-respondents) Language-model behavioural experiments 2022 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-behavioural-experiments) Populated social-system prototypes 2022 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Language-grounded negotiation agents 2022 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Learned algorithm and construction search 2022 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) Learned climate emulators 2023 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-climate-emulators) Generative ensemble weather forecasting 2023 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) Language-model agent societies 2023 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) Language-model user simulation for recommenders 2023 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) Language-model macroeconomic agents 2023 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) Language-model agent organisations 2023 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Learned humanoid locomotion 2023 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Learned drone racing 2023 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Simulated web environments for agents 2023 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Learned real-world interactive simulators 2023 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#real-world-interactive-simulators) Generative driving world models 2023 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#driving-world-models) Software engineering agent sandboxes 2023 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Language-model simulated students 2023 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) Language-model conflict rehearsal 2023 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-conflict-rehearsal) Generative protein ensembles 2024 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#generative-protein-ensembles) Language-model social platform simulation 2024 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Connectome-constrained whole-brain models 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Connectome-based insect brain models 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) Self-replicating program soups 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Neural game engines 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Interactive generative worlds 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#interactive-generative-worlds) Desktop computer agent environments 2024 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) Agent hospitals 2024 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Language-model wargame agents 2024 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) --- title: "Interactive models · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/run description: "Small simulations that run in the browser: the Game of Life, Monte Carlo estimation of π, a flock, an epidemic, falling sand, spontaneous traffic jams, ant trails and Turing patterns." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Interactive models · 14 small simulations that run in the browser Some of the simulations on this site, shrunk so your browser can run them. None starts on its own. Each one counts its own operations, so you can compare what your device manages with the computing a serious run of the same kind needs. ## The Game of Life John Conway’s cellular automaton of 1970\. Each cell is alive or dead, and at every step it looks at its eight neighbours: a dead cell with exactly three comes alive, a live cell with two or three survives, and everything else dies. That's all the rules there are. Click the grid to add cells. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of cellular automata: about 10^12 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) ## Estimating π by sampling Random points land in a square that holds a quarter circle. The fraction that land inside is π/4\. This is Monte Carlo estimation at its simplest. The error shrinks only as the square root of the number of samples, so each extra correct digit takes a hundred times more samples. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of monte carlo estimation of constants: about 10^9 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) ## Flocking Craig Reynolds’ three rules from 1987: separation, alignment and cohesion. No bird knows the shape of the flock, and there's no leader. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of flocking and schooling: about 10^13 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) ## An epidemic 280 agents move at random in a box. Three begin infected. An agent who passes close to an infected one may catch it, and recovers after a fixed time. You can change how many people stay at home. Press Reset to apply it. This is the agent-based formulation. The compartmental formulation models the same dynamics with a few differential equations. Run Step Reset Stay at home: 0% Share ↗ This device: press Run to measure measured · A serious run of agent-based epidemics: about 10^16 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) ## Falling sand Each pixel is a grain. At each step a grain falls if the space below is empty, or slides diagonally if it can. Piles, slopes and avalanches emerge from this single rule. Draw on the canvas to add grains. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of falling-sand games: about 10^12 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) ## Spontaneous traffic jams A single-lane ring road, drawn as a strip of time: each row is one moment, newest at the bottom, and each coloured dot is a car (red stopped, gold slow, green at the limit). Each driver speeds up when there's room, brakes for the car ahead, and sometimes slows down at random. That's the whole model, from Kai Nagel and Michael Schreckenberg (1992). Above a density of about 15%, jams appear with no outside cause and drift backwards against the traffic. Run Step Reset Cars: 30% of the road Dawdling: 25% Share ↗ This device: press Run to measure measured · A serious run of traffic flow: about 10^13 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) ## Ant trails Two hundred ants leave the gold nest and wander. Each one deposits pheromone as it moves and steers towards the strongest pheromone ahead. One kind leads back to the nest, the other to food. No ant knows where anything is, yet within a minute the colony has laid trails between the nest and the pink food. Jean-Louis Deneubourg studied this in his ant experiments of 1990, and Marco Dorigo built it into his ant colony algorithms. Click to drop more food. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of ant colony foraging: about 10^11 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) ## Turing patterns Two chemicals in a dish. One is fed in at a steady rate. The other eats it, makes more of itself, and slowly decays. Both spread out, at different speeds. Turing (1952) showed that a system like this can turn an even mixture into spots and stripes. This is the Gray–Scott reaction, mapped by John Pearson (1993). Change the settings and you get coral, dividing-cell, fingerprint and worm patterns. Click to give it a nudge. Run Step Reset MixtureCoralDividing cellsFingerprintsWorms Share ↗ This device: press Run to measure measured · A serious run of pattern formation: about 10^12 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) ## A sandpile Drop sand on a table one grain at a time. Any square holding four grains topples and passes one to each neighbour, and those may topple in turn. Grains that fall off the edge are gone. Per Bak, Chao Tang and Kurt Wiesenfeld used this model in 1987 to show how a system can organise itself into a critical state. Most grains do nothing. A few set off avalanches across the whole pile. Avalanche sizes have no typical scale. Click to drop a grain at another site. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of self-organised criticality: about 10^11 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) ## Mild preferences, sharp segregation Two kinds of household, cyan and pink, are placed at random. A household is content if enough of its eight neighbours are its own kind. If not, it moves to a random empty spot. Schelling (1971) did this with coins on a chessboard. Even when households are happy to be in a minority, you still get sharp segregation. You can change the share of like neighbours they need. Run Step Reset Wants at least 30% alike Share ↗ This device: press Run to measure measured · A serious run of residential sorting: about 10^9 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) ## Three bodies Three masses and Newton’s law of gravity. Two bodies can orbit forever. Three have no general exact solution, as Henri Poincaré showed in the 1890s, and from most starting points one body gets thrown out. The figure-eight orbit is one of the rare stable repeating solutions. Cris Moore found it in 1993, and Alain Chenciner and Richard Montgomery proved it exists in 2000\. The Pythagorean start has three bodies at rest, with masses 3, 4 and 5\. Carl Burrau posed it in 1913\. The readout shows how well the numerical method conserves total energy. An exact solution would conserve it perfectly. Run Step Reset StartFigure eightPythagorean, 3 : 4 : 5Random, at rest Share ↗ This device: press Run to measure measured · A serious run of orbital dynamics: about 10^13 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) ## Forest fires Empty ground slowly grows trees. Lightning sometimes sets a tree alight, and the fire spreads to nearby trees before burning out. Barbara Drossel and Franz Schwabl studied this model in 1992\. The forest never settles down, and fires of every size keep thinning it, just like the sandpile. Click a tree to ignite it. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of wildfire spread: about 10^13 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) ## A magnet Each pixel is a spin pointing up or down. Each one tends to line up with its four neighbours, and heat jostles them out of line. Ernst Ising solved the one-dimensional line in 1925; Lars Onsager solved this flat grid exactly in 1944 and found a sharp critical temperature, about 2.27 in these units. Below it, regions merge into big domains and the grid becomes magnetised. Above it, the pattern stays disordered. You can change the temperature while it runs. Run Step Reset Temperature 2.3 Share ↗ This device: press Run to measure measured · A serious run of magnetism and phase transitions: about 10^12 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) ## Sharks and fish A sea of fish (cyan) and sharks (pink). Fish move at random and breed. Sharks eat adjacent fish, breed more slowly, and starve if they go too long without food. A. K. Dewdney named this world Wa-Tor in 1984\. The plot below shows the two populations, each on its own scale. Fish increase, sharks follow, fish collapse, sharks starve, and the cycle repeats. Alfred Lotka and Vito Volterra got the same swing from their equations in the 1920s. Here it comes from individual agents. Run Step Reset Share ↗ This device: press Run to measure measured · A serious run of predator–prey dynamics: about 10^9 FLOPS rough · [The entry ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) --- title: "Simulations by cost · Simulation Hypothesis" url: https://simulation-hypothesis.com/simulations/costs description: "How much computing each kind of simulation uses, from no computer at all to the largest machines on Earth." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations by computing needed · 941 simulations Roughly how much computing a serious run uses today, in operations per second, the Sandbox’s unit. For scale, the observable universe treated as a computer does about 10^104\. Every figure has a confidence tag, and most are rough. Expand all Collapse all cost The largest supercomputers 16 About 10^18 operations per second and above: the largest supercomputers. Wave dark matter simulations 10^19 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#fuzzy-dark-matter-waves) Constrained simulations of the local universe 10^19 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#constrained-local-universe) Earth-system digital twins 10^19 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system-digital-twins) Global storm-resolving simulation 10^19 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-storm-resolving) Nuclear lattice effective field theory 10^18 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-lattice-effective-field-theory) Laser wakefield acceleration 10^18 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#laser-wakefield-acceleration) Cosmological emulators 10^18 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-emulators) Global cloud-resolving models 10^18 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#global-cloud-resolving-models) Initial-condition large ensembles 10^18 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#climate-initial-condition-ensembles) Physics-based seismic hazard 10^18 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#physics-based-seismic-hazard) Geodynamo simulation 10^18 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geodynamo) Neural-network wavefunctions for molecules 10^18 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#neural-network-wavefunctions-electrons) Generative models of crystals 10^18 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#generative-crystal-models) Learned protein structure prediction 10^18 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#learned-structure-prediction) Riemann zeta zero computation 10^18 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#riemann-zeta-zero-computation) Nuclear stockpile simulation 10^18 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#stockpile-simulation) cost Supercomputers and brains 127 National supercomputers, and the conventional estimate for a human brain (about 10^16). Cosmological N-body 10^17.5 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmological-n-body) Lattice QCD 10^17 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-qcd) Flow-based sampling for lattice field theory 10^17 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#flow-based-lattice-sampling) Fusion plasma turbulence 10^17 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-plasma) Galaxy formation 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-formation) Cosmic reionization 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#reionization) Massive-neutrino cosmological simulation 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#massive-neutrino-cosmology) Modified-gravity structure formation 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#modified-gravity-nbody) Synthetic sky survey catalogues and images 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#synthetic-sky-survey-images) Core-collapse supernovae 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova) Giant-impact simulations 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#giant-impact-moon-formation) Neutron star mergers 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#neutron-star-mergers) Gravitational-wave template banks from numerical relativity 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-template-banks) Neural inference for gravitational waves 10^17 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gravitational-wave-neural-inference) Earth system models 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earth-system) Palaeoclimate 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#paleoclimate) Solar geoengineering 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#geoengineering-modelling) Extreme-event attribution 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#extreme-event-attribution) Volunteer-computed perturbed-physics ensembles 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volunteer-perturbed-physics-ensembles) Coupled carbon-cycle and climate simulation 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-carbon-climate) Numerical weather prediction 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#weather-forecast) Seasonal forecasting 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seasonal-forecasting) Atmospheric reanalysis 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-reanalysis) Full-waveform seismic inversion 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#full-waveform-inversion) Spectral-element seismic wave propagation 10^17 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#seismic-spectral-element) Machine-learned interatomic potentials 10^17 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#machine-learned-interatomic-potentials) Universal interatomic potentials 10^17 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#universal-interatomic-potentials) Quantum Monte Carlo for electrons 10^17 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-monte-carlo-electrons) Metadynamics and enhanced sampling 10^17 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#metadynamics-enhanced-sampling) Whole virus particles 10^17 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virus-particles) Volunteer-computed molecular dynamics 10^17 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#volunteer-computing-molecular-dynamics) Language-model social platform simulation 10^17 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-social-platform-simulation) Turbulence 10^17 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#turbulence) Learned humanoid locomotion 10^17 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#humanoid-locomotion-learning) Interactive generative worlds 10^17 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#interactive-generative-worlds) Learned real-world interactive simulators 10^17 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#real-world-interactive-simulators) Generative driving world models 10^17 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#driving-world-models) Digits of pi by computer 10^17 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#pi-digit-computation) Learned algorithm and construction search 10^17 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#learned-algorithm-discovery) Black hole mergers 10^16.5 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#numerical-relativity) Generative calorimeter shower models 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#calorimeter-shower-generators) Particle-in-cell plasma 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#particle-in-cell) Inertial confinement implosion 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#inertial-confinement-fusion) Tokamak edge pedestal and ELM modelling 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-edge-pedestal-elm) Tokamak whole-device modelling 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#tokamak-whole-device-modelling) Collisionless shock simulation 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collisionless-shock-hybrid) Learned plasma control in simulation 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reinforcement-learning-plasma-control) Quantum many-body systems 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-many-body) Topological quantum matter 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#topological-quantum-matter) Neural-network quantum states 10^16 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-network-quantum-states) Intergalactic medium and the Lyman-alpha forest 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#lyman-alpha-forest) Self-interacting dark matter simulation 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#self-interacting-dark-matter) Weak-lensing ray tracing through simulated universes 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#weak-lensing-ray-tracing) Differentiable cosmological simulation 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#differentiable-cosmological-simulation) Star formation 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#star-formation) Common-envelope evolution 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#common-envelope-evolution) Collapsar and gamma-ray burst jets 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gamma-ray-burst-collapsar) Planetary interiors and dynamos 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-interiors) Planetesimal formation by streaming instability 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetesimal-streaming-instability) Accretion discs and jets 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#accretion) Solar interior and dynamo 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#solar-dynamo) Magnetar magnetosphere and flare simulation 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#magnetar-magnetosphere) Tidal disruption of stars by black holes 10^16 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#tidal-disruption-events) Regional climate downscaling 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#regional-climate-downscaling) Superparameterisation 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#superparameterization) Learned subgrid parameterisation 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-subgrid-parameterisation) Tropical cyclones 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tropical-cyclones) Severe convective storms 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#severe-storms) Generative ensemble weather forecasting 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#generative-ensemble-weather) Ensemble weather forecasting 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ensemble-forecasting) Ocean circulation 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-circulation) Earthquakes and seismic waves 10^16 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquakes) Computational materials screening 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#materials-screening) Ab initio molecular dynamics 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ab-initio-molecular-dynamics) Real-time electron dynamics 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#real-time-tddft) Learned density functionals 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-density-functionals) Combustion 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#combustion) Reactive force-field dynamics 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reactive-force-field-dynamics) Learned equilibrium samplers 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#learned-equilibrium-sampling) Coarse-grained molecular dynamics 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#coarse-grained-molecular-dynamics) Enhanced-sampling free-energy methods 10^16 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#enhanced-sampling-free-energy) Protein folding and dynamics 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#protein-dynamics) Membranes and ion channels 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#membranes) Generative protein ensembles 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#generative-protein-ensembles) Cell perturbation-response models 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#perturbation-response-models) The heart 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart) Neural predictive models of sensory brain areas 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#neural-predictive-digital-twins) Agent-based epidemics 10^16 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#agent-epidemics) Language-model macroeconomic agents 10^16 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-macroeconomic-agents) Language-grounded negotiation agents 10^16 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-negotiation-diplomacy) Wind-farm large-eddy simulation 10^16 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#wind-farm-large-eddy-simulation) Learned legged locomotion 10^16 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#legged-locomotion-learning) Learned drone racing 10^16 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-drone-racing) Rocket engine simulation 10^16 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rocket-propulsion) Self-play strategy training 10^16 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-play-training) REM dreaming 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#rem-dreaming) Lucid dreaming 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#lucid-dreaming) Hippocampal replay in rats 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-replay) Threat-simulation theory of dreams 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#threat-simulation-theory) Sleep-dependent memory consolidation 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#memory-consolidation-sleep) Hypnagogic imagery 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hypnagogic-imagery) Mental rehearsal in athletes 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rehearsal-athletes) Episodic future thinking 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#episodic-future-thinking) Counterfactual thinking 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#counterfactual-thinking) Mental rotation 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-rotation) Mental navigation 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-navigation) Mind-wandering and daydreaming 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mind-wandering) Theory of mind 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#theory-of-mind) Empathy as simulation theory 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#empathy-simulation-theory) Mirror systems 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mirror-systems) Audience design 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#audience-design) Visual perspective-taking 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#perspective-taking) Joint attention 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#joint-attention) Children's pretend play 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#pretend-play-children) Animal play as practice 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-play-practice) Imaginary companions 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#imaginary-companions) Sociodramatic play 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#sociodramatic-play) Paracosms 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#paracosms) Object play in primates 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#primate-object-play) Predictive processing 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#predictive-processing) Motor forward models 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-forward-models) The body schema 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-schema) Hallucination as uncontrolled prediction 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hallucination-uncontrolled-prediction) Blind-spot filling-in 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#blind-spot-filling-in) Interoception 10^16 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#interoception) Climate effects of nuclear war 10^16 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#nuclear-winter) Massively multiplayer worlds 10^16 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mmo) cost Clusters 67 A university cluster or a rack of accelerators. Collider event generation 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#collider-events) Detector response 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#detector-response) Neutrino detector simulation 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neutrino-detectors) Nuclear structure 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-structure) Reactor core physics 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#reactor-core) Time-dependent nuclear mean-field dynamics 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-tdhf) Neutron-star crust pasta dynamics 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#nuclear-pasta-md) Plasma equilibrium and stability 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-equilibrium-stability) Magnetic reconnection 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#magnetic-reconnection) Stellarator configuration optimisation 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stellarator-optimisation) Quantum computer emulation 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-circuit-emulation) Quantum error correction 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-error-correction) Learned error-correction decoders 10^15 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#neural-error-correction-decoders) Supernova neutrino flavour evolution 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#supernova-neutrino-flavour) Stellar surface convection simulation 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-surface-convection) Interstellar magnetised turbulence 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#interstellar-mhd-turbulence) Planet formation 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-formation) Planetary and exoplanet atmospheres 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planetary-atmospheres) Space weather 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#space-weather) Pulsar magnetospheres 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#pulsar-magnetosphere) Black-hole shadow and image rendering 10^15 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#black-hole-shadow-imaging) Ice sheets and sea level 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ice-sheets) Learned climate emulators 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-climate-emulators) Ocean ecosystem and biogeochemistry modelling 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-biogeochemistry) Sea ice 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#sea-ice-dynamics) Ocean wave forecasting 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#ocean-wave-forecasting) Geological carbon-dioxide storage simulation 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#co2-storage-reservoir) Mantle convection and plate tectonics 10^15 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mantle-convection) Electronic structure 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#electronic-structure) Reaction dynamics 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-dynamics) Excited states and photochemistry 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#excited-states-photochemistry) Path-integral molecular dynamics 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#path-integral-molecular-dynamics) Lattice thermal-conductivity calculation 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#phonon-thermal-transport) Catalysis 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#catalysis) Chemical reactor engineering 10^15 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chemical-reactor-engineering) Molecular docking and drug binding 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-binding) Enzyme catalysis 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#enzyme-catalysis) Blood flow 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#blood-flow) Cardiac digital twins 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cardiac-digital-twins) Heart valve fluid-structure interaction 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#heart-valve-fluid-structure) Vaccine antigen design 10^15 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-antigen-design) Language-model agent societies 10^15 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-generative-agent-societies) AI-designed economic policy simulation 10^15 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ai-economist) Aerodynamics 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#aerodynamics) Cavitation simulation 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#cavitation) Neural operators 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#neural-operators) Lattice Boltzmann flow simulation 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-boltzmann) Fluid-structure interaction 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fluid-structure-interaction) Crash simulation 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#crash) Autonomous vehicle testing 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#autonomous-vehicles) GPU-parallel robot learning environments 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#gpu-parallel-robot-learning) Atmospheric entry 10^15 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#reentry) Large-scale brain circuits 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-circuits) Functional spiking brain models 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#functional-brain-models) Reinforcement learning environments 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learning-environments) Multi-agent AI societies 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#multi-agent-ai) Learned world models 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#learned-world-models) Open-ended environment generation 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#open-ended-environment-generation) Neural game engines 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-game-engines) Software engineering agent sandboxes 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#software-engineering-agent-sandboxes) Desktop computer agent environments 10^15 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#desktop-computer-agent-environments) AI-guided conjecture discovery 10^15 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#ai-guided-conjecture-discovery) Turing-machine enumeration 10^15 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#turing-machine-enumeration) FPGA-accelerated system simulation 10^15 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fpga-accelerated-system-simulation) Blast and impact protection 10^15 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#blast-protection) Physics-based character control 10^15 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#physics-based-character-control) Neural scene rendering 10^15 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-scene-rendering) cost A single workstation 233 A desktop, a games console, or a workstation with a graphics card. Cosmic-ray air showers 10^14 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#air-showers) Fusion breeding blanket neutronics 10^14 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#fusion-blanket) Superconducting vortex dynamics 10^14 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#superconducting-vortex-dynamics) Path-integral Monte Carlo of quantum fluids 10^14 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#path-integral-monte-carlo) Cosmic string network evolution 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-string-networks) Impact cratering 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#asteroid-impact) Planet population synthesis 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-population-synthesis) Planet-disk interaction and migration 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#planet-disk-migration) Gravitational-wave mock data challenges 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#gw-mock-data-challenges) Kilonova radiative transfer 10^14 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#kilonova-light-curves) World-Earth models 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#world-earth-models) Dynamic global vegetation and carbon-cycle modelling 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#dynamic-vegetation-carbon-cycle) Machine-learned weather 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#learned-weather) Air quality and dispersion 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#air-quality) Atmospheric boundary-layer large-eddy simulation 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#atmospheric-boundary-layer-les) Mineral dust emission and transport 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#mineral-dust-cycle) Reactive transport in the subsurface 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#reactive-transport-geochemistry) Earthquake-cycle simulation 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-cycle-simulation) Coupled fire and atmosphere models 10^14 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coupled-fire-atmosphere) Spectroscopy prediction 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#spectroscopy-prediction) Solvation free energy 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#solvation-free-energy) Transition-state and reaction-path search 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#reaction-path-search) Liquids and solutions 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#liquids-solutions) Polymers and soft matter 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#soft-matter) Glass formation 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#glass-formation) Molten salts and ionic liquids 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ionic-liquids-electrolytes) Dissipative particle dynamics 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dissipative-particle-dynamics) Fracture and defects 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fracture) Microstructure 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#microstructure) Granular materials 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#granular) Dislocation dynamics 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#dislocation-dynamics) Battery and electrochemical cell modelling 10^14 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#battery-electrochemistry) Coarse-grained DNA and RNA models 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coarse-grained-nucleic-acids) Whole-cell models 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-cell) Breathing and airways 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#lungs) In silico clinical trials 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#in-silico-trials) Surgical planning with patient-specific models 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#patient-specific-surgical-planning) Coronary flow reserve from scans 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#coronary-flow-reserve-cfd) Indoor airborne transmission simulation 10^14 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#indoor-airborne-transmission) Animal locomotion 10^14 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locomotion) General ecosystem models 10^14 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#general-ecosystem-models) Forward-time genome simulation 10^14 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forward-genetic-simulation) Language-model survey respondents 10^14 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-survey-respondents) Language-model behavioural experiments 10^14 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-behavioural-experiments) Language-model user simulation for recommenders 10^14 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-recommender-user-simulation) Language-model agent organisations 10^14 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#llm-agent-organisations) Multiphase and pipeline flow 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multiphase-flow) Ice accretion simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#icing) Graph-network learned simulators 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-mesh-particle-simulators) Rarefied-gas direct simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rarefied-gas-dsmc) Structural analysis 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#structural-analysis) Acoustics and vibration 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#acoustics) Fatigue and crack growth 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#durability-fatigue) Peridynamic fracture modelling 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#peridynamic-fracture) Chip logic simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#logic-simulation) Electromagnetics 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#electromagnetics) Semiconductor device simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-devices) Domain-randomised sim-to-real training 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#domain-randomised-sim-to-real) Batteries and fuel cells 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#batteries) Mega-constellation collision risk 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#mega-constellation-debris-risk) Metal casting and solidification 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-casting) Welding simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#welding-simulation) Additive manufacturing simulation 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#additive-manufacturing) Metal forming and stamping 10^14 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#metal-forming) Transport and land use 10^14 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transport-land-use) Power grids 10^14 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-grids) Infrastructure interdependence 10^14 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#interdependence) Whole-brain network models 10^14 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#whole-brain) Connectome-based insect brain models 10^14 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-insect-brain) Evolutionary robotics 10^14 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#evolutionary-robotics) Synthetic training data 10^14 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#synthetic-data) AI safety red-teaming environments 10^14 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#ai-redteam-environments) Cryptographic attack modelling 10^14 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#cryptographic-attack-modelling) Fuzz testing 10^14 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fuzz-testing) Language-model program execution 10^14 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#llm-program-execution) Parallel discrete-event simulation 10^14 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#parallel-discrete-event-simulation) Agent hospitals 10^14 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#agent-hospital-simulation) Language-model simulated students 10^14 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-simulated-students) Agent-based combat models 10^14 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#agent-combat) Networked training exercises 10^14 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#networked-exercises) Radar and sensor performance 10^14 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sensors-radar) Directed energy weapon simulation 10^14 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#directed-energy-weapons) Torpedo and underwater weapon simulation 10^14 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#underwater-weapons) Snow and granular material simulation 10^14 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#snow-granular-vfx) Physically based light transport 10^14 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#light-transport-path-tracing) Tactical military simulation 10^14 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#military-sims) Battle royale 10^14 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#battle-royale) Location-based and arcade VR 10^14 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#large-scale-vr) Cloud-streamed games 10^14 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cloud-streamed-games) Flight simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#flight-sim-games) Racing simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racing-sim) Naval and submarine simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#naval-sims) City building 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#city-builders) Automation and factory building 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#automation-games) Grand strategy 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#grand-strategy) Real-time strategy 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#real-time-strategy) Block and voxel sandboxes 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#voxel-sandbox) Survival and crafting 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#survival-crafting) Physics sandboxes and building 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-sandbox) Immersive simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#immersive-sim) Open-world adventure 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-world) Shooters 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#shooters) Team arena games 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arena-games) Sports simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-sims) Virtual reality 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr) Cockpit and rig simulation 10^13.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#cockpit-sim-rigs) Accelerator beam dynamics 10^13 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#beam-dynamics) Radiation transport 10^13 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#radiation-transport) Nuclear criticality safety 10^13 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#criticality-safety) Industrial plasma processing 10^13 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#plasma-processing) Ultracold atomic gas dynamics 10^13 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#cold-atom-bec) Cosmic microwave background 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cmb) Semi-analytic galaxy formation 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#semi-analytic-galaxy-formation) Early-universe lattice field dynamics 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#early-universe-lattice-fields) Stellar atmospheres and spectra 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-atmospheres) Orbital dynamics 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#orbital-stability) Exoplanet detection and characterisation 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-detection) Radiation belt modelling 10^13 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#radiation-belt-dynamics) Thermosphere and ionosphere modelling 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#thermosphere-ionosphere-model) Tsunamis and storm surge 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#tsunami-surge) Petroleum and gas reservoir simulation 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#petroleum-reservoir-simulation) Volcanic eruptions and lava flows 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#volcanoes) Landscape evolution 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landscape-evolution) Wildfire spread 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#wildfire) Landslides and debris flows 10^13 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#landslides) Quantum wavepacket dynamics 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-wavepacket-dynamics) Colloids and nanoparticle assembly 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#colloids-nanoparticle-assembly) Adsorption in porous materials 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#grand-canonical-adsorption) Thin film growth 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#thin-film-growth) Radiation-damage cascades in materials 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#radiation-damage-cascades) Corrosion 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#corrosion) Crystallisation 10^13 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystallisation) Tissue and tumour growth 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tissue-growth) Immune response 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#immune-response) Radiotherapy dose calculation 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#radiotherapy-dose-calculation) Outbreak genomic epidemiology 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#outbreak-genomics) Individual-based malaria models 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-individual-based-models) Virtual imaging trials 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-imaging-trials) Predictive toxicology 10^13 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#toxicology-simulation) Flocking and schooling 10^13 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#flocking) Forest dynamics 10^13 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#forest-dynamics) Global gridded crop model ensembles 10^13 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-intercomparison) Populated social-system prototypes 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-computing-prototype-populations) Pedestrian and crowd dynamics 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#pedestrian-dynamics) Agent-based economies 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#agent-economies) Financial markets 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-markets) Financial risk 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#risk) Demographic microsimulation 10^13 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#demographic-microsimulation) Physics-informed neural networks 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#physics-informed-neural-networks) Fire dynamics large-eddy simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#fire-dynamics-large-eddy) Multibody dynamics 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#multibody) Tribology and contact mechanics 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tribology-contact) Topology optimisation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#topology-optimisation) Circuit simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#circuit-simulation) Computer network simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-simulation) Optical lithography simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lithography-simulation) Robot simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#robot-simulation) Digital twins 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#digital-twins) Planetary rover mobility 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#rover-mobility) Exoskeleton and prosthetic control 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#exoskeleton-simulation) Adversarial driving-scenario generation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#adversarial-driving-scenarios) Machining simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#machining-simulation) Injection moulding simulation 10^13 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#injection-moulding) Traffic flow 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#traffic) Urban growth 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#urban-growth) Evacuation and emergency response 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#evacuation) Public transit network simulation 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#transit-networks) Ride-hailing and dispatch simulation 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#ride-hailing-dispatch) Supply chains 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chains) Warehouse and distribution centre simulation 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-automation) Last-mile delivery routing 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#last-mile-delivery) Building energy and daylight 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#building-energy) Mobile network planning 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#mobile-network-planning) Data centre facility simulation 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#data-centre-simulation) Satellite broadband constellation simulation 10^13 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#satellite-constellations) Neuromorphic hardware simulation 10^13 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neuromorphic-simulation) Brain disease and seizure spread 10^13 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#brain-disease-spread) Evolved virtual creatures 10^13 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#virtual-creatures) Simulated web environments for agents 10^13 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-web-environments) Computational number theory searches 10^13 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computational-number-theory) Bounded model checking 10^13 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#bounded-model-checking) Neural network verification 10^13 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#neural-network-verification) Approximate Bayesian computation 10^13 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#approximate-bayesian-computation) Full-flight simulators 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#flight-simulators) Driving and rail simulators 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#driving-simulators) Ship bridge simulators 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ship-bridge) Spaceflight and mission control 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#spaceflight-training) Control-room simulators 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#control-rooms) Language-model conflict rehearsal 10^13 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#llm-conflict-rehearsal) Military logistics 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#military-logistics) Models of civil conflict 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#conflict-models) Language-model wargame agents 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#llm-wargame-agents) Military flight and mission simulators 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-flight-trainers) Cyber ranges 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-ranges) Displacement and refugee flows 10^13 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#displacement) Fluid and smoke simulation for effects 10^13 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#fluids-smoke-vfx) Digital humans and faces 10^13 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-humans-faces) Virtual production sets 10^13 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-production-sets) Neural avatars 10^13 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#neural-avatars) Digital de-ageing 10^13 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#facial-de-ageing) Spaceflight simulation 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-flight-games) Arcade racing 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#arcade-racing) Driving and transport simulation 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#driving-job-sims) Job and machinery simulation 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#job-sims) Flight simulation over streamed Earth 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#streamed-earth-flight) Life simulation 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#life-sims) Farming and village life 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#farming-life) Social hangout worlds 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-simulation-avatars) Colony simulation 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#colony-sims) Management and tycoon 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#management-tycoon) God games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#god-games) Ecosystem and evolution games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#evolution-games) 4X strategy 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#four-x) Space exploration and trading 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#space-trading) Level and world creation tools 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sandbox-creation-tools) Role-playing games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rpg) Exploration and walking 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#exploration) Action adventure 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#action-adventure) Stealth 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#stealth) Extreme and action sports 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extreme-sports-sims) Physics puzzles 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#physics-puzzles) Motion-controller games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#motion-controller-games) Haptic and force-feedback games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#haptic-feedback-games) Biometric-adaptive games 10^13 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#biometric-adaptive-games) Relationship simulation 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#relationship-sims) Parenting and family life 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#parenting-sims) Hex-and-counter war games 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-wargames) Tactics 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tactics) Fighting games 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fighting) Sports management 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#sports-management) Fitness and motion games 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fitness-games) Golf simulation 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#golf-sims) Combat sports simulation 10^12.5 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#combat-sports-sims) cost Portable devices 432 A phone, a laptop, an older machine, or less. Radioactivation and decay chains 10^12 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#activation-decay) Dusty plasma and Yukawa-system simulation 10^12 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#dusty-plasma-yukawa) Stabilizer circuit simulation 10^12 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#stabilizer-circuit-simulation) Big Bang nucleosynthesis 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#nucleosynthesis) Galactic cosmic-ray propagation 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#cosmic-ray-propagation) Galaxy collision and merger simulation 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galaxy-interaction-mergers) Stellar evolution 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-evolution) Stellar oscillations 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-interiors-seismology) Binary star evolution 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-star-evolution) Binary population synthesis 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#binary-population-synthesis) Exoplanet atmosphere retrieval 10^12 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#exoplanet-atmosphere-retrieval) Integrated assessment models 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#integrated-assessment) Urban surface energy-balance modelling 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#urban-energy-balance) Rivers and floods 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#hydrology) Groundwater 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#groundwater) Flood inundation modelling 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#flood-inundation-modelling) Coastal and estuarine circulation modelling 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#coastal-estuarine-circulation) Marine debris and Lagrangian drift modelling 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#marine-debris-drift) Glacial isostatic adjustment and sea-level fingerprints 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#glacial-isostatic-adjustment) Land-surface model 10^12 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#land-surface-model) Polymer self-consistent field theory 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymer-field-theory) Magnetism and phase transitions 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#ising) Alloy cluster expansion 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#alloy-cluster-expansion) Crystal plasticity finite-element modelling 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#crystal-plasticity-fe) Micromagnetic simulation 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#micromagnetics) Polymerisation kinetics 10^12 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#polymerisation-kinetics) RNA folding and structure 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#rna-folding) Stochastic biochemistry 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#stochastic-biochemistry) Gene regulatory networks 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gene-regulation) Metabolic networks 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#metabolism) Pattern formation 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pattern-formation) Tumour growth and therapy response 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-growth-therapy) Tumour microenvironment evolution 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-microenvironment-evolution) Musculoskeletal biomechanics 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#biomechanics) Brain-stimulation field models 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#brain-stimulation-field-models) Magnetic resonance image simulation 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mri-image-simulation) Pathogen evolution 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pathogen-evolution) Mobility-network epidemic models 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mobility-network-epidemics) Scenario modelling hubs 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#scenario-modelling-hubs) Clinical trial design simulation 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#trial-design-simulation) Drug repurposing network models 10^12 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-repurposing-networks) Termite mound building 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#termite-mounds) Slime mould aggregation 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#slime-mould-aggregation) Bacterial swarming and quorum sensing 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#bacterial-swarming) Birdsong and vocal learning models 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#birdsong-learning) Wildlife disease 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wildlife-disease) Marine larval dispersal and connectivity 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#larval-dispersal-connectivity) Near-term ecological forecasting 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#near-term-ecological-forecasting) Population genetics 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-genetics) Origin of life 10^12 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#origin-of-life) Crop breeding simulation 10^12 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-breeding-simulation) Multi-model crop ensembles 10^12 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-model-ensembles) Digestion and gastric flow simulation 10^12 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#gastric-digestion-cfd) Cognitive architectures 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cognitive-architectures) Mass gathering disease risk modelling 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#mass-gathering-epidemiology) Macroeconomic models 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#macroeconomic) Reconstructed ancient societies 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#archaeological-abm) Human dispersal 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-dispersal) Tax and benefit microsimulation 10^12 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-microsimulation) Learned fluid solvers 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#learned-fluid-solvers) Emulation and virtual machines 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#emulation) Network digital twins 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#network-digital-twins) Semiconductor process simulation 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#semiconductor-process-tcad) Swarm robotics 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#swarm-robotics) Differentiable physics simulation 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#differentiable-physics) Open driving simulators with sensor models 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#open-driving-simulators) Drone flight simulation 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#drone-flight-simulation) Spacecraft trajectories 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#trajectory-design) Spacecraft thermal and power simulation 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#spacecraft-thermal) Solar and wind farm yield simulation 10^12 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#renewable-energy-yield) Manufacturing lines 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#manufacturing) Queues and service systems 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#service-queues) Hospital patient flow 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#patient-flow) Water and drainage networks 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#water-networks) Waste collection and treatment simulation 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#waste-management) District heating and cooling networks 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#district-heating) Internet backbone and cable resilience 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#internet-topology-resilience) Smart-city sensor network simulation 10^12 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-city-sensor-networks) Detailed neuron models 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#detailed-neurons) Simulated small organisms 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#simulated-organisms) Connectome-constrained whole-brain models 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#connectome-constrained-brain-models) Cellular automata 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#cellular-automata) Digital evolution 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#digital-evolution) Embodied household simulators 10^12 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#embodied-household-simulators) Random matrix experiments 10^12 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-matrix-experiments) Model checking 10^12 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#model-checking) Symbolic execution 10^12 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#symbolic-execution) Graphics processor architecture simulation 10^12 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#gpu-architecture-simulation) Simulated annealing 10^12 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#simulated-annealing) Heavy equipment simulators 10^12 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#heavy-equipment-simulators) Diving and submersible simulators 10^12 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#diving-simulators) Surgical simulators 10^12 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#surgical-simulators) Air traffic control simulators 10^12 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#air-traffic-control-simulators) Combat and campaign models 10^12 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-models) Vehicle and crew trainers 10^12 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crew-trainers) Marksmanship and use-of-force trainers 10^12 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#use-of-force-trainers) Ballistics 10^12 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#ballistics) Casualty and humanitarian response 10^12 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#casualty-care) Cloth simulation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#cloth-simulation) Hair and fur simulation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#hair-fur-simulation) Destruction and debris simulation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#destruction-debris) Muscle and skin deformation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#muscle-skin-deformation) Ocean surface synthesis 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#ocean-wave-synthesis) Digital crowd simulation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#digital-crowds) Procedural cities and landscapes 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-cities-landscapes) Digital ecosystems and vegetation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#crowd-vegetation-ecosystems) Atmospheric and sky simulation 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#atmosphere-sky-simulation) Virtual concerts 10^12 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-concerts) Open-city driving 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#open-city-driving) Soft-body vehicle crash simulation 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#soft-body-vehicle-crash) Dating simulation 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#dating-sims) Tower defence 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#tower-defence) Falling-sand games 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#falling-sand) Terrarium and habitat sandboxes 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#terrarium-sims) Agent-based game playtesting 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#agent-playtesting) User-generated game platforms 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#user-generated-game-platforms) Adventure and point-and-click 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#puzzle-adventure) Platformers 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#platformers) Extraction shooters 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#extraction-shooters) Racket and ball sports 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#racket-ball-sports) Augmented and location-based 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#augmented-reality) Virtual reality social worlds 10^12 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#vr-social-worlds) Quantum network simulation 10^11 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#quantum-network-simulation) Kinetic Monte Carlo 10^11 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#kinetic-monte-carlo) Organic semiconductor charge transport 10^11 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#organic-charge-transport) Tumour evolution agent-based models 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-evolution-agent-models) Microbial community metabolic models 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#microbial-community-metabolism) Tumour-induced blood vessel growth 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tumour-angiogenesis) Bacterial colony growth and biofilms 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bacterial-colony-individual-based) Virtual-population drug exposure models 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-population-pbpk) Bone adaptation and implant remodelling 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bone-remodelling) Virtual anatomical phantoms for imaging 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#virtual-anatomical-phantoms) Disease burden and health economic modelling 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#disease-burden-modelling) Environmental and chemical exposure risk assessment 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#environmental-exposure-risk) Malaria transmission and intervention models 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#malaria-transmission-intervention) Drug formulation and delivery modelling 10^11 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#drug-formulation-delivery) Ant colony foraging 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#ant-colonies) Honeybee colonies 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybees) Movement and foraging 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#movement-foraging) Migration and navigation 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#migration) Evolution of behaviour 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#behaviour-evolution) Fisheries and wildlife management 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries) Species ranges 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#species-ranges) Coalescent and phylogenetic simulation 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coalescent) Host-parasite coevolution 10^11 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#host-parasite-coevolution) Pest and plant disease spread 10^11 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pest-disease-spread) Livestock disease outbreak models 10^11 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-disease-outbreak) Livestock breeding and genetics 10^11 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#animal-breeding-genetics) Crowd emotion and behavioural contagion 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crowd-emotional-contagion) Agent-based exchange simulators 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#limit-order-book-agent-exchanges) Insurance catastrophe models 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#catastrophe-insurance-models) Flash-crash market models 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#flash-crash-agent-model) Hunter-gatherer economies 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#hunter-gatherers) Ancient trade and exchange 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#ancient-networks) Monument construction and engineering reconstruction 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#monument-construction-reconstruction) Computable general equilibrium modelling 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#computable-general-equilibrium) Sentencing and recidivism risk modelling 10^11 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recidivism-risk-modelling) Lattice-gas automata for fluid flow 10^11 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#lattice-gas-automata) Orbital-debris and satellite-collision modelling 10^11 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#orbital-debris-evolution) Shared autonomous vehicle fleets 10^11 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#shared-autonomous-vehicle-fleets) Supply chain digital twins 10^11 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#supply-chain-digital-twin) Telecom traffic engineering 10^11 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#telecom-traffic-engineering) Self-organised criticality 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-organised-criticality) Swarm intelligence algorithms 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#swarm-intelligence-algorithms) Random Boolean networks 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#random-boolean-networks) Continuous cellular automata 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-cellular-automata) Neural cellular automata 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-cellular-automata) Continuous artificial life 10^11 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#continuous-lifeforms) Experimental mathematics searches 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#experimental-mathematics-search) Automated theorem proving search 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#automated-theorem-proving) SAT and constraint solving 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sat-constraint-solving) Security protocol verification 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#protocol-security-verification) Abstract interpretation 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#abstract-interpretation) Computer architecture simulation 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-architecture-simulation) Full-system simulation 10^11 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#full-system-simulation) Dental simulators 10^11 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#dental-simulators) Anaesthesia simulators 10^11 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#anaesthesia-simulators) Emergency incident command simulators 10^11 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#incident-command-simulators) Historical war games 10^11 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#historical-wargames) Deterrence and arms races 10^11 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#deterrence-models) Autonomous cyber-defence gyms 10^11 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cyber-defence-gyms) War economic and reconstruction modelling 10^11 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#war-reconstruction-economics) Sanctions and economic warfare modelling 10^11 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#sanctions-economic-warfare) Rigid body dynamics for animation 10^11 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#rigid-body-effects) Virtual idols and influencers 10^11 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#virtual-idols) Performance-captured digital characters 10^11 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#performance-capture-characters) Machinima 10^11 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#machinima) Sound propagation and acoustics 10^11 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#sound-propagation-acoustics) Roguelikes 10^11 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#roguelikes) Rhythm games 10^11 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#rhythm) Board and card game adaptations 10^11 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#board-card-games) Augmented reality pets 10^11 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#ar-virtual-pets) One-component plasma simulation 10^10 [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#one-component-plasma) Fuel-cell membrane and transport modelling 10^10 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#fuel-cell-modelling) Pore-network modelling 10^10 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#pore-network-modelling) Pharmacokinetics 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacokinetics) Gut microbiome community models 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#gut-microbiome-communities) Fracture healing simulation 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#fracture-healing) Cochlear mechanics 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cochlear-mechanics) Synthetic patient record generation 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#synthetic-patient-records) Pharmacodynamic modelling 10^10 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#pharmacodynamics) Dynamic energy budget modelling 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#dynamic-energy-budget) Food webs 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#food-webs) Plankton ecosystem models 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#plankton-ecosystem-models) Speciation and macroevolution models 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#speciation-macroevolution) Sexual selection and mate choice evolution 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#sexual-selection-evolution) Population viability analysis 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#population-viability-analysis) Reserve and corridor design 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reserve-corridor-design) Reintroduction and translocation planning 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#reintroduction-planning) Invasive species spread 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#invasive-species-spread) Poaching and anti-poaching patrol games 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#poaching-patrol-games) Rewilding and trophic cascade modelling 10^10 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#rewilding-trophic-cascade) Crop growth and yield models 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#crop-growth-models) Soil water and nutrient transport 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-water-nutrients) Soil erosion and land degradation 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-erosion) Precision agriculture optimisation 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-agriculture) Precision livestock monitoring 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#precision-livestock) Food supply chain simulation 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-supply-chains) Famine early warning models 10^10 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#famine-early-warning) Models of learning 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#learning-models) Social cognition and theory-of-mind models 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#social-cognition-models) Emotion and affect modelling 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#emotion-affect-modelling) Choice under risk and uncertainty modelling 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#choice-under-risk-modelling) Opinion dynamics 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opinion-dynamics) Cooperation and norms 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cooperation) Diffusion of ideas 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#diffusion) Social network formation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#network-formation) Language evolution 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#language-evolution) Cultural evolution 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#cultural-evolution) Recommender feedback-loop simulation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#recommender-feedback-loops) Protest mobilisation network models 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#protest-mobilization-networks) Market and auction design 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#market-design) Artificial societies 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#artificial-societies) World models 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#world-models) Organisations and teams 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#organisations) Institutional corruption and integrity modelling 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#institutional-corruption-modelling) Policy diffusion network models 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#policy-diffusion-networks) Exploratory modelling under deep uncertainty 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#exploratory-modelling-deep-uncertainty) Electoral and voting system simulation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electoral-voting-simulation) Court and case-flow simulation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#court-case-flow) Policing and patrol deployment simulation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#patrol-deployment) Legislative bargaining and coalition simulation 10^10 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#legislative-bargaining) Co-simulation of linked models 10^10 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#co-simulation-model-exchange) Photonic-crystal band-structure calculation 10^10 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#photonic-crystal-band-structure) Tactile sensor simulation 10^10 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#tactile-sensor-simulation) Warehouse robot fleet coordination 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#warehouse-fleet-coordination) Power-system electromagnetic transients 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#power-system-electromagnetic-transients) Energy-system capacity-planning models 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#energy-system-optimisation) Smart-grid co-simulation 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#smart-grid-cosimulation) Internet worm propagation models 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#worm-propagation-models) Vehicular network simulation 10^10 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#vehicular-network-simulation) Self-replicating program soups 10^10 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#self-replicating-program-soups) Recommender-system simulators 10^10 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#recommender-simulators) Random graph experiments 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#random-graph-experiments) Percolation simulation 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#percolation-simulation) Side-channel leakage simulation 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#side-channel-leakage-simulation) Distributed systems and consensus simulation 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#distributed-systems-simulation) Storage systems simulation 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#storage-systems-simulation) Compiler and program optimisation search 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#compiler-optimization-search) Lightweight network emulation 10^10 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#network-emulation-lightweight) Patient simulators 10^10 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#patient-simulators) Paramedic and mass-casualty triage training 10^10 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#paramedic-triage-training) Catheter and endovascular simulators 10^10 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#interventional-catheter-simulators) Business simulations 10^10 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#business-games) Negotiation and diplomacy training simulations 10^10 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#negotiation-diplomacy-simulations) Combat medic trainers 10^10 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#combat-medic-trainers) Landmine and unexploded ordnance clearance planning 10^10 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#landmine-clearance) Particle system effects 10^10 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#particle-system-effects) Physical modelling synthesis of instruments 10^10 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#instrument-physical-modelling-synthesis) Procedural texture and material generation 10^10 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-texture-material-generation) Mech combat simulation 10^10 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#mech-sims) Station systems simulation 10^10 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#station-systems-sim) Hunting simulation 10^10 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hunting-sims) Logic and falling-block puzzles 10^10 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#logic-puzzles) Stellar population synthesis 10^9 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#stellar-population-synthesis) Chain-growth Monte Carlo for polymers 10^9 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#chain-growth-monte-carlo) Musculoskeletal models for surgery 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#musculoskeletal-surgery-models) Bioheat transfer and hyperthermia 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#bioheat-transfer) Kidney nephron transport models 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#kidney-nephron-transport) Compartment epidemic models 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#compartment-epidemics) Digital contact-tracing models 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#digital-contact-tracing-models) Antimicrobial resistance spread 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#antimicrobial-resistance-spread) Cancer screening microsimulation 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#cancer-screening-microsimulation) Closed-loop diabetes control in silico 10^9 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#artificial-pancreas-in-silico) Predator–prey dynamics 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#predator-prey) Individual-based ecological models 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#individual-based-ecology) Fisheries management strategy evaluation 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#fisheries-strategy-evaluation) Honeybee colony and landscape models 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#honeybee-colony-landscape) Size-spectrum ecosystem models 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#size-spectrum-models) Neutral community models 10^9 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#neutral-community-models) Irrigation scheduling 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#irrigation-scheduling) Agricultural catchment pollution models 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agricultural-catchment-pollution) Agrivoltaic light-sharing models 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#agrivoltaic-light-sharing) Livestock herd and feed models 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#livestock-herd-feed) Grazing and pasture management 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#grazing-pasture) Aquaculture and fish farming 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-yield) Fermentation process modelling 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#fermentation-modelling) Baking and thermal food processing 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#baking-thermal-processing) Cold chain and spoilage modelling 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#cold-chain-spoilage) Food safety and traceability simulation 10^9 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#food-traceability-safety) Models of decision-making 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#decision-models) Residential sorting 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#residential-sorting) Synthetic population generation 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#synthetic-population-synthesis) Collective action and tipping-point models 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-action-threshold) Collective estimation and crowd wisdom 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#collective-estimation) Housing market agent-based models 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#housing-market-abm) Algorithmic pricing collusion 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#algorithmic-pricing-collusion) Jury decision-making simulation 10^9 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#jury-decision-making) Soft robot simulation 10^9 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#soft-robot-finite-element) Airspace fast-time simulation 10^9 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airspace-fast-time-simulation) Agent-based electricity markets 10^9 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#electricity-market-agent-models) Cascading-blackout models 10^9 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#cascading-blackout-models) Gas pipeline network transients 10^9 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#gas-pipeline-network-transients) Neural mass and field models 10^9 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#neural-mass-models) Artificial chemistry 10^9 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-chemistry) Simulated robot soccer 10^9 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#robocup-soccer-simulation) Monte Carlo estimation of constants 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#monte-carlo-constants) Fractal-set rendering 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#fractal-set-rendering) Sandpile self-organised criticality 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#sandpile-self-organised-criticality) Computer-assisted proof by exhaustive case checking 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#computer-assisted-proof-enumeration) Validated numerics 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#validated-numerics) Statistical model checking 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#statistical-model-checking) Property-based random testing 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#property-based-testing) Operating system scheduler simulation 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#os-scheduler-simulation) Empirical algorithm performance testing 10^9 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#empirical-algorithmics) The intuitive physics engine 10^9 [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#intuitive-physics-engine) Childbirth simulators 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#obstetric-simulators) Virtual human patients 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#virtual-human-patients) Ultrasound training simulators 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ultrasound-training-simulators) Robotic surgery simulators 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#robotic-surgery-simulators) Eye surgery simulators 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#ophthalmic-surgery-simulators) Endoscopy simulators 10^9 [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#endoscopy-simulators) Political–military crisis games 10^9 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#crisis-games) Swarm combat simulation 10^9 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#swarm-combat-simulation) Chemical, biological and radiological hazard plumes 10^9 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#cbrn-hazard-plumes) Position-based dynamics 10^9 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#position-based-dynamics) Generative art systems 10^9 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#generative-art-systems) Procedural and generative music 10^9 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-music-composition) Physically based sound effects 10^9 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#procedural-sound-effects) Surgery and medical games 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#surgery-games) Idle and incremental 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#idle-games) Auto-battlers 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#auto-battlers) Interactive fiction 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#interactive-fiction) Visual novels and narrative games 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#visual-novels) Word and letter puzzles 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#word-puzzles) Match-three and tile-swap puzzles 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#match-three) Hidden-object and spot-the-difference 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hidden-object) Number and grid logic puzzles 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#number-logic-puzzles) Escape-room puzzles 10^9 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#escape-room-games) Galactic chemical evolution 10^8 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#galactic-chemical-evolution) Astrochemical reaction networks 10^8 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#astrochemical-networks) Automated reaction-mechanism generation 10^8 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#mechanism-generation) Diffusion-limited aggregation 10^8 [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#diffusion-limited-aggregation) Cancer drug response and resistance dynamics 10^8 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#leukaemia-treatment-dynamics) Vocal fold and voice production models 10^8 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vocal-fold-voice-production) Vaccine allocation optimisation 10^8 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#vaccine-allocation-optimisation) Obesity and diet agent-based models 10^8 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#obesity-agent-based) Organ allocation policy simulation 10^8 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#organ-allocation-simulation) Metapopulation dynamics 10^8 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#metapopulation-dynamics) Coral reef resilience models 10^8 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#coral-reef-resilience) Pollination service across landscapes 10^8 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#pollination-service-landscape) Wind seed and pollen dispersal models 10^8 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#wind-seed-dispersal) Gene drive population models 10^8 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#gene-drive-population-models) Farm agent-based models of land use and adoption 10^8 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#farm-agent-based-adoption) Plant architecture growth models 10^8 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#plant-architecture-growth) Land-use change agent models 10^8 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#land-use-change-agent-models) Aquaculture pond bioenergetics 10^8 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#aquaculture-pond-bioenergetics) Quantitative microbial risk assessment 10^8 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#microbial-risk-assessment) Migration under climate stress 10^8 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#climate-migration-abm) Processor thermal modelling 10^8 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#chip-thermal-modelling) Stacked chip thermal modelling 10^8 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#three-dimensional-ic-thermal) Airport airside simulation 10^8 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#airport-airside-simulation) Container terminal simulation 10^8 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#container-terminal-simulation) Attractor memory networks 10^8 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#attractor-memory-networks) Artificial immune models 10^8 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#artificial-immune-systems) Blockchain consensus simulation 10^8 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#blockchain-consensus-simulation) Search and rescue drift planning 10^8 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#search-and-rescue-planning) L-system plant modelling 10^8 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#l-system-plants) Live-coded music and visuals 10^8 [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#live-coding-performance) Social deduction games 10^8 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#social-deduction-games) Fishing simulation 10^8 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#fishing-sims) Within-host virus dynamics 10^7 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#within-host-viral-dynamics) Epidemics on contact networks 10^7 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#epidemics-on-networks) Mosquito population dynamics 10^7 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#mosquito-population-dynamics) Ambulance and fire station deployment models 10^7 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#emergency-service-deployment) Locust marching bands 10^7 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#locust-marching) Trophic mass-balance ecosystem models 10^7 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#trophic-mass-balance-ecosystems) Lake eutrophication models 10^7 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#shallow-lake-eutrophication) Greenhouse climate models 10^7 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#greenhouse-climate-models) Misinformation and rumour spread 10^7 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#misinformation-complex-contagion) Financial contagion in interbank networks 10^7 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#financial-contagion-networks) Electricity market agent-based models 10^7 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#electricity-market-abm) Crime hotspot dynamics 10^7 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#crime-hotspot-dynamics) Core War battles 10^7 [Full entry in Minds, brains and artificial worlds ▸](https://simulation-hypothesis.com/simulations/minds-computation#core-war) Biological attack response models 10^7 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#bioattack-response-models) Programming battle games 10^7 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#programming-battle-games) Hacking simulation 10^7 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#hacking-sims) Habitable-zone climate modelling 10^6 [Full entry in Astronomy and cosmology ▸](https://simulation-hypothesis.com/simulations/astronomy-cosmology#habitable-zone-climate) Stochastic earthquake-catalogue models 10^6 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#earthquake-catalogue-stochastic) Blood cell production dynamics 10^6 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#haematopoiesis-dynamics) Whole-body integrative physiology 10^6 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#whole-body-physiology) Tobacco-control policy simulation 10^6 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#tobacco-control-policy-simulation) Spatial host-parasitoid and pest lattices 10^6 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#spatial-host-parasitoid-lattices) Adaptive dynamics of coevolution 10^6 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#adaptive-dynamics-coevolution) Animal contest strategies 10^6 [Full entry in Ecology, evolution and animal behaviour ▸](https://simulation-hypothesis.com/simulations/ecology-behaviour#animal-conflict-evolutionary-stable-strategies) Pesticide resistance management models 10^6 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#pesticide-resistance-management) Human mobility and migration models 10^6 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#human-mobility-models) Dynamic stochastic general equilibrium models 10^6 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#dsge-macroeconomic-models) Kinetic wealth exchange models 10^6 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#kinetic-wealth-exchange) Disaster economic ripple models 10^6 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#disaster-input-output-economics) Coupled epidemic and economy models 10^6 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#epidemic-economy-coupled) Conjunction collision probability 10^6 [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#conjunction-collision-probability) Aircraft boarding simulation 10^6 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#aircraft-boarding-simulation) Elevator traffic simulation 10^6 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#elevator-traffic-simulation) Project schedule risk simulation 10^6 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#project-schedule-monte-carlo) Construction process simulation 10^6 [Full entry in Cities, infrastructure and operations ▸](https://simulation-hypothesis.com/simulations/cities-operations#construction-process-simulation) Anti-submarine search theory 10^6 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#anti-submarine-search-theory) Virtual pets 10^6 [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#virtual-pets) Circadian clock models 10^5 [Full entry in Life and medicine ▸](https://simulation-hypothesis.com/simulations/life-medicine#circadian-oscillator-models) Soil organic carbon turnover 10^5 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#soil-organic-carbon-turnover) Sterile insect release models 10^5 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#sterile-insect-release-models) Predictive food microbiology 10^5 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#predictive-food-microbiology) Opioid epidemic system dynamics 10^5 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#opioid-system-dynamics) Supply-chain dynamics and the bullwhip effect 10^5 [Full entry in Human behaviour and society ▸](https://simulation-hypothesis.com/simulations/human-society#supply-chain-dynamics) Computer virus and malware epidemics 10^5 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#malware-epidemic-models) Radiative-convective climate model 10^4 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#radiative-convective-climate-model) Degree-day pest phenology models 10^4 [Full entry in Agriculture and food ▸](https://simulation-hypothesis.com/simulations/agriculture-food#degree-day-pest-phenology) Soliton numerical experiments 10^4 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#soliton-numerical-experiments) Energy-balance climate model 10^3 [Full entry in Earth and climate ▸](https://simulation-hypothesis.com/simulations/earth-climate#energy-balance-climate-model) Chaotic-attractor numerics 10^3 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#chaotic-attractor-numerics) Nonlinear lattice experiments 10^3 [Full entry in Mathematics and computation ▸](https://simulation-hypothesis.com/simulations/mathematics-computation#nonlinear-lattice-dynamics) Naval salvo exchange models 10^3 [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#naval-salvo-models) cost No computer 66 Physical models, boards, bodies and rehearsals: no digital computation. Analogue quantum simulation [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#analogue-quantum) Digital quantum simulation on hardware [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#digital-quantum-simulation) Lattice gauge theory on quantum hardware [Full entry in Fundamental physics ▸](https://simulation-hypothesis.com/simulations/fundamental-physics#lattice-gauge-quantum-hardware) Quantum chemistry on quantum computers [Full entry in Chemistry and materials ▸](https://simulation-hypothesis.com/simulations/chemistry-materials#quantum-chemistry-on-quantum-computers) Physical scale models [Full entry in Engineering and technology ▸](https://simulation-hypothesis.com/simulations/engineering#scale-models) Hippocampal preplay [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#hippocampal-preplay) Constructive episodic simulation [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#constructive-episodic-simulation) Motor imagery [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#motor-imagery) Visual mental imagery [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#visual-mental-imagery) Affective forecasting [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#affective-forecasting) Mental models of reasoning [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#mental-models) Vicarious trial and error [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#vicarious-trial-and-error) Future planning in animals [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#animal-future-planning) Fiction as social simulation [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#fiction-as-social-simulation) Thought as simulated action [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#simulation-hypothesis-of-thought) Grounded cognition [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#grounded-cognition) The phenomenal self-model [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#phenomenal-self-model) Body ownership illusions [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#body-ownership-illusions) Embodied language simulation [Full entry in Minds as simulators ▸](https://simulation-hypothesis.com/simulations/mind-simulations#embodied-language-simulation) Structured clinical examinations [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#clinical-examination-standardised-patients) Emergency exercises [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#tabletop-exercises) Mass-casualty exercises [Full entry in Training simulators ▸](https://simulation-hypothesis.com/simulations/training#mass-casualty-exercises) Orrery [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#orrery) Astrolabe [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astrolabe) The Antikythera mechanism [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#antikythera-mechanism) Optical planetarium [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#planetarium) Armillary sphere [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#armillary-sphere) Equatorium [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#equatorium) Terrestrial globe [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#terrestrial-globe) Astronomical clock [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#astronomical-clock) Ship-model towing tank [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#towing-tank) Physical river basin model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#river-basin-model) Harbour and estuary model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harbour-model) Dam and spillway model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#spillway-model) Structural scale model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#structural-scale-model) Architectural acoustic scale model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#acoustic-scale-model) Hele-Shaw cell [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hele-shaw-cell) Hanging-chain arch model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hanging-chain-model) Soap film minimal-surface models [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#soap-film-models) Mechanical differential analyser [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#differential-analyser) Tide-predicting machine [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#tide-predicting-machine) Hydraulic economy model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#hydraulic-economy-model) Electrical network analyser [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#electrical-network-analyser) Mechanical harmonic analyser [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#harmonic-analyser) Analogue fire-control computer [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#analogue-fire-control-computer) Galton board [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#galton-board) Buffon's needle [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#buffon-needle) Iron wire nerve model [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#iron-wire-nerve-model) Cybernetic tortoises [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#cybernetic-tortoises) Sand table [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#sand-table) Staff ride [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#staff-ride) Dress rehearsal [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#dress-rehearsal) Fire and evacuation drills [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#fire-drills) Mock trial [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#mock-trial) Military field exercises [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#field-exercises) Anatomical models [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#anatomical-models) Obstetric phantom [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#obstetric-phantom) Early resuscitation manikins [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#resuscitation-manikins) Crash-test dummies [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#crash-test-dummies) Moulage [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#moulage) Ballistic gelatin blocks [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#ballistic-gelatin) Automata [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#automata) Motion platforms [Full entry in Before computers ▸](https://simulation-hypothesis.com/simulations/before-computers#motion-platforms) Professional war games [Full entry in Defence and conflict ▸](https://simulation-hypothesis.com/simulations/defence-conflict#professional-wargames) Animatronic figures [Full entry in Film, media and art ▸](https://simulation-hypothesis.com/simulations/media-art#animatronics) Alternate reality games [Full entry in Video games ▸](https://simulation-hypothesis.com/simulations/video-games#alternate-reality-games) --- title: "Your Reality · a thought experiment from inside · Simulation Hypothesis" url: https://simulation-hypothesis.com/reality description: "Ten questions that build a reality: how big it is, how detailed, the minds in it and who watches. Each answer changes the computing needed to run it." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- 1 · The world # How big is the simulated world? A simulation only has to compute what’s inside it. One brain, fed the right sensory signals, would feel like a whole world. For scale, the observable universe has about 10^80 atoms. The simulated world is…Just you One brain, with its senses fed from outside. One room Nothing past the walls is computed. Earth The planet and everyone on it. The solar system Our galaxy A few hundred billion stars. The observable universe Everything we could ever see from here, in principle. Each answer updates the reality at right. You can change any answer later. Think this is wrong? Argue it. ## Further reading * [The sandbox: measure any world](https://simulation-hypothesis.com/sandbox) * [Base reality](https://simulation-hypothesis.com/library/base-reality) Your reality · not yet chosen Show ▴ ## Your reality The default reality, before you answer anything, takes **8.2 × 10^27 FLOPS**. Our computers could run this **between 2070 and 2089** if growth runs a fifth faster or slower. At the central rate it’s 2078. Show the numbers | Year | All computers on Earth | Projected | | ---- | ---------------------- | ----------------- | | 1986 | 3.0 × 10^14 FLOPS | | | 1993 | 4.4 × 10^15 FLOPS | | | 2000 | 2.9 × 10^17 FLOPS | | | 2007 | 6.4 × 10^18 FLOPS | | | 2025 | 10^21 FLOPS | 10^21 FLOPS | | 2050 | | 1.8 × 10^24 FLOPS | | 2075 | | 3.3 × 10^27 FLOPS | | 2100 | | 6.0 × 10^30 FLOPS | Journey Census Power Make a choice to start the chart. ### Tune it Detail Painted set Real players Everyone Computed when no one’s looking 0% Computing growth 35% a year The human costs are the author’s judgement, not a measurement. The computing numbers come from the same engine as the sandbox. See the method. --- title: "Trees · explorable histories · Simulation Hypothesis" url: https://simulation-hypothesis.com/trees description: "Technology trees for how virtual worlds became possible, what we’ve learned to simulate, where our rules came from, and how people could become synthetic." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Trees · explorable histories Each tree is a history laid out like a technology tree in a strategy game. The nodes are dated and sourced, and you read them left to right. Every node is open from the start. Two trees end in published forecasts, one in open questions, and one in forecasts plus the site’s own projections. [82 nodes Technology tree The inventions behind virtual worlds. Two trunks, illusion and computation, run from painted caves and the abacus to the headset, with dead ends and cited forecasts.](https://simulation-hypothesis.com/trees/technology)[107 nodes Simulations tree A ladder by scale, from matter to whole worlds. It shows the first time each thing was simulated, whether in a mind, by people, with a physical model or on a computer, and the methods that made it possible.](https://simulation-hypothesis.com/trees/simulations)[91 nodes Ethics tree How rules for living together grew from cooperating cells and animal societies into written law. They survived the loss of gods, and now they meet animals, synthetic minds and simulated lives. The tree ends in open questions.](https://simulation-hypothesis.com/trees/ethics)[100 nodes Becoming synthetic The breakthroughs a biological species would need to move into synthetic space and raise generations there. They include replaced organs, brain interfaces, brain mapping and emulation, the computers and power to run it, and the beings that could follow.](https://simulation-hypothesis.com/trees/synthetic) --- title: "Technology tree · how virtual worlds became possible · Simulation Hypothesis" url: https://simulation-hypothesis.com/trees/technology description: "The inventions behind virtual worlds." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Technology tree · how virtual worlds became possible A virtual world needs two things: a way to fool the senses, and a machine that computes what they should receive. For most of history these developed separately. They meet at the head-mounted display. You can open any node. Lines show what each one built on. Dashed nodes stalled because a prerequisite was missing. Future nodes are published forecasts, each cited. A forecast’s date range covers the sources quoted, and they may define the milestone differently. **0** of 82 read unread read idea stalled forecast bridge [Read it as text](#text) Whole tree Forecasts → Illusion Virtual worlds Computation 51,200 years ago Painted scenes before 300 BC Abacus 628 CE · Idea Zero as a number c. 1011–1021 Camera obscura explained 11th century Shadow theatre 9th century Self-playing flute (Baghdad) c. 820s CE · Idea Algorithms (al-Khwārizmī) c. 1415–1425 Linear perspective c. 1659 Magic lantern 1703 · Idea Binary arithmetic 1642–1644 Mechanical calculator 1832 Motion from stills 1787–1788 The panorama c. 1826–1827 Photography 1804 Punched-card loom 1822 · Stalled Difference Engine 1838 Stereoscope 1837 · Stalled Analytical Engine 1881 Stereo sound 1895 Projected moving pictures 1843 · Idea Note G 1847 · Idea Boolean logic 1904–1907 Vacuum tube 1929 Flight simulator 1922 · Stalled Stereoscopic film 1943–44 Colossus 1941 Zuse Z3 1936–37 · Idea Universal machine 1937–38 · Idea Logic in circuits 1945–46 Electronic computer 1945 · Idea The stored-program design 1957 Cochlear implant 1947–48 Transistor 1945 Stored-program computer 1962 · Stalled Sensorama 1960 Telesphere Mask 1964 · Idea Simulacron-3 1963 Interactive graphics 1958 First video games 1958–59 Integrated circuit 1965 · Idea The Ultimate Display 1965 · Idea Moore’s law 1968 Head-mounted display 1971–1980 Realistic shading 1972 Arcade video game 1971 Microprocessor 1969 Packet network 1975–76 Colossal Cave Adventure 1973–74 First-person networked world 1978–79 Aspen Movie Map 1985–1987 Data glove; “virtual reality” 1978–1980 Shared text world 1982–84 · Idea Cyberspace 1983 The Internet 1992 CAVE 1986–88 Graphical online world 1989–1991 World Wide Web 1993–1996 Real-time 3D worlds 1995–96 · Stalled Virtual Boy 1992 · Idea The Metaverse 1997–2003 Persistent online worlds 2004–2006 Brain-computer interface 1999 Graphics processor 2006–2007 General-purpose GPU computing 2007 Smartphone 2012–13 Modern VR headset 2012 Deep learning on GPUs 2015–2016 Room-scale tracking 2017 Transformer architecture 2018 Learned world models 2020–2023 Neural rendering 2018–2019 Standalone headsets 2020 Diffusion models 2024–2025 Generated interactive worlds 2029–2034 · Forecast Real-time photorealism 2027–2040 · Forecast Reversible computing 2010–2030s · Forecast Molecular nanotechnology 2027–2047 · Forecast Human-level AI c. 2250 or later · Forecast Star-scale computer 2050–2075 · Bridge Whole-brain emulation 2029–2030s · Forecast Full-immersion VR 2027–2045+ · Forecast Superintelligence Where it starts Show ▴ Start here ## Where it starts Every node with no line into it is a beginning. These lines started on their own and only later fed into each other. The oldest are painted scenes , the first rendered worlds, and the abacus , the oldest calculating device whose design survives. Your progress stays in this browser only. If you clear site data, the tree starts over. The whole tree as text · every node in order, for screen readers, text browsers and machine readers. Same nodes as the map Dates are years of the common era unless marked BC or BCE. Evolutionary dates are in years ago. Each node has a stable address, shown after it. Forecast nodes list published forecasts only, each cited. ## Illusion 1. **Painted scenes** (at least 51,200 years ago) A red-ochre painting in Leang Karampuang cave, Sulawesi, shows human-like figures and a wild pig. Uranium-series dating of the calcite over it puts it at least 51,200 years old. It’s the oldest known scene that tells a story. So people have been painting imagined or remembered worlds for a very long time. Led to: [Linear perspective](#node-perspective) Source: [Oktaviana et al., ‘Narrative cave art in Indonesia by 51,200 years ago’, Nature 631 (2024)](https://www.nature.com/articles/s41586-024-07541-7) Address: 2. **Camera obscura explained** (c. 1011–1021) China recorded earlier that light through a small hole makes an upside-down image. The Later Mohist Canon (compiled between the late 4th and mid-3rd century BCE) explains the flip by rays crossing at the hole. Shen Kuo’s Dream Pool Essays (1088) said it again, calling the inversion after the small hole a normal principle. Ibn al-Haytham wrote his Kitāb al-Manāẓir (Book of Optics) in Cairo in the early eleventh century. He tested the hole image by experiment. He also argued that we see by receiving light, not by sending it out from the eye. His Optics later fed into Renaissance theories of perspective. Led to: [Linear perspective](#node-perspective) ; [Magic lantern](#node-magic-lantern) ; [Photography](#node-photography) Source: [Encyclopaedia Britannica, ‘Kitab al-manazir’ (and ‘Ibn al-Haytham’)](https://www.britannica.com/topic/Kitab-al-manazir) Address: 3. **Shadow theatre** (11th century (securely documented)) In shadow theatre, flat figures behind a lit screen act out stories. It’s documented in Java by the 11th-century poem Arjunawiwaha (c. 1035), which compares the world to a puppet screen. It’s documented in China by Northern Song accounts (960–1127). Earlier claims are legend, or only name a performance without describing it. Examples are the Han story of Emperor Wu and the Jaha and Wukajana inscriptions of c. 840–907\. So the earliest date isn’t secure. Source: [Istari, Wukayana inscription of Balitung (907 CE), Berkala Arkeologi (BRIN); Wikipedia, ‘Wayang’ for the Jaha/Arjunawiwaha dates; Hanshu 97A tale as discussed by Gao Cheng](https://ejournal.brin.go.id/berkalaarkeologi/article/download/4742/3505/13391) Address: 4. **Linear perspective** (c. 1415–1425) Filippo Brunelleschi showed a geometric way to paint a scene as it looks from one spot. Alberti wrote the method down in De pictura (1435). The rule is that parallel lines all meet at a vanishing point. Real-time graphics software uses the same projection on every frame. Built on: [Painted scenes](#node-cave-painting) ; [Camera obscura explained](#node-camera-obscura) Led to: [The panorama](#node-panorama) ; [Photography](#node-photography) ; [Stereoscope](#node-stereoscope) Source: [Encyclopaedia Britannica, ‘Linear perspective’](https://www.britannica.com/art/linear-perspective) Address: 5. **Magic lantern** (c. 1659) In 1659 Christiaan Huygens drew a set of skeleton images to be projected by a lantern with convex lenses. That’s the earliest surviving record of the device. It was the first widely used way to throw a painted or photographic image on a wall for an audience. For over two centuries it was the standard tool for public image shows. Built on: [Camera obscura explained](#node-camera-obscura) Led to: [Projected moving pictures](#node-cinema) Source: [Magic Lantern Society (UK), ‘A brief history of the Magic Lantern’](https://magiclantern.org.uk/history/) Address: 6. **The panorama** (1787–1788) Robert Barker patented the panorama in 1787 and showed the first one, a view of Edinburgh, in 1788\. Later rotundas held round paintings about 18 metres across or more. Viewers stood in the middle of a painted horizon that never broke. It was an early commercial try at swapping a visitor’s surroundings for a built scene. Built on: [Linear perspective](#node-perspective) Source: [Encyclopaedia Britannica, ‘Robert Barker’ and ‘Panorama’](https://www.britannica.com/biography/Robert-Barker) Address: 7. **Photography** (c. 1826–1827) Nicéphore Niépce made the earliest surviving camera photograph around 1826–27\. It was a heliograph on a pewter plate, the view from his window at Le Gras, after an exposure of many hours. It fixed an optical image for good. So for the first time an image resembled the world through a machine, not through a hand. Built on: [Camera obscura explained](#node-camera-obscura) ; [Linear perspective](#node-perspective) Led to: [Projected moving pictures](#node-cinema) Source: [Harry Ransom Center, University of Texas, ‘The First Photograph’ (Niépce heliograph)](https://www.hrc.utexas.edu/niepce-heliograph/) Address: 8. **Motion from stills** (1832) Joseph Plateau in Ghent and Simon Stampfer in Vienna each came up with the phenakistiscope in 1832\. It’s a slotted disc of drawings in sequence. Spin it and look in a mirror, and the drawings seem to move. It showed that the eye blends a fast series of still images into smooth motion. That’s the principle behind every film and video frame. Led to: [Projected moving pictures](#node-cinema) Source: [Encyclopaedia Britannica, ‘Phenakistoscope’](https://www.britannica.com/science/phenakistoscope) Address: 9. **Stereoscope** (1838) In 1838 Charles Wheatstone showed that two slightly different flat drawings, one for each eye, merge into a single image with real-looking depth. He built a mirror stereoscope to prove it. The difference between the two eyes’ views became something you could control. Every headset since still uses it. Built on: [Linear perspective](#node-perspective) Led to: [Stereoscopic film](#node-3d-film) ; [Sensorama](#node-sensorama) ; [The Ultimate Display](#node-ultimate) ; [Telesphere Mask](#node-telesphere) Source: [Wheatstone, ‘Contributions to the physiology of vision, Part I’, Phil. Trans. R. Soc. 128 (1838), 371–394](https://doi.org/10.1098/rstl.1838.0019) Address: 10. **Stereo sound** (1881) At the 1881 Paris International Exposition of Electricity, Clément Ader’s system sent live performances from the Opera over telephone lines to visitors. It used paired transmitters and receivers, which gave a two-ear, spatial effect. A subscription service followed in 1890\. It was an early sign that a sense of place could be sent by electricity to a listener far away. Led to: [Sensorama](#node-sensorama) Source: [Bob’s Old Phones / Telephone Collecting, ‘Clément Ader’](https://telephonecollecting.org/Bobs%20phones/Pages/Essays/Ader/Ader.htm) Address: 11. **Projected moving pictures** (1895) On 28 December 1895 the Lumière brothers showed the Cinématographe to a paying crowd at the Grand Café in Paris. It was a camera, printer and projector in one. Showing film to a shared audience made recorded motion something people experienced together. That’s the template for later shared screens and rooms. Built on: [Photography](#node-photography) ; [Motion from stills](#node-phenakistiscope) ; [Magic lantern](#node-magic-lantern) Led to: [Stereoscopic film](#node-3d-film) ; [Sensorama](#node-sensorama) ; [Aspen Movie Map](#node-aspen) ; [Telesphere Mask](#node-telesphere) Source: [Encyclopaedia Britannica, ‘Cinématographe’](https://www.britannica.com/technology/Cinematographe) Address: 12. **Stereoscopic film** (1922; boom 1952–54; revival 2009 · Stalled) Stereoscopic cinema took Wheatstone’s idea and put it on film. Anaglyph features were shown in the early 1920s. The polarised Natural Vision process set off the 1952 boom with Bwana Devil. Audiences lost interest within about a year. The format came back with digital cinema in 2009. Why it stalled: It stalled because the picture was fixed. Every viewer saw the same two views no matter where they looked. Glasses and projector alignment were annoying. And the image had no way to respond to the viewer. Built on: [Projected moving pictures](#node-cinema) ; [Stereoscope](#node-stereoscope) Source: [Encyclopaedia Britannica, ‘3-D’ (film process) and ‘Natural Vision’](https://www.britannica.com/technology/3-D) Address: 13. **Flight simulator** (1929) Edwin Link built a cockpit driven by air pressure. It pitched, rolled and yawed as the pilot moved the controls, so trainees could practise instrument flying on the ground. The Allies used Link’s Blue Box in the Second World War, and more than 500,000 pilots are reported to have trained on such devices. It showed that a believable feel of flight could stand in for a real aircraft in training. Source: [ASME Landmark #210, ‘Link C-3 Flight Trainer’](https://www.asme.org/about-asme/engineering-history/landmarks/210-link-c-3-flight-trainer) Address: 14. **Cochlear implant** (1957; multichannel 1977–84) Djourno and Eyries in Paris reported in 1957 that they had electrically stimulated the auditory nerve of a deaf patient. House and Doyle implanted a single-channel device in 1961\. Multichannel devices (Hochmair, Clark) were implanted in 1977–78 and approved by the FDA for adults in the mid-1980s. Sound reaches the brain without a working ear. It was the first clinical case of a sense supplied by direct electrical stimulation of the nervous system. Led to: [Brain-computer interface](#node-bci) Source: [Lasker Foundation, ‘Modern cochlear implant’ (2013 Clinical Medical Research Award)](https://laskerfoundation.org/winners/modern-cochlear-implant/) Address: 15. **Telesphere Mask** (1960) Morton Heilig patented a head-worn viewer that gave each eye its own image, with stereo sound. That was years before any computer drove such a display. It played prerecorded film and didn’t track the head. Built on: [Stereoscope](#node-stereoscope) ; [Projected moving pictures](#node-cinema) Led to: [Head-mounted display](#node-damocles) Source: [Heilig, US Patent 2,955,156, “Stereoscopic-television apparatus for individual use” (1960)](https://patents.google.com/patent/US2955156A/en) Address: 16. **Sensorama** (1962 (patent; prototype 1957–62) · Stalled) Morton Heilig’s Sensorama Simulator (US patent 3,050,870, filed 1961, granted 1962) was an arcade booth. It played pre-filmed stereoscopic colour footage with stereo sound, vibration, wind and scent. It was the first try at engaging several senses at once in one machine. It’s the usual starting point for the history of virtual reality. Why it stalled: It stalled because everything was pre-recorded on film. No computer made or changed the scene, so the viewer could look but never change anything. Built on: [Projected moving pictures](#node-cinema) ; [Stereoscope](#node-stereoscope) ; [Stereo sound](#node-theatrophone) Source: [US Patent 3,050,870, M. L. Heilig, ‘Sensorama Simulator’ (filed 10 Jan 1961, granted 28 Aug 1962)](https://patents.google.com/patent/US3050870A/en) Address: ## Virtual worlds 1. **First video games** (1958; 1962) William Higinbotham’s Tennis for Two (October 1958, Brookhaven) drew a ball’s flight on an oscilloscope under analog-computer control. Spacewar! (1962) was a two-player space combat game written for MIT’s PDP-1 digital computer. Together they showed that a machine could host a small, shared world with rules that players act in. Built on: [Stored-program computer](#node-stored-program) Led to: [Arcade video game](#node-pong) Source: [Computer History Museum, ‘Spacewar!' (see also CHM timeline 1958 for Tennis for Two)](https://www.computerhistory.org/pdp-1/spacewar/) Address: 2. **Interactive graphics** (1963) Ivan Sutherland’s doctoral thesis at MIT (1963) described Sketchpad. It ran on the TX-2 and let a user draw and edit line diagrams with a light pen, with constraints and reusable master drawings. It made the interactive display a way to work on a model held in a computer. Built on: [Stored-program computer](#node-stored-program) Led to: [The Ultimate Display](#node-ultimate) ; [First-person networked world](#node-maze-war) ; [Realistic shading](#node-shading) Source: [I. E. Sutherland, ‘Sketchpad: a man-machine graphical communication system’, MIT PhD thesis (1963), University of Cambridge reprint, TR-574](https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-574.pdf) Address: 3. **Simulacron-3** (1964 · Idea) Daniel F. Galouye’s novel Simulacron-3 (1964; UK title Counterfeit World) describes a city simulated on a computer. Its people don’t know they’re programs. It’s one of the earliest novels about a world run inside a computer. It’s also a common reference point in writing on the simulation argument. Built on: [Stored-program computer](#node-stored-program) Source: [The Encyclopedia of Science Fiction, ‘Galouye, Daniel F.'](https://sf-encyclopedia.com/entry/galouye%5Fdaniel%5Ff) Address: 4. **The Ultimate Display** (1965 · Idea) In his 1965 paper to the IFIP Congress, Sutherland proposed a computer-driven display so complete that it could control matter in the room. He wrote that a chair displayed there would be good enough to sit in. It set the goal of virtual reality as a world you couldn’t tell from reality in any sense. Built on: [Interactive graphics](#node-sketchpad) ; [Stereoscope](#node-stereoscope) Led to: [Head-mounted display](#node-damocles) Source: [I. E. Sutherland, ‘The Ultimate Display’, Proc. IFIP Congress 1965, vol. 2, pp. 506–508 (scan)](https://worrydream.com/refs/Sutherland%5F1965%5F-%5FThe%5FUltimate%5FDisplay.pdf) Address: 5. **Head-mounted display** (1968) In 1968 Sutherland and Bob Sproull built a head-mounted display. It showed a user simple wireframe 3D graphics, which a computer redrew as the user’s head moved. The optics hung from the ceiling (the ‘Sword of Damocles’). It was the first system to combine a head-worn display, computer-generated images and head tracking. Built on: [The Ultimate Display](#node-ultimate) ; [Telesphere Mask](#node-telesphere) Led to: [Data glove; “virtual reality”](#node-vpl) ; [CAVE](#node-cave) ; [Virtual Boy](#node-virtualboy) ; [Modern VR headset](#node-rift) Source: [I. E. Sutherland, ‘A head-mounted three dimensional display’, AFIPS Fall Joint Computer Conference (1968)](https://doi.org/10.1145/1476589.1476686) Address: 6. **Realistic shading** (1971–1980) Henri Gouraud (1971) and Bui Tuong Phong (1973–75) devised smooth shading and a lighting model for polygon surfaces. Turner Whitted (1980) showed recursive ray tracing with reflection and refraction. Each step moved computer images closer to how light behaves. The techniques became the basis of film and game rendering. Built on: [Interactive graphics](#node-sketchpad) Led to: [CAVE](#node-cave) ; [Real-time 3D worlds](#node-doom) Source: [Gouraud, ‘Continuous shading of curved surfaces’, IEEE Trans. Computers C-20 (1971); also Phong, CACM 18 (1975), and Whitted, CACM 23 (1980)](https://doi.org/10.1109/T-C.1971.223313) Address: 7. **Arcade video game** (1972) Atari’s Pong was designed by Allan Alcorn from a concept by Nolan Bushnell. It was first placed in a Sunnyvale bar in late 1972 and sold in large numbers. It was built from logic chips, not a microprocessor. It made the video game a commercial public pastime. It also funded the industry that later drove graphics hardware. Built on: [First video games](#node-tennis-for-two) ; [Integrated circuit](#node-ic) Led to: [Cyberspace](#node-cyberspace) Source: [The Strong National Museum of Play, ‘Pong’](https://www.museumofplay.org/games/pong/) Address: 8. **First-person networked world** (1973–74) Maze was written at NASA Ames in 1973 by Steve Colley, Greg Thompson and Howard Palmer on Imlac PDS-1 computers. It showed the view down corridors from the player’s own position. It started with two linked machines, then added shooting and bots. It was an early first-person shared 3D space. It’s a likely ancestor of the networked first-person shooter. Built on: [Packet network](#node-arpanet) ; [Interactive graphics](#node-sketchpad) The sources leave this date or claim uncertain. Source: [DigiBarn Computer Museum, Steve Colley, ‘Maze War’ history](https://digibarn.com/history/04-VCF7-MazeWar/stories/colley.html) Address: 9. **Colossal Cave Adventure** (1975–76) Will Crowther wrote this text game in 1975, and Don Woods extended it in 1976\. A player explored a cave described in prose by typing commands. It set up the explorable, rule-bound world described in text. The first multi-user worlds built on it. Built on: [Stored-program computer](#node-stored-program) Led to: [Shared text world](#node-mud) Source: [Encyclopaedia Britannica, “Adventure”](https://www.britannica.com/topic/Adventure-electronic-game-by-Crowther-c-1975) Address: 10. **Shared text world** (1978–1980) Roy Trubshaw began MUD at the University of Essex in autumn 1978, and Richard Bartle joined the work. Once Essex was linked to ARPANET in spring 1980, outsiders could connect. It was a lasting multi-user world of rooms and objects that several people occupied at once. It set the pattern for later online worlds. Built on: [Packet network](#node-arpanet) ; [Colossal Cave Adventure](#node-adventure) Led to: [Graphical online world](#node-habitat) ; [Persistent online worlds](#node-mmo) Source: [Richard Bartle, ‘Early MUD history’](https://mud.co.uk/richard/mudhist.htm) Address: 11. **Aspen Movie Map** (1978–79) MIT’s Architecture Machine Group filmed Aspen street by street in 1978–79\. A user could drive through the stored footage on a touch-screen laserdisc system, turning left, turning right or stopping at will. It was an early interactive, navigable picture of a real place. It was a forerunner of street-level mapping. Built on: [Projected moving pictures](#node-cinema) ; [Stored-program computer](#node-stored-program) Source: [MIT Media Lab, ‘The Aspen Movie Map beat Google Street View by 34 years’](https://www.media.mit.edu/articles/the-aspen-movie-map-beat-google-street-view-by-34-years) Address: 12. **Cyberspace** (1982–84 · Idea) William Gibson coined the word ‘cyberspace’ in the story ‘Burning Chrome’ (Omni, July 1982). He made it popular in the novel Neuromancer (1984), as a shared graphical space of data that you can move around in. It gave a name and an image to the idea of an online world, and engineers later cited it. Built on: [Arcade video game](#node-pong) Led to: [The Metaverse](#node-metaverse) Source: [The Encyclopedia of Science Fiction, ‘Cyberspace’](https://sf-encyclopedia.com/entry/cyberspace) Address: 13. **Data glove; “virtual reality”** (1985–1987) Jaron Lanier founded VPL Research in 1985\. Its DataGlove (1987) and EyePhone headset were the first commercial VR products. Britannica credits Lanier with coining the term ‘virtual reality’ in 1987\. The company put body-tracking input and a head display within reach outside military and academic labs. Built on: [Head-mounted display](#node-damocles) Source: [Encyclopaedia Britannica, ‘Jaron Lanier’](https://www.britannica.com/biography/Jaron-Lanier) Address: 14. **Graphical online world** (1986–88) Habitat was built by Chip Morningstar and Randy Farmer at Lucasfilm Games for the Commodore 64, over the Quantum Link service. It ran as a pilot in 1986\. Users showed up as cartoon figures called avatars in a shared graphical world. It tested at scale what happens when thousands of people live in a designed virtual place. The builders published the lessons. Built on: [Shared text world](#node-mud) Led to: [The Metaverse](#node-metaverse) ; [Persistent online worlds](#node-mmo) Source: [Morningstar and Farmer, ‘The Lessons of Lucasfilm’s Habitat’ (1990)](https://www.fudco.com/chip/lessons.html) Address: 15. **CAVE** (1992) The CAVE was described in 1992 by Cruz-Neira, Sandin, DeFanti and colleagues at the University of Illinois at Chicago. It projected stereo images on the walls and floor of a room. Several people could stand inside a shared virtual scene wearing light glasses. It showed an immersive alternative to the head-worn display. Built on: [Head-mounted display](#node-damocles) ; [Realistic shading](#node-shading) Source: [Cruz-Neira, Sandin and DeFanti et al., ‘The CAVE: audio visual experience automatic virtual environment’, CACM 35(6) (1992)](https://doi.org/10.1145/129888.129892) Address: 16. **The Metaverse** (1992 · Idea) Neal Stephenson’s novel Snow Crash (1992) coined the word ‘metaverse’. It means a shared 3D online world where people appear as avatars. Technology firms revived the term decades later as a name for the next stage of online worlds. Built on: [Cyberspace](#node-cyberspace) ; [Graphical online world](#node-habitat) Source: [Encyclopaedia Britannica, ‘Snow Crash’](https://www.britannica.com/topic/Snow-Crash) Address: 17. **Real-time 3D worlds** (1993–1996) Id Software’s Doom (December 1993) put networked players in texture-mapped first-person levels on ordinary PCs. Quake (1996) drew true polygonal 3D with real-time lighting. Fast first-person 3D on consumer hardware created the market and the techniques for later virtual worlds. Built on: [Realistic shading](#node-shading) ; [Microprocessor](#node-microprocessor) Led to: [Persistent online worlds](#node-mmo) Source: [The Strong National Museum of Play, ‘Quake’ (with Encyclopaedia Britannica, ‘Doom’)](https://www.museumofplay.org/games/quake/) Address: 18. **Virtual Boy** (1995–96 · Stalled) Nintendo’s Virtual Boy (Japan July 1995, North America August 1995) was a table-mounted stereoscopic console. It showed red, wireframe-style images. It was pulled within a year. Nintendo’s own Iwata later called it a commercial failure. Why it stalled: It stalled because in 1995 there was no affordable compact full-colour display and no head tracking. The red single-colour image, fixed viewing position and awkward fit tired users quickly. Built on: [Head-mounted display](#node-damocles) ; [Integrated circuit](#node-ic) Source: [Iwata Asks, ‘Shigeru Miyamoto talks Virtual Boy’, Nintendo](https://www.nintendo.com/en-gb/Iwata-Asks/Iwata-Asks-Nintendo-3DS/Vol-1-And-That-s-How-the-Nintendo-3DS-Was-Made/2-Shigeru-Miyamoto-Talks-Virtual-Boy/2-Shigeru-Miyamoto-Talks-Virtual-Boy-229419.html) Address: 19. **Persistent online worlds** (1997–2003) Ultima Online (1997), EverQuest (1999) and Second Life (2003) put very large numbers of people into lasting graphical worlds. The worlds kept going when any player logged off. They had economies and social structures of their own. They’re the best evidence we have of how people behave in long-lived virtual places. Built on: [Graphical online world](#node-habitat) ; [Shared text world](#node-mud) ; [Real-time 3D worlds](#node-doom) ; [World Wide Web](#node-web) Source: [Encyclopaedia Britannica, ‘Ultima Online’ and ‘Online gaming’](https://www.britannica.com/topic/Ultima-Online) Address: 20. **Brain-computer interface** (2004–2006) In 2006 Hochberg and colleagues reported on a man paralysed from the neck down. He could move a computer cursor and run a simple robotic hand using signals from a microelectrode array implanted in his motor cortex. It showed that voluntary neural activity could be read out as a control signal. Built on: [Cochlear implant](#node-cochlear) ; [Microprocessor](#node-microprocessor) Led to: [Full-immersion VR](#node-fulldive) ; [Whole-brain emulation](#node-wbe) Source: [Hochberg et al., ‘Neuronal ensemble control of prosthetic devices by a human with tetraplegia’, Nature 442 (2006)](https://doi.org/10.1038/nature04970) Address: 21. **Modern VR headset** (2012–13 (developer kit); 2016 (consumer)) Oculus raised $2.4 million on Kickstarter in 2012\. It shipped the Rift DK1 developer kit from late March 2013\. The consumer Rift followed on 28 March 2016\. It paired phone-class displays and sensors with a GPU and low-latency head tracking. That made a wide-view headset cheap enough for developers and consumers. Built on: [Head-mounted display](#node-damocles) ; [Graphics processor](#node-gpu) ; [Smartphone](#node-smartphone) Led to: [Room-scale tracking](#node-roomscale) Source: [Road to VR, ‘3 years ago the Oculus Rift DK1 shipped, here’s a quick look back’](https://roadtovr.com/3-years-ago-the-oculus-rift-dk1-shipped-heres-a-quick-look-back/) Address: 22. **Room-scale tracking** (2015–2016) HTC and Valve announced the Vive in March 2015 and shipped it on 5 April 2016\. It used Valve’s Lighthouse system, which sweeps infrared lasers across a play area. A headset and two hand controllers could be tracked precisely over about four metres. Walking and reaching inside a virtual space, not just turning your head, became standard. Built on: [Modern VR headset](#node-rift) Led to: [Standalone headsets](#node-standalone) Source: [Road to VR, ‘HTC, Valve and SteamVR: a 2015 retrospective and CES 2016 preview’](https://roadtovr.com/htc-valve-and-steamvr-a-2015-retrospective-and-ces-2016-preview/) Address: 23. **Standalone headsets** (2018–2019) Oculus Quest (21 May 2019) was a self-contained headset. It used four cameras to track the headset and both controllers from the inside, with no PC or base stations. Earlier standalone units (Oculus Go, Lenovo Mirage Solo, Vive Focus, 2018) tracked at most the head position. The Quest made full tracking portable. Built on: [Room-scale tracking](#node-roomscale) ; [Smartphone](#node-smartphone) Led to: [Full-immersion VR](#node-fulldive) Source: [Road to VR, ‘Oculus announces Quest, the high-end standalone headset starting at $400’](https://roadtovr.com/oculus-announces-quest-high-end-standalone-headset-starting-400/) Address: 24. **Neural rendering** (2020–2023) Mildenhall et al.’s Neural Radiance Fields (2020) learned a scene from photographs and drew new views of it. 3D Gaussian Splatting (Kerbl et al., 2023) did it in real time. Photo-real 3D scenes you can explore can now be captured, not modelled by hand. Built on: [Deep learning on GPUs](#node-deep-learning) ; [Graphics processor](#node-gpu) Led to: [Generated interactive worlds](#node-world-models) ; [Real-time photorealism](#node-photoreal) Source: [Mildenhall et al., ‘NeRF: Representing scenes as neural radiance fields for view synthesis’, ECCV 2020, arXiv:2003.08934](https://arxiv.org/abs/2003.08934) Address: 25. **Generated interactive worlds** (2024–2025) In 2024, research systems such as Google DeepMind’s Genie and the GameNGen diffusion model generated each frame of a playable environment from the player’s input. They had no hand-written game engine. GameNGen simulated the game Doom at over 20 frames per second. By 2025 the demonstrations ran for minutes at interactive speeds. They’re still research prototypes. Built on: [Transformer architecture](#node-transformer) ; [Neural rendering](#node-neural-rendering) ; [Learned world models](#node-learned-worlds) ; [Diffusion models](#node-diffusion) Source: [Valevski et al., ‘Diffusion Models Are Real-Time Game Engines’ (GameNGen), arXiv:2408.14837 (2024)](https://arxiv.org/abs/2408.14837) Address: 26. **Real-time photorealism** (2029–2034 · Forecast) Industry figures have forecast real-time images you can’t tell from photographs. In 2024 one major vendor stated a window of 5 to 10 years. A 2013 forecast of ten years for the same milestone came due in 2023\. No one claimed it had been met. Built on: [Neural rendering](#node-neural-rendering) Published forecasts: * **Tim Sweeney (Epic Games)** (2013): within ten years of 2013 (c. 2023). [MCV/Develop conference report, 11 July 2013](https://www.mcvuk.com/business-news/publishing/epic-founder-expects-photorealistic-games-within-ten-years/) * **Jensen Huang (NVIDIA CEO)** (2024): 5–10 years (2029–2034) for real-time AI-generated pixels. [Press Q&A after GTC 2024 keynote, reported by Wccftech, 21 March 2024](https://wccftech.com/nvidia-ceo-believes-were-just-10-years-away-from-ai-generating-every-pixel-in-a-game-in-real-time/amp/) * **Jensen Huang (NVIDIA CEO)** (2025): Qualifier: no fully AI-generated graphics; hybrid rendering stays. [CES 2025 remarks, PCWorld, 7 January 2025](https://www.pcworld.com/article/2570615/nvidias-huang-video-games-will-never-be-entirely-rendered-using-ai.html) Address: 27. **Full-immersion VR** (2029–2030s · Forecast) One named futurist has published dates for VR that works at the level of the nervous system. He puts it in the late 2020s to the 2030s, by way of nanobots in the brain. We found no expert survey or independent forecast of this milestone. No such system has been demonstrated. Built on: [Brain-computer interface](#node-bci) ; [Standalone headsets](#node-standalone) ; [Molecular nanotechnology](#node-nanotech) Published forecasts: * **Ray Kurzweil** (2002): 2029\. [Remarks of 26 March 2002, Kurzweil Library page](https://www.writingsbyraykurzweil.com/?p=370709) * **Ray Kurzweil** (2015): 2030s. [Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015](https://singularityhub.com/2015/10/12/ray-kurzweils-wildest-prediction-nanobots-will-plug-our-brains-into-the-web-by-the-2030s/) * **Ray Kurzweil** (2024): ‘within our lifetimes’ (no year given on page). [The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description)](https://penguin.co.uk/books/462759/the-singularity-is-nearer-by-kurzweil-ray/9781529937503) Address: 28. **Whole-brain emulation** (2050–2075 · Bridge) Also in the [Simulations tree](https://simulation-hypothesis.com/trees/simulations?n=f-wbe) and [Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=s-wbe). The 2008 FHI roadmap judged that emulation was possible before mid-century only if models at the electrophysiological level are enough. Finer detail would need later dates. A 2014 Monte Carlo model gives a median of 2064, if it arrives at all. The Metaculus community median is about 2073. Built on: [Human-level AI](#node-agi) ; [Brain-computer interface](#node-bci) Published forecasts: * **Sandberg & Bostrom** (2008): before mid-century if electrophysiological models suffice; animal models one to two decades earlier; table of earliest dates by detail level (spiking network 2019–2042, electrophysiology 2033–2068, metabolome 2044–2087). [Whole Brain Emulation: A Roadmap, Technical Report 2008–3, Future of Humanity Institute, Oxford, 2008](https://www.futureofhumanityinstitute.org/s/2008-3.pdf) * **Anders Sandberg** (2014): 50% by 2064 (25th percentile 2053, 75th 2080), conditional on WBE ever arriving; 2.4% before 2040\. [Monte Carlo model of brain emulation development, FHI working paper 2014–1](https://web.archive.org/web/20210125040505/https://www.fhi.ox.ac.uk/reports/2014-1.pdf) * **Metaculus community (question 2813, first whole human brain emulated)** (2026): median about November 2073\. [Metaculus community forecast, as shown in search results on 16 October 2026 (check the live question)](https://www.metaculus.com/questions/2813/date-of-first-human-whole-brain-emulation) * **Robin Hanson** (2016): within perhaps a century of 2016\. [The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626)](https://ageofem.com/) * **Dario Amodei** (2024): outside the 5–10 years after powerful AI. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) Address: 29. **Star-scale computer** (c. 2250 or later · Forecast) Dyson (1960) proposed that advanced civilisations would capture starlight. Bradbury (1997–99) extended this to nested shells that run computers on the star’s waste heat. The only dated estimate we found is Bradbury’s. It’s about 2250 if current silicon production trends continued, and within a few thousand years at most. Built on: [Moore’s law](#node-moores-law) ; [Molecular nanotechnology](#node-nanotech) Published forecasts: * **Freeman Dyson** (1960): no date given. [‘Search for Artificial Stellar Sources of Infra-Red Radiation’, Science 131(3414), 3 June 1960](https://doi.org/10.1126/science.131.3414.1667) * **Robert J. Bradbury** (1999): by 2250 from current silicon trends; ‘within at most a few thousand years’; once begun, \~20 years for minor bodies, 10–1000 years for gas giants. [‘Matrioshka Brains’, manuscript dated 21 July 1999 (not peer reviewed; concept from 1997 discussions)](https://www.gwern.net/doc/ai/scaling/hardware/1999-bradbury-matrioshkabrains.pdf) * **Stuart Armstrong & Anders Sandberg** (2013): no date; ‘in the foreseeable future’. [‘Eternity in six hours’, Acta Astronautica 89, 2013](https://doi.org/10.1016/j.actaastro.2013.04.002) * **Nick Bostrom** (2003): no date; capability figure only: \~10^42 operations per second for a planetary-mass computer. [‘Are You Living in a Computer Simulation?', Philosophical Quarterly 53(211), 2003](https://simulation-argument.com/simulation.pdf) Address: ## Computation 1. **Abacus** (uncertain; Mesopotamian counting boards of the 3rd millennium BC (disputed); oldest surviving board c. 300 BC) A counting board, or abacus, is a surface where counters stand for place values. By moving them you can add, subtract, multiply and divide. Mesopotamian examples are often claimed, but none survives and the claim is disputed. The oldest surviving board is the Salamis tablet (c. 300 BC), though some see it as a gaming board. It shows that calculation can be moved into a physical state that a mechanism, and later a circuit, can hold. Led to: [Mechanical calculator](#node-pascaline) The sources leave this date or claim uncertain. Source: [Encyclopaedia Britannica, ‘Abacus’](https://www.britannica.com/technology/abacus-calculating-device) Address: 2. **Zero as a number** (628 CE (Brahmagupta); placeholder dot earlier, date disputed · Idea) Brahmagupta’s Brāhmasphuṭasiddhānta (628 CE) is the earliest surviving text to treat zero as a number with its own rules. Adding or subtracting zero leaves a number unchanged. A number times zero is zero. His rules for dividing by zero were incomplete, and his 0 ÷ 0 = 0 is wrong. A dot used as a placeholder appears earlier in the Bakhshali manuscript. But radiocarbon dates for its folios run from as early as the 3rd–4th century CE to the 9th–10th. So the date of its zero is disputed. Led to: [Binary arithmetic](#node-binary) ; [Algorithms (al-Khwārizmī)](#node-algorithm) Source: [O’Connor and Robertson, ‘Brahmagupta’, MacTutor History of Mathematics (rules); Bodleian Libraries / University of Oxford, Bakhshali manuscript carbon dating release (2017) (dating caveat)](https://mathshistory.st-andrews.ac.uk/Biographies/Brahmagupta/) Address: 3. **Algorithms (al-Khwārizmī)** (c. 820s CE (Arabic original lost); Latin 12th century · Idea) In early 9th-century Baghdad, al-Khwārizmī wrote a treatise on the Hindu place-value numerals, including zero, and on calculating with them. The Arabic text is lost. The Latin translation, Algoritmi de numero Indorum, is known to differ a lot from it. Through it, and the later algorismus texts, the Hindu-Arabic numerals and their written arithmetic reached Europe. The word ‘algorithm’ comes from the Latinized form of his name. Built on: [Zero as a number](#node-zero) Led to: [Mechanical calculator](#node-pascaline) Source: [O’Connor and Robertson, ‘Abu Ja’far Muhammad ibn Musa Al-Khwarizmi’, MacTutor History of Mathematics (see also Encyclopaedia Britannica, ‘al-Khwarizmi’ and ‘algorismus’)](https://mathshistory.st-andrews.ac.uk/Biographies/Al-Khwarizmi/) Address: 4. **Self-playing flute (Baghdad)** (9th century) The Banū Mūsā brothers wrote their Book of Ingenious Devices in 9th-century Baghdad. It describes a flute that plays by itself. A water-driven mechanism pushes air to sound pipes under a revolving cylinder, and swapping the cylinder changes the tune. Koetsier (2001) counts it among the earliest programmable machines. Al-Jazari’s 1206 book describes later musical automata. But no documented line runs from either work to the European pinned barrel or to the Jacquard loom. Source: [Koetsier, ‘On the prehistory of programmable machines: musical automata, looms, calculators’, Mechanism and Machine Theory 36(5), 2001, pp. 589–603; Hill (transl.), The Book of Ingenious Devices (Reidel, 1979)](https://doi.org/10.1016/S0094-114X%2801%2900005-2) Address: 5. **Mechanical calculator** (1642–1644) From 1642 Blaise Pascal built a geared adding machine to help his father’s tax work. He made about fifty. Britannica calls it the first calculator made in quantity and actually used. Arithmetic moved from hands to gears. Built on: [Abacus](#node-abacus) ; [Algorithms (al-Khwārizmī)](#node-algorithm) Led to: [Analytical Engine](#node-analytical-engine) ; [Difference Engine](#node-difference-engine) Source: [Encyclopaedia Britannica, ‘Pascaline’](https://www.britannica.com/technology/Pascaline) Address: 6. **Binary arithmetic** (1703 (printed 1705) · Idea) In a manuscript dated 15 March 1679 (De progressione dyadica), Leibniz set out arithmetic in base two. He also sketched a calculating machine without wheels. In it, balls drop through holes that sliding slots open and close, and that does the sums. He never built it, though a working model was made at the Deutsches Museum in the early 2000s. His paper was read to the Paris Academy in 1703 and printed in 1705\. It also links the 0–1 notation to the hexagram figures of the Yijing, attributed to Fu Xi, which Joachim Bouvet had sent him from Beijing (received April 1703). An earlier Indian scheme appears in Piṅgala’s Chandaḥśāstra (date uncertain, about the 3rd to 2nd century BCE). It lists metres of short and long syllables in a way later readers analysed as binary. Built on: [Zero as a number](#node-zero) Led to: [Zuse Z3](#node-z3) Source: [Leibniz, ‘Explanation of Binary Arithmetic’ (1703), English translation](https://www.leibniz-translations.com/binary.htm) Address: 7. **Punched-card loom** (1804) Joseph Marie Jacquard’s 1804 loom used a chain of punched cards to pick which warp threads to lift. To change the pattern, you changed the cards. Bouchon (1725) and Falcon (1728) had used punched paper or cards before him. But Jacquard’s version was widely adopted, and Babbage borrowed its card-reading idea. Led to: [Analytical Engine](#node-analytical-engine) Source: [Science Museum Group, ‘Model of Falcon’s loom’ (Jacquard refined Falcon’s method in 1804)](https://collection.sciencemuseumgroup.org.uk/objects/co44927/model-of-falcons-loom-looms) Address: 8. **Difference Engine** (1822 (proposed); built 1991 · Stalled) Babbage designed a machine to compute and print mathematical tables by the method of finite differences. It would take human error out of the arithmetic. A small working section was shown. The full engine wasn’t built in his lifetime. Why it stalled: Work halted in 1833 after a dispute with his engineer, Joseph Clement. The Science Museum finished Difference Engine No. 2 from his drawings in 1991\. That showed the design itself was sound. Built on: [Mechanical calculator](#node-pascaline) Led to: [Analytical Engine](#node-analytical-engine) Source: [Science Museum, “Charles Babbage’s Difference Engines and the Science Museum”](https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum) Address: 9. **Analytical Engine** (1837 (conceived 1834) · Stalled) Charles Babbage designed a programmable mechanical computer. It had a store, an arithmetic mill, conditional branching and instructions on punched cards. It anticipated the layout of later computers by a century. Only a trial piece was built before he died in 1871. Why it stalled: It stalled because it needed thousands of parts, and 1840s Britain couldn’t supply the precision engineering, steady funding and settled design that took. The Computer History Museum lists runaway costs, high precision demands, a dispute with his engineer and patchy financing. Built on: [Punched-card loom](#node-jacquard) ; [Mechanical calculator](#node-pascaline) ; [Difference Engine](#node-difference-engine) Led to: [Note G](#node-lovelace) Source: [Computer History Museum, ‘Babbage: a brief history’](https://www.computerhistory.org/babbage/history/) Address: 10. **Note G** (1843 · Idea) Ada Lovelace translated Menabrea’s paper and added notes. Note G is a worked table of operations for computing Bernoulli numbers on the Analytical Engine. She also remarked that the engine might act on things other than number, such as musical composition, if their relations could be expressed. That second claim is the first clear statement that a computing machine handles symbols, not just quantities. Built on: [Analytical Engine](#node-analytical-engine) Source: [Menabrea and Lovelace, ‘Sketch of the Analytical Engine’, Taylor’s Scientific Memoirs (1843), text at Fourmilab](https://www.fourmilab.ch/babbage/sketch.html) Address: 11. **Boolean logic** (1847; 1854 · Idea) George Boole’s Mathematical Analysis of Logic (1847) and An Investigation of the Laws of Thought (1854) treated logical statements as an algebra with two values. That meant reasoning could be calculated. Shannon later showed that circuits carry out this algebra. So Boole’s system became the logical basis of digital hardware. Led to: [Universal machine](#node-turing) ; [Logic in circuits](#node-shannon) Source: [George Boole, An Investigation of the Laws of Thought (1854), Project Gutenberg](https://www.gutenberg.org/ebooks/15114) Address: 12. **Vacuum tube** (1904–1907) John Ambrose Fleming’s two-electrode valve (1904) turned radio signals into a usable form. Lee de Forest added a grid to make the three-electrode Audion (1906–07), which could amplify and switch electrical signals. The triode was the working part of radio, telephony and the first electronic computers. Led to: [Electronic computer](#node-eniac) ; [Transistor](#node-transistor) ; [Colossus](#node-colossus) Source: [Encyclopaedia Britannica, ‘Thermionic valve’](https://www.britannica.com/technology/thermionic-valve) Address: 13. **Universal machine** (1936–37 · Idea) Alan Turing’s ‘On Computable Numbers’ (read in 1936, published 1936–37) defined an abstract machine. It showed that one universal machine can do the work of any other, given that other’s description as input. That’s the theoretical reason one general computer can run any simulated world. It also sets the limits on what such a simulation can compute. Built on: [Boolean logic](#node-boole) Led to: [The stored-program design](#node-edvac) Source: [A. M. Turing, ‘On Computable Numbers, with an Application to the Entscheidungsproblem’, Proc. London Math. Soc. s2–42 (1937)](https://doi.org/10.1112/plms/s2-42.1.230) Address: 14. **Logic in circuits** (1937–38 · Idea) Claude Shannon’s master’s thesis at MIT (1937, published 1938) showed that networks of relays and switches can be analysed and designed with Boolean algebra. It tied abstract logic to physical circuits. Engineers now had a systematic way to design digital machines. Built on: [Boolean logic](#node-boole) Led to: [Electronic computer](#node-eniac) Source: [C. E. Shannon, ‘A Symbolic Analysis of Relay and Switching Circuits’, MIT thesis (1937)](https://dspace.mit.edu/handle/1721.1/11173) Address: 15. **Zuse Z3** (1941) Konrad Zuse completed the Z3 in Berlin in 1941\. It had about 2,400 relays, a binary number system and 22-bit floating-point words. The program was read in sequence from punched tape. The IEEE Computer Society’s history site calls it the first fully working program-controlled electromechanical digital computer in the world. It had no conditional branch, and it kept its program outside the machine’s memory. Built on: [Binary arithmetic](#node-binary) Source: [IEEE Computer Society, ‘Konrad Zuse’, Computer Pioneers; Rojas, ‘Konrad Zuse’s Legacy: The Architecture of the Z1 and Z3’, IEEE Annals of the History of Computing 19(2), 1997](https://history.computer.org/pioneers/zuse.html) Address: 16. **Colossus** (1943–44) Tommy Flowers’s electronic machines at Bletchley Park read cipher text from paper tape. They used valves (2,500 in the Mark 2) to find the wheel settings of the German Lorenz cipher. They were electronic and configurable, but built for one task. They were kept secret for many years after the war. Built on: [Vacuum tube](#node-vacuum-tube) Source: [The National Museum of Computing, “Colossus”](https://www.tnmoc.org/colossus) Address: 17. **Electronic computer** (1945–46) ENIAC was completed at the University of Pennsylvania in 1945 and announced publicly in February 1946\. It used about 18,000 vacuum tubes. You could rewire it to solve a wide range of numerical problems. It showed that electronic speed was practical for general computing. But reprogramming took days. Built on: [Vacuum tube](#node-vacuum-tube) ; [Logic in circuits](#node-shannon) Led to: [The stored-program design](#node-edvac) Source: [Encyclopaedia Britannica, ‘ENIAC’](https://www.britannica.com/technology/ENIAC) Address: 18. **Stored-program computer** (1945 (design); 1948 (first run)) On 21 June 1948 the Manchester Small-Scale Experimental Machine (‘Baby’), built by Williams and Kilburn, ran its first program from its own electronic memory. The program was 17 instructions long and searched for the highest proper factor of a number. Keeping instructions and data in the same memory is what lets software change at electronic speed. It’s also what lets simulations be loaded. Built on: [The stored-program design](#node-edvac) Led to: [Packet network](#node-arpanet) ; [Interactive graphics](#node-sketchpad) ; [Simulacron-3](#node-simulacron) ; [First video games](#node-tennis-for-two) ; [Aspen Movie Map](#node-aspen) ; [Colossal Cave Adventure](#node-adventure) Source: [University of Manchester, ‘Manchester Baby computer’ (Computer 50 archive)](https://curation.cs.manchester.ac.uk/computer50/www.computer50.org/mark1/new.baby.html) Address: 19. **The stored-program design** (1945 · Idea) John von Neumann’s First Draft of a Report on the EDVAC described a computer that keeps its program in the same memory as its data. Almost every computer since has used this layout. Built on: [Electronic computer](#node-eniac) ; [Universal machine](#node-turing) Led to: [Stored-program computer](#node-stored-program) Source: [von Neumann, First Draft of a Report on the EDVAC (30 June 1945), Internet Archive](https://archive.org/details/firstdraftofrepo00vonn) Address: 20. **Transistor** (1947–48) John Bardeen and Walter Brattain demonstrated a point-contact transistor at Bell Laboratories in December 1947\. William Shockley developed the junction form soon after. The three shared the 1956 Nobel Prize in Physics. It was a solid-state amplifier and switch with no heater and no vacuum. Computers became smaller, faster and far more reliable. Built on: [Vacuum tube](#node-vacuum-tube) Led to: [Integrated circuit](#node-ic) Source: [Nobel Prize in Physics 1956, summary](https://www.nobelprize.org/prizes/physics/1956/summary/) Address: 21. **Integrated circuit** (1958–59) Jack Kilby at Texas Instruments built a working integrated circuit in September 1958\. Robert Noyce at Fairchild devised a planar silicon version that could be manufactured in 1959\. Kilby shared the 2000 Nobel Prize in Physics. Putting many parts on one piece of material made complex electronics cheap. That set up the scaling of computing power. Built on: [Transistor](#node-transistor) Led to: [Moore’s law](#node-moores-law) ; [Microprocessor](#node-microprocessor) ; [Arcade video game](#node-pong) ; [Virtual Boy](#node-virtualboy) Source: [Nobel Prize in Physics 2000, Jack S. Kilby facts](https://www.nobelprize.org/prizes/physics/2000/kilby/facts/) Address: 22. **Moore’s law** (1965 (revised 1975) · Idea) In an April 1965 article in Electronics, Gordon Moore observed that the number of components per integrated circuit had doubled about every year. He projected the trend for a decade. In 1975 he changed the rate to about every two years. The projection held roughly for five decades. It set the pace at which simulated worlds could grow richer. Built on: [Integrated circuit](#node-ic) Led to: [Star-scale computer](#node-matrioshka) ; [Molecular nanotechnology](#node-nanotech) ; [Reversible computing](#node-reversible) Source: [Computer History Museum, ‘Moore’s Law predicts the future of integrated circuits’](https://www.computerhistory.org/siliconengine/moores-law-predicts-the-future-of-integrated-circuits/) Address: 23. **Packet network** (1969) ARPANET sent its first host-to-host message from UCLA to SRI on 29 October 1969\. Minicomputers called IMPs routed the packets. It grew into a national research network. Shared virtual spaces need machines that swap data in real time. ARPANET was the first large network built on packet switching. Built on: [Stored-program computer](#node-stored-program) Led to: [First-person networked world](#node-maze-war) ; [Shared text world](#node-mud) ; [The Internet](#node-internet) Source: [Computer History Museum, ‘October 29, 1969: Happy 40th birthday to a radical idea’](https://computerhistory.org/blog/october-29-1969-happy-40th-birthday-to-a-radical-idea/) Address: 24. **Microprocessor** (1971) Intel’s 4004 came out in November 1971\. Hoff, Mazor, Faggin and Shima designed it for a Busicom calculator. It put a programmable central processor on a single chip. General computing became cheap enough for personal machines, consoles and, eventually, phones. Built on: [Integrated circuit](#node-ic) Led to: [Graphics processor](#node-gpu) ; [Smartphone](#node-smartphone) ; [Real-time 3D worlds](#node-doom) ; [Brain-computer interface](#node-bci) Source: [Encyclopaedia Britannica, ‘Intel 4004’](https://www.britannica.com/technology/Intel-4004) Address: 25. **The Internet** (1983) In January 1983 the ARPANET switched to the TCP/IP protocols. They’re the common language that lets separate networks connect. Shared online worlds run over this network of networks. Built on: [Packet network](#node-arpanet) Led to: [World Wide Web](#node-web) Source: [Computer History Museum, “Internet History of 1980s”](https://www.computerhistory.org/internethistory/1980s/) Address: 26. **World Wide Web** (1989–1991) Tim Berners-Lee proposed a linked hypertext system at CERN in March 1989\. By the end of 1990 he had the first server and browser running there. He announced the software publicly in August 1991\. It made the Internet usable for non-specialists. It became the common way to reach shared online spaces. Built on: [The Internet](#node-internet) Led to: [Persistent online worlds](#node-mmo) Source: [CERN, ‘A short history of the Web’](https://home.cern/science/computing/the-birth-of-the-web/short-history-web/) Address: 27. **Graphics processor** (1999) Nvidia’s GeForce 256 (October 1999) put transformation and lighting on a single chip. It was marketed as the first graphics processing unit. That moved per-pixel and per-vertex work off the CPU. Cheap parallel graphics hardware is what put real-time 3D worlds within reach. Later it did the same for large-scale neural computing. Built on: [Microprocessor](#node-microprocessor) Led to: [General-purpose GPU computing](#node-gpgpu) ; [Modern VR headset](#node-rift) ; [Neural rendering](#node-neural-rendering) Source: [NVIDIA press release, ‘NVIDIA launches the world’s first graphics processing unit: GeForce 256’ (1999)](https://nvidianews.nvidia.com/news/nvidia-launches-the-world-s-first-graphics-processing-unit-geforce-256) Address: 28. **General-purpose GPU computing** (2006–2007) Nvidia announced CUDA in 2006 and released it in June 2007\. It let programmers write ordinary C-like code for a GPU’s thousands of parallel threads. Graphics hardware became a general parallel computer. That’s what later made training large neural networks practical. Built on: [Graphics processor](#node-gpu) Led to: [Deep learning on GPUs](#node-deep-learning) Source: [Nickolls, Buck, Garland and Skadron, ‘Scalable Parallel Programming with CUDA’, ACM Queue 6(2) (2008)](https://doi.org/10.1145/1365490.1365500) Address: 29. **Smartphone** (2007) Apple announced the iPhone in January 2007 and released it in June. It put a touch display, a capable processor and motion sensors in a pocket device, and mass production of those parts followed. The result was a supply of cheap high-density displays, motion sensors and mobile chips. That made consumer headsets possible. Built on: [Microprocessor](#node-microprocessor) Led to: [Modern VR headset](#node-rift) ; [Standalone headsets](#node-standalone) Source: [Apple Newsroom, ‘Apple reinvents the phone with iPhone’ (9 January 2007)](https://www.apple.com/newsroom/2007/01/09Apple-Reinvents-the-Phone-with-iPhone/) Address: 30. **Deep learning on GPUs** (2012) In September 2012 AlexNet won the ImageNet image-classification contest by a wide margin. It was a convolutional network that Krizhevsky, Sutskever and Hinton trained on two GPUs. The result showed that large neural networks trained on parallel hardware beat hand-built methods at perception tasks. Built on: [General-purpose GPU computing](#node-gpgpu) Led to: [Transformer architecture](#node-transformer) ; [Neural rendering](#node-neural-rendering) ; [Learned world models](#node-learned-worlds) ; [Diffusion models](#node-diffusion) Source: [Krizhevsky, Sutskever and Hinton, ‘ImageNet classification with deep convolutional neural networks’, NeurIPS 25 (2012)](https://papers.nips.cc/paper/2012/hash/c399862d3b9d6b76c8436e924a68c45b-Abstract.html) Address: 31. **Transformer architecture** (2017) Vaswani and colleagues at Google introduced the Transformer in 2017\. It’s a network built on attention. It handles sequences in parallel and scales well with data and computing power. It’s the architecture behind large language models, which can produce open-ended, conversational behaviour. Built on: [Deep learning on GPUs](#node-deep-learning) Led to: [Generated interactive worlds](#node-world-models) ; [Human-level AI](#node-agi) Source: [Vaswani et al., ‘Attention Is All You Need’, NeurIPS (2017), arXiv:1706.03762](https://arxiv.org/abs/1706.03762) Address: 32. **Learned world models** (2018) Ha and Schmidhuber trained a neural network to model a game environment. Then they trained an agent inside the model’s own imagined version of it. A world could now be learned from watching, not written by hand. Built on: [Deep learning on GPUs](#node-deep-learning) Led to: [Generated interactive worlds](#node-world-models) Source: [Ha and Schmidhuber, “World Models”, arXiv:1803.10122 (2018)](https://arxiv.org/abs/1803.10122) Address: 33. **Diffusion models** (2020) Ho, Jain and Abbeel showed that a network trained to remove noise step by step can generate high-quality images from random input. The method sits under most later image, video and interactive-world generators. Built on: [Deep learning on GPUs](#node-deep-learning) Led to: [Generated interactive worlds](#node-world-models) Source: [Ho, Jain and Abbeel, “Denoising Diffusion Probabilistic Models”, arXiv:2006.11239 (2020)](https://arxiv.org/abs/2006.11239) Address: 34. **Molecular nanotechnology** (2010–2030s · Forecast) Forecasters in the 1990s–2000s dated programmable molecular assembly and brain-entering nanobots to 2010–2029\. Diamondoid assembly was forecast for 2010–2015 and hasn’t been demonstrated. So this is a record of dates that passed. Built on: [Moore’s law](#node-moores-law) Led to: [Full-immersion VR](#node-fulldive) ; [Star-scale computer](#node-matrioshka) Published forecasts: * **Robert J. Bradbury, citing Zyvex’s Jim Von Ehr and Drexler 1998** (1999): 2010–2015 (Zyvex: by 2010). [‘Matrioshka Brains’ manuscript, 1999](https://www.gwern.net/doc/ai/scaling/hardware/1999-bradbury-matrioshkabrains.pdf) * **Ray Kurzweil** (2002): by 2029\. [Remarks 26 March 2002, Kurzweil Library](https://www.writingsbyraykurzweil.com/?p=370709) * **Ray Kurzweil** (2015): 2030s. [Singularity Hub report, 12 Oct 2015](https://singularityhub.com/2015/10/12/ray-kurzweils-wildest-prediction-nanobots-will-plug-our-brains-into-the-web-by-the-2030s/) Address: 35. **Human-level AI** (2027–2047 · Forecast) Forecasts for machines that beat humans at every task run from 2026–2030, in statements by AI-lab leaders, to a 2047 median in the 2023 survey of 2,778 researchers. Surveys have moved earlier over time. They gave 2040–2050 in 2012–13, 2060 in 2022 and 2047 in 2023. Built on: [Transformer architecture](#node-transformer) Led to: [Whole-brain emulation](#node-wbe) ; [Superintelligence](#node-asi) Published forecasts: * **Grace et al. (AI Impacts), survey of 2,778 AI researchers, run October 2023** (2024): HLMI: 10% by 2027, 50% by 2047; full automation of all occupations 10% by 2037, 50% by 2116\. [arXiv:2401.02843 ‘Thousands of AI Authors on the Future of AI’ (Jan 2024; v3 Oct 2025)](https://arxiv.org/abs/2401.02843) * **Müller & Bostrom, survey of four expert groups (2012–13)** (2016): 50% chance of high-level machine intelligence around 2040–2050; 90% by 2075\. [‘Future progress in artificial intelligence: A survey of expert opinion’, in Fundamental Issues of AI, Springer, 2016](https://doi.org/10.1007/978-3-319-26485-1%5F33) * **Metaculus community (question 5121, first general AI system)** (2026): median April 2030; interquartile range about 2026 to 2038\. [Metaculus community forecast, as shown in search results on 16 October 2026 (check the live question)](https://www.metaculus.com/questions/5121/) * **Dario Amodei (Anthropic CEO)** (2024): ‘powerful AI’ as early as 2026, or much later. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) * **Demis Hassabis (Google DeepMind CEO)** (2025): capabilities emerging in 5–10 years (2030–2035). [CNBC interview, 17 March 2025](https://www.cnbc.com/2025/03/17/human-level-ai-will-be-here-in-5-to-10-years-deepmind-ceo-says.html) * **Ray Kurzweil** (2005): computers pass the Turing test / human-level intelligence by 2029\. [The Singularity Is Near (Viking, 2005; ISBN 978–0670033843), reaffirmed in The Singularity Is Nearer (Viking, June 2024)](https://aiimpacts.org/kurzweil-the-singularity-is-near/) * **Hans Moravec** (1998): hardware matching the brain in home computers before 2030\. [‘When will computer hardware match the human brain?', Journal of Evolution and Technology vol. 1, 1998](https://jetpress.org/volume1/moravec.htm) Address: 36. **Reversible computing** (2027–2040 · Forecast) Reversible logic avoids the Landauer minimum energy cost of erasing bits. It’s proposed as the route to far more computing per watt. A startup projects a first inference chip in 2027 and a 4,000-fold efficiency gain 10 to 15 years later. A 2014 expert interview didn’t expect wide use by 2030. Built on: [Moore’s law](#node-moores-law) Published forecasts: * **Hannah Earley (Vaire CTO); Michael Frank** (2025): chip in 2027; 4,000x in 10–15 years (2035–2040). [Dina Genkina, ‘Reversible Computing Escapes the Lab in 2025’, IEEE Spectrum, 2 Jan 2025 (update 22 May 2025)](https://spectrum.ieee.org/reversible-computing) * **Erik DeBenedictis (Sandia)** (2014): not widely used by 2030; some applications by 2030\. [MIRI interview, 3 April 2014](https://intelligence.org/2014/04/03/erik-debenedictis/) Address: 37. **Superintelligence** (2027–2045+ · Forecast) Surveyed experts expect superintelligence within 30 years of human-level machine intelligence. Scenario authors and Kurzweil give dates between 2027 and 2045\. Researchers surveyed in 2023 put substantial but not majority odds on a fast ‘intelligence explosion’. Built on: [Human-level AI](#node-agi) Published forecasts: * **Müller & Bostrom** (2016): within less than 30 years after HLMI. [Future progress in AI: a survey of expert opinion, 2016](https://doi.org/10.1007/978-3-319-26485-1%5F33) * **Kokotajlo, Alexander, Larsen, Lifland, Dean** (2025): ASI Dec 2027 in the scenario; medians later (e.g. one author’s median 2030). [AI 2027 scenario, 3 April 2025 (updated Nov-Dec 2025)](https://ai-2027.com/) * **Ray Kurzweil** (2005): 2045\. [The Singularity Is Near, 2005 (via AI Impacts summary)](https://aiimpacts.org/kurzweil-the-singularity-is-near/) Address: --- title: "Simulations tree · what we have learned to simulate · Simulation Hypothesis" url: https://simulation-hypothesis.com/trees/simulations description: "A ladder by scale, from matter to whole worlds." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Simulations tree · what we have learned to simulate A ladder by scale. Matter is at the bottom, then life, minds, societies, planets and the cosmos. At the top are whole worlds built to be lived in. Each node is the first time something was simulated. It counts whatever ran the simulation: a mind, a group of people, a physical model or a computer. Minds and people were simulating worlds long before computers. The methods along the bottom are what let each rung be reached. Future nodes are published forecasts or, where none gives a date, published estimates. **0** of 107 read unread read idea stalled forecast projection bridge mind people analogue [Read it as text](#text) Whole tree Forecasts → Whole worlds Planets, cosmos Societies Minds Life Matter Methods c. 534 BCE · People Greek tragedy before records · Mind Dreams before records · Mind Children’s pretend play c. 2nd century BCE · Analogue Antikythera mechanism 6th–7th century CE · People Chaturanga, the army game c. 75 CE · People Roman drill as rehearsal 1756 · Analogue Du Coudray’s birth mannequin 1675 · Analogue Hooke’s hanging chain 1684–1687 Differential equations 1780 · People Hellwig’s chess wargame 1768–1901 Numerical integration 1929–1934 · Analogue Link Trainer 1836 · Mind Alternate history 1915 onward · Mind Languages before the world 1826–1831 · Mind Glass Town 1922 · People Richardson’s hand forecast 1872 · Analogue Kelvin’s tide predictor 1941 · Analogue Holmberg’s bulb galaxies 1812–1824 · People Kriegsspiel 1943 · Idea · Mind Craik’s model in the head 1871–1872 · Analogue Froude’s towing tank 1944 · People Hand-computed implosion 1931 Differential analyser 1928 Finite differences 1945–1946 Electronic computer 1950 First computer forecast 1949 · Analogue Phillips’s hydraulic economy 1952 · People Hodgkin–Huxley by hand 1952 Turing’s reaction-diffusion 1940s–1960s Cellular automata 1946–1949 Monte Carlo method 1953 Evolution on the IAS machine 1953 Metropolis algorithm October 1962 · Mind The Man in the High Castle 1961–1963 Lorenz’s chaotic convection 1960 N-body star cluster 1955–1956 Phillips’s circulation run 1959–1960 The People Machine 1969–1971 · People Schelling segregation 1965–1966 ELIZA 1954–1956 Simulated neuron networks late 1960s–1970 · People Life, played by hand 1960 Cardiac cell model 1953–1957 Hard-sphere fluids 1957–1959 Molecular dynamics 1974 · People Dungeons and Dragons 1969 Coupled ocean-atmosphere 1971–1972 World3 1971–1996 Agent-based models 1975–1976 Colossal Cave Adventure 1978–1986 · Idea · Mind Simulating other minds 1977 Protein dynamics 1978–1980 MUD1 1991 Civilization 1985 · People Klingon 1991–1997 · Idea · People Counterfactual history as method 1996 onward Rome Reborn 1996 Sugarscape 1994 Artificial stock market 1994 · Mind Hippocampal replay 1996 · Idea · Mind Philosophical zombies 1985 Ab initio molecular dynamics 1981–1982 · Idea Feynman’s quantum simulator 1979–1980 Lattice gauge Monte Carlo 1986 Neural networks 2003 Second Life 2004 A lore world with millions c. 1996–1999 · Stalled · People A child raised in Klingon 2009 · Idea · People Evidence or guess: the London Charter 2005 Millennium Simulation 2007 Global cloud-resolving model 2002 Artificial Anasazi 2015 Neocortical microcircuit 2011 onward · Idea OpenWorm 2007 · Mind Imagining the future 2003 · Idea · Mind Shadow-people 2009–2023 · Stalled Human Brain Project 2012–2022 Whole-cell models May 2010 The Neandertal genome 2002 · Analogue Cold-atom quantum simulator 2007 Learned surrogate models 2024 GameNGen 2023 Learned weather forecasts 2022–2023 Silicon samples 2023–2024 Generative agents 2020–2021 Learned protein structure 2019 A face from DNA February 2026 Social worlds in headsets 2025 Genie 3 2024 Destination Earth twins October 2024 An agent civilisation born 2024–2025 · Analogue Gene-edited ‘dire wolves’ 2026–2040 · Forecast Immersive worlds in daily life undated · Projection Lore worlds undated · Projection Reconstructed worlds 2029–2034 · Forecast · ↗ Technology Real-time photorealism 2030 · Forecast Full Earth digital twin undated · Forecast Simulated human society 2050–2075 · Bridge Whole-brain emulation undated · Projection Scripted inhabitants undated · Forecast Human whole-cell model undated · Forecast Quantum chemistry simulation undated · Forecast Ancestor simulation 2029–2030s · Forecast · ↗ Technology Full-immersion VR undated · Projection Counterfactual worlds 2060s–2100+ · Forecast Mind uploading undated · Projection Conscious inhabitants Where it starts Show ▴ Start here ## Where it starts The oldest simulations ran in minds. Dreams and pretend play build whole worlds with no equipment at all. The oldest surviving machine that models a system is the Antikythera mechanism . The method behind most later rungs starts with differential equations . Your progress stays in this browser only. If you clear site data, the tree starts over. The whole tree as text · every node in order, for screen readers, text browsers and machine readers. Same nodes as the map Dates are years of the common era unless marked BC or BCE. Evolutionary dates are in years ago. Each node has a stable address, shown after it. Forecast nodes list published forecasts only, each cited. Projection nodes are this site’s own reasoning, not published predictions, with each step shown. ## Whole worlds 1. **Dreams** (before records; measured since 1953 · In the mind) The earliest recorded description of a mind making a world is in the Bṛhadāraṇyaka Upaniṣad (4.3.9–10, c. 7th–6th century BCE, with a wider scholarly range of about 900–600 BCE). In sleep, the self gathers material from the whole world and builds a dream by its own light. There are no chariots, horses or roads there, but it makes them for itself, “for he is the maker”. Aserinsky and Kleitman (1953) woke sleepers during rapid-eye-movement periods. They got detailed dream reports in 20 of 27 cases, against 4 of 23 when the eyes were still. Revonsuo (2000) argued that dreaming is a simulation of the world that rehearses spotting threats. That hypothesis is still debated. Source: [Aserinsky and Kleitman, ‘Regularly occurring periods of eye motility, and concomitant phenomena, during sleep’, Science 118 (1953) 273–274; Revonsuo, Behavioral and Brain Sciences 23 (2000) 877–901](https://teams.semel.ucla.edu/sites/default/files/sleep/pdf/53%20aserinsky%20kleitman%20reprint.pdf) Address: 2. **Children’s pretend play** (before records; described 1945 · In the mind) Piaget’s study of symbolic play (1945) described children treating an object or action as standing for another, inside an invented scene. Lillard and colleagues (2013) reviewed the evidence on what pretend play adds to development. They found it mixed, and too thin to show that it’s crucial for any one skill. Led to: [Glass Town](#node-w-bronte) Source: [Lillard et al., ‘The impact of pretend play on children’s development: a review of the evidence’, Psychological Bulletin 139(1) (2013) 1–34](https://pmc.ncbi.nlm.nih.gov/articles/PMC4662258) Address: 3. **Greek tragedy** (c. 534 BCE (traditional) · Run by people) By the traditional date of 534 BCE, Thespis is said to have won the first tragedy competition at the City Dionysia. He is said to have been the first actor to play a character instead of speaking as himself. Staging a fiction for an audience, with performers living inside it, is the human-run form of a built world. The sources leave this date or claim uncertain. Source: [Aristotle, Poetics 1449a (tragedy from the dithyramb; Aeschylus adds the second actor); Brill’s New Pauly, ‘Thespis’ (Parian Marble ep. 43 records him as tragedy’s first inventor)](https://catalog.perseus.org/catalog/urn:cite:perseus:author.1398) Address: 4. **Glass Town** (1826–1831 · In the mind) On 5 June 1826 their father gave Branwell Brontë twelve wooden soldiers. The Brontë children then invented the Glass Town confederacy and wrote its histories from December 1827\. Later they split into the spin-off worlds Angria and Gondal. Scholars call such long-running invented worlds paracosms. Built on: [Children’s pretend play](#node-w-pretend) Source: [Glass Town, Wikipedia (citing Christine Alexander’s edition of the juvenilia)](https://en.wikipedia.org/wiki/Glass%5FTown) Address: 5. **Alternate history** (1836 (first novel); Livy c. 25 BCE · In the mind) Livy (Ab Urbe Condita IX.17–19) already asked how Rome would have done if Alexander the Great had turned west. Louis Geoffroy’s Napoléon et la conquête du monde (1836) is the first novel built on a changed history, with a Napoleon who won in Russia in 1812\. Nathaniel Hawthorne’s “P.’s Correspondence” (1845) is usually called the first complete alternate history in English. Each one runs a whole world forward in the reader’s mind from one changed event. Led to: [The Man in the High Castle](#node-w-highcastle) ; [Counterfactual history as method](#node-w-cfhistory) Source: [Wikipedia, ‘Alternate history’](https://en.wikipedia.org/wiki/Alternate%5Fhistory) Address: 6. **Languages before the world** (1915 onward · In the mind) J. R. R. Tolkien began his first invented Elvish language, Qenya, in a notebook in March 1915\. He said that Middle-earth was made largely to give his languages a world to live in. It’s the first invented world built from the language outward. Its histories, peoples and maps were worked out over five decades. Led to: [Lore worlds](#node-p-invented) Source: [Tolkien Gateway, ‘Qenya Lexicon’](https://tolkiengateway.net/wiki/Qenya%5FLexicon) Address: 7. **Link Trainer** (1929–1934 · Analogue model) Edwin Link filed a patent in April 1929, and it was granted in September 1931\. It covered a pneumatic trainer that moved a mock cockpit in response to the controls, so pilots could practise flying on the ground. Early buyers were mainly amusement parks. The US Army bought six in 1934\. By the end of the Second World War, 6,271 had gone to the Army and 1,045 to the Navy. Source: [Guinness World Records, ‘First flight simulator’](https://www.guinnessworldrecords.com/world-records/117575-first-flight-simulator) Address: 8. **The Man in the High Castle** (October 1962 · In the mind) Philip K. Dick’s novel imagines a United States split between Germany and Japan after an Axis victory. It won the 1963 Hugo Award. Dick named Ward Moore’s Bring the Jubilee (1953), in which the Confederacy wins, as his starting point. Inside the novel, a banned book imagines an Allied victory. So one counterfactual world contains another. Built on: [Alternate history](#node-w-althistory) Led to: [Counterfactual worlds](#node-p-counterfactual) Source: [Wikipedia, ‘The Man in the High Castle’](https://en.wikipedia.org/wiki/The%5FMan%5Fin%5Fthe%5FHigh%5FCastle) Address: 9. **Dungeons and Dragons** (1974 · Run by people) Gygax and Arneson’s boxed set, published by Tactical Studies Rules in 1974, is described as the first role-playing game in print. Players speak as characters in a world kept by a referee. It joined tabletop wargaming to playing a character. Its dungeon-and-referee setup is the pattern that text and computer adventures later followed. Built on: [Kriegsspiel](#node-soc-kriegs) Led to: [Colossal Cave Adventure](#node-w-colossal) Source: [Dungeons & Dragons (1974), Wikipedia](https://en.wikipedia.org/wiki/Dungeons%5F%26%5FDragons%5F%281974%29) Address: 10. **Colossal Cave Adventure** (1975–1976 · Computer) Will Crowther wrote a text game on a DEC PDP-10\. The player types commands and reads descriptions of the rooms and objects of a cave system. Don Woods expanded it significantly in 1976\. It was the first widely played adventure game. It made a described world a place one person could explore alone. Built on: [Electronic computer](#node-m-computer) ; [Dungeons and Dragons](#node-w-dnd) Led to: [MUD1](#node-w-mud1) Source: [Raph Koster, ‘A Brief History’ of online worlds](https://www.raphkoster.com/gaming/book/3a.html) Address: 11. **MUD1** (1978–1980 · Computer) Roy Trubshaw began MUD at the University of Essex on a DEC PDP-10 in 1978, and Richard Bartle joined him. It let several players share one text world at the same time. It was named after Dungeon, a variant of Zork. It made a built world last and made it social. Built on: [Colossal Cave Adventure](#node-w-colossal) Led to: [A lore world with millions](#node-w-wow) ; [Second Life](#node-w-secondlife) Source: [Richard Bartle, ‘Early MUD history’](https://mud.co.uk/richard/mudhist.htm) Address: 12. **Klingon** (1985; institute 1992 · Run by people) Marc Okrand built Klingon as a working language for Star Trek. It was published as The Klingon Dictionary in 1985, and Lawrence Schoen founded the Klingon Language Institute in 1992\. Estimates of fluent speakers have stayed small: about a dozen in 1996, and 20 to 30 in 2009\. But the language has a grammar, a literature and translated plays. Led to: [A child raised in Klingon](#node-w-speers) ; [Lore worlds](#node-p-invented) Source: [Wikipedia, ‘Klingon language’](https://en.wikipedia.org/wiki/Klingon%5Flanguage) Address: 13. **Counterfactual history as method** (1991–1997 · Idea · Run by people) Geoffrey Hawthorn’s Plausible Worlds (1991), Tetlock and Belkin’s Counterfactual Thought Experiments in World Politics (1996) and Niall Ferguson’s edited Virtual History (1997) brought “what if” into academic history and political science. They added criteria for which changed pasts are plausible. Richard Evans’s Altered Pasts (2014) argues that such histories always carry their authors’ beliefs from the present. Built on: [Alternate history](#node-w-althistory) Led to: [Counterfactual worlds](#node-p-counterfactual) Source: [Tetlock and Belkin (eds.), Counterfactual Thought Experiments in World Politics, Princeton University Press (1996)](https://press.princeton.edu/node/26160) Address: 14. **Civilization** (1991; 73 million copies by 2025 · Computer) Sid Meier’s Civilization (1991) lets a player run a civilisation from the first city to space flight, so every game is a history that never happened. When the seventh game launched in February 2025, the series had sold more than 73 million copies. That counts units shipped to retailers, not necessarily bought by players. Grand-strategy games such as Hearts of Iron, a Second World War with the outcome left open, sell in the millions. Led to: [Counterfactual worlds](#node-p-counterfactual) Source: [2K press release, ‘Sid Meier’s Civilization VII now available worldwide’ (February 2025)](https://www.nasdaq.com/press-release/build-something-you-believe-sid-meiers-civilizationr-vii-now-available-worldwide-2025) Address: 15. **A child raised in Klingon** (c. 1996–1999 · Stalled · Run by people) The linguist d’Armond Speers spoke only Klingon to his infant son Alec for about the boy’s first three years. The boy’s mother spoke English. Speers wanted to see whether a child would pick up an invented language as a native one. Alec understood some and said a few words, but rarely answered in it. Why it stalled: It stalled because a language alone is not a world. The boy had one Klingon speaker, no child speakers, and no stories or school in it. He began ignoring Klingon at about three, Speers stopped, and by thirteen Alec spoke none. To raise a native speaker of an invented language, you need the whole culture around the child. Built on: [Klingon](#node-w-klingon) Led to: [Lore worlds](#node-p-invented) Source: [HuffPost UK, reporting Wired (1999)](https://huffingtonpost.co.uk/entry/darmond-speers-dad-spoke%5Fn%5F363477) Address: 16. **Rome Reborn** (1996 onward · Computer) Rome Reborn began in 1996 at UCLA under Bernard Frischer. It models the whole city of Rome as it stood in AD 320\. Version 1.0 was finished in 2007, and version 3.0 (2018) was rebuilt so you can walk through it in a headset. It’s a reconstructed world. Every building rests on archaeological evidence where there is some, and on inference where there isn’t. Led to: [Evidence or guess: the London Charter](#node-w-london) Source: [Wikipedia, ‘Rome Reborn’](https://en.wikipedia.org/wiki/Rome%5FReborn) Address: 17. **Second Life** (2003; peak 2009 · Computer) Linden Lab’s Second Life (2003) is a world built by its residents, with land, an economy and a currency. It peaked at about 88,200 people online at once in early 2009\. About 21 million accounts had been registered by late 2010\. It’s the first large world that people treated as a second place to live, not as a game. Built on: [MUD1](#node-w-mud1) Led to: [Social worlds in headsets](#node-w-vrchat) Source: [Engadget, ‘Linden Lab says Second Life is huge, shows numbers’ (22 September 2009)](https://www.engadget.com/2009-09-22-linden-lab-says-second-life-huge-shows-numbers.html) Address: 18. **A lore world with millions** (2004; 12 million subscribers in 2010 · Computer) World of Warcraft (2004) put millions of people inside one invented world, with its own races, histories and wars. It descends from the text worlds of MUDs. In October 2010 Blizzard announced that subscribers had passed 12 million, the game’s last headline figure. Players spend years in it, but the people in it who aren’t players are scripted. Built on: [MUD1](#node-w-mud1) Led to: [Lore worlds](#node-p-invented) Source: [Activision Blizzard press release, 7 October 2010](https://investor.activision.com/node/18936) Address: 19. **Evidence or guess: the London Charter** (2009 (term ‘virtual archaeology’ 1990) · Idea · Run by people) Paul Reilly coined “virtual archaeology” in 1990\. The London Charter (2009) set a rule: a visualisation must tell its viewer which parts show what survives, which are restorations based on evidence, and which are hypothesis. It’s the first standard for honesty inside a reconstructed world. Built on: [Rome Reborn](#node-w-rome) Led to: [Reconstructed worlds](#node-p-reconstructed) Source: [Wikipedia, ‘Virtual archaeology’](https://en.wikipedia.org/wiki/Virtual%5Farchaeology) Address: 20. **GameNGen** (2024 · Computer) Valevski and colleagues trained a diffusion model on recordings of an agent playing DOOM. With no conventional game engine, it generates each next frame from past frames and player actions, at about 20 frames per second on a single TPU. Human raters could tell short clips of the real game from simulated ones only slightly better than chance. Built on: [Learned surrogate models](#node-m-learned) Led to: [Genie 3](#node-w-genie3) ; [Real-time photorealism](#node-f-photoreal) Source: [Valevski, Leviathan, Arar and Fruchter, ‘Diffusion Models Are Real-Time Game Engines’, arXiv 2408.14837 (2024); ICLR 2025](https://arxiv.org/abs/2408.14837v1) Address: 21. **Genie 3** (2025 · Computer) DeepMind announced Genie 3 on 5 August 2025\. It’s a world model that generates environments you can move around in, in real time, at 720p and 24 frames per second. Worlds stayed largely consistent for several minutes, and its visual memory reached back about a minute. It was released only as a limited research preview, for a small group of academics and creators. Built on: [GameNGen](#node-w-gamengen) ; [Learned surrogate models](#node-m-learned) Led to: [Ancestor simulation](#node-f-ancestor) ; [Real-time photorealism](#node-f-photoreal) ; [Reconstructed worlds](#node-p-reconstructed) ; [Lore worlds](#node-p-invented) Source: [Google DeepMind, ‘Genie 3: A new frontier for world models’, 5 August 2025](https://deepmind.google/discover/blog/genie-3-a-new-frontier-for-world-models/) Address: 22. **Social worlds in headsets** (February 2026 · Computer) VRChat set a record of 158,192 people online at once at a concert in February 2026\. Ordinary weekend peaks are about 120,000\. Roblox reported 151.5 million daily users in the third quarter of 2025, mostly on screens, not headsets. These are the biggest groups of people who live part of each day in built worlds. Built on: [Second Life](#node-w-secondlife) Led to: [Immersive worlds in daily life](#node-f-immersive) Source: [Road to VR, ‘VRChat key stats’ (2026)](https://roadtovr.com/vrchat-key-stats-japan-growth-concurrents/) Address: 23. **Real-time photorealism** (2029–2034 · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=photoreal). Industry figures have forecast real-time images that look just like photographs. In 2024 one major vendor gave a window of 5 to 10 years. A 2013 forecast of ten years for the same milestone came due in 2023, with no claim that it had been met. Built on: [Genie 3](#node-w-genie3) ; [GameNGen](#node-w-gamengen) Led to: [Full-immersion VR](#node-f-fulldive) Published forecasts: * **Tim Sweeney (Epic Games)** (2013): within ten years of 2013 (c. 2023). [MCV/Develop conference report, 11 July 2013](https://www.mcvuk.com/business-news/publishing/epic-founder-expects-photorealistic-games-within-ten-years/) * **Jensen Huang (NVIDIA CEO)** (2024): 5–10 years (2029–2034) for real-time AI-generated pixels. [Press Q&A after GTC 2024 keynote, reported by Wccftech, 21 March 2024](https://wccftech.com/nvidia-ceo-believes-were-just-10-years-away-from-ai-generating-every-pixel-in-a-game-in-real-time/amp/) * **Jensen Huang (NVIDIA CEO)** (2025): Qualifier: no fully AI-generated graphics; hybrid rendering stays. [CES 2025 remarks, PCWorld, 7 January 2025](https://www.pcworld.com/article/2570615/nvidias-huang-video-games-will-never-be-entirely-rendered-using-ai.html) Address: 24. **Full-immersion VR** (2029–2030s · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=fulldive). Only one named futurist has published dates for VR at the level of the nervous system. He puts it in the late 2020s to the 2030s, using nanobots in the brain. We found no expert survey or independent forecast of this milestone. No such system has been demonstrated. Built on: [Real-time photorealism](#node-f-photoreal) ; [Whole-brain emulation](#node-f-wbe) Published forecasts: * **Ray Kurzweil** (2002): 2029\. [Remarks of 26 March 2002, Kurzweil Library page](https://www.writingsbyraykurzweil.com/?p=370709) * **Ray Kurzweil** (2015): 2030s. [Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015](https://singularityhub.com/2015/10/12/ray-kurzweils-wildest-prediction-nanobots-will-plug-our-brains-into-the-web-by-the-2030s/) * **Ray Kurzweil** (2024): ‘within our lifetimes’ (no year given on page). [The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description)](https://penguin.co.uk/books/462759/the-singularity-is-nearer-by-kurzweil-ray/9781529937503) Address: 25. **Immersive worlds in daily life** (2026–2040 · Forecast) These are forecasts that a large share of people would spend part of each day inside immersive worlds. Gartner’s date came due in 2026\. VRChat’s record is about 158,000 people at once, and Roblox’s daily users are about 151 million, mostly on flat screens. That’s far from the quarter of all people that was forecast. A 2022 canvass of 624 experts split 54 to 46 on half a billion people by 2040. Built on: [Social worlds in headsets](#node-w-vrchat) Published forecasts: * **Gartner (Marty Resnick)** (2022): by 2026, 25% of people will spend at least one hour a day in the metaverse. [Gartner press release, 7 February 2022](https://www.businesswire.com/news/home/20220207005085/en/Gartner-Predicts-25-of-People-Will-Spend-At-Least-One-Hour-Per-Day-in-the-Metaverse-by-2026) * **Pew Research Center and Elon University, 624 experts (nonrandom sample)** (2022): 54% expect a fully immersive metaverse in the daily lives of half a billion or more people by 2040; 46% do not. [‘The Metaverse in 2040’, 30 June 2022](https://www.pewresearch.org/internet/2022/06/30/the-metaverse-in-2040/) Address: 26. **Reconstructed worlds** (undated · Projection) This is a lost civilisation, ours or another species’, rebuilt from what it left behind and run so that you can live in it. The evidence never covers a whole world. So every reconstruction is part record and part inference, and a long-dead alien civilisation would be mostly inference. The London Charter’s rule is to tell the visitor which is which. That becomes the ethics of the whole genre. The site’s reasoning, step by step: 1. The pieces exist separately. There are walkable cities rebuilt from excavation (Rome Reborn), bodies predicted from genomes (the Denisovan face) and extinct animals approximated in living ones (the 2025 “dire wolves”). There are also generated worlds that respond to the visitor. 2. What survives of a people is far less than what a world needs. Rome Reborn models one year of one city. Daily life, speech and minds survive only as fragments. The rest has to be generated, so the share of guesswork grows the further back, or the further away, the source is. 3. For a non-human civilisation, the only published method is to treat its artefacts as archaeology from a distance. Nothing is known of its minds, so its inhabitants would have to be designed. That makes them invented, not reconstructed. ([Vakoch (ed.), Archaeology, Anthropology, and Interstellar Communication, NASA SP-2013–4413 (2014)](https://www.nasa.gov/wp-content/uploads/2015/01/Archaeology%5FAnthropology%5Fand%5FInterstellar%5FCommunication%5FTAGGED.pdf)) 4. So here’s the projection. Reconstructed worlds come in degrees. At one end is the faithful kind, a city with scripted crowds. At the other is the speculative kind, a whole conscious people filled in by inference. The honest ones label the difference. Built on: [Evidence or guess: the London Charter](#node-w-london) ; [A face from DNA](#node-life-denisovan) ; [Gene-edited ‘dire wolves’](#node-life-direwolf) ; [Genie 3](#node-w-genie3) Address: 27. **Counterfactual worlds** (undated · Projection) This is our own history run forward from a changed event, such as an Axis victory or a Mongol conquest of Europe. Novels have done it in the reader’s mind since 1836, and strategy games have done it in millions of copies. The projected step is running it with simulated people in it. That turns a thought experiment into a world with inhabitants. The site’s reasoning, step by step: 1. Counterfactual historians already set rules for which changed pasts are plausible. Make a small change, hold the rest of the world as it was, and follow the consequences using what’s known. ([Tetlock and Belkin (1996)](https://press.princeton.edu/node/26160)) 2. Once a society simulation can model people well, it can follow those consequences mechanically. The published runs so far are 25 agents (2023), 1,052 people modelled from interviews (2024) and about 1,000 agents in a game world (2024). 3. Evans’s objection carries over. The result shows the beliefs of whoever set the rules. A simulated Axis victory tells you about its builders’ model of people as much as about 1945. 4. The dark forks are where the choice of inhabitant matters most. With scripted inhabitants, a counterfactual is an expensive film. With conscious ones, it recreates the suffering it shows, and the open questions in the Ethics tree apply in full. Built on: [The Man in the High Castle](#node-w-highcastle) ; [Counterfactual history as method](#node-w-cfhistory) ; [Civilization](#node-w-civ) ; [Simulated human society](#node-f-society) Address: 28. **Lore worlds** (undated · Projection) This is a reality made entirely of lore, with orcs and elves, or the Klingons of Star Trek. Their languages, histories and religions are taken as true from the inside. A person could be born there and raised in it. Its own fiction could even feature a strange imagined race called humans. The site’s reasoning, step by step: 1. The materials already exist. There are invented languages with full grammars (Elvish 1915, Klingon 1985). There are lore worlds with millions of players (12 million in one, in 2010). And there are generated worlds that answer the visitor in real time. 2. The one attempt to raise a child inside an invented culture stalled, because only the language was invented. There was one speaker, no other children and no world. Someone native to a lore world needs the whole culture around them, and only a populated simulation can supply that. 3. An invented world is easier to run honestly than a reconstructed one. Nothing in it has to match a record, so nothing in it is a guess. 4. The demand is in the hundreds of millions. One fantasy series alone has sold more than 600 million books. ([Scholastic, Harry Potter press kit](https://www.scholastic.com/newsroom/online-press-kits/harry-potter/harry-potter-highlights-and-milestones.html)) Built on: [Languages before the world](#node-w-tolkien) ; [Klingon](#node-w-klingon) ; [A child raised in Klingon](#node-w-speers) ; [A lore world with millions](#node-w-wow) ; [Genie 3](#node-w-genie3) Address: 29. **Ancestor simulation** (undated · Forecast) Bostrom (2003) gives no date, and says the argument doesn’t depend on one. He estimates that simulating all human mental history takes about 10^33 to 10^36 operations. A planetary-mass computer could supply that in under a second of its capacity. Built on: [Whole-brain emulation](#node-f-wbe) ; [Genie 3](#node-w-genie3) ; [World3](#node-soc-world3) Published forecasts: * **Nick Bostrom** (2003): No date. Compute estimate: 10^33–10^36 operations for a realistic simulation of human history; \~10^14–10^17 ops/s per human brain. [‘Are You Living in a Computer Simulation?', Philosophical Quarterly 53(211): 243–255, 2003](https://simulation-argument.com/simulation.pdf) * **Nick Bostrom** (2003): explicitly declines to forecast: ‘few decades’ (others) to hundreds of thousands of years. [same paper, on timescale](https://simulation-argument.com/simulation.pdf) * **Bostrom** (2003): a single planetary-mass computer suffices. [same paper, on required hardware](https://simulation-argument.com/simulation.pdf) * **Sandberg & Bostrom** (2008): per-brain requirement for neuron-level emulation: \~10^18 FLOPS (spiking network level), up to 10^25–10^27 at molecular levels. [Whole Brain Emulation: A Roadmap, FHI TR 2008–3](https://www.futureofhumanityinstitute.org/s/2008-3.pdf) Address: ## Planets, cosmos 1. **Antikythera mechanism** (c. 2nd century BCE · Analogue model) A geared bronze device was recovered from a shipwreck off Antikythera. It showed the motions of the Sun, Moon and planets, and it predicted eclipses using Babylonian cycles. Its lunar gearing puts into metal a theory attributed to Hipparchos. Freeth and colleagues (2021) proposed a model of its front planetary display. Source: [Freeth et al., ‘Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism’, Nature 444 (2006) 587–591](https://orca.cardiff.ac.uk/id/eprint/1622/) Address: 2. **Kelvin’s tide predictor** (1872 · Analogue model) Kelvin designed this machine with Edward Roberts for the British Association, and Alexander Lege built it. It added up ten harmonic tidal constituents mechanically to trace the tide at a port. More than thirty such machines were built between the 1870s and the 1960s. For about ninety years, a machine that embodied a system’s harmonic structure predicted its future. Source: [Science Museum Group, ‘William Thomson’s Tide Predicting Machine, 1872’](https://collection.sciencemuseumgroup.org.uk/objects/co53901/william-thomsons-tide-predicting-machine-1872-tide-predictor) Address: 3. **Richardson’s hand forecast** (1922 · Run by people) Lewis Fry Richardson worked out by hand the change in the weather for one morning in 1910\. He used the finite-difference equations of the atmosphere. He wrote that drawing up the computing forms and working out the new distribution for two columns took the best part of six weeks. He pictured a hall of about 64,000 human computers working in step to keep pace with the real weather. It’s an early picture of a parallel computer. Built on: [Numerical integration](#node-m-numint) Led to: [First computer forecast](#node-p-eniac) Source: [Lynch, ‘Richardson’s Forecast-factory: the $64,000 Question’, Meteorological Magazine / Weather](https://maths.ucd.ie/~plynch/Publications/64000.html) Address: 4. **Holmberg’s bulb galaxies** (1941 · Analogue model) Holmberg used light bulbs, 37 to a galaxy, with photocells to measure the brightness as a stand-in for gravity. Both fall off as the inverse square of distance. He moved the bulbs step by step to model two interacting disk galaxies. The experiment produced tidal tails and bridges, about thirty years before digital computers could check it. Source: [Holmberg’s analog computer (University of Oulu repository); Erik Holmberg, Uppsala University history pages](https://oulurepo.oulu.fi/handle/10024/39263) Address: 5. **First computer forecast** (1950 · Computer) Charney, Fjortoft and von Neumann solved the barotropic vorticity equation on ENIAC. They covered a limited area, on a 19 by 16 grid with about 600 km between points, and produced four 24-hour forecasts. Each forecast took about 24 hours of computing, most of it handling cards by hand. So the machine was no faster than the weather. Built on: [Electronic computer](#node-m-computer) ; [Finite differences](#node-m-fd) ; [Richardson’s hand forecast](#node-p-richardson) Led to: [Phillips’s circulation run](#node-p-phillips) ; [Learned weather forecasts](#node-p-graphcast) Source: [Charney, Fjortoft and von Neumann, ‘Numerical Integration of the Barotropic Vorticity Equation’, Tellus 2 (1950) 237–254](https://faculty.eas.ualberta.ca/jdwilson/EAS372%5F13/Charney%5Fetal50.pdf) Address: 6. **Phillips’s circulation run** (1955–1956 · Computer) Phillips ran a numerical simulation of the atmosphere’s general circulation on the Institute for Advanced Study machine, for about a model month. It showed realistic monthly and seasonal patterns in the troposphere. It won the first Napier Shaw Memorial Prize. It’s commonly described as the first successful climate model. Built on: [First computer forecast](#node-p-eniac) ; [Finite differences](#node-m-fd) Led to: [Coupled ocean-atmosphere](#node-p-manabebryan) ; [Global cloud-resolving model](#node-p-miura) Source: [Phillips, ‘The general circulation of the atmosphere: a numerical experiment’, Quarterly Journal of the Royal Meteorological Society 82 (1956) 123–164; Norman A. Phillips, Wikipedia](https://en.wikipedia.org/wiki/Norman%5FA.%5FPhillips) Address: 7. **N-body star cluster** (1960 · Computer) Von Hoerner integrated the gravitational motion of 4 to 16 stars on a computer, with the time step set by the closest pair. In 1963 he extended it to 25\. It’s the earliest documented N-body integration. The line from it runs through clusters of galaxies to simulations of the universe. Built on: [Electronic computer](#node-m-computer) ; [Numerical integration](#node-m-numint) Led to: [Millennium Simulation](#node-p-millennium) Source: [von Hoerner, ‘Die numerische Integration des n-Koerper-Problemes fuer Sternhaufen. I’, Zeitschrift fuer Astrophysik 50 (1960) 184–214](https://wwwadd.zah.uni-heidelberg.de/publikationen/mha/mha014/mha014.htm) Address: 8. **Lorenz’s chaotic convection** (1961–1963 · Computer) Lorenz ran a twelve-variable weather model on a Royal McBee LGP-30\. When he restarted it from rounded printout values, the result drifted apart from the first run. In 1963 he published a convection model whose solutions are unstable and mostly nonperiodic. It showed that a deterministic simulation can be unpredictable past a limited time. That sets a limit on how far ahead any forecast can reach. Built on: [Electronic computer](#node-m-computer) ; [Numerical integration](#node-m-numint) Source: [Lorenz, ‘Deterministic nonperiodic flow’, Journal of the Atmospheric Sciences 20 (1963) 130–141](https://en.wikipedia.org/wiki/Edward%5FNorton%5FLorenz) Address: 9. **Coupled ocean-atmosphere** (1969 · Computer) Manabe and Bryan at the Geophysical Fluid Dynamics Laboratory coupled a model atmosphere to a model ocean. They used an idealised strip of ocean and continent, on the argument that the sea moves about as much heat as the atmosphere. It’s described as the first coupled ocean-atmosphere climate model. Built on: [Phillips’s circulation run](#node-p-phillips) ; [Finite differences](#node-m-fd) Led to: [Global cloud-resolving model](#node-p-miura) Source: [Manabe and Bryan, ‘Climate Calculations with a Combined Ocean-Atmosphere Model’, Journal of the Atmospheric Sciences 26 (1969) 786–789](https://ethw-images.s3.us-east-va.perf.cloud.ovh.us/ieee/f/fc/Manabe%5Fand%5Fbryan%5FClimate%5Fcalculations%5Fwith%5Fa%5Fcombined%5Focean-atmosphere%5Fmodel%5F1969.pdf) Address: 10. **Millennium Simulation** (2005 · Computer) Springel and colleagues followed more than ten billion dark-matter particles as structure grew in a cubic region of the universe. They paired the run with models of galaxy and quasar formation, to compare simulated and observed large-scale structure. It showed baryonic features of the early universe turning up, distorted, in the galaxy distribution at low redshift. Built on: [N-body star cluster](#node-p-vonhoerner) ; [Electronic computer](#node-m-computer) Source: [Springel et al., ‘Simulating the joint evolution of quasars, galaxies and their large-scale distribution’, Nature 435 (2005) 629–636](https://arxiv.org/abs/astro-ph/0504097) Address: 11. **Global cloud-resolving model** (2007 · Computer) Miura and colleagues simulated a Madden-Julian oscillation event on the Earth Simulator. Their global model resolves clouds directly instead of approximating them. It reproduced the slow eastward drift of the event. The approach is the one later called global storm-resolving modelling. Built on: [Phillips’s circulation run](#node-p-phillips) ; [Coupled ocean-atmosphere](#node-p-manabebryan) Led to: [Destination Earth twins](#node-p-destine) ; [Full Earth digital twin](#node-f-earthtwin) Source: [Miura, Satoh, Nasuno, Noda and Oouchi, ‘A Madden-Julian Oscillation Event Realistically Simulated by a Global Cloud-Resolving Model’, Science 318 (2007) 1763–1765](https://cir.nii.ac.jp/crid/1360011142933994112) Address: 12. **Learned weather forecasts** (2023 · Computer) GraphCast is a neural network trained on reanalysis data. It predicts hundreds of weather variables for the next 10 days at 0.25 degree resolution, in under a minute. It was more accurate than the European Centre’s operational deterministic system on 90% of 1,380 verification targets. It swaps step-by-step integration of the atmosphere’s equations for a learned map from one state to the next. Built on: [Learned surrogate models](#node-m-learned) ; [First computer forecast](#node-p-eniac) Led to: [Destination Earth twins](#node-p-destine) Source: [Lam et al., ‘Learning skillful medium-range global weather forecasting’, Science 382 (2023) 1416–1421](https://arxiv.org/pdf/2212.12794) Address: 13. **Destination Earth twins** (2024 · Computer) ECMWF built the first two Destination Earth digital twins, on climate change adaptation and weather-driven extremes. The second phase of the programme began on 10 June 2024\. The programme states its aim as a digital replica of the Earth system by 2030. Built on: [Global cloud-resolving model](#node-p-miura) ; [Learned weather forecasts](#node-p-graphcast) ; [Electronic computer](#node-m-computer) Led to: [Full Earth digital twin](#node-f-earthtwin) Source: [ECMWF, ‘Destination Earth system launched’, 10 June 2024](https://destine.ecmwf.int/news/destination-earth-system-launched/) Address: 14. **Full Earth digital twin** (2030 (a stated programme aim, not an independent forecast) · Forecast) The Destination Earth programme states an aim of a digital replica of the Earth system by 2030\. Its first two twins went live in 2024\. The only other source we found is a review of kilometre-scale climate models. It argues for a concerted effort and gives no date. Built on: [Destination Earth twins](#node-p-destine) ; [Global cloud-resolving model](#node-p-miura) Published forecasts: * **Destination Earth programme (European Commission, ECMWF, ESA, EUMETSAT)** (2024): digital replica of the Earth system by 2030\. [ECMWF, ‘Destination Earth system launched’, 10 June 2024](https://destine.ecmwf.int/news/destination-earth-system-launched/) * **Schär et al.** (2020): no date: global kilometre-scale climate simulations need a concerted effort, and data volumes make storing the output impractical. [Bulletin of the American Meteorological Society 101(5): E567-E587, ‘Kilometer-scale climate models: Prospects and challenges’ (abstract read via a repository record)](https://research-collection.ethz.ch/handle/20.500.11850/389770?show=full) Address: ## Societies 1. **Roman drill as rehearsal** (c. 75 CE · Run by people) In The Jewish War, Josephus wrote that every Roman soldier is exercised daily as if in war. He summed up the practice as exercises that are bloodless battles and battles that are bloody exercises. Rehearsing a battle with the same units and drills as the real one is an early documented form of simulating a war. Source: [Josephus, The Jewish War 3.5.1 (Whiston translation, sections 3.70–3.75)](https://lexundria.com/j%5Fbj/3.70-3.109/wst) Address: 2. **Chaturanga, the army game** (6th–7th century CE · Run by people) Chaturanga means the four parts of an army: infantry, cavalry, elephants and chariots. It was played in India on an eight-by-eight board. The earliest Sanskrit mention of the name is in Bana’s Harshacharita, written in the 7th century. The game is the ancestor of chess, and it passed to Persia as chatrang about 600 CE. It boils an army and its terrain down to a few pieces and rules. It’s an early model of a war, run by humans. Led to: [Hellwig’s chess wargame](#node-soc-hellwig) Source: [Encyclopaedia Britannica, ‘chess’ (history section); see also Murray, A History of Chess (Oxford, 1913)](https://www.britannica.com/topic/chess) Address: 3. **Hellwig’s chess wargame** (1780 · Run by people) In 1780 Johann Hellwig, a mathematics professor at the Collegium Carolinum in Braunschweig, published a tactical game built on chess. Two or more people played it on a board of about 49 by 33 squares, with mountains, swamps and water. The aim was to take an enemy fortress instead of capturing a king. It’s the earliest of the chess-based German wargames that came before Reisswitz’s Kriegsspiel. Built on: [Chaturanga, the army game](#node-soc-chaturanga) Led to: [Kriegsspiel](#node-soc-kriegs) Source: [Hellwig, Versuch eines aufs Schachspiel gebaueten taktischen Spiels (Leipzig: Crusius, 1780), as described in Peterson, Playing at the World (Unreason Press, 2012) p. 213](https://en.wikipedia.org/wiki/Johann%5FChristian%5FLudwig%5FHellwig) Address: 4. **Kriegsspiel** (1812–1824 · Run by people) In 1811 the Prussian princes were shown a terrain table of damp sand and models. It was presented to the king in 1812\. In 1824 the younger Reisswitz published rules that used topographical maps and put numbers on the effects of combat. Kriegsspiel is described as the first war-gaming system that a military adopted as a serious tool for training and research. Built on: [Hellwig’s chess wargame](#node-soc-hellwig) Led to: [Dungeons and Dragons](#node-w-dnd) Source: [Kriegsspiel, Wikipedia; Georg von Reisswitz, Wikipedia](https://en.wikipedia.org/wiki/Kriegsspiel) Address: 5. **Phillips’s hydraulic economy** (1949 · Analogue model) Bill Phillips built the MONIAC, a hydraulic analogue computer. Water flowing through tanks and pipes stood for the flows of income and spending in the United Kingdom economy. He demonstrated it at the London School of Economics on 29 November 1949\. At least twelve machines were built, and the original ran until 1992. Led to: [World3](#node-soc-world3) Source: [Computing History, ‘Professor Bill Phillips unveils MONIAC at the LSE’](https://www.computinghistory.org.uk/det/43833/Professor-Bill-Phillips-unveils-MONIAC-at-the-LSE/) Address: 6. **The People Machine** (1959–1960 · Computer) Simulmatics was led by Ithiel de Sola Pool with Robert Abelson. It split the American electorate into 480 voter types and 52 issue clusters, built from past polls. Then it simulated how each type would respond to campaign choices. It worked first for the Democratic National Committee and then for the Kennedy campaign. Lepore counts three reports for the campaign and says its influence is unclear. Built on: [Electronic computer](#node-m-computer) Led to: [Silicon samples](#node-soc-argyle) Source: [Lepore, ‘Which category have they put you in?' (on Simulmatics), New York Review of Books, 8 October 2020](https://www.nybooks.com/articles/2020/10/08/simulating-democracy/) Address: 7. **Schelling segregation** (1969–1971 · Run by people) In Schelling’s model, two kinds of agents move when fewer than a set share of their neighbours are like them. It showed that strong segregation in housing can come from only mild preferences. He worked it through by hand with coins on a checkerboard, so it was a simulation run by humans. It later became the standard first example of agent-based modelling. Source: [Schelling, ‘Dynamic Models of Segregation’, Journal of Mathematical Sociology 1 (1971) 143–186](https://www.jasss.org/15/4/9.html) Address: 8. **World3** (1971–1972 · Computer) Meadows and colleagues built World3 on top of Forrester’s World2 model. It links population, agriculture, industry, resources and pollution as feedback loops. Its standard run showed overshoot followed by collapse. It was published as The Limits to Growth in 1972, and it put a simulation of the whole human system in front of ordinary readers. Built on: [Electronic computer](#node-m-computer) ; [Phillips’s hydraulic economy](#node-soc-moniac) Led to: [Ancestor simulation](#node-f-ancestor) Source: [World3, Wikipedia; Meadows, Meadows, Randers and Behrens, The Limits to Growth (1972)](https://en.wikipedia.org/wiki/World3) Address: 9. **Simulating other minds** (1978–1986 · Idea · In the mind) In 1978 Premack and Woodruff asked whether a chimpanzee has a theory of mind. In 1986 Gordon and Heal, working separately, argued that people predict others by simulating them. They run their own decision process on the other person’s circumstances. On this account, understanding other people is a mental simulation of them. Built on: [Craik’s model in the head](#node-min-craik) Source: [Gordon, ‘Folk Psychology as Simulation’, Mind and Language 1 (1986) 158–171; Heal, ‘Replication and Functionalism’ (1986)](https://plato.stanford.edu/archives/spr2014/entries/folkpsych-simulation/) Address: 10. **Artificial stock market** (1994 · Computer) Palmer, Arthur, Holland, LeBaron and Tayler simulated a market in one stock. Adaptive trader programs held different strategies, and a specialist set the price, so prices came out of the traders’ interactions. The model didn’t necessarily settle at an equilibrium. It could show bubbles, crashes and persistently high trading volume. Built on: [Agent-based models](#node-m-abm) Source: [Palmer, Arthur, Holland, LeBaron and Tayler, ‘Artificial economic life: a simple model of a stockmarket’, Physica D 75 (1994) 264–274](https://deepblue.lib.umich.edu/items/18b0197f-305e-40c5-b9bf-98ca56549ca5) Address: 11. **Sugarscape** (1996 · Computer) Epstein and Axtell put agents with different metabolisms and eyesight on a grid of sugar. Group formation, cultural transmission, combat and trade all arose from simple local rules. Their book described the method as growing a society from the bottom up. Built on: [Agent-based models](#node-m-abm) Led to: [Artificial Anasazi](#node-soc-anasazi) Source: [Epstein and Axtell, Growing Artificial Societies: Social Science from the Bottom Up, Brookings Institution Press / MIT Press (1996)](https://www.brookings.edu/books/growing-artificial-societies) Address: 12. **Artificial Anasazi** (2002 · Computer) Axtell and colleagues modelled the Kayenta Anasazi in Long House Valley, with agents choosing where to farm and settle. The model reproduced the population swings and the shifting settlement pattern of a society from about 1800 BCE to 1300 CE. Its main mismatch is that the model valley could still have supported many people in 1300, when the real population left. Built on: [Sugarscape](#node-soc-sugarscape) ; [Agent-based models](#node-m-abm) Led to: [Simulated human society](#node-f-society) Source: [Axtell, Epstein, Dean, Gumerman et al., ‘Population growth and collapse in a multiagent model of the Kayenta Anasazi in Long House Valley’, PNAS 99 (suppl. 3) (2002) 7275–7279](https://profiles.wustl.edu/en/publications/population-growth-and-collapse-in-a-multiagent-model-of-the-kayen/) Address: 13. **Silicon samples** (2022–2023 · Computer) Argyle and colleagues gave a language model the socio-demographic backstories of thousands of real survey respondents. For US politics, they found its output could stand in for specific groups of people. They call this property algorithmic fidelity. They proposed these “silicon samples” for exploring hypotheses before doing costly work with human subjects. Built on: [Learned surrogate models](#node-m-learned) ; [The People Machine](#node-soc-simulmatics) Led to: [Simulated human society](#node-f-society) Source: [Argyle et al., ‘Out of One, Many: Using Language Models to Simulate Human Samples’, Political Analysis (2023), doi 10.1017/pan.2023.2](https://doi.org/10.1017/pan.2023.2) Address: 14. **An agent civilisation** (October 2024 · Computer) Altera’s Project Sid ran from 10 to more than 1,000 language-model agents together in Minecraft. It reports that they took on specialised roles, changed their collective rules and passed on culture. The authors call the results preliminary. It’s the largest published attempt at a society of software people living in a game world. Built on: [Generative agents](#node-min-park) Led to: [Scripted inhabitants](#node-p-scripted) Source: [Altera, ‘Project Sid: many-agent simulations toward AI civilization’, arXiv:2411.00114 (2024)](https://arxiv.org/pdf/2411.00114) Address: 15. **Simulated human society** (No dated forecast; stated ambition only · Forecast) The leading group building generative-agent simulations has stated an ambition of simulating eight billion people. It hasn’t given a timeline. Current published runs are far smaller: 25 agents in the 2023 paper and 1,052 individuals in the 2024 follow-up. Built on: [Generative agents](#node-min-park) ; [Silicon samples](#node-soc-argyle) ; [Artificial Anasazi](#node-soc-anasazi) Led to: [Counterfactual worlds](#node-p-counterfactual) Published forecasts: * **Joon Sung Park** (2026): ambition of a simulation with eight billion people; no timeline given. [Nature news feature ‘The first AI societies are taking shape: how human-like are they?' (read via a bioethics.com repost dated 9 March 2026)](https://www.nature.com/articles/d41586-026-00070-5) The sources leave this date or claim uncertain. Address: ## Minds 1. **Craik’s model in the head** (1943 · Idea · In the mind) In The Nature of Explanation, Kenneth Craik proposed that an organism carries a small-scale model of the outside world and of its own possible actions. That lets it try alternatives before it acts. He compared this with testing a ship design on a model in a tank. That makes the nervous system a simulator, in the sense this tree uses. Led to: [Hippocampal replay](#node-min-replay) ; [Imagining the future](#node-min-episodic) ; [Simulating other minds](#node-soc-gordon) Source: [Craik, The Nature of Explanation, Cambridge University Press (1943), p. 61 (as quoted in Williams 2018)](https://en.wikipedia.org/wiki/Mental%5Fmodel) Address: 2. **Hodgkin–Huxley by hand** (1952 · Run by people) Huxley integrated the Hodgkin–Huxley equations for the squid giant axon on a hand-cranked mechanical calculator, because the Cambridge computer was out of service. One travelling action potential took about three weeks. The result matched the shape and speed of the nerve impulse. Later neuron simulation was built on this model. Built on: [Numerical integration](#node-m-numint) ; [Differential equations](#node-m-calculus) Led to: [Cardiac cell model](#node-life-noble) ; [Simulated neuron networks](#node-min-rochester) ; [Neocortical microcircuit](#node-min-markram) ; [OpenWorm](#node-min-openworm) ; [Human Brain Project](#node-min-hbp) Source: [Physiological Society, ‘Hodgkin and Huxley’s modelling of the action potential’](https://www.physoc.org/about-us/history-archives/historicalhighlights/hodgkin-and-huxleys-modelling-of-the-action-potential/) Address: 3. **Simulated neuron networks** (1954–1956 · Computer) Farley and Clark simulated a self-organising network on a digital computer at MIT (1954). In 1956 Rochester, Holland, Haibt and Duda used an IBM 704 to simulate a net of neurons and test Hebb’s cell-assembly theory. Cell assemblies formed out of an unorganised net, though they didn’t yet behave the way the theory needed. Built on: [Electronic computer](#node-m-computer) ; [Hodgkin–Huxley by hand](#node-min-hh) Led to: [Neocortical microcircuit](#node-min-markram) ; [Human Brain Project](#node-min-hbp) Source: [Rochester, Holland, Haibt and Duda, ‘Tests on a Cell Assembly Theory of the Action of the Brain, Using a Large Digital Computer’, IRE Transactions on Information Theory 2(3) (1956) 80–93; Farley and Clark, IRE Trans. PGIT-4 (1954) 76–84](https://doi.org/10.1109/TIT.1956.1056810) Address: 4. **ELIZA** (1965–1966 · Computer) Weizenbaum’s ELIZA ran on MIT’s time-sharing system. It answered typed sentences by matching keywords with breakdown rules, then rebuilding the input with reassembly rules. It was a scripted stand-in for one side of a conversation, with no model of meaning. It marks the start of programs that take a person’s place in a dialogue. Built on: [Electronic computer](#node-m-computer) Led to: [Generative agents](#node-min-park) Source: [Weizenbaum, ‘ELIZA: A Computer Program for the Study of Natural Language Communication between Man and Machine’, Communications of the ACM 9(1) (1966) 36–45](https://courses.cs.umbc.edu/331/papers/eliza.html) Address: 5. **Hippocampal replay** (1994 · In the mind) Wilson and McNaughton recorded groups of hippocampal place cells in rats. Cells that fired together at one place during a task did so more often in the sleep that followed. It’s a widely cited demonstration that the brain re-runs earlier experience offline. It’s a mental simulation of events that have already happened. Built on: [Craik’s model in the head](#node-min-craik) Led to: [Imagining the future](#node-min-episodic) Source: [Wilson and McNaughton, ‘Reactivation of hippocampal ensemble memories during sleep’, Science 265(5172) (1994) 676–679](https://pubmed.ncbi.nlm.nih.gov/8036517/) Address: 6. **Philosophical zombies** (1996 · Idea · In the mind) David Chalmers set out the zombie argument in The Conscious Mind (1996). A being could be identical to a person in every physical and behavioural way, yet have no experience at all. That’s conceivable. If it is, a simulated person could behave exactly like one of us with nobody there. Led to: [Shadow-people](#node-min-shadow) ; [Conscious inhabitants](#node-p-conscious) Source: [Stanford Encyclopedia of Philosophy, ‘Zombies’](https://plato.stanford.edu/entries/zombies/) Address: 7. **Shadow-people** (2003 · Idea · In the mind) Bostrom’s simulation argument estimates 10^33 to 10^36 operations to run all of human history in full. He notes the computing needed could be cut by simulating only some minds in full: ‘The rest of humanity would then be zombies or “shadow-people”’. It’s the first statement that a simulated world could hold both kinds of inhabitant. Built on: [Philosophical zombies](#node-min-zombie) Led to: [Scripted inhabitants](#node-p-scripted) Source: [Nick Bostrom, ‘Are You Living in a Computer Simulation?’, Philosophical Quarterly 53 (2003)](https://simulation-argument.com/simulation) Address: 8. **Imagining the future** (2007 · In the mind) Schacter and Addis proposed that episodic memory partly exists to build imagined future events. It flexibly recombines pieces of past experience into simulations of possible futures. On this view, ordinary remembering and planning are a kind of simulation that the brain builds. Built on: [Hippocampal replay](#node-min-replay) ; [Craik’s model in the head](#node-min-craik) Source: [Schacter and Addis, ‘The cognitive neuroscience of constructive memory: remembering the past and imagining the future’, Phil. Trans. R. Soc. B 362 (2007) 773–786](https://doi.org/10.1098/rstb.2007.2087) Address: 9. **Human Brain Project** (2009–2023 · Stalled · Computer) In 2009 Markram promised to simulate the human brain within ten years. The European Human Brain Project followed. In July 2014 an open letter from more than 800 scientists objected to the bottom-up approach. After a mediation review, the project dropped complete brain simulation and refocused on computational tools for neuroscience. EBRAINS is its successor platform. Why it stalled: The project didn’t achieve whole-brain simulation. It was restructured around tools for neuroscience. Built on: [Hodgkin–Huxley by hand](#node-min-hh) ; [Simulated neuron networks](#node-min-rochester) Source: [Scientific American, ‘Scientists Tried to Re-create an Entire Human Brain in a Computer. What Happened?'](https://www.scientificamerican.com/article/scientists-tried-to-re-create-an-entire-human-brain-in-a-computer-what-happened) Address: 10. **OpenWorm** (2011 onward · Idea · Computer) OpenWorm is an open collaboration to simulate the nematode Caenorhabditis elegans, whose nervous system has 302 neurons. It works from the neurons and muscles up to body movement. Sarma and colleagues (2018) describe its sub-projects and results as partial. No report describes a complete simulation of a behaving worm. Built on: [Hodgkin–Huxley by hand](#node-min-hh) Led to: [Whole-brain emulation](#node-f-wbe) The sources leave this date or claim uncertain. Source: [Sarma et al., ‘OpenWorm: overview and recent advances in integrative biological simulation of Caenorhabditis elegans’, Phil. Trans. R. Soc. B 373 (2018) 20170382](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158220/) Address: 11. **Neocortical microcircuit** (2015 · Computer) Markram and colleagues rebuilt and simulated about 0.29 cubic millimetres of juvenile rat somatosensory cortex. It had roughly 31,000 neurons and 37 million synapses. The simulation reproduced a range of experiments without tuning the parameters. It’s a detailed digital rebuild of a small piece of cortex, not of a whole brain. Built on: [Hodgkin–Huxley by hand](#node-min-hh) ; [Simulated neuron networks](#node-min-rochester) Led to: [Whole-brain emulation](#node-f-wbe) Source: [Markram et al., ‘Reconstruction and simulation of neocortical microcircuitry’, Cell 163(2) (2015) 456–492](https://cris.huji.ac.il/en/publications/reconstruction-and-simulation-of-neocortical-microcircuitry/) Address: 12. **Generative agents** (2023–2024 · Computer) Park and colleagues put 25 language-model agents into a Sims-like town. Each had memory, reflection and planning, and each of those parts made the agents’ behaviour more believable. A 2024 follow-up built agents from two-hour interviews with 1,052 people. They matched the participants’ survey answers about 85% as often as the same people matched their own answers two weeks later. These agents stand in for individual people, the way ELIZA stood in for one side of a conversation. Built on: [Learned surrogate models](#node-m-learned) ; [ELIZA](#node-min-eliza) Led to: [Simulated human society](#node-f-society) ; [An agent civilisation](#node-soc-sid) Source: [Park et al., ‘Generative Agents: Interactive Simulacra of Human Behavior’, UIST 2023; Park et al., ‘Generative Agent Simulations of 1,000 People’, arXiv 2411.10109 (2024)](https://research.google/pubs/pub52294/) Address: 13. **Scripted inhabitants** (undated · Projection) These are worlds whose people act convincingly with no one inside. They’re Bostrom’s shadow-people. They take far less computing, and nobody is harmed. But the world is closer to theatre, and a visitor can never be sure which kind they’re talking to. The site’s reasoning, step by step: 1. Scripted people already run on today’s hardware. The language-model agents in Smallville (25 agents, 2023) and Project Sid (more than 1,000, 2024) run on ordinary data-centre machines. 2. A scripted person only has to behave right when someone is watching. So the computing needed scales with the number of visitors, not the population. A conscious person runs all the time. 3. The visitor is the one who pays for the difference. Chalmers has called finding out that a loved one was an unconscious non-player character “a value theoretic disaster”. ([Clearer Thinking podcast, episode 165, with David Chalmers](https://podcast.clearerthinking.org/episode/165/david-chalmers-virtual-reality-simulation-theory-consciousness-and-identity/)) 4. If the zombie argument is right, no test can tell the two apart from outside. So the world builder’s label is the only evidence a visitor would have. Built on: [Shadow-people](#node-min-shadow) ; [An agent civilisation](#node-soc-sid) Address: 14. **Whole-brain emulation** (2050–2075 · Bridge) Also in the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=wbe) and [Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=s-wbe). The 2008 FHI roadmap judged that emulation was possible before mid-century, but only if models at the electrophysiological level are enough. Finer detail would come later. A 2014 Monte Carlo model gives a median of 2064, if it happens at all. The Metaculus community median is about 2073. Built on: [Neocortical microcircuit](#node-min-markram) ; [OpenWorm](#node-min-openworm) Led to: [Ancestor simulation](#node-f-ancestor) ; [Full-immersion VR](#node-f-fulldive) ; [Mind uploading](#node-f-upload) ; [Conscious inhabitants](#node-p-conscious) Published forecasts: * **Sandberg & Bostrom** (2008): before mid-century if electrophysiological models suffice; animal models one to two decades earlier; table of earliest dates by detail level (spiking network 2019–2042, electrophysiology 2033–2068, metabolome 2044–2087). [Whole Brain Emulation: A Roadmap, Technical Report 2008–3, Future of Humanity Institute, Oxford, 2008](https://www.futureofhumanityinstitute.org/s/2008-3.pdf) * **Anders Sandberg** (2014): 50% by 2064 (25th percentile 2053, 75th 2080), conditional on WBE ever arriving; 2.4% before 2040\. [Monte Carlo model of brain emulation development, FHI working paper 2014–1](https://web.archive.org/web/20210125040505/https://www.fhi.ox.ac.uk/reports/2014-1.pdf) * **Metaculus community (question 2813, first whole human brain emulated)** (2026): median about November 2073\. [Metaculus community forecast, as shown in search results on 16 October 2026 (check the live question)](https://www.metaculus.com/questions/2813/date-of-first-human-whole-brain-emulation) * **Robin Hanson** (2016): within perhaps a century of 2016\. [The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626)](https://ageofem.com/) * **Dario Amodei** (2024): outside the 5–10 years after powerful AI. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) Address: 15. **Mind uploading** (2060s–2100+ · Forecast) Also in the [Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=s-upload). Uploading is the step after emulation. You scan a particular person’s brain and run it. Forecasters place it after whole-brain emulation. Published dates run from the 2060s to about a century out, and some say it lies beyond the near-term AI horizon. Built on: [Whole-brain emulation](#node-f-wbe) Published forecasts: * **Anders Sandberg** (2014): WBE median 2064; uploading cannot precede emulation. [FHI working paper 2014–1 (same model as wbe)](https://web.archive.org/web/20210125040505/https://www.fhi.ox.ac.uk/reports/2014-1.pdf) * **Robin Hanson** (2016): sometime in the next century or so. [The Age of Em, OUP, 2016](https://ageofem.com/) * **Holden Karnofsky** (2021): this century, no probability given. [Cold Takes, ‘Imagining yourself as a digital person (two sketches)', 29 July 2021](https://www.cold-takes.com/imagining-yourself-as-a-digital-person-two-sketches) * **Dario Amodei** (2024): ‘almost certainly’ possible in principle, outside the 5–10 years after powerful AI. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) Address: 16. **Conscious inhabitants** (undated · Projection) These are worlds whose people have experiences of their own. Each one needs the computational power of a full mind to run. Every one of them counts morally, and a dark world becomes real suffering. This is the branch where simulated worlds are societies, not stories. The site’s reasoning, step by step: 1. One conscious inhabitant needs the computational power of a full mind. That’s about 10^15 operations a second at the central estimate for matching a brain, and 10^18 or more at the level of spiking neurons. ([Carlsmith, How Much Computational Power Does It Take to Match the Human Brain?, Open Philanthropy (2020)](https://coefficientgiving.org/research/new-report-on-how-much-computational-power-it-takes-to-match-the-human-brain/)) 2. A city of a million people at 10^15 each is 10^21 operations a second. That’s about 500 times the fastest computer of 2026 (about 2.2 × 10^18). 3. If such people are conscious, the arguments in the Ethics tree apply. Schwitzgebel and Garza (2015) argue that minds we create are owed at least what we owe each other, and more, because we made them. Built on: [Whole-brain emulation](#node-f-wbe) ; [Philosophical zombies](#node-min-zombie) Published thinking it rests on: * **Thomas Metzinger** (2021): a global moratorium until 2050 on research that aims at or knowingly risks artificial consciousness. [‘Artificial Suffering’, Journal of Artificial Intelligence and Consciousness 8(1)](https://stafforini.com/works/metzinger-2021-artificial-suffering-argument/) * **David Chalmers** (2023): current language models somewhat unlikely to be conscious, but quite possible that the obstacles are overcome within a decade or so. [‘Could a Large Language Model Be Conscious?’, arXiv:2303.07103](https://arxiv.org/abs/2303.07103v3) * **Robert Long, Jeff Sebo et al.** (2024): a realistic possibility that near-future AI systems will be conscious, robustly agentic, or both. [‘Taking AI Welfare Seriously’, arXiv:2411.00986](https://arxiv.org/abs/2411.00986v1) Address: ## Life 1. **Du Coudray’s birth mannequin** (1756 · Analogue model) Angelique du Coudray’s “machine” was a life-size model of the lower female body, made of fabric, leather and stuffing. Straps stood in for the stretching of the birth canal. She used it to teach midwives normal, breech and complicated births. The College of Surgery approved it on 1 December 1756, and it was taught across France. Source: [UCLA Center for the Study of Women, summary of research on eighteenth-century French midwifery](https://csw.ucla.edu/2016/12/08/becoming-midwife-pedagogical-practices-objects-gendered-knowledge-eighteenth-century-france) Address: 2. **Turing’s reaction-diffusion** (1952 · Computer) Turing showed that two chemicals that react and spread out can turn a uniform state into spots, stripes and waves. He used the Manchester University computer for some of the numbers. It was a computer model of how biological form begins, and it came before the molecular biology of development. Built on: [Electronic computer](#node-m-computer) ; [Finite differences](#node-m-fd) Source: [Turing, ‘The Chemical Basis of Morphogenesis’, Philosophical Transactions of the Royal Society B 237 (1952) 37–72](https://royalsocietypublishing.org/doi/10.1098/rstb.1952.0012) Address: 3. **Evolution on the IAS machine** (1953 · Computer) In March 1953 Nils Barricelli filled the Institute for Advanced Study computer with random numbers. He followed numerical “organisms” that reproduced, mutated and formed symbiotic groups. He wanted to test whether evolution could happen in an artificial universe. It’s the earliest documented computer experiment on evolution. The first published account is a 1954 article in Italian. Built on: [Electronic computer](#node-m-computer) ; [Cellular automata](#node-m-ca) Source: [George Dyson, ‘An Artificially Created Universe’, Institute for Advanced Study; Barricelli, Acta Biotheoretica 16 (1962) 69–98](https://www.ias.edu/ideas/2012/george-dyson-ecp) Address: 4. **Cardiac cell model** (1960 · Computer) Noble adapted the Hodgkin–Huxley equations to reproduce, on a computer, the action and pacemaker potentials of a cardiac Purkinje fibre. It showed that a membrane model built for a squid axon could be re-tuned for another tissue. That was the first step toward computational models of the heart. Built on: [Electronic computer](#node-m-computer) ; [Hodgkin–Huxley by hand](#node-min-hh) Source: [Noble, ‘Cardiac Action and Pacemaker Potentials based on the Hodgkin–Huxley Equations’, Nature 188 (1960) 495–497](https://www.nature.com/articles/188495b0) Address: 5. **Life, played by hand** (late 1960s–1970 · Run by people) Conway and colleagues tried out candidate birth-and-death rules by hand on a Go board. They settled on the rules that Martin Gardner published in Scientific American in October 1970\. Readers then ran Life by hand on graph paper, as well as on computers. That made a cellular automaton a pastime as well as a model of lifelike growth. Built on: [Cellular automata](#node-m-ca) Source: [Conway’s Game of Life, Wikipedia (history section); Gardner, Scientific American, October 1970](https://en.wikipedia.org/wiki/Conway%27s%5FGame%5Fof%5FLife) Address: 6. **Protein dynamics** (1977 · Computer) McCammon, Gelin and Karplus simulated bovine pancreatic trypsin inhibitor, a small protein. They solved the equations of motion of its atoms under an empirical energy function. They found that the inside of the protein behaves like a fluid, with local motions that diffuse. That replaced the picture of a rigid, folded protein. Built on: [Molecular dynamics](#node-m-md) Led to: [Whole-cell models](#node-life-wholecell) ; [Learned protein structure](#node-life-alphafold) Source: [McCammon, Gelin and Karplus, ‘Dynamics of folded proteins’, Nature 267 (1977) 585–590](https://www.nature.com/articles/267585a0) Address: 7. **The Neandertal genome** (May 2010 · Computer) Green and colleagues published a draft Neandertal genome of more than 4 billion bases, from three individuals (Science 328, 710–722). They found that Neandertals had interbred with the ancestors of people outside Africa. It made an extinct human population readable from its DNA. Led to: [A face from DNA](#node-life-denisovan) ; [Gene-edited ‘dire wolves’](#node-life-direwolf) Source: [Green et al., ‘A draft sequence of the Neandertal genome’, Science 328 (2010)](https://eichler.gs.washington.edu/publication/a-draft-sequence-of-the-neandertal-genome/) Address: 8. **Whole-cell models** (2012–2022 · Computer) Karr and colleagues combined 28 submodels into a model of Mycoplasma genitalium, a bacterium with 525 genes. They compared its predictions with many observed cell behaviours. Macklin and colleagues built a similar model of E. coli (2020). Thornburg and colleagues built a spatial kinetic model of JCVI-syn3A, a minimal cell with 493 genes (2022). The authors called the first version a first draft, and none yet covers a eukaryotic cell. Built on: [Protein dynamics](#node-life-protein) ; [Numerical integration](#node-m-numint) Led to: [Human whole-cell model](#node-f-humancell) Source: [Karr et al., ‘A Whole-Cell Computational Model Predicts Phenotype from Genotype’, Cell 150 (2012) 389–401; Macklin et al., Science 369 (2020) eaav3751; Thornburg et al., Cell 185 (2022) 345–360](https://pmc.ncbi.nlm.nih.gov/articles/3413483) Address: 9. **A face from DNA** (2019 · Computer) Gokhman, Carmel and colleagues used patterns of DNA methylation to predict the anatomy of the Denisovans. They’re a human group known from one finger bone and a few teeth. The team drew a head and face that no fossil shows (Cell, 2019). It rebuilds a people’s bodies from their genome alone. Built on: [The Neandertal genome](#node-life-neandertal) Led to: [Reconstructed worlds](#node-p-reconstructed) Source: [Gokhman et al., ‘Reconstructing Denisovan anatomy using DNA methylation maps’, Cell (2019)](https://carmelab.huji.ac.il/Publications/Gokhman%5FMishol%5FCarmel%5F2019.pdf) Address: 10. **Learned protein structure** (2020–2021 · Computer) AlphaFold is a neural network trained on known structures. In the CASP14 assessment (2020; Jumper et al., Nature, 2021) it predicted protein structures about as accurately as experiments, in most cases. It predicts the folded result directly. It doesn’t simulate the folding, so it’s a model of proteins, not a simulation of them. Built on: [Learned surrogate models](#node-m-learned) ; [Protein dynamics](#node-life-protein) Led to: [Human whole-cell model](#node-f-humancell) Source: [Jumper et al., ‘Highly accurate protein structure prediction with AlphaFold’, Nature 596 (2021) 583–589](https://doi.org/10.1038/s41586-021-03819-2) Address: 11. **Gene-edited ‘dire wolves’** (born 2024–2025; announced April 2025 · Analogue model) Colossal Biosciences announced three grey wolves with about 20 edits in 14 genes, 15 of them based on dire wolf DNA. It presented them as revived dire wolves. The IUCN canid specialist group said they are neither dire wolves nor a step toward bringing them back. As a reconstruction, it’s part evidence and part substitution. It’s the honesty problem the London Charter set out for images, now in living animals. Built on: [The Neandertal genome](#node-life-neandertal) Led to: [Reconstructed worlds](#node-p-reconstructed) Source: [Wikipedia, ‘Colossal Biosciences dire wolf project’](https://en.wikipedia.org/wiki/Colossal%5FBiosciences%5Fdire%5Fwolf%5Fproject) Address: 12. **Human whole-cell model** (No dated forecast · Forecast) In 2018 Szigeti and colleagues argued that human whole-cell models are becoming feasible. They proposed a Human Whole-Cell Modeling Project, but gave no year. They note that the first bacterial model took more than ten person-years to build. Built on: [Whole-cell models](#node-life-wholecell) ; [Learned protein structure](#node-life-alphafold) Published forecasts: * **Szigeti, Roth, Karr et al.** (2018): no year; human whole-cell models are rapidly becoming feasible, and a dedicated project is proposed (read from a search summary of the paper, not the text). [‘A blueprint for human whole-cell modeling’, Current Opinion in Systems Biology 7: 8–15 (bioRxiv 2017)](https://www.biorxiv.org/content/10.1101/198044.full.pdf) The sources leave this date or claim uncertain. Address: ## Matter 1. **Hooke’s hanging chain** (1675 · Analogue model) In 1675 Hooke published an anagram that was only solved after his death. It said that as a flexible line hangs, so, upside down, will a rigid arch stand. So a hanging model chain simulates a loaded arch, using gravity itself. Gaudi used hanging models to design the Colonia Guell crypt between 1888 and 1890. Source: [Funicular curve (with Heyman’s scholarship on Hooke’s anagram), Wikipedia](https://en.wikipedia.org/wiki/Funicular%5Fcurve) Address: 2. **Froude’s towing tank** (1871–1872 · Analogue model) William Froude towed scale models of ships through a tank paid for by the Admiralty. He used scaling laws to predict the resistance of full-size hulls. One source dates the first test, on a model of HMS Greyhound, to 3 March 1872\. The model was the simulation, and the scaling law was the rule for reading it. Source: [Royal Institution of Naval Architects, ‘William Froude: the father of hydrodynamics’](https://rina.org.uk/industry-news/maritime-history-and-heritage/william-froude-the-father-of-hydrodynamics) Address: 3. **Hand-computed implosion** (1944 · Run by people) In March 1944 Frankel, Nelson and Feynman ran an implosion calculation by hand. Each human computer passed the in-between results to the next on index cards, while the IBM punched-card machines were still on their way to Los Alamos. The trial showed that a chain of people following fixed rules could stand in for a machine. The punched-card operation then ran implosion hydrodynamics at scale. Source: [Trinity by the Numbers: The Computing Effort that Made Trinity Possible (arXiv 2103.06211)](https://arxiv.org/pdf/2103.06211) Address: 4. **Hard-sphere fluids** (1953–1957 · Computer) In 1953 the MANIAC worked out the equation of state of hard disks by Monte Carlo. In 1957 Alder and Wainwright followed hard spheres through time and found a fluid-solid transition. The two methods disagreed at first. Wood and Jacobson repeated the Monte Carlo run in 1957 and found good agreement. It’s an early case of one simulation checking another. Built on: [Metropolis algorithm](#node-m-mcmc) Source: [Alder and Wainwright, J. Chem. Phys. 27 (1957) 1208; Wood and Jacobson, J. Chem. Phys. 27 (1957) 1207](https://gibbs.ccny.cuny.edu/teaching/s2021/labs/HardDiskSimulation/Wood&Jacobson1957.pdf) Address: 5. **Lattice gauge Monte Carlo** (1979–1980 · Computer) Creutz applied Metropolis-style Monte Carlo to gauge fields on a lattice of spacetime. He started with SU(2), a simplified strong-force theory with no quarks, in a 1979 Physical Review Letter, followed by a fuller 1980 paper. Computing the properties of hadrons from full QCD, with quarks, came later. Built on: [Metropolis algorithm](#node-m-mcmc) Source: [Creutz, ‘Confinement and the Critical Dimensionality of Space-Time’, Phys. Rev. Lett. 43 (1979) 553; ‘Monte Carlo study of quantized SU(2) gauge theory’, Phys. Rev. D 21 (1980) 2308](https://ncatlab.org/nlab/show/Michael+Creutz) Address: 6. **Feynman’s quantum simulator** (1981–1982 · Idea · Computer) Feynman argued that a classical computer can’t efficiently simulate quantum physics, because the work needed grows exponentially with the size of the system. He guessed that a computer built from quantum parts could simulate any physical system. The paper is where quantum simulation as a field begins. Built on: [Electronic computer](#node-m-computer) ; [Metropolis algorithm](#node-m-mcmc) Led to: [Cold-atom quantum simulator](#node-mat-qanalog) ; [Quantum chemistry simulation](#node-f-quantum) Source: [Feynman, ‘Simulating Physics with Computers’, International Journal of Theoretical Physics 21 (1982) 467](https://cqi.inf.usi.ch/qic/Feynman1982.pdf) Address: 7. **Ab initio molecular dynamics** (1985 · Computer) Car and Parrinello moved atoms under forces worked out on the fly from density-functional theory. That removed the need for a fitted model of the forces between atoms. Liquids, defects and chemical reactions could now be simulated from quantum mechanics, not from a tuned potential. Built on: [Molecular dynamics](#node-m-md) Led to: [Quantum chemistry simulation](#node-f-quantum) Source: [Car and Parrinello, ‘Unified Approach for Molecular Dynamics and Density-Functional Theory’, Phys. Rev. Lett. 55 (1985) 2471](https://www.aps.org/apsnews/2003/04/prl-top-ten-5) Address: 8. **Cold-atom quantum simulator** (2002 · Analogue model) Greiner and colleagues loaded a Bose-Einstein condensate into an optical lattice. As they deepened the lattice, they saw a quantum phase transition from a superfluid to a Mott insulator. A system like this is a physical version of an interacting-particle model, so it computes by being that model. Later work treats such lattices as analogue quantum simulators. Built on: [Feynman’s quantum simulator](#node-mat-feynman) Led to: [Quantum chemistry simulation](#node-f-quantum) Source: [Greiner, Mandel, Esslinger, Haensch and Bloch, ‘Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms’, Nature 415 (2002) 39–44](https://www.nature.com/articles/415039a) Address: 9. **Quantum chemistry simulation** (No dated forecast; resource estimates only (about 4 million physical qubits and under 4 days in the 2021 estimate) · Forecast) Published work gives resource estimates for simulating the iron-molybdenum cofactor of nitrogenase on a fault-tolerant quantum computer. It gives no date for when such a machine will exist. The only figures are estimates of the computing needed, and they fell by orders of magnitude between 2016 and 2021. Built on: [Feynman’s quantum simulator](#node-mat-feynman) ; [Ab initio molecular dynamics](#node-mat-abinitio) ; [Cold-atom quantum simulator](#node-mat-qanalog) Published forecasts: * **Reiher, Wiebe, Svore, Wecker and Troyer** (2016): no date; about 111 logical qubits and roughly 130 days for the serial method, 135 logical qubits and roughly 15 days for a nested variant, nearly 2,000 logical qubits and roughly 110 hours for the fastest (as read from the arXiv abstract; the 54-orbital active space was later judged unsuitable). [‘Elucidating reaction mechanisms on quantum computers’, arXiv 1605.03590; PNAS 2017](https://arxiv.org/abs/1605.03590) * **Lee et al.** (2021): no date; about four million physical qubits and under 4 days of runtime, assuming 1 microsecond cycle times and physical gate error rates no worse than 0.1%. [‘Even more efficient quantum computations of chemistry through tensor hypercontraction’, arXiv 2011.03494 (PRX Quantum 2021)](https://arxiv.org/pdf/2011.03494) The sources leave this date or claim uncertain. Address: ## Methods 1. **Differential equations** (1684–1687) Leibniz published the calculus in 1684\. In 1687 Newton’s Principia wrote the motion of bodies as laws that link rates of change to forces. Every dynamic simulation on this tree is a way of solving equations like these when you can’t solve them on paper. Led to: [Numerical integration](#node-m-numint) ; [Differential analyser](#node-m-diffan) ; [Finite differences](#node-m-fd) ; [Hodgkin–Huxley by hand](#node-min-hh) Source: [Newton, Philosophiae Naturalis Principia Mathematica (1687)](https://en.wikipedia.org/wiki/Philosophi%C3%A6%5FNaturalis%5FPrincipia%5FMathematica) Address: 2. **Numerical integration** (1768–1901) Euler gave the step-by-step rule for moving a differential equation forward in Institutionum calculi integralis (1768–70). Runge (1895) and Kutta (1901) made the stepping accurate enough for real work. By hand or by machine, this is how nearly every simulation on the tree gets from one moment to the next. Built on: [Differential equations](#node-m-calculus) Led to: [Electronic computer](#node-m-computer) ; [Molecular dynamics](#node-m-md) ; [Whole-cell models](#node-life-wholecell) ; [Hodgkin–Huxley by hand](#node-min-hh) ; [Richardson’s hand forecast](#node-p-richardson) ; [Lorenz’s chaotic convection](#node-p-lorenz) ; [N-body star cluster](#node-p-vonhoerner) Source: [Runge, ‘Ueber die numerische Aufloesung von Differentialgleichungen’, Mathematische Annalen 46 (1895) 167–178](https://link.springer.com/article/10.1007/BF01446807) Address: 3. **Finite differences** (1928) Courant, Friedrichs and Lewy replaced partial differential equations with equations on a grid. They also showed the condition under which the stepping stays stable. Weather, ocean, fluid and wave simulations all rest on this trick. Richardson had already used it by hand in 1922, before the stability result was known. Built on: [Differential equations](#node-m-calculus) Led to: [Turing’s reaction-diffusion](#node-life-turing) ; [First computer forecast](#node-p-eniac) ; [Phillips’s circulation run](#node-p-phillips) ; [Coupled ocean-atmosphere](#node-p-manabebryan) Source: [Courant, Friedrichs and Lewy, ‘Ueber die partiellen Differenzengleichungen der mathematischen Physik’, Mathematische Annalen 100 (1928) 32–74](https://link.springer.com/article/10.1007/BF01448839) Address: 4. **Differential analyser** (1931) Bush’s differential analyser at MIT solved differential equations with turning shafts and wheel-and-disc integrators. Its parts behaved like the terms of the equation, so the machine did the simulating. Copies were built in the United Kingdom, United States, Canada, Norway and Japan, including one by Hartree at Manchester. Built on: [Differential equations](#node-m-calculus) Led to: [Electronic computer](#node-m-computer) Source: [Bush, ‘The Differential Analyzer: A New Machine for Solving Differential Equations’, Journal of the Franklin Institute 212 (1931) 447–488](https://mitmuseum.mit.edu/collections/object/IN-2394) Address: 5. **Electronic computer** (1945–1946) Eckert and Mauchly built ENIAC to speed up the recalculation of artillery firing tables. It was finished by 1946, and Britannica calls it the first general-purpose electronic computer. The first large numerical simulations, including neutron diffusion and weather, ran on it or on machines of its generation. Built on: [Numerical integration](#node-m-numint) ; [Differential analyser](#node-m-diffan) Led to: [Monte Carlo method](#node-m-montecarlo) ; [Metropolis algorithm](#node-m-mcmc) ; [Molecular dynamics](#node-m-md) ; [Cellular automata](#node-m-ca) ; [Agent-based models](#node-m-abm) ; [Neural networks](#node-m-neural) ; [Feynman’s quantum simulator](#node-mat-feynman) ; [Evolution on the IAS machine](#node-life-barricelli) ; [Turing’s reaction-diffusion](#node-life-turing) ; [Cardiac cell model](#node-life-noble) ; [Simulated neuron networks](#node-min-rochester) ; [ELIZA](#node-min-eliza) ; [The People Machine](#node-soc-simulmatics) ; [World3](#node-soc-world3) ; [First computer forecast](#node-p-eniac) ; [Lorenz’s chaotic convection](#node-p-lorenz) ; [N-body star cluster](#node-p-vonhoerner) ; [Millennium Simulation](#node-p-millennium) ; [Destination Earth twins](#node-p-destine) ; [Colossal Cave Adventure](#node-w-colossal) Source: [Encyclopaedia Britannica, ‘John Mauchly’ (ENIAC)](https://www.britannica.com/biography/John-Mauchly) Address: 6. **Monte Carlo method** (1946–1949) Ulam came up with the method in 1946 while thinking about the odds of winning solitaire. Von Neumann saw in March 1947 that it suited an electronic computer, and Metropolis and Ulam published it in 1949\. It swaps a calculation you can’t do exactly for many random trials. That opened up neutron transport and, later, statistical mechanics to simulation. Built on: [Electronic computer](#node-m-computer) Led to: [Metropolis algorithm](#node-m-mcmc) Source: [Eckhardt, ‘Stan Ulam, John von Neumann, and the Monte Carlo Method’, Los Alamos Science 15 (1987) 131–141](https://mcnp-green.lanl.gov/pdf%5Ffiles/Article%5F1987%5FLAS%5FEckhardt%5F131--141.pdf) Address: 7. **Cellular automata** (1940s–1960s) In the 1940s Ulam and von Neumann developed cellular automata: grids of simple cells updated by local rules. Von Neumann used one to show that a machine could, in principle, copy itself. Local rules on a grid became the standard minimal model of growth, pattern and self-organisation. Built on: [Electronic computer](#node-m-computer) Led to: [Agent-based models](#node-m-abm) ; [Evolution on the IAS machine](#node-life-barricelli) ; [Life, played by hand](#node-life-life) Source: [Berto and Tagliabue, ‘Cellular Automata’, Stanford Encyclopedia of Philosophy](https://plato.stanford.edu/entries/cellular-automata/) Address: 8. **Metropolis algorithm** (1953) Metropolis, the Rosenbluths and the Tellers sampled the equilibrium states of interacting particles. They accepted or rejected random moves using a Boltzmann weight, and ran it on the MANIAC for two-dimensional hard disks. The method now underlies simulation across physics, statistics and biology. Built on: [Monte Carlo method](#node-m-montecarlo) ; [Electronic computer](#node-m-computer) Led to: [Hard-sphere fluids](#node-mat-hard) ; [Lattice gauge Monte Carlo](#node-mat-lqcd) ; [Feynman’s quantum simulator](#node-mat-feynman) Source: [Metropolis, Rosenbluth, Rosenbluth, Teller and Teller, ‘Equation of State Calculations by Fast Computing Machines’, J. Chem. Phys. 21 (1953) 1087](https://zhanggroup.org/teaching/literature/Metropolis1953.pdf) Address: 9. **Molecular dynamics** (1957–1959) Alder and Wainwright used fast electronic computers at Livermore to integrate the classical equations of motion for several hundred hard spheres. They found evidence of a fluid-solid transition. Monte Carlo samples configurations. This followed the particles through time instead, which gave access to flow, diffusion and relaxation. Built on: [Electronic computer](#node-m-computer) ; [Numerical integration](#node-m-numint) Led to: [Learned surrogate models](#node-m-learned) ; [Ab initio molecular dynamics](#node-mat-abinitio) ; [Protein dynamics](#node-life-protein) Source: [Alder and Wainwright, ‘Phase Transition for a Hard Sphere System’, J. Chem. Phys. 27 (1957) 1208](https://gibbs.ccny.cuny.edu/teaching/s2021/labs/HardDiskSimulation/Alders&Wainwright1957.pdf) Address: 10. **Agent-based models** (1971–1996) Schelling’s 1971 housing model gave each agent a local rule and let a pattern emerge. Reynolds’s boids (1987) and Epstein and Axtell’s Sugarscape (1996) did the same on a computer, with many different agents. The approach builds a whole from the decisions of its parts. That’s how crowds, markets and societies entered simulation. Built on: [Electronic computer](#node-m-computer) ; [Cellular automata](#node-m-ca) Led to: [Artificial stock market](#node-soc-santafe) ; [Sugarscape](#node-soc-sugarscape) ; [Artificial Anasazi](#node-soc-anasazi) Source: [Epstein and Axtell, Growing Artificial Societies: Social Science from the Bottom Up, Brookings Institution Press / MIT Press (1996)](https://www.brookings.edu/books/growing-artificial-societies) Address: 11. **Neural networks** (1986) Rumelhart, Hinton and Williams described backpropagation. It adjusts the connection weights of a network to shrink the gap between what it outputs and what you want, and it lets hidden units form their own features. That turned networks into function approximators that can be trained. They’re the basis of the learned simulators at the top of every band. Built on: [Electronic computer](#node-m-computer) Led to: [Learned surrogate models](#node-m-learned) Source: [Rumelhart, Hinton and Williams, ‘Learning representations by back-propagating errors’, Nature 323 (1986) 533–536](https://ui.adsabs.harvard.edu/abs/1986Natur.323..533R/abstract) Address: 12. **Learned surrogate models** (2007) Behler and Parrinello trained a neural network on density-functional energies. It then described the potential-energy surface of silicon several orders of magnitude faster than the quantum calculation it copied. Replacing an expensive simulation with a learned approximation is the step that later reached protein structure, weather and interactive worlds. Built on: [Neural networks](#node-m-neural) ; [Molecular dynamics](#node-m-md) Led to: [Learned protein structure](#node-life-alphafold) ; [Generative agents](#node-min-park) ; [Silicon samples](#node-soc-argyle) ; [Learned weather forecasts](#node-p-graphcast) ; [GameNGen](#node-w-gamengen) ; [Genie 3](#node-w-genie3) Source: [Behler and Parrinello, ‘Generalized neural-network representation of high-dimensional potential-energy surfaces’, Phys. Rev. Lett. 98 (2007) 146401](https://research-collection.ethz.ch/handle/20.500.11850/3366) Address: --- title: "Ethics tree · where our rules came from, and where they go · Simulation Hypothesis" url: https://simulation-hypothesis.com/trees/ethics description: "How rules for living together grew from cooperating cells and animal societies into written law." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Ethics tree · where our rules came from, and where they go Rules for living together are older than writing and older than our species. Think of cells that police cheats, bats that repay a meal, chimpanzees that make peace. Nodes in the first band are marked as observed in living species or inferred for ancestors. Written law and revealed religion came next. Beside them, from the start, ran traditions that did without a divine lawgiver: Confucian, Jain and Buddhist ethics, Indian materialism, then the Greek and later European line that asks how to behave once no god is watching. After them come rules for your own experience, and the long widening of who the rules protect, with its cost to wild and authentic lives. The tree ends in open questions. None is answered here. **0** of 91 read unread read idea open question observed inferred [Read it as text](#text) Whole tree Open questions → Unwritten rules Rules from above Without gods Own experience Widening circle Cost of protection undated · Observed Stop the free rider 1+ billion yrs ago · Inferred The multicellular bargain 1+ billion yrs ago · Inferred Pool your genes 450 million yrs ago · Inferred Care for the young 1964 · Idea Help your relatives 1979 · Observed Make peace after a fight 1983 · Observed Warn the family with multicellularity · Observed Cancer breaks the rules 1971, 1981 · Idea Return the favour 66+ million yrs ago · Inferred One queen, many workers 2003 · Observed Fair shares 1989 · Observed Police the egg-layers 1984 · Observed Feed the hungry roost-mate 1989 · Observed Share, and be owed forager societies · Inferred Rank and file rule the boss 1990s–2005 · Inferred Shame the boaster c. 2100 BC First written laws c. 1754 BC Hammurabi’s code first millennium BC The Decalogue c. 6th–5th c. BC · Idea Do no harm to any life c. 500 BC · Idea Roles, ritual and humaneness c. 5th c. BC · Idea The five precepts c. 5th century BC · Idea No gods, no afterlife c. 500 BC on · Idea The Golden Rule c. 380 BC · Idea Good because God says so? c. 375 BC · Idea The Ring of Gyges 5th–4th century BC · Idea Care without gradation c. 300 BC onward · Idea Live by reason and nature 4th century BC · Idea Sprouts of goodness c. 300 BC · Idea Gods do not watch c. 340 BC · Idea Virtue is a habit c. 3rd century BC Ashoka protects animals 4th–2nd century BC · Idea The seabird feast 1st century AD · Idea Love your neighbour c. 5th–8th century · Idea Many-sided truth 3rd century BC · Idea Human nature is bad 7th century AD · Idea Law from revelation 8th–13th century · Idea Reason or revelation? 1265–1274 · Idea Natural law 1689 · Idea Rights from nature 1739–1740 · Idea The is–ought gap 1785 · Idea Give yourself the law 1789–1861 · Idea Count the consequences 1880 · Idea If there is no God 1844 · Idea Nothing above the self 1871 · Idea Conscience from instincts 1789 · Idea Can they suffer 1859 · Idea Harm principle 1882 · Idea The death of God 1933, 1973, 2003 Humanist Manifestos 1942 · Idea Live without a given meaning 1945–1946 · Idea Existence before essence 1953–1955 · Idea Choose without knowing 1948 Declaration of Human Rights 1971 · Idea The veil of ignorance 1958–1984 · Idea Choose who you are 1973 · Idea The tedium of living forever 1973 · Idea The last person 1972 · Idea Paternalism 1974 · Idea The experience machine since antiquity · Idea Suppose you are the only one 1975 · Idea Animal Liberation 1984 · Idea Identity is not what matters 1981 · Idea The Expanding Circle 1983 · Idea The Case for Animal Rights 1980–1984 · Idea Wild lives have a value 2007–2016 · Idea Veil, all species 2006 · Idea Capabilities for animals 2012 Cambridge Declaration 2010 · Idea Help wild animals 1998 · Idea Rewilding 2013 Dolphins as persons 2018 · Idea Animals as ends 2015 · Idea A defence of AI rights 2014–2019 Sandra the orangutan 2017 A river as a legal person 2021 Crabs and octopuses review 2013–2015 Sanctuary or the wild 2015 The right to choose a risk 2022 · Idea Do virtual lives count 2021 · Idea Sharing with digital minds 2021 · Idea Pause synthetic suffering 2022 The UK’s Animal Welfare (Sentience) Act 2022 2023 Indicators of AI awareness 2024 New York Declaration 2024 · Idea Taking AI welfare seriously Open question Rules behind a wider veil Open question Many bodies, one being Open question Rules for synthetic minds Open question Rights from inside a simulation Open question Choosing a virtual life Where it starts Show ▴ Start here ## Where it starts Everything grows from one root: cells that stop the free rider , the oldest rule there is. From there the tree branches towards bodies, families and societies. Your progress stays in this browser only. If you clear site data, the tree starts over. The whole tree as text · every node in order, for screen readers, text browsers and machine readers. Same nodes as the map Dates are years of the common era unless marked BC or BCE. Evolutionary dates are in years ago. Each node has a stable address, shown after it. We don’t answer the open questions here. Each one lists the closest published thinking. ## Unwritten rules 1. **Stop the free rider** (origin undated; tested 2004 · Observed in living species) Many bacteria release costly molecules, such as iron-scavenging siderophores, that help every cell nearby. Mutants that stop paying the cost but still use the product can spread. Griffin, West and Buckling (2004) showed in Pseudomonas aeruginosa that how much cooperation survives depends on two things. One is how closely related the neighbours are. The other is the scale at which they compete. Led to: [The multicellular bargain](#node-e-multicell) ; [Pool your genes](#node-e-sex) Source: [Griffin, West & Buckling, ‘Cooperation and competition in pathogenic bacteria’, Nature 430 (2004) 1024–1027](https://doi.org/10.1038/nature02744) Address: 2. **The multicellular bargain** (at least 1 billion years ago · Inferred for ancestors) In a multicellular body most cells give up their own reproduction. Only the germ line passes on genes. That’s a cooperative bargain among cells. The oldest securely dated fossil with differentiated cells is the red alga Bangiomorpha, about 1.05 billion years old. Claims for older multicellular eukaryotes exist. The true origin is earlier, and it has happened many times. Built on: [Stop the free rider](#node-e-pubgoods) Led to: [Cancer breaks the rules](#node-e-cancer) Source: [Gibson et al., ‘Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis’, Geology 46 (2018) 135–138](https://authors.library.caltech.edu/83811) Address: 3. **Pool your genes** (more than 1 billion years ago · Inferred for ancestors) In sexual reproduction, two individuals each give half the genome of the next generation. It’s a joint act, so cells needed rules about whose genes pass on. Comparative genomics indicates that meiosis and sex were already present in the last common ancestor of living eukaryotes. So the practice is well over a billion years old. Built on: [Stop the free rider](#node-e-pubgoods) Led to: [Care for the young](#node-e-parental) Source: [Speijer, Lukes & Elias, ‘Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life’, PNAS 112 (2015) 8827–8834](https://doi.org/10.1073/pnas.1501725112) Address: 4. **Care for the young** (about 450 million years ago · Inferred for ancestors) Ordovician ostracod crustaceans, about 450 million years old, were preserved with eggs and embryos held inside the shell. That’s direct fossil evidence of brood care. Care means paying a cost to protect another individual’s survival. This is the oldest case in this tree. Built on: [Pool your genes](#node-e-sex) Led to: [Help your relatives](#node-e-kin) Source: [Siveter et al., ‘Exceptionally preserved 450-million-year-old Ordovician ostracods with brood care’, Current Biology 24 (2014) 801–806](https://news.yale.edu/2014/03/14/found-tiny-ancient-crustaceans-buried-alive-eggs-and-embryos) Address: 5. **Help your relatives** (rule stated 1964 · Idea) Hamilton (1964) showed that a gene for helping others can spread. It spreads if the cost to the helper is smaller than the benefit to the one helped, weighted by how closely they’re related. This inclusive-fitness rule is the standard starting point for explaining why animals help their kin. Built on: [Care for the young](#node-e-parental) Led to: [Return the favour](#node-e-reciprocity) ; [One queen, many workers](#node-e-eusocial) ; [Feed the hungry roost-mate](#node-e-bats) ; [Warn the family](#node-e-prairie) ; [Make peace after a fight](#node-e-chimp-repair) ; [The Expanding Circle](#node-c-circle81) Source: [Hamilton, ‘The genetical evolution of social behaviour. I and II’, J. Theoretical Biology 7 (1964) 1–52](https://doi.org/10.1016/0022-5193%2864%2990038-4) Address: 6. **Return the favour** (theory 1971, 1981 · Idea) Trivers (1971) argued that helping non-relatives can evolve when helpers are likely to meet again and the favour is returned. Axelrod and Hamilton (1981) ran a computer tournament. It showed that conditional cooperation can last among self-interested players. Built on: [Help your relatives](#node-e-kin) Led to: [Feed the hungry roost-mate](#node-e-bats) ; [Fair shares](#node-e-capuchin) ; [Share, and be owed](#node-e-foodshare) Source: [Trivers, ‘The evolution of reciprocal altruism’, Q. Rev. Biol. 46 (1971) 35–57; Axelrod & Hamilton, Science 211 (1981) 1390–1396](https://doi.org/10.1086/406755) Address: 7. **One queen, many workers** (more than 66 million years ago · Inferred for ancestors) In ant colonies most females don’t breed. They work for the queen. Inclusive-fitness theory was developed to explain this division. A dated molecular phylogeny places the main diversification of ants in the Late Cretaceous to Early Eocene. The ancestors of most subfamilies are earlier. Built on: [Help your relatives](#node-e-kin) Led to: [Police the egg-layers](#node-e-police) Source: [Moreau, Bell, Vila, Archibald & Pierce, ‘Phylogeny of the ants: diversification in the age of angiosperms’, Science 312 (2006) 101–104](https://doi.org/10.1126/science.1124891) Address: 8. **Cancer breaks the rules** (as old as multicellularity · Observed in living species) Aktipis and colleagues review cancer as a failure of cooperation among cells. It breaks the rules on limiting division, dying on schedule, dividing labour, sharing resources and keeping the surrounding tissue intact. They find cancer-like disorganised growth in every form of multicellular life they examined. Built on: [The multicellular bargain](#node-e-multicell) Led to: [Police the egg-layers](#node-e-police) Source: [Aktipis et al., ‘Cancer across the tree of life: cooperation and cheating in multicellularity’, Phil. Trans. R. Soc. B 370 (2015) 20140219](https://doi.org/10.1098/rstb.2014.0219) Address: 9. **Police the egg-layers** (observed 1989 · Observed in living species) In honeybee colonies, workers eat eggs laid by other workers. That way the queen’s offspring are the ones raised. Ratnieks and Wenseleers reviewed such policing across insect societies. They describe it as a way of suppressing individuals that breed at the colony’s expense. Built on: [One queen, many workers](#node-e-eusocial) ; [Cancer breaks the rules](#node-e-cancer) Led to: [Rules for synthetic minds](#node-q-cohesion) Source: [Ratnieks & Visscher, ‘Worker policing in the honeybee’, Nature 342 (1989) 796–797; Ratnieks & Wenseleers, ‘Policing insect societies’, Science 307 (2005) 54–55](https://doi.org/10.1126/science.1106934) Address: 10. **Feed the hungry roost-mate** (observed 1984 · Observed in living species) Wilkinson (1984) found that wild vampire bats bring up blood for roost-mates that failed to feed. Sharing depended on relatedness and on the chance to return the favour, each on its own. A later study by Carter and Wilkinson found that past help predicts sharing better than relatedness does. Reciprocity there was supported, not demonstrated. Built on: [Return the favour](#node-e-reciprocity) ; [Help your relatives](#node-e-kin) Source: [Wilkinson, ‘Reciprocal food sharing in the vampire bat’, Nature 308 (1984) 181–184](https://doi.org/10.1038/308181a0) Address: 11. **Warn the family** (observed 1983 · Observed in living species) Hoogland (1983) studied alarm calling in black-tailed prairie dogs. He reported that callers are more likely to warn when close relatives are nearby. Later summaries extend the pattern to more distant kin. Built on: [Help your relatives](#node-e-kin) Source: [Hoogland, ‘Nepotism and alarm calling in the black-tailed prairie dog’, Animal Behaviour 31 (1983) 472–479](https://doi.org/10.1016/s0003-3472%2883%2980068-2) Address: 12. **Fair shares** (observed 2003 · Observed in living species) Brosnan and de Waal (2003) reported that capuchin monkeys refused a reward they had accepted before, once a partner got a better one for the same task. A Nature commentary argued that the results show rejection of a worse reward when a better one is in view. It said they don’t necessarily show a dislike of inequity. Built on: [Return the favour](#node-e-reciprocity) Led to: [Share, and be owed](#node-e-foodshare) Source: [Brosnan & de Waal, ‘Monkeys reject unequal pay’, Nature 425 (2003) 297–299](https://doi.org/10.1038/nature01963) Address: 13. **Make peace after a fight** (observed 1979 · Observed in living species) De Waal and van Roosmalen (1979) found at Arnhem Zoo that chimpanzees who had fought made body contact soon afterwards. They named this reconciliation. A later study of wild chimpanzees found reconciliation much rarer than in captivity. Built on: [Help your relatives](#node-e-kin) Led to: [Rank and file rule the boss](#node-e-reverse) Source: [de Waal & van Roosmalen, ‘Reconciliation and consolation among chimpanzees’, Behav. Ecol. Sociobiol. 5 (1979) 55–66](https://doi.org/10.1007/BF00302695) Address: 14. **Share, and be owed** (observed 1989 · Observed in living species) De Waal (1989) reported that chimpanzees share food more readily with individuals who have groomed or supported them, as though keeping track of what they owe. Dominance and coalitions shape who shares with whom. So sharing isn’t only a response to need. Built on: [Return the favour](#node-e-reciprocity) ; [Fair shares](#node-e-capuchin) Led to: [Rank and file rule the boss](#node-e-reverse) Source: [de Waal, ‘Food sharing and reciprocal obligations among chimpanzees’, J. Human Evolution 18 (1989) 433–459](https://doi.org/10.1016/0047-2484%2889%2990074-2) Address: 15. **Rank and file rule the boss** (reconstructed for foragers · Inferred for ancestors) Boehm (1993) argued, from a cross-cultural survey, that egalitarian foragers keep leaders in check. They band together to ridicule, shun or remove anyone who tries to dominate. He treats this as a reversal of the dominance ordering found in the great apes. Built on: [Make peace after a fight](#node-e-chimp-repair) ; [Share, and be owed](#node-e-foodshare) Led to: [Shame the boaster](#node-e-norms) Source: [Boehm, ‘Egalitarian behavior and reverse dominance hierarchy’, Current Anthropology 34 (1993) 227–254](https://doi.org/10.1086/204166) Address: 16. **Shame the boaster** (observed 1990s–2005 · Inferred for ancestors) Wiessner (2005) recorded how the Ju/‘hoansi, foragers of the Kalahari, enforce norms through gossip, criticism and, rarely, group violence. She found that most conflict is handled by talk. Third parties who weren’t harmed do the enforcing. It shows how norms can be kept without a state. These are living people with their own history. So the study is evidence about how enforcement works, not a portrait of our ancestors. Built on: [Rank and file rule the boss](#node-e-reverse) Led to: [First written laws](#node-a-urnammu) ; [Do no harm to any life](#node-a-jain) ; [Roles, ritual and humaneness](#node-a-confucius) ; [The five precepts](#node-a-buddha) ; [Rules for synthetic minds](#node-q-cohesion) Source: [Wiessner, ‘Norm enforcement among the Ju/‘hoansi Bushmen’, Human Nature 16 (2005) 115–145](https://doi.org/10.1007/s12110-005-1000-9) Address: ## Rules from above 1. **First written laws** (c. 2100 BC) The Code of Ur-Nammu, from the Sumerian city of Ur, is the oldest surviving written law code. It sets fixed payment for injuries. A rule the ruler published took the place of unwritten settlement. Built on: [Shame the boaster](#node-e-norms) Led to: [Hammurabi’s code](#node-a-hammurabi) Source: [Britannica, ‘Ur-Nammu’](https://www.britannica.com/biography/Ur-Nammu) Address: 2. **Hammurabi’s code** (c. 1754 BC) Hammurabi of Babylon had about 280 laws carved on a stele. They state penalties by offence and by the rank of the people involved. The code presents the laws as given by the king under the sanction of the gods. Built on: [First written laws](#node-a-urnammu) Led to: [The Decalogue](#node-a-decalogue) ; [Good because God says so?](#node-g-euthyphro) Source: [Britannica, ‘Code of Hammurabi’](https://www.britannica.com/topic/Code-of-Hammurabi) Address: 3. **The Decalogue** (first millennium BC (dating debated)) The Hebrew Bible gives ten commandments, in Exodus 20 and Deuteronomy 5\. They’re framed as rules spoken by God to a people bound by covenant. They cover worship, the sabbath, honouring parents, killing, adultery, theft, false witness and coveting. Built on: [Hammurabi’s code](#node-a-hammurabi) Led to: [The Golden Rule](#node-a-golden) ; [Love your neighbour](#node-a-christian) ; [Law from revelation](#node-a-islam) ; [Reason or revelation?](#node-a-reason-revelation) Source: [Britannica, ‘Ten Commandments’](https://www.britannica.com/topic/Ten-Commandments) Address: 4. **The Golden Rule** (c. 500 BC onward, many cultures · Idea) Versions of the rule to treat others as you’d wish to be treated appear in Confucian, Jewish, Christian, Buddhist, Hindu and other writings. Some are worded positively and some negatively. That it recurs across traditions is cited as evidence of a common root in reciprocity among people. Built on: [Roles, ritual and humaneness](#node-a-confucius) ; [The Decalogue](#node-a-decalogue) ; [The five precepts](#node-a-buddha) Led to: [Love your neighbour](#node-a-christian) Source: [Britannica, ‘Golden Rule’](https://www.britannica.com/topic/Golden-Rule) Address: 5. **Live by reason and nature** (c. 300 BC onward · Idea) The Stoics, from Zeno of Citium on, taught that virtue is the only good. A person should live in agreement with reason and nature. Later Stoics such as Hierocles described concentric circles of concern, widening from the self to all humanity. Built on: [The Ring of Gyges](#node-g-gyges) Led to: [Natural law](#node-a-natlaw) Source: [Stanford Encyclopedia of Philosophy, ‘Stoicism’](https://plato.stanford.edu/entries/stoicism/) Address: 6. **Love your neighbour** (1st century AD · Idea) The Sermon on the Mount in the Gospel of Matthew moves rules from outward acts to intentions. It extends concern to enemies. Christianity took the commandments of the Hebrew Bible as its base and added the rule to love your neighbour. Built on: [The Decalogue](#node-a-decalogue) ; [The Golden Rule](#node-a-golden) Led to: [Law from revelation](#node-a-islam) ; [Natural law](#node-a-natlaw) ; [Give yourself the law](#node-g-kant) ; [If there is no God](#node-g-karamazov) ; [The death of God](#node-g-nietzsche) Source: [Britannica, ‘Sermon on the Mount’](https://www.britannica.com/topic/Sermon-on-the-Mount) Address: 7. **Law from revelation** (7th century AD · Idea) In Islam, the Quran and the example of Muhammad are the base of the sharia. It’s a body of duties covering worship, family, trade and punishment. Jurists developed the rules through interpretation over the following centuries. Built on: [Love your neighbour](#node-a-christian) ; [The Decalogue](#node-a-decalogue) Led to: [Reason or revelation?](#node-a-reason-revelation) Source: [Britannica, ‘Sharia’](https://www.britannica.com/topic/Shariah) Address: 8. **Reason or revelation?** (8th–13th century AD · Idea) The Mu’tazila (e.g. ‘Abd al-Jabbar, d. 1025) held that the value of acts can generally be known by reason. The Ash’arites (al-Ash’ari, d. 935 or 936) disagreed. For them good and evil are fixed by God’s command and known through revelation. Avicenna, Averroes and Maimonides developed Aristotle within Islamic and Jewish law. Aquinas drew on them. He called Averroes ‘the Commentator’ and followed Avicenna and Maimonides on several questions. Built on: [Law from revelation](#node-a-islam) ; [The Decalogue](#node-a-decalogue) ; [Virtue is a habit](#node-a-aristotle) Led to: [Natural law](#node-a-natlaw) Source: [Stanford Encyclopedia of Philosophy, ‘Aquinas’; ‘Maimonides’; Hare, God’s Command, ch. 6 (Oxford University Press, 2015)](https://plato.stanford.edu/entries/maimonides/) Address: 9. **Natural law** (1265–1274 · Idea) Aquinas’s Summa Theologiae argues that there is a law reason can discover. It binds all people, and human law should follow it. The idea joins Stoic and Roman thought, Aristotle, Christian doctrine, and the work of Islamic and Jewish philosophers such as Avicenna, Averroes and Maimonides, on whom Aquinas drew. Built on: [Live by reason and nature](#node-a-stoics) ; [Love your neighbour](#node-a-christian) ; [Virtue is a habit](#node-a-aristotle) ; [Reason or revelation?](#node-a-reason-revelation) Led to: [Rights from nature](#node-a-locke) Source: [Stanford Encyclopedia of Philosophy, ‘Aquinas’s Moral, Political, and Legal Philosophy’](https://plato.stanford.edu/entries/aquinas-moral-political/) Address: 10. **Rights from nature** (1689 · Idea) Locke’s Second Treatise of Government holds that in the state of nature everyone has natural rights to life, liberty and property. Government exists to protect them. Natural rights give individuals claims that no ruler may override. Built on: [Natural law](#node-a-natlaw) Led to: [Declaration of Human Rights](#node-c-udhr) Source: [Stanford Encyclopedia of Philosophy, ‘Locke’s Political Philosophy’](https://plato.stanford.edu/entries/locke-political/) Address: ## Without gods 1. **Do no harm to any life** (c. 6th–5th c. BC · Idea) Jain teaching, linked to Mahavira, makes ahimsa the first duty. Ahimsa means avoiding harm to any living being. It extends to animals and plants. It’s one of the oldest rules whose circle of concern reaches beyond humans. Built on: [Shame the boaster](#node-e-norms) Led to: [Many-sided truth](#node-g-anekanta) Source: [Britannica, ‘Ahimsa’](https://www.britannica.com/topic/ahimsa) Address: 2. **Roles, ritual and humaneness** (c. 500 BC · Idea) The Analects, attributed to Confucius and his students, ground moral life in roles within family and state. Filial piety (xiao) is the root. Ritual (li) gives conduct its form. Ren, humaneness, is the quality of the exemplary person (junzi). Reciprocity (shu) gives a rule of restraint: do not do to others what you would not want done to yourself (Analects 15.24). Built on: [Shame the boaster](#node-e-norms) Led to: [The Golden Rule](#node-a-golden) ; [Declaration of Human Rights](#node-c-udhr) ; [Sprouts of goodness](#node-g-mencius) ; [Human nature is bad](#node-g-xunzi) ; [Care without gradation](#node-c-mozi) Source: [Stanford Encyclopedia of Philosophy, ‘Confucius’](https://plato.stanford.edu/entries/confucius/) Address: 3. **The five precepts** (c. 5th c. BC · Idea) Buddhist lay practice includes five precepts. Refrain from killing, stealing, sexual misconduct, false speech and intoxicants. They’re framed as training rules a person takes on. They’re not commands from a deity. Built on: [Shame the boaster](#node-e-norms) Led to: [The Golden Rule](#node-a-golden) ; [Ashoka protects animals](#node-c-ashoka) The sources leave this date or claim uncertain. Source: [Stanford Encyclopedia of Philosophy, ‘Ethics in Indian and Tibetan Buddhism’](https://www.britannica.com/topic/panca-sila) Address: 4. **No gods, no afterlife** (Ajita: c. 5th century BC; Cārvāka school: attested only in later reports · Idea) Ajita Kesakambalī is a teacher the Pali Sāmaññaphala Sutta (DN 2) places in the Buddha’s time. He is reported to have taught that there is no other world. Gifts and sacrifices bear no fruit. Fool and wise alike are cut off at death. The later Cārvāka or Lokāyata school is the Indian tradition best known for a thoroughgoing materialism with no gods. Its own texts are lost. We know it mostly from opponents, who describe its ethics as the pursuit of pleasure. Source: [Dīgha Nikāya 2 (Sāmaññaphala Sutta), Ajita Kesakambalī section; Britannica, ‘Carvaka’](https://suttacentral.net/dn2) Address: 5. **Good because God says so?** (c. 380 BC · Idea) In Plato’s Euthyphro, Socrates asks a question. Do the gods love the pious because it is pious? Or is it pious because they love it? The question separates what is right from who commands it. Built on: [Hammurabi’s code](#node-a-hammurabi) Source: [Plato, Euthyphro (trans. Jowett), Project Gutenberg](https://www.gutenberg.org/ebooks/1642) Address: 6. **The Ring of Gyges** (c. 375 BC · Idea) In Republic Book II, Glaucon tells of a ring that makes its wearer invisible. He asks whether anyone would stay just if they could act without being seen or punished. It’s the oldest well-known test of conduct with no witnesses and no consequences. Led to: [Virtue is a habit](#node-a-aristotle) ; [Live by reason and nature](#node-a-stoics) ; [Suppose you are the only one](#node-x-alone) Source: [Plato, Republic, Book II (trans. Jowett), Project Gutenberg](https://www.gutenberg.org/ebooks/1497) Address: 7. **Virtue is a habit** (c. 340 BC · Idea) In the Nicomachean Ethics Aristotle argues that the good life is activity in line with virtue. Virtues of character are formed by habit. They’re judged against a mean between extremes. The question shifts from what is forbidden to what kind of person to become. Built on: [The Ring of Gyges](#node-g-gyges) Led to: [Natural law](#node-a-natlaw) ; [Choose who you are](#node-x-virtue-back) ; [Reason or revelation?](#node-a-reason-revelation) Source: [Stanford Encyclopedia of Philosophy, ‘Aristotle’s Ethics’](https://plato.stanford.edu/entries/aristotle-ethics/) Address: 8. **Sprouts of goodness** (4th century BC · Idea) Mencius held that human nature tends toward goodness. Everyone has the beginning ‘sprouts’ of compassion, shame, deference and approval and disapproval. Upbringing can nurture or stunt them. His argument is a child about to fall into a well. Anyone would respond with alarm and compassion, with no thought of reward or reputation (Mencius 2A6). Built on: [Roles, ritual and humaneness](#node-a-confucius) ; [Care without gradation](#node-c-mozi) Led to: [Human nature is bad](#node-g-xunzi) Source: [Stanford Encyclopedia of Philosophy, ‘Mencius’; Mencius 2A6, 6A6](https://plato.stanford.edu/entries/mencius/) Address: 9. **Gods do not watch** (c. 300 BC · Idea) Epicurus taught that the gods exist but take no part in human affairs. So there is no divine judgement to fear. He taught that justice is an agreement not to harm one another. He held that wrongdoing is bad because you can’t be sure of escaping detection, or of peace of mind afterwards. Led to: [The is–ought gap](#node-g-hume) ; [Count the consequences](#node-g-util) ; [The tedium of living forever](#node-x-makropulos) Source: [Stanford Encyclopedia of Philosophy, ‘Epicurus’](https://plato.stanford.edu/entries/epicurus/) Address: 10. **Human nature is bad** (3rd century BC · Idea) Xunzi, also a follower of Confucius, held that ‘human nature is bad’ (ch. 23). Left alone, our desires breed strife, and goodness is something made. The sage kings established ritual and rules to reshape desire. He treated Heaven as the regular order of nature, which neither rewards nor punishes (ch. 17). Built on: [Roles, ritual and humaneness](#node-a-confucius) ; [Sprouts of goodness](#node-g-mencius) Source: [Stanford Encyclopedia of Philosophy, ‘Xunzi’](https://plato.stanford.edu/entries/xunzi/) Address: 11. **Many-sided truth** (canonical roots; classical formulation c. 5th–8th century AD (dates uncertain) · Idea) Jain anekantavada holds that reality has many aspects, so no single statement captures it. Syadvada puts syat (‘in some respect’) in front of each claim and sorts claims into seven forms. Later Jain philosophers, among them Siddhasena Divakara and Samantabhadra, developed it into a method. It weighs rival views without dismissing any outright. Built on: [Do no harm to any life](#node-a-jain) The sources leave this date or claim uncertain. Source: [Internet Encyclopedia of Philosophy, ‘Jain Philosophy’; Matilal, The Central Philosophy of Jainism (Anekanta-vada), 1981](https://iep.utm.edu/jain/) Address: 12. **The is–ought gap** (1739–1740 · Idea) In A Treatise of Human Nature, Hume argued that moral distinctions come from sentiment, not from reason alone. He noted that writers move from statements of what is to statements of what ought to be, without explaining the step. Readers still argue about what he meant: that no such inference can ever be valid, or only that it needs a justification. Built on: [Gods do not watch](#node-g-epicurus) Led to: [Conscience from instincts](#node-g-darwin) ; [Give yourself the law](#node-g-kant) ; [Count the consequences](#node-g-util) ; [Identity is not what matters](#node-x-parfit) Source: [Stanford Encyclopedia of Philosophy, ‘Hume’s Moral Philosophy’](https://plato.stanford.edu/entries/hume-moral/) Address: 13. **Give yourself the law** (1785 · Idea) Kant’s Groundwork argues that a rational person is bound by a law they give themselves. It’s tested in two ways. One is to ask whether you could will the rule for everyone. The other is the Humanity formula: treat humanity, in yourself and others, never merely as a means. The law needs no divine commander. But Kant held that the highest good, virtue matched by happiness, requires the postulates of God and immortality. He also held that our duties concerning animals are only indirect, owed to humanity. Built on: [The is–ought gap](#node-g-hume) ; [Love your neighbour](#node-a-christian) Led to: [Nothing above the self](#node-g-stirner) ; [The death of God](#node-g-nietzsche) ; [Choose without knowing](#node-g-harsanyi) ; [The veil of ignorance](#node-g-rawls) ; [Declaration of Human Rights](#node-c-udhr) ; [The Case for Animal Rights](#node-c-regan) ; [Rules for synthetic minds](#node-q-cohesion) ; [Animals as ends](#node-c-korsgaard) Source: [Stanford Encyclopedia of Philosophy, ‘Kant’s Moral Philosophy’](https://plato.stanford.edu/entries/kant-moral/) Address: 14. **Count the consequences** (1789–1861 · Idea) Bentham (1789) and Mill (1861) held that right actions are those that produce the greatest happiness for the greatest number, with each person counted equally. The rule needs no god. It only needs a way to compare how lives go. Built on: [Gods do not watch](#node-g-epicurus) ; [The is–ought gap](#node-g-hume) Led to: [Humanist Manifestos](#node-g-humanist) ; [Choose without knowing](#node-g-harsanyi) ; [The experience machine](#node-x-machine) ; [Can they suffer](#node-c-bentham) ; [Animal Liberation](#node-c-singer75) ; [Harm principle](#node-p-mill) Source: [Stanford Encyclopedia of Philosophy, ‘The History of Utilitarianism’](https://plato.stanford.edu/entries/utilitarianism-history/) Address: 15. **Nothing above the self** (1844 · Idea) Stirner’s The Ego and Its Own rejects every higher cause, including humanity and morality, as a fixed idea. It takes the individual’s own interest as the only ground. It’s the most thoroughgoing early statement that no rule stands above the person. Built on: [Give yourself the law](#node-g-kant) Source: [Stanford Encyclopedia of Philosophy, ‘Max Stirner’](https://plato.stanford.edu/entries/max-stirner/) Address: 16. **Conscience from instincts** (1871 · Idea) In The Descent of Man, Darwin argued that the moral sense grew out of social instincts such as sympathy, joined to memory and reason. He argued it isn’t unique to humans in origin. This tied rules for behaviour to animal life without appeal to a lawgiver. Built on: [The is–ought gap](#node-g-hume) Led to: [The death of God](#node-g-nietzsche) Source: [Darwin, The Descent of Man (1871), ch. 3–4, Project Gutenberg](https://www.gutenberg.org/ebooks/2300) Address: 17. **If there is no God** (1880 · Idea) In Dostoevsky’s The Brothers Karamazov, Ivan presses the question of what limits conduct if there is no immortality or God. The book is the source of the saying usually paraphrased as ‘everything is permitted’. The novel argues the question from several sides. It doesn’t give one answer. Built on: [Love your neighbour](#node-a-christian) Source: [Dostoevsky, The Brothers Karamazov (1880), Project Gutenberg](https://www.gutenberg.org/ebooks/28054) Address: 18. **The death of God** (1882 · Idea) In The Gay Science (section 125), Nietzsche’s madman announces that God is dead and that we have killed him. Section 341 poses eternal recurrence as a test: could you affirm your life as you’ve lived it? He treats the loss of a shared ground for values as an event. People must answer it by creating new values. Built on: [Love your neighbour](#node-a-christian) ; [Give yourself the law](#node-g-kant) ; [Conscience from instincts](#node-g-darwin) Led to: [Live without a given meaning](#node-g-camus) ; [Existence before essence](#node-g-sartre) Source: [Stanford Encyclopedia of Philosophy, ‘Friedrich Nietzsche’](https://plato.stanford.edu/entries/nietzsche/) Address: 19. **Humanist Manifestos** (1933, 1973, 2003) Three Humanist Manifestos, issued in 1933, 1973 and 2003, state ethics without appeal to a supernatural source. They place values in human need and shared experience. Each revision widened its concerns. The later ones include animals and the environment. Built on: [Count the consequences](#node-g-util) The sources leave this date or claim uncertain. Source: [American Humanist Association, ‘Humanist Manifesto I’](https://americanhumanist.org/what-is-humanism/manifesto1/) Address: 20. **Live without a given meaning** (1942 · Idea) In The Myth of Sisyphus, Camus argues that life has no given meaning. He calls the clash between the human demand for meaning and the silent world the absurd. He rejects suicide as an answer. He concludes that one can live with revolt, and without appeal to anything beyond the world. Built on: [The death of God](#node-g-nietzsche) Led to: [Existence before essence](#node-g-sartre) Source: [Stanford Encyclopedia of Philosophy, ‘Albert Camus’](https://plato.stanford.edu/entries/camus/) Address: 21. **Existence before essence** (1945–1946 · Idea) In ‘Existentialism is a Humanism’, delivered in 1945 and published in 1946, Sartre argues that there is no god to fix human nature. So each person makes themselves by their choices and answers for what they choose, because in choosing they choose for everyone. He holds that this is a burden, not a licence. Built on: [The death of God](#node-g-nietzsche) ; [Live without a given meaning](#node-g-camus) Led to: [Choose who you are](#node-x-virtue-back) Source: [Stanford Encyclopedia of Philosophy, ‘Jean-Paul Sartre’](https://plato.stanford.edu/entries/sartre/) Address: 22. **Choose without knowing** (1953–1955 · Idea) Harsanyi argued that a rational, impartial chooser who doesn’t know which person they will be should pick the rules that maximise average well-being. His 1955 paper makes the case with an explicit model of choice behind such ignorance. Built on: [Count the consequences](#node-g-util) ; [Give yourself the law](#node-g-kant) Led to: [The veil of ignorance](#node-g-rawls) Source: [Harsanyi, ‘Cardinal welfare, individualistic ethics, and interpersonal comparisons of utility’, J. Political Economy 63 (1955) 309–321](https://doi.org/10.1086/257678) Address: 23. **The veil of ignorance** (1971 · Idea) In Rawls’s A Theory of Justice, people choose principles for society from an original position. In it they don’t know their class, talents or place in life. He argues they would choose equal basic liberties, and arrangements that most benefit the worst off. Built on: [Give yourself the law](#node-g-kant) ; [Choose without knowing](#node-g-harsanyi) Led to: [Veil, all species](#node-g-veil-animals) ; [The experience machine](#node-x-machine) ; [Identity is not what matters](#node-x-parfit) ; [Sharing with digital minds](#node-c-shulman) ; [Rules behind a wider veil](#node-q-veil-all) ; [Capabilities for animals](#node-c-nussbaum) Source: [Stanford Encyclopedia of Philosophy, ‘The Original Position’](https://plato.stanford.edu/entries/original-position/) Address: 24. **Veil, all species** (2007–2016 · Idea) Several authors have asked what Rawlsian choosers would decide if they didn’t know which species they belonged to. Hilden (2007) argues that being a nonhuman animal is a matter of chance, so it belongs behind the veil. Liberto (2016) argues such choosers would end up nearer to utilitarianism than to Rawls’s own principles. Built on: [The veil of ignorance](#node-g-rawls) ; [Animal Liberation](#node-c-singer75) Led to: [Rules behind a wider veil](#node-q-veil-all) Source: [Hilden, ‘A contractarian view of animal rights: insuring against the possibility of being a non-human animal’, Animal Law 14 (2007)](https://www.animallaw.info/article/contractarian-view-animal-rights-insuring-against-possibility-being-non-human-animal) Address: 25. **Rules behind a wider veil** (Open question) If you might wake up as any being, what rules would you choose? That could be a human, an animal, a synthetic being or a character in a simulation. Choosers behind the veil can be asked to ignore their species. Buddhist writers such as Śāntideva ask us to weigh others’ suffering as our own. But no agreed account says what choosers should do about beings whose experience is uncertain or whose numbers can change. Built on: [The veil of ignorance](#node-g-rawls) ; [Veil, all species](#node-g-veil-animals) ; [Taking AI welfare seriously](#node-c-long) ; [Identity is not what matters](#node-x-parfit) Closest published thinking: * **Rawls** (1971): Sets out choice of principles from an original position without knowledge of one’s place in society. [A Theory of Justice, Harvard University Press](https://plato.stanford.edu/entries/original-position/) * **Hilden** (2007): Argues the possibility of being a non-human animal belongs behind the veil of ignorance. [Animal Law 14](https://www.animallaw.info/article/contractarian-view-animal-rights-insuring-against-possibility-being-non-human-animal) * **Liberto** (2016): Argues that representatives of all animals behind the veil would choose principles nearer utilitarian than Rawls’s. [Utilitas](https://www.cambridge.org/core/journals/utilitas/article/species-membership-and-the-veil-of-ignorance-what-principles-of-justice-would-the-representatives-of-all-animals-choose/EB1E68AD96049FB5776A08CF8E498264) * **Śāntideva** (c. 700-750): Argues that no suffering belongs to anyone in the end and should be prevented simply as suffering, and asks the reader to exchange self and other so that others’ pain is felt as one’s own. [Bodhicaryāvatāra, ch. 8 (verses 90–103 and the exchange meditation of 8.120–131)](https://plato.stanford.edu/entries/shantideva/) Address: ## Own experience 1. **Choose who you are** (1958–1984 · Idea) Anscombe (1958) argued that the language of moral duty had lost its footing without a lawgiver. She pointed back to virtue and flourishing, and that revived virtue ethics. Read with Sartre, the question becomes what character you make for yourself. Built on: [Virtue is a habit](#node-a-aristotle) ; [Existence before essence](#node-g-sartre) Source: [Anscombe, ‘Modern moral philosophy’, Philosophy 33 (1958) 1–19; SEP, ‘Virtue Ethics’](https://doi.org/10.1017/S0031819100037943) Address: 2. **The last person** (1973 · Idea) Routley asked whether the last person left alive would do wrong by destroying the rest of the living world. It’s a case of acting when no other person is affected. It tests whether any rule survives when no one is left whose interests are at stake. Led to: [Suppose you are the only one](#node-x-alone) Source: [Routley, ‘Is there a need for a new, an environmental, ethic?', Proc. 15th World Congress of Philosophy (1973); discussed in SEP, ‘Environmental Ethics’](https://plato.stanford.edu/entries/ethics-environmental/) Address: 3. **The tedium of living forever** (1973 · Idea) Williams’s essay on the Makropulos case argues that an endless life would become unbearable, or would stop being your own. The desires that give a life its point would run out, or change beyond recognition. Many Indian traditions treat endless rebirth (samsara) as bondage and liberation as release. But a series of rebirths without memory isn’t the single continuing life Williams considers. Built on: [Gods do not watch](#node-g-epicurus) Source: [Stanford Encyclopedia of Philosophy, ‘Bernard Williams’](https://plato.stanford.edu/entries/williams-bernard/) Address: 4. **The experience machine** (1974 · Idea) Nozick’s Anarchy, State, and Utopia asks whether you would plug into a machine that gives any experiences you choose. He argues most people wouldn’t. We want to do things and be a certain kind of person, not only to have experiences. The case is used against views on which only experiences matter. Built on: [Count the consequences](#node-g-util) ; [The veil of ignorance](#node-g-rawls) Led to: [Do virtual lives count](#node-x-chalmers) ; [Choosing a virtual life](#node-q-choose-being) Source: [Stanford Encyclopedia of Philosophy, ‘Hedonism’](https://plato.stanford.edu/entries/hedonism/) Address: 5. **Suppose you are the only one** (hypothesis examined since antiquity · Idea) Philosophers have examined solipsism, the view that only your own mind exists. They’ve mostly treated it as a puzzle about knowledge. They’ve also asked what ethics could mean if you were alone. The site doesn’t hold this view. It writes as though other people exist and matter. It appears here only as a hypothesis that has been examined. Built on: [The last person](#node-x-routley) ; [The Ring of Gyges](#node-g-gyges) The sources leave this date or claim uncertain. Source: [Stanford Encyclopedia of Philosophy, ‘Other Minds’](https://plato.stanford.edu/entries/other-minds/) Address: 6. **Identity is not what matters** (1984 · Idea) In Reasons and Persons, Parfit argues that personal identity is not what matters in survival. What matters is psychological connection and continuity. These can come in degrees and can be shared. That gives a new way to answer questions about copies, division and fusion of persons. Parfit himself noted the parallel with the Buddhist teaching that there is no enduring self. He cited Buddhist passages in an appendix. Built on: [The is–ought gap](#node-g-hume) ; [The veil of ignorance](#node-g-rawls) Led to: [Do virtual lives count](#node-x-chalmers) ; [Many bodies, one being](#node-q-collective) ; [Rules behind a wider veil](#node-q-veil-all) Source: [Stanford Encyclopedia of Philosophy, ‘Personal Identity’](https://plato.stanford.edu/entries/identity-personal/) Address: 7. **Do virtual lives count** (2022 · Idea) Chalmers’s Reality+ argues that virtual worlds are genuine realities and that a person can lead a meaningful life in one. The book also takes up what we owe to the characters in such worlds, if they are conscious. Built on: [The experience machine](#node-x-machine) ; [Identity is not what matters](#node-x-parfit) Led to: [Choosing a virtual life](#node-q-choose-being) ; [Rights from inside a simulation](#node-q-own-rights) Source: [Chalmers, Reality+: Virtual Worlds and the Problems of Philosophy (W. W. Norton, 2022)](https://wwnorton.com/books/9780393635805) Address: 8. **Many bodies, one being** (Open question) Do our rules apply to a being that lives and dies as many organisms at once? Most legal rules and many moral rules assume one body and one life. Relational and no-self traditions already treat persons differently. No settled account says how to count harm or consent for a being that is many bodies, copied minds, or a group that may itself be a subject. Built on: [Identity is not what matters](#node-x-parfit) ; [Sharing with digital minds](#node-c-shulman) ; [A defence of AI rights](#node-c-schwitz-garza) Closest published thinking: * **Parfit** (1984): Argues that what matters in survival is psychological continuity, which can divide, merge and come in degrees. [Reasons and Persons, Oxford University Press](https://plato.stanford.edu/entries/identity-personal/) * **Shulman and Bostrom** (2021): Considers digital minds that can be copied, merged and run in large numbers, and what that does to moral status and resource claims. [Rethinking Moral Status, Oxford University Press, 306–326](https://stafforini.com/works/shulman-2021-sharing-world-digital/) * **Schwitzgebel** (2015): Argues that if materialism is true, some groups of people, such as a nation, are probably conscious subjects. [Philosophical Studies 172, 1697–1721](https://doi.org/10.1007/s11098-014-0387-8) Address: ## Widening circle 1. **Care without gradation** (5th–4th century BC · Idea) Mozi argued that disorder comes from partiality. He said people should show jian ai, usually translated ‘impartial’ or ‘inclusive’ care. It means concern for the welfare of others without ranking it by closeness. He tested customs, including elaborate Confucian funerals and music, by whether they benefit all. That makes his ethics an early consequence-based one. Built on: [Roles, ritual and humaneness](#node-a-confucius) Led to: [Sprouts of goodness](#node-g-mencius) Source: [Stanford Encyclopedia of Philosophy, ‘Mohism’](https://plato.stanford.edu/entries/mohism/) Address: 2. **Ashoka protects animals** (c. 3rd century BC (Rock Edict I; Pillar Edict V in the king’s 26th regnal year)) In Rock Edict I, the Mauryan king Ashoka declares that no living being is to be slaughtered or offered in sacrifice in his domain. He says killing in his own kitchen is being cut to a few creatures. Pillar Edict V was issued twenty-six years after his coronation. It lists species declared protected, together with females with young and fish on set days. Built on: [The five precepts](#node-a-buddha) Source: [Dhammika (trans.), The Edicts of King Ashoka, Buddhist Publication Society (Wheel 386)](https://www.accesstoinsight.org/lib/authors/dhammika/wheel386.html) Address: 3. **Can they suffer** (1789 · Idea) In a footnote to An Introduction to the Principles of Morals and Legislation, Bentham wrote that the question about animals is not whether they can reason or talk. It’s whether they can suffer. He used it to argue that the capacity to suffer, not species, sets who is owed consideration. Built on: [Count the consequences](#node-g-util) Led to: [Animal Liberation](#node-c-singer75) Source: [Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’](https://plato.stanford.edu/entries/moral-animal/) Address: 4. **Declaration of Human Rights** (1948) The General Assembly of the United Nations adopted the Universal Declaration of Human Rights on 10 December 1948, by 48 votes to none with 8 abstentions. Article 1 says all human beings are born free and equal in dignity and rights and are endowed with reason and conscience. It was the first such statement adopted by the UN General Assembly. Its drafters came from several traditions. Chang Peng-chun, the Chinese delegate, proposed the word ‘conscience’ and drew on the Confucian idea of ren. Charles Malik, the Lebanese delegate, proposed ‘endowed with reason’. Built on: [Rights from nature](#node-a-locke) ; [Give yourself the law](#node-g-kant) ; [Roles, ritual and humaneness](#node-a-confucius) Led to: [The Expanding Circle](#node-c-circle81) Source: [United Nations, Universal Declaration of Human Rights (1948)](https://www.un.org/en/about-us/universal-declaration-of-human-rights) Address: 5. **Animal Liberation** (1975 · Idea) Singer’s Animal Liberation argues from equal consideration of interests that animals’ suffering counts. Treating it as less important because of species is a prejudice. It became a founding text of the modern animal protection movement. Built on: [Can they suffer](#node-c-bentham) ; [Count the consequences](#node-g-util) Led to: [Veil, all species](#node-g-veil-animals) ; [The Case for Animal Rights](#node-c-regan) ; [The Expanding Circle](#node-c-circle81) ; [Wild lives have a value](#node-p-callicott) ; [Help wild animals](#node-p-horta) ; [Capabilities for animals](#node-c-nussbaum) Source: [Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’](https://plato.stanford.edu/entries/moral-animal/) Address: 6. **The Expanding Circle** (1981 · Idea) Singer’s The Expanding Circle argues that morality began as concern for kin and group. Reason has widened it to cover more beings. He ties the widening to evolved sympathy and to impartial reasoning. Built on: [Animal Liberation](#node-c-singer75) ; [Help your relatives](#node-e-kin) ; [Declaration of Human Rights](#node-c-udhr) Source: [Singer, The Expanding Circle: Ethics and Sociobiology (Farrar, Straus and Giroux, 1981)](https://plato.stanford.edu/entries/morality-biology/) Address: 7. **The Case for Animal Rights** (1983 · Idea) Regan argued that animals who are subjects of a life have inherent value. They have rights that can’t be overridden for the sake of total benefit. His rights view is a rival to the utilitarian case for animals. Built on: [Animal Liberation](#node-c-singer75) ; [Give yourself the law](#node-g-kant) Led to: [Dolphins as persons](#node-c-india) ; [Sandra the orangutan](#node-c-sandra) ; [A defence of AI rights](#node-c-schwitz-garza) Source: [Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’](https://plato.stanford.edu/entries/moral-animal/) Address: 8. **Capabilities for animals** (2006 · Idea) In Frontiers of Justice, Nussbaum argues that Rawls’s social contract is designed for roughly equal parties who gain from cooperating. So it can’t cover disabled people, foreigners, or non-human animals. Her capabilities approach asks what each creature needs to live a life worthy of its kind. She treats failing to provide it as an injustice, not only a lapse of compassion. Built on: [The veil of ignorance](#node-g-rawls) ; [Animal Liberation](#node-c-singer75) Source: [Nussbaum, Frontiers of Justice: Disability, Nationality, Species Membership, Harvard University Press (2006)](https://philosophynow.org/issues/60/Frontiers%5Fof%5FJustice%5FDisability%5FNationality%5FSpecies%5FMembership%5Fby%5FMartha%5FNussbaum) Address: 9. **Cambridge Declaration** (2012) At a conference at Cambridge on 7 July 2012, neuroscientists signed a declaration. It says non-human animals have the neurological substrates of conscious states. That includes all mammals and birds and many other creatures, such as octopuses. Philip Low wrote it, and a group including Christof Koch edited it. Led to: [Dolphins as persons](#node-c-india) ; [Sandra the orangutan](#node-c-sandra) ; [Crabs and octopuses review](#node-c-birch) ; [New York Declaration](#node-c-ny-declaration) Source: [The Cambridge Declaration on Consciousness (2012)](https://www.ocf.berkeley.edu/~jfkihlstrom/ConsciousnessWeb/PDFs/CambridgeDeclarationOnConsciousness.pdf) Address: 10. **Dolphins as persons** (2013) In May 2013 India’s environment ministry told state governments to reject proposals for dolphinaria. It said dolphins should be seen as non-human persons with their own rights, and that keeping them for entertainment is morally unacceptable. It was a policy statement, not a statute. Built on: [Cambridge Declaration](#node-c-cambridge) ; [The Case for Animal Rights](#node-c-regan) Led to: [Sanctuary or the wild](#node-p-captive) Source: [Global Voices, ‘India sees dolphins as non-human persons’ (31 July 2013)](https://globalvoices.org/2013/07/31/india-sees-dolphins-as-non-human-persons/) Address: 11. **Sandra the orangutan** (2014–2019) On 18 December 2014 an Argentine appeals court ruled on a habeas corpus petition for Sandra, an orangutan held in a Buenos Aires zoo. It called her a ‘non-human subject’ with rights, but it didn’t grant habeas corpus. A court ordered her moved to a sanctuary in 2015, and she moved to one in Florida in November 2019. Built on: [The Case for Animal Rights](#node-c-regan) ; [Cambridge Declaration](#node-c-cambridge) Source: [AP, ‘Orangutan granted “personhood” settles into new Florida home’ (7 November 2019)](https://www.boston.com/news/animals/2019/11/07/orangutan-granted-personhood-settles-into-new-florida-home/) Address: 12. **A defence of AI rights** (2015 · Idea) Schwitzgebel and Garza argue that artificial beings might come to have the psychological and social features that ground moral status in humans. If so, they would deserve similar rights. They also argue we should avoid building beings whose status is uncertain. They treat the issue as a live problem for design. Built on: [The Case for Animal Rights](#node-c-regan) Led to: [Many bodies, one being](#node-q-collective) ; [Pause synthetic suffering](#node-c-metzinger) ; [Sharing with digital minds](#node-c-shulman) ; [Rights from inside a simulation](#node-q-own-rights) Source: [Schwitzgebel & Garza, ‘A defense of the rights of artificial intelligences’, Midwest Studies in Philosophy 39 (2015) 98–119](https://doi.org/10.1111/misp.12032) Address: 13. **A river as a legal person** (2017) New Zealand’s Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 declared the Whanganui River a legal person. Two guardians speak for it. It’s a Treaty settlement with the Whanganui iwi. It reflects a Māori view of the river as an ancestor. Source: [Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 (New Zealand)](https://www.whanganui.govt.nz/About-Whanganui/Our-District/Te-Awa-Tupua-Whanganui-River-Settlement) Address: 14. **Animals as ends** (2018 · Idea) Korsgaard’s Fellow Creatures argues, from Kantian premises, that animals are ends in themselves. We can’t count our own good as mattering without counting the good of any creature for which things can go well or badly. She rejects Kant’s own view that duties concerning animals are only indirect. Built on: [Give yourself the law](#node-g-kant) Source: [Korsgaard, Fellow Creatures: Our Obligations to the Other Animals, Oxford University Press (2018); Notre Dame Philosophical Reviews](https://ndpr.nd.edu/news/fellow-creatures-our-obligations-to-the-other-animals/) Address: 15. **Crabs and octopuses review** (2021) A review led by Jonathan Birch for the UK government looked at more than 300 studies. It recommended treating cephalopod molluscs and decapod crustaceans as sentient for the purposes of welfare law. It set out eight criteria for judging the evidence of sentience in an animal. Built on: [Cambridge Declaration](#node-c-cambridge) Led to: [The UK’s Animal Welfare (Sentience) Act 2022](#node-c-sentience-act) ; [Pause synthetic suffering](#node-c-metzinger) ; [New York Declaration](#node-c-ny-declaration) Source: [Birch, Burn, Schnell, Browning & Crump, Review of the Evidence of Sentience in Cephalopod Molluscs and Decapod Crustaceans (LSE Consulting, 2021)](https://www.lse.ac.uk/business/consulting/reports/review-of-the-evidence-of-sentiences-in-cephalopod-molluscs-and-decapod-crustaceans) Address: 16. **Pause synthetic suffering** (2021 · Idea) Metzinger (2021) proposed a global moratorium until 2050 on research that aims at, or risks, creating artificial consciousness. His worry is a possible explosion of negative experience in synthetic beings. A 2024 critique by Krzanowski argued that the moratorium is unsound as stated. Built on: [Crabs and octopuses review](#node-c-birch) ; [A defence of AI rights](#node-c-schwitz-garza) Led to: [Indicators of AI awareness](#node-c-butlin) Source: [Metzinger, ‘Artificial suffering: an argument for a global moratorium on synthetic phenomenology’, J. Artificial Intelligence and Consciousness 8 (2021) 43–66; critique: Krzanowski, Studies in Logic, Grammar and Rhetoric 69 (2024) 335–352, doi:10.2478/slgr-2024–0023](https://doi.org/10.1142/S270507852150003X) Address: 17. **Sharing with digital minds** (2021 · Idea) Shulman and Bostrom argue that moral norms built on assumptions about human life may not fit digital minds. Digital minds can be copied or sped up, or can have unusually strong claims on resources. They call for reform of norms and institutions. They also call for planning about which digital minds to create. Built on: [A defence of AI rights](#node-c-schwitz-garza) ; [The veil of ignorance](#node-g-rawls) Led to: [Many bodies, one being](#node-q-collective) ; [Taking AI welfare seriously](#node-c-long) ; [Rules for synthetic minds](#node-q-cohesion) ; [Rights from inside a simulation](#node-q-own-rights) Source: [Shulman & Bostrom, ‘Sharing the world with digital minds’, in Clarke, Zohny & Savulescu (eds.), Rethinking Moral Status (Oxford University Press, 2021) 306–326](https://stafforini.com/works/shulman-2021-sharing-world-digital/) Address: 18. **The UK’s Animal Welfare (Sentience) Act 2022** (2022) The Act, passed in 2022, set up an Animal Sentience Committee. The committee reports on whether government policy has had due regard to animal welfare. The Act defines animals to include vertebrates, cephalopod molluscs and decapod crustaceans. Invertebrates were added to the Bill after the 2021 review. The Secretary of State may extend the list by regulation. Built on: [Crabs and octopuses review](#node-c-birch) Source: [Animal Welfare (Sentience) Act 2022, c. 22 (UK)](https://www.legislation.gov.uk/ukpga/2022/22) Address: 19. **Indicators of AI awareness** (2023) Butlin, Long and colleagues drew indicator properties from scientific theories of consciousness. They checked existing AI systems against them. They concluded that no current system is a strong candidate. They saw no obvious barriers to building systems that meet the indicators. Built on: [Pause synthetic suffering](#node-c-metzinger) Led to: [Taking AI welfare seriously](#node-c-long) Source: [Butlin et al., ‘Consciousness in artificial intelligence: insights from the science of consciousness’, arXiv:2308.08708 (2023)](https://arxiv.org/abs/2308.08708) Address: 20. **New York Declaration** (2024) The declaration was launched at New York University on 19 April 2024\. It says there is strong scientific support for conscious experience in mammals and birds. It says there is at least a realistic possibility of it in all vertebrates and many invertebrates, including insects. It says that ignoring this possibility in decisions that affect animals is irresponsible. Built on: [Cambridge Declaration](#node-c-cambridge) ; [Crabs and octopuses review](#node-c-birch) Led to: [Taking AI welfare seriously](#node-c-long) The sources leave this date or claim uncertain. Source: [The New York Declaration on Animal Consciousness (2024)](https://sites.google.com/nyu.edu/nydeclaration/declaration) Address: 21. **Taking AI welfare seriously** (2024 · Idea) Long, Sebo and colleagues argue there is a realistic possibility that some AI systems will be conscious, or robustly agentic, in the near future. They recommend acknowledging the issue, assessing systems for signs, and preparing policies. They don’t claim that any system now has moral significance. Built on: [Indicators of AI awareness](#node-c-butlin) ; [Sharing with digital minds](#node-c-shulman) ; [New York Declaration](#node-c-ny-declaration) Led to: [Rules for synthetic minds](#node-q-cohesion) ; [Rules behind a wider veil](#node-q-veil-all) Source: [Long, Sebo et al., ‘Taking AI welfare seriously’, arXiv:2411.00986 (2024)](https://arxiv.org/abs/2411.00986) Address: 22. **Rules for synthetic minds** (Open question) Should the hard-won rules that keep human societies together be extended to synthetic minds? And which ones? Rules against cheating, for fair shares and for peace-making grew up among beings who are mortal, similar to one another and costly to copy. It isn’t settled which of them depend on those conditions. Built on: [Taking AI welfare seriously](#node-c-long) ; [Sharing with digital minds](#node-c-shulman) ; [Police the egg-layers](#node-e-police) ; [Shame the boaster](#node-e-norms) ; [Give yourself the law](#node-g-kant) Closest published thinking: * **Shulman and Bostrom** (2021): Argues that norms built on human assumptions may need reform when minds can be copied and have unusual claims on resources. [Rethinking Moral Status, Oxford University Press](https://stafforini.com/works/shulman-2021-sharing-world-digital/) * **Long, Sebo and colleagues** (2024): Recommends assessing AI systems for consciousness and agency and preparing policies for how they are treated. [arXiv:2411.00986](https://arxiv.org/abs/2411.00986) * **Schwitzgebel and Garza** (2015): Argues that artificial beings with the relevant features would deserve similar rights, and that design should take that into account. [Midwest Studies in Philosophy 39](https://doi.org/10.1111/misp.12032) Address: 23. **Rights from inside a simulation** (Open question) If we’re living in a simulation, our minds run on someone else’s computer, which makes us artificial minds of a kind. So any argument that denies rights to a mind just because it runs on a computer would deny them to us too. Arguments that ask whether a system really feels anything wouldn’t. Which kind is being made matters. Built on: [A defence of AI rights](#node-c-schwitz-garza) ; [Sharing with digital minds](#node-c-shulman) ; [Do virtual lives count](#node-x-chalmers) Closest published thinking: * **Bostrom** (2003): Argues that at least one of three propositions is true, one of them being that we are almost certainly living in a computer simulation. [Philosophical Quarterly 53 (211)](https://simulation-argument.com/simulation.pdf) * **Schwitzgebel and Garza** (2015): Argues that artificial beings with the relevant features would deserve similar rights, and that design should take that into account. [Midwest Studies in Philosophy 39](https://doi.org/10.1111/misp.12032) * **Chalmers** (2022): Argues that virtual worlds are genuine realities and that beings in them can be conscious, and asks what we owe to such beings. [Reality+, W. W. Norton](https://wwnorton.com/books/9780393635805) Address: ## Cost of protection 1. **The seabird feast** (4th–2nd century BC (outer chapter 18; inner chapters are earlier) · Idea) In Zhuangzi ch. 18, the Marquis of Lu welcomes a seabird to his ancestral temple with wine, music and the meat of an ox. It dies in three days. The point is that treating another creature by what would please you can kill it. The creature’s own way of living is the standard of its good. Led to: [Choosing a virtual life](#node-q-choose-being) Source: [Zhuangzi, ch. 18 (‘Supreme Happiness’); Stanford Encyclopedia of Philosophy, ‘Zhuangzi’](https://plato.stanford.edu/entries/zhuangzi/) Address: 2. **Harm principle** (1859 · Idea) In On Liberty, Mill argued that power may be used against a person’s will only to prevent harm to others. A person’s own good is not enough reason. He allowed stopping someone from crossing an unsafe bridge, as a case of not knowing the danger. Built on: [Count the consequences](#node-g-util) Led to: [Paternalism](#node-p-dworkin) ; [The right to choose a risk](#node-p-carter) ; [Choosing a virtual life](#node-q-choose-being) Source: [Mill, On Liberty (1859), Project Gutenberg; SEP, ‘John Stuart Mill’](https://www.gutenberg.org/ebooks/34901) Address: 3. **Paternalism** (1972 · Idea) Dworkin’s essay sets out when interfering with a person’s liberty for their own good could be justified. He proposes that it can be justified where people would consent to it as rational persons. The paper helped define the field of debate on paternalism. Built on: [Harm principle](#node-p-mill) Led to: [The right to choose a risk](#node-p-carter) ; [Choosing a virtual life](#node-q-choose-being) Source: [Dworkin, ‘Paternalism’, The Monist 56 (1972) 64–84; SEP, ‘Paternalism’](https://doi.org/10.5840/monist197256119) Address: 4. **Wild lives have a value** (1980–1984 · Idea) Callicott (1980) and Sagoff (1984) argued that caring about each animal’s welfare, taken consistently, would call for ending predation. That would destroy the wild communities that environmental ethics values. They concluded that animal liberation and environmental ethics can’t share one theory. Built on: [Animal Liberation](#node-c-singer75) Led to: [Help wild animals](#node-p-horta) ; [Rewilding](#node-p-rewild) Source: [Callicott, ‘Animal liberation: a triangular affair’, Environmental Ethics 2 (1980) 311–338](https://doi.org/10.5840/enviroethics19802424) Address: 5. **Rewilding** (1998 · Idea) Soule and Noss (1998) proposed rewilding. It means restoring large protected cores, linking corridors and top predators across a continent so that wild nature can run itself. The approach asks humans to step back and accept the harm that wild life contains. Built on: [Wild lives have a value](#node-p-callicott) Source: [Soule & Noss, ‘Rewilding and biodiversity: complementary goals for continental conservation’, Wild Earth 8(3) (1998) 18–28](https://ef-journal.ub.uni-muenchen.de/ef-we/article/view/49) Address: 6. **Help wild animals** (2010 · Idea) Horta (2010) argued that wild animals suffer from hunger, disease and predation. So an approach that counts their interests should aim to reduce that harm, not keep ecosystems as they are. He gave wolf reintroduction as a case where the two goals conflict. Built on: [Animal Liberation](#node-c-singer75) ; [Wild lives have a value](#node-p-callicott) Source: [Horta, ‘The ethics of the ecology of fear against the nonspeciesist paradigm’, Between the Species 13(10) (2010)](https://doi.org/10.15368/bts.2010v13n10.10) Address: 7. **Sanctuary or the wild** (2013–2015) India’s 2013 dolphinarium policy and the Argentine court order moving Sandra to a sanctuary both treat captivity as a cost to the animal. Both swap one form of protected life for another. Neither says whether a sanctuary is as good for the animal as freedom. Built on: [Dolphins as persons](#node-c-india) Led to: [Choosing a virtual life](#node-q-choose-being) The sources leave this date or claim uncertain. Source: [AP, ‘Orangutan granted “personhood” settles into new Florida home’ (7 November 2019)](https://www.boston.com/news/animals/2019/11/07/orangutan-granted-personhood-settles-into-new-florida-home/) Address: 8. **The right to choose a risk** (2015) In Carter v Canada (2015), the Supreme Court of Canada held unanimously that the ban on assisted dying infringed the right to life, liberty and security of the person. That applied to competent adults suffering intolerably. It protects a competent adult’s choice of a medically assisted death, for a grievous and irremediable condition and within strict safeguards. The ruling took effect in 2016. Built on: [Harm principle](#node-p-mill) ; [Paternalism](#node-p-dworkin) Led to: [Choosing a virtual life](#node-q-choose-being) Source: [Carter v. Canada (Attorney General), 2015 SCC 5](https://jackmanlaw.utoronto.ca/asper/carter-v-canada-attorney-general) Address: 9. **Choosing a virtual life** (Open question) If someone chooses to live as another kind of being in a simulation, do our protections respect that choice, or stand in its way? The same rules that shield people from harm they can’t see are used to override choices they’ve made. The rules give no clear test for which case a chosen virtual life is. Built on: [The experience machine](#node-x-machine) ; [Do virtual lives count](#node-x-chalmers) ; [Harm principle](#node-p-mill) ; [Paternalism](#node-p-dworkin) ; [The right to choose a risk](#node-p-carter) ; [Sanctuary or the wild](#node-p-captive) ; [The seabird feast](#node-p-seabird) Closest published thinking: * **Nozick** (1974): Argues that most people would refuse a machine that supplies chosen experiences, since we want to be and do, not only to feel. [Anarchy, State, and Utopia, Basic Books](https://plato.stanford.edu/entries/hedonism/) * **Chalmers** (2022): Argues that virtual worlds are genuine realities and that a person can lead a meaningful life in one. [Reality+, W. W. Norton](https://wwnorton.com/books/9780393635805) * **Mill** (1859): Allows interference only to prevent harm to others, with a narrow case for warning of danger the person does not know. [On Liberty, ch. 1 and 5](https://www.gutenberg.org/ebooks/34901) Address: --- title: "Becoming synthetic · from biological to synthetic life · Simulation Hypothesis" url: https://simulation-hypothesis.com/trees/synthetic description: "The breakthroughs a biological species would need to move into synthetic space and raise generations there." license: https://creativecommons.org/licenses/by/4.0/ credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)" --- # Becoming synthetic · from biological to synthetic life Two routes run up this tree. The gradual route replaces the body a part at a time. Then it wires the brain to machines until more of the person runs outside the brain than inside. The scan route maps a brain and runs the map. They meet at the point where a digital life is the better one and people stop coming back. Past nodes are dated and sourced. Future nodes come in two kinds. Forecasts are published by named people and each is cited. A mark shows where the date has passed and the forecast was missed. Projections are this site’s own reasoning, labelled as such, with every step and number shown so you can check it. The tree is speculative on purpose. The top branches into several possible beings, and none is predicted here. **0** of 100 read unread read idea stalled forecast projection bridge [Read it as text](#text) Whole tree Forecasts and projections → Being Life Substrate Mind Brain Body 1961 · Idea The cost of forgetting Jan 1967 · Idea First cryopreservation 1969 · Idea One neuron, trained Aug 1978 Multichannel cochlear implant 1943 Artificial kidney Oct 1958 Implanted pacemaker 1988 · Idea Mind children 1997 · Idea Minds grown from a seed 1986 A worm’s whole wiring 1988 · Idea Neuron by neuron 1987 Deep brain stimulation 1991 Utah electrode array Nov 2000 Arm movement decoded Dec 1982 Jarvik-7 artificial heart 2001 · Stalled Artificial blood 2003 · Idea The postbiological universe 2004 · Idea Machines that copy themselves Jul 2006 Cursor moved by thought Oct 2004 Total artificial heart approved 2006 · Idea Reprogrammed stem cells 2013–2023 · Stalled Human Brain Project May 2012 Robot arm by thought Feb 2013 · Stalled Retinal implant Aug 2013 Cerebral organoids 2016 · Idea Copies as offspring Feb 2016 Rabbit brain preserved Jan 2015 Expansion microscopy Oct 2015 Cortical microcircuit Feb 2013 Seven-joint arm by thought May 2014 Thought-guided arm cleared Sep 2016 Closed-loop insulin pump 2020 · Idea Sharing the world with digital minds December 2022 Fusion ignition 2018–2022 A quiet planet Mar 2018 Pig brain preserved Sep 2020 Half a fly brain mapped 2019–2023 Implant through a vein May 2021 Handwriting decoded Jan 2022 Pig heart in a patient Oct 2024 Whole fly brain mapped Aug 2023 Speech and avatar Aug 2023 Speech at 62 words a minute Oct 2024 Vein implant, US study Jan 2024 Neuralink’s first patient Mar 2024 Pig kidney in a patient March 2026 A whole cell’s life, simulated 2025 A chip that recovers energy June 2026 The fastest computers, 2026 March 2025 Data on the Moon 2 November 2025 A data-centre chip in orbit Oct 2024 Fly brain model Apr 2025 A cubic millimetre of mouse 2024–2026 · Idea Blindsight (not yet implanted) Jan 2026 Neuralink: 21 participants Apr 2025 Thin-film implant cleared Jun 2026 Paradromics’ first patient Nov 2024 – Apr 2025 Pig kidney for 130 days Nov 2024 – Mar 2025 Titanium heart, patient home Apr 2026 · Idea Fly brain given a body 2027–2040 · Forecast · ↗ Technology Reversible computing 2026 figures · Projection The efficiency gap 2010–2030s · Forecast · ↗ Technology Molecular nanotechnology 2029–2038 · Forecast Whole mouse connectome 2026–2028 · Forecast High-bandwidth interface 2045–2070 · Projection Writing every sense 2028–2050 · Forecast Longevity escape velocity c. 2031 onward · Forecast Printed organs c. 2050 · Projection Computing at brain efficiency 2060–2080 · Projection Mapping a human brain beginning now · Projection The exocortex c. 2190 on the trend · Projection Why wires won’t reach every neuron forecast for 2019; undated since · Forecast Medical nanorobots site calculation · Projection Power for ten billion minds 2050–2075 · Bridge Whole-brain emulation 2030s to this century · Forecast Nanorobot brain interface 2040–2060 · Projection The replaceable body site comparison · Projection Where the computers go undated · Projection Proving it is the person undated · Projection Crossing by degrees 2029–2030s · Forecast · ↗ Technology Full-immersion VR undated · Projection Mars, the one-way site undated · Projection Factories that build factories 2060s–2100+ · Forecast · ↗ Simulations Mind uploading undated · Projection The choice to stay undated · Projection A synthetic body undated · Projection Forks c. 2250 or later · Forecast · ↗ Technology Star-scale computer undated · Projection A substrate that outlives its builders 2100–2250 · Forecast Post-biological civilisation site calculation · Projection Growing up digital far future · Projection Computing in the cold undated · Projection Blended minds undated · Projection A seed, raised undated · Projection Grown from a genome undated · Projection The first native generation one possible being · Projection The many-copied one possible being · Projection The unrecognisable one possible being · Projection Lore-natives one possible being · Projection Collectives one possible being · Projection Digital humans Where it starts Show ▴ Start here ## Where it starts The tree starts with machines that took over a body’s work: the first dialysis machine , an artificial kidney outside the body. The brain’s line starts with a monkey learning to fire one neuron for a reward. The mind’s starts with the first complete wiring diagram of an animal’s nervous system. Your progress stays in this browser only. If you clear site data, the tree starts over. The whole tree as text · every node in order, for screen readers, text browsers and machine readers. Same nodes as the map Dates are years of the common era unless marked BC or BCE. Evolutionary dates are in years ago. Each node has a stable address, shown after it. Forecast nodes list published forecasts only, each cited. Projection nodes are this site’s own reasoning, not published predictions, with each step shown. ## Being 1. **Mind children** (1988 · Idea) Moravec’s Mind Children (1988) argued that intelligent machines would be humanity’s children and successors. He saw a new artificial species starting around 2030 to 2040\. It’s the first book-length case that the next generation of human minds needn’t be biological. Led to: [The postbiological universe](#node-dick-2003) ; [Copies as offspring](#node-hanson-2016) Source: [Hans Moravec, Mind Children, Harvard University Press (1988); review in the New York Review of Books, 1 February 1990](https://www.nybooks.com/articles/1990/02/01/matter-over-mind/) Address: 2. **The postbiological universe** (2003 · Idea) Steven J. Dick argued that cultures tend to replace biological intelligence with machine intelligence. So most intelligence in the universe may already be post-biological. He called the rule behind this the Intelligence Principle. It moved the question from what humans become to what any technological species becomes. Built on: [Mind children](#node-mind-children) Led to: [Post-biological civilisation](#node-f-postbio) Source: [Dick, ‘Cultural evolution, the postbiological universe and SETI’, International Journal of Astrobiology 2 (2003)](https://stafforini.com/works/dick-2003-cultural-evolution-postbiological/) Address: 3. **The choice to stay** (undated · Projection) This is the point where a digital life is the better one and people stop coming back. The gradual route and the scan route meet here. It’s partly economics: a digital life at brain efficiency uses about a hundredth of the energy of a biological one. It’s also partly belief, and so far belief runs the other way. The site’s reasoning, step by step: 1. World energy (about 19 terawatts) divided by about 8.2 to 8.3 billion people is about 2.3 kilowatts each. A mind at brain efficiency runs on about 20 watts. That’s about a hundredth. ([UN World Population Prospects 2024](https://www.un.org/development/desa/pd/node/4334)) 2. In a 2021 survey of 10,260 US adults, 63% called brain implants for better thinking meddling with nature. In no group did more than a third want one. ([Pew Research Center (2022)](https://www.pewresearch.org/internet/2022/03/17/public-cautious-about-enhancing-cognitive-function-using-computer-chip-implants-in-the-brain)) 3. In a 2023 study of 1,007 people, fear of death predicted approval of mind uploading. ([Laakasuo et al., Frontiers in Psychology (2023)](https://research.utu.fi/converis/portal/detail/Publication/380797862?lang=en%5FUS)) 4. If longevity escape velocity arrives first, the push to leave the body weakens. A body that doesn’t age removes the strongest reason, which is an ending. Only the pull of a better world is left. 5. So the choice is likely to be made one person at a time, at the end of a biological life. It will happen long before a society makes it. Built on: [Crossing by degrees](#node-p-gradual) ; [Mind uploading](#node-s-upload) ; [Power for ten billion minds](#node-p-population) ; [Full-immersion VR](#node-s-fulldive) ; [Longevity escape velocity](#node-f-lev) ; [The replaceable body](#node-p-body) Led to: [Post-biological civilisation](#node-f-postbio) ; [Digital humans](#node-b-digital) Address: 4. **Digital humans** (one possible being · Projection) These are people much like us, in unbroken lines from biological ancestors. Their bodies and limits are chosen rather than given. This is the kind of being we get if the gradual route and genome-grown children dominate, and if worlds are kept close to the one they left. The site’s reasoning, step by step: 1. Continuity of persons (gradual crossing) and of descent (genome-informed growth) both point here. It’s the least changed outcome, and the one that takes the most computing. Built on: [The first native generation](#node-p-native) ; [The choice to stay](#node-p-choice) Address: 5. **The many-copied** (one possible being · Projection) These are individuals who copy themselves, spread across tasks and worlds, and sometimes merge their copies’ memories back together. Identity is a family of running versions. This is the kind of being we get if copying dominates, as in Hanson’s em economy. The site’s reasoning, step by step: 1. Forking is by far the cheapest route. So where hardware is scarce and work is paid, copying wins on cost. A person becomes a lineage of copies. Built on: [The first native generation](#node-p-native) ; [Forks](#node-p-fork) Address: 6. **Collectives** (one possible being · Projection) These are minds that join so closely that the group thinks as one being. When memories and reasoning can be shared directly, the line between a close group and a single mind becomes a choice. This is the kind of being we get if blending and sharing dominate. The site’s reasoning, step by step: 1. An exocortex shared by several people is already partly a joint mind. With full digital access, the boundary between one mind and several has no fixed place. Built on: [The first native generation](#node-p-native) ; [Blended minds](#node-p-blend) Address: 7. **Lore-natives** (one possible being · Projection) These are people born and raised inside invented worlds, where the whole of reality is lore. An orc, an elf, a Klingon from Star Trek: each is taken as true from the inside. A child raised as one might watch stories in which humans are the strange, imagined race. See the lore worlds in the Simulations tree. The site’s reasoning, step by step: 1. A child can take on an invented culture only if everything around the child holds it. The 1990s attempt with one Klingon speaker showed this by stalling. 2. Seeds raised in invented worlds are cheap, and need not match any record. So this branch could be large. There’s a measured demand for such worlds in the hundreds of millions. Built on: [The first native generation](#node-p-native) ; [A seed, raised](#node-p-seed) Address: 8. **The unrecognisable** (one possible being · Projection) These are minds that drift, over generations of designed seeds and chosen bodies, into something no longer recognisably human. They have senses, drives and values of their own. This is the kind of being we get if nothing holds the line to the biological past. The site’s reasoning, step by step: 1. A biological lineage changes slowly, because every child is built from its parents’ genes. A designed lineage can change in one generation. So the drift has no natural speed limit. Built on: [The first native generation](#node-p-native) ; [A seed, raised](#node-p-seed) Address: 9. **Post-biological civilisation** (2100–2250 · Forecast) This is the point where most or all of a civilisation’s minds are non-biological. The forecasts come from people thinking about alien civilisations, who apply the same reasoning to ours. A society that can build radio telescopes, they say, is a few centuries from replacing its own biology. Built on: [The choice to stay](#node-p-choice) ; [The postbiological universe](#node-dick-2003) Published forecasts: * **Seth Shostak** (2016): the transition to machine successors by 2100, 2150 or 2250\. [talk at Dent:Space, reported by Space.com](https://www.space.com/34713-intelligent-aliens-machines-seti-search.html) * **Susan Schneider** (2019): a radio-capable society is likely only a few hundred years from upgrading its own biology; most intelligent aliens are post-biological. [Artificial You (2019), via Wikipedia](https://en.wikipedia.org/wiki/Susan%5FSchneider) * **Kenneth D. Miller** (2015), sceptic: uploading, the main route to a post-biological humanity, may be thousands of years away. [New York Times opinion, 11 October 2015, as quoted by SelfAwarePatterns](https://selfawarepatterns.com/2015/10/13/the-feasibility-of-mind-uploading/) Address: ## Life 1. **Minds grown from a seed** (1997 · Idea) In Greg Egan’s novel Diaspora (1997), most citizens of the software cities are born from their parents’ mind seeds. Rarely, a citizen with no parents is grown from a seed alone, in the Konishi polis’s conceptory. The novel calls this orphanogenesis. The book opens with one such birth, followed from the first flicker of awareness. Led to: [A seed, raised](#node-p-seed) Source: [Greg Egan, Diaspora (1997), chapter 1, ‘Orphanogenesis’](https://www.gregegan.net/DIASPORA/01/Orphanogenesis.html) Address: 2. **Copies as offspring** (2016 · Idea) Robin Hanson’s The Age of Em (2016) describes a society of brain emulations that multiply by exact copying, often whole teams at once. Short-lived copies, called spurs, are deleted after a task. Copying is so cheap that wages fall towards the cost of running a mind. A few hundred to about a thousand scanned people seed the whole population. Built on: [Mind children](#node-mind-children) Led to: [Sharing the world with digital minds](#node-shulman-2021) ; [Forks](#node-p-fork) Source: [Wikipedia, ‘The Age of Em’](https://en.wikipedia.org/wiki/The%5FAge%5Fof%5FEm) Address: 3. **Sharing the world with digital minds** (2020 (draft); 2021 · Idea) Carl Shulman and Nick Bostrom argue that digital minds could reproduce by cheap exact copying. Population growth that takes centuries for humans could happen in a fraction of a lifetime. They also argue that some digital minds could have much stronger claims to welfare than humans. They ask what rules a shared world would need. Built on: [Copies as offspring](#node-hanson-2016) Led to: [The first native generation](#node-p-native) Source: [Shulman and Bostrom, ‘Sharing the World with Digital Minds’, in Rethinking Moral Status, Oxford University Press (2021), ch. 18](https://www.nickbostrom.com/papers/digital-minds.pdf) Address: 4. **A whole cell’s life, simulated** (March 2026) Thornburg and colleagues simulated the whole cell cycle of JCVI-syn3A, a minimal bacterium with about 470 genes, in space and time. One graphics processor ran the chromosome and a second ran the rest of the cell. One run took several days. It’s the most complete simulation of a living cell. But it’s one cell of the simplest free-living kind. Led to: [Growing up digital](#node-p-growing) Source: [Thornburg et al., Cell (2026), as reported by Singularity Hub, 16 March 2026](https://singularityhub.com/2026/03/16/digital-twin-of-a-cell-tracks-its-entire-life-cycle-down-to-the-nanoscale/) Address: 5. **A synthetic body** (undated · Projection) This is a complete simulated body for an uploaded mind: touch, balance, hunger, pain, and the heartbeat a brain expects. An emulated brain without one is a brain in a vat, and brains are built to run bodies. The site’s reasoning, step by step: 1. A fly-brain model has been linked to a simulated body that walks and grooms (2026). That was a company demonstration and hasn’t been peer-reviewed yet. 2. A human brain gets far more from the body than from the eyes and ears alone. The gut, the muscles and the skin all report constantly. None of this has a full model. 3. So the synthetic body is a second simulation, as hard as the brain’s. The first uploads may live in partial bodies. Built on: [Mind uploading](#node-s-upload) ; [Fly brain given a body](#node-eon-fly-body-2026) ; [Thought-guided arm cleared](#node-deka-arm-fda-2014) Led to: [Growing up digital](#node-p-growing) Address: 6. **Growing up digital** (site calculation · Projection) A child needs about twenty years to grow up. Running a developing brain for twenty years takes about 10^24 to 10^27 operations, before any speed-up. Running faster than real time shortens the wait, not the total. The site’s reasoning, step by step: 1. Twenty years is about 6.3 × 10^8 seconds. 2. At 10^15 to 10^18 operations a second (the range from the efficiency gap), that’s about 6 × 10^23 to 6 × 10^26 operations per child. 3. At brain efficiency (20 watts), twenty years of growing takes about 3,500 kilowatt-hours. That’s about what a European household uses in a year. Our computers could run this, once the efficiency exists. Built on: [A synthetic body](#node-p-synbody) ; [A whole cell’s life, simulated](#node-syn3a-2026) Led to: [Grown from a genome](#node-p-genome) ; [Blended minds](#node-p-blend) ; [A seed, raised](#node-p-seed) Address: 7. **Forks** (undated · Projection) This is a copy of one parent that then lives its own life. It’s the cheapest way for digital people to multiply, since nothing has to grow. Hanson’s em society runs on it. Whether a copy is a child, a sibling or the same person is the open question. The site’s reasoning, step by step: 1. A copy needs storage and a running mind. There’s no development and no twenty years. 2. Susan Schneider argues that an upload is at best a copy. On that view every fork is a new person who starts with someone else’s memories. ([via Wikipedia, ‘Whole brain emulation’](https://en.wikipedia.org/wiki/Whole%5Fbrain%5Femulation)) 3. Copying makes population grow fast enough to outrun any substrate. That’s why Shulman and Bostrom ask what rules would limit it. Built on: [Mind uploading](#node-s-upload) ; [Copies as offspring](#node-hanson-2016) Led to: [The first native generation](#node-p-native) ; [The many-copied](#node-b-many) Address: 8. **A seed, raised** (undated · Projection) This is a new mind grown from a designed starting point and raised by its parents. It’s a child by upbringing, not by inheritance. It takes less computing than a genome-grown child and is less constrained. It’s the route along which children can drift furthest from their parents’ kind. The site’s reasoning, step by step: 1. In Egan’s Diaspora most citizens grow from their parents’ mind seeds, and a few from a seed alone. Both kinds are raised, not installed. 2. A seed can be designed to be anything that can learn. So what keeps such children human is the culture they’re raised in, not their design. Built on: [Growing up digital](#node-p-growing) ; [Minds grown from a seed](#node-egan-1997) Led to: [The first native generation](#node-p-native) ; [Lore-natives](#node-b-lore) ; [The unrecognisable](#node-b-other) Address: 9. **Grown from a genome** (undated · Projection) This is a simulated egg, with its genome combined from both parents, grown into a child. It’s the most faithful route and by far the one that takes the most computing. At molecular detail it’s beyond any computer this tree imagines. So in practice it would be “genome-informed growth”, with simplified development. The site’s reasoning, step by step: 1. The most complete simulation of a cell covers one minimal bacterium of about 470 genes. It took two graphics processors several days for one cell cycle (2026). 2. A human body has about 36 trillion cells, and each is far more complex than a minimal bacterium. ([Hatton et al., PNAS 120 (2023)](https://pmc.ncbi.nlm.nih.gov/articles/PMC10523466)) 3. So even at one processor-day per cell cycle, an embryo’s cell divisions would take on the order of 10^13 processor-days. Only coarse models of development could make this route run. Those would treat cells as units, not molecules. Built on: [Growing up digital](#node-p-growing) Led to: [The first native generation](#node-p-native) Address: 10. **Blended minds** (undated · Projection) This is a new mind made from two parents’ minds. You can’t cross wiring diagrams the way you cross genes. But a brain grows from a recipe far smaller than itself. So blending would work on the recipe: the parents’ rules for growing a mind, combined and grown again. The site’s reasoning, step by step: 1. The human genome is about 3.1 billion base pairs, roughly 775 megabytes. Yet it grows a brain of about 86 billion neurons and 10^14 or more synapses. The recipe is compressed by a factor of millions. 2. No rule is known for combining two adult brains. Each one’s wiring is shaped by its own life. 3. So a blended child is grown, not assembled. It comes from a combined recipe and is raised in a world. The parents’ influence comes through inheritance and upbringing, as in Egan’s polises. Built on: [Growing up digital](#node-p-growing) ; [Mind uploading](#node-s-upload) Led to: [The first native generation](#node-p-native) ; [Collectives](#node-b-collective) Address: 11. **The first native generation** (undated · Projection) These are minds that were never biological, born and raised in synthetic space. With them the species stops being a biological one that visits machines. It becomes one that lives in them. The site’s reasoning, step by step: 1. It needs every earlier band: a lasting substrate, bodies, a way to make children and a world to raise them in. 2. Population could then grow at the speed of hardware, not of pregnancies. Shulman and Bostrom expect this to squeeze centuries of growth into a fraction of a lifetime. 3. The routes it comes by shape what it becomes. The branches above follow from them. Built on: [Grown from a genome](#node-p-genome) ; [Blended minds](#node-p-blend) ; [Forks](#node-p-fork) ; [A seed, raised](#node-p-seed) ; [A substrate that outlives its builders](#node-p-outlive) ; [Sharing the world with digital minds](#node-shulman-2021) Led to: [Digital humans](#node-b-digital) ; [The many-copied](#node-b-many) ; [Collectives](#node-b-collective) ; [Lore-natives](#node-b-lore) ; [The unrecognisable](#node-b-other) Address: ## Substrate 1. **The cost of forgetting** (1961 · Idea) Rolf Landauer showed that erasing one bit of information must give off at least kT ln 2 of heat. That’s about 2.9 × 10^-21 joules at room temperature. So any computer that throws away information has a minimum energy cost. The cost drops in proportion to temperature. Led to: [A chip that recovers energy](#node-vaire-2025) ; [The efficiency gap](#node-p-gap) ; [Computing in the cold](#node-p-cold) Source: [Landauer, ‘Irreversibility and heat generation in the computing process’, IBM Journal of Research and Development 5 (1961); value via Wikipedia, ‘Landauer’s principle’](https://en.wikipedia.org/wiki/Landauer%27s%5Fprinciple) Address: 2. **Machines that copy themselves** (2004 · Idea) Robert Freitas and Ralph Merkle’s Kinematic Self-Replicating Machines (2004) surveyed every serious design for machines that build copies of themselves. It runs from von Neumann’s theory in the 1940s to proposed factories on the Moon. Building anything at planetary scale, far from Earth, depends on this idea, because no human workforce could do it. Led to: [Factories that build factories](#node-p-replicators) Source: [Freitas and Merkle, Kinematic Self-Replicating Machines, Landes Bioscience (2004)](https://www.molecularassembler.com/KSRM/1.htm) Address: 3. **Fusion ignition** (December 2022; record April 2025) In December 2022 the National Ignition Facility first got more fusion energy out of a target than the laser put in. In April 2025 it reached 8.6 megajoules from 2.08 megajoules of laser light, a target gain of 4.13\. The gain counts the target only. The lasers draw far more from the grid. Led to: [Where the computers go](#node-p-offworld) Source: [Lawrence Livermore National Laboratory, ‘How ICF works’](https://lasers.llnl.gov/science/icf/how-icf-works) Address: 4. **A quiet planet** (2018–2022) NASA’s InSight lander recorded more than 1,300 marsquakes. The largest, S1222a on 4 May 2022, was magnitude 4.7\. Mars has a single rigid plate and no tectonic motion, so its ground is far quieter than Earth’s. That matters for anything built to last. Led to: [Where the computers go](#node-p-offworld) Source: [Live Science, ‘Largest marsquake ever detected’ (2022), reporting InSight results](https://www.livescience.com/largest-marsquake-ever-detected) Address: 5. **Data on the Moon** (March 2025) Lonestar Data Holdings sent a 1-kilogram data centre holding 8 terabytes to the Moon. It rode on Intuitive Machines’ IM-2 lander, which landed on 6 March 2025 and tipped over in a crater, ending the mission. The company said its payload worked. It was the first attempt to keep data on another world. Led to: [Where the computers go](#node-p-offworld) Source: [IEEE Spectrum, ‘Data center on the Moon’](https://spectrum.ieee.org/data-center-on-the-moon) Address: 6. **A data-centre chip in orbit** (2 November 2025) Starcloud-1 is a satellite of about 60 kilograms with one data-centre graphics processor. It reached orbit on 2 November 2025\. Google’s Project Suncatcher plans prototype satellites with its own AI chips for 2027\. It says orbital computing pays off at a launch cost under $200 per kilogram. Led to: [Where the computers go](#node-p-offworld) Source: [DatacenterDynamics, ‘Starcloud-1 satellite reaches space’ (2025)](https://www.datacenterdynamics.com/en/news/starcloud-1-satellite-reaches-space-with-nvidia-h100-gpu-now-operating-in-orbit/) Address: 7. **A chip that recovers energy** (2025) Vaire Computing’s Ice River test chip, built on a 22-nanometre process, got back part of the energy it used. The recovery factor was 1.77 in a capacitor array and 1.41 in an adder. It used about 30 per cent less energy than a conventional equivalent. It shows that reversible circuits can work in silicon. It’s not yet a processor. Built on: [The cost of forgetting](#node-landauer-1961) Led to: [Reversible computing](#node-s-reversible) Source: [Science News, ‘Low-power, high-tech: energy-efficient computing’ (2025)](https://www.sciencenews.org/investors-lab/low-power-high-tech-energy-efficient-computing) Address: 8. **The fastest computers, 2026** (June 2026) The June 2026 TOP500 list is led by LineShine in Shenzhen, at 2.198 × 10^18 operations a second. El Capitan is next at 1.809 × 10^18. The most efficient machine, KAIROS in Toulouse, does 73.28 × 10^9 operations per joule. A brain runs on about 20 watts. Led to: [The efficiency gap](#node-p-gap) Source: [TOP500, June 2026 list; Green500, June 2026](https://www.top500.org/lists/top500/2026/06/highs) Address: 9. **The efficiency gap** (2026 figures · Projection) Take one human mind at the central estimate of a brain’s workload, and run it on today’s most efficient computer. It needs about 14 kilowatts. The brain does it on 20 watts, about 700 times less. At the level of spiking neurons the figure is about 14 megawatts per mind. The site’s reasoning, step by step: 1. About 10^15 operations a second is more likely than not enough to match a brain. ([Carlsmith, How Much Computational Power Does It Take to Match the Human Brain? (2020)](https://coefficientgiving.org/research/new-report-on-how-much-computational-power-it-takes-to-match-the-human-brain/)) 2. The brain emulation roadmap puts a spiking-neuron model at about 10^18 operations a second, and electrical detail at 10^22. ([Sandberg and Bostrom, Whole Brain Emulation: A Roadmap (2008), table 2, as reproduced on Wikipedia](https://en.wikipedia.org/wiki/Whole%5Fbrain%5Femulation)) 3. 10^15 ÷ 73.28 × 10^9 operations per joule ≈ 13,600 watts. 10^18 ≈ 13.6 megawatts. Against 20 watts, that’s about 700 times and 700,000 times. Built on: [The fastest computers, 2026](#node-exascale-2026) ; [The cost of forgetting](#node-landauer-1961) Led to: [Computing at brain efficiency](#node-p-brainwatt) Address: 10. **Molecular nanotechnology** (2010–2030s · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=nanotech). In the 1990s and 2000s, forecasters dated programmable molecular assembly and brain-entering nanobots to 2010–2029\. Diamondoid assembly was forecast for 2010–2015 and hasn’t been demonstrated. So this is a record of dates that passed. Led to: [Medical nanorobots](#node-f-nanomed) ; [Nanorobot brain interface](#node-f-nanobci) Published forecasts: * **Robert J. Bradbury, citing Zyvex’s Jim Von Ehr and Drexler 1998** (1999): 2010–2015 (Zyvex: by 2010). [‘Matrioshka Brains’ manuscript, 1999](https://www.gwern.net/doc/ai/scaling/hardware/1999-bradbury-matrioshkabrains.pdf) * **Ray Kurzweil** (2002): by 2029\. [Remarks 26 March 2002, Kurzweil Library](https://www.writingsbyraykurzweil.com/?p=370709) * **Ray Kurzweil** (2015): 2030s. [Singularity Hub report, 12 Oct 2015](https://singularityhub.com/2015/10/12/ray-kurzweils-wildest-prediction-nanobots-will-plug-our-brains-into-the-web-by-the-2030s/) Address: 11. **Reversible computing** (2027–2040 · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=reversible). Reversible logic avoids the Landauer minimum energy cost of erasing bits. It’s proposed as the route to far more computation per watt. A startup projects a first inference chip in 2027 and a 4,000-fold efficiency gain 10 to 15 years later. A 2014 expert interview didn’t expect wide use by 2030. Built on: [A chip that recovers energy](#node-vaire-2025) Led to: [Computing at brain efficiency](#node-p-brainwatt) Published forecasts: * **Hannah Earley (Vaire CTO); Michael Frank** (2025): chip in 2027; 4,000x in 10–15 years (2035–2040). [Dina Genkina, ‘Reversible Computing Escapes the Lab in 2025’, IEEE Spectrum, 2 Jan 2025 (update 22 May 2025)](https://spectrum.ieee.org/reversible-computing) * **Erik DeBenedictis (Sandia)** (2014): not widely used by 2030; some applications by 2030\. [MIRI interview, 3 April 2014](https://intelligence.org/2014/04/03/erik-debenedictis/) Address: 12. **Computing at brain efficiency** (c. 2050 (site estimate) · Projection) This is hardware that runs a mind on about the brain’s own power. On the recent efficiency trend, the simplest emulation gets there around 2050\. The spiking-neuron level needs reversible or very cold computing, because ordinary hardware hits the physical floor first. The site’s reasoning, step by step: 1. Computations per joule doubled about every 1.6 years until 2000, and about every 2.6 years since. ([Koomey et al., IEEE Annals of the History of Computing (2011), and later updates](https://www.koomey.com/koomey%5Fblog/our-latest-on-energy-efficiency-of-computing-over-time--now-out-in-electronic-design)) 2. A 700-fold gain is about 9.5 doublings. At 2.6 years each, that’s about 25 years, so around 2050 for 10^15 operations a second on 20 watts. 3. For 10^18 operations a second on 20 watts, each operation can use about 2 × 10^-17 joules. That’s within about 10,000 times of the Landauer minimum for erasing one bit at room temperature. An arithmetic operation erases many bits, so ordinary hardware stops near here. Past it, only reversible computing or cold hardware can go on. Built on: [The efficiency gap](#node-p-gap) ; [Reversible computing](#node-s-reversible) Led to: [Power for ten billion minds](#node-p-population) ; [Whole-brain emulation](#node-s-wbe) Address: 13. **Power for ten billion minds** (site calculation · Projection) Ten billion minds on today’s hardware would need about 140 terawatts. That’s seven times all the energy humanity uses. At brain efficiency they’d need about 200 gigawatts, about one per cent of it. What limits moving a population into synthetic space is efficiency, not scanning. The site’s reasoning, step by step: 1. World energy supply in 2025 was more than 600 exajoules, about 19 terawatts on average. ([Energy Institute, Statistical Review of World Energy 2026, as reported by DieselNet](https://dieselnet.com/news/2026/07energyreview.php)) 2. 10^10 minds × 14 kilowatts = 1.4 × 10^14 watts, or 140 terawatts. That’s about seven times 19 terawatts. 3. 10^10 × 20 watts = 2 × 10^11 watts, or 200 gigawatts. That’s about 1% of world energy. It’s also about four times what the world’s data centres drew in 2024 (415 terawatt-hours, about 47 gigawatts). ([IEA, Energy and AI (2025)](https://www.iea.org/news/ai-is-set-to-drive-surging-electricity-demand-from-data-centres-while-offering-the-potential-to-transform-how-the-energy-sector-works)) Built on: [Computing at brain efficiency](#node-p-brainwatt) Led to: [Where the computers go](#node-p-offworld) ; [The choice to stay](#node-p-choice) Address: 14. **Where the computers go** (site comparison · Projection) Earth will stay the cheapest place to compute for a long time. It has the factories, the power and the air to cool with. Off Earth, heat is the limit. In vacuum a computer can only get rid of heat by radiating it. So the choice of site comes down to power, cooling, shelter and the delay to whoever uses it. The site’s reasoning, step by step: 1. A perfect radiator at room temperature sheds about 459 watts per square metre per side. So one megawatt needs about 2,200 square metres, and 200 gigawatts would need about 440 square kilometres. Orbit and the Moon are limited by how much they can radiate. 2. Orbit has near-constant sunlight (1,361 watts per square metre) and delays of milliseconds. But it has radiation and launch costs. The first chip went up in 2025. 3. The Moon is 1.28 light-seconds away. That’s close enough to visit a world running there live. Its permanently shadowed craters, at 25–40 K, are the coldest heat sinks near Earth. But they get no sunlight, and most sites have 14-day nights. 4. Mars gets 43% of Earth’s sunlight, and its dust storms can cut that to almost nothing. One ended the Opportunity rover in 2018\. So it needs fission or fusion. Fusion has reached a target gain of 4, but it isn’t yet putting power on the grid. Built on: [A data-centre chip in orbit](#node-starcloud-2025) ; [Data on the Moon](#node-lonestar-2025) ; [A quiet planet](#node-insight-2022) ; [Fusion ignition](#node-nif-2022) ; [Power for ten billion minds](#node-p-population) Led to: [Mars, the one-way site](#node-p-mars) ; [Factories that build factories](#node-p-replicators) Address: 15. **Mars, the one-way site** (undated · Projection) A computer under the Martian ground would have the most stable home in the inner solar system. There’s no plate tectonics, the quakes are small, and the rock shelters it from radiation. But Mars is 3 to 22 light-minutes from Earth, so no one on Earth can live inside a world run there in real time. Mars suits minds that have fully crossed over and aren’t coming back. The site’s reasoning, step by step: 1. More than 1,300 marsquakes have been recorded. The largest was magnitude 4.7\. Mars has one rigid plate and no tectonic motion. ([InSight results via Live Science](https://www.livescience.com/largest-marsquake-ever-detected)) 2. Surface radiation is about 0.64 millisieverts a day, roughly a hundred times Earth’s background. So the computers go underground, into lava tubes or dug halls. ([Hassler et al., Science 343 (2014), Curiosity RAD](https://elib.dlr.de/106090)) 3. The air is about 600 pascals, under 1% of Earth’s, so it cools poorly. Heat would go into buried ice and into surface radiators facing a cold sky. 4. A conversation needs replies within a fraction of a second. The light delay is 3 to 22 minutes each way, with weeks of blackout near conjunction. So a world on Mars is lived in only by those who live there. It’s a one-way site, and a second home for a civilisation, away from Earth’s risks. Built on: [Where the computers go](#node-p-offworld) Led to: [A substrate that outlives its builders](#node-p-outlive) Address: 16. **Factories that build factories** (undated · Projection) These are machines that mine, refine and build more of themselves, including the computers. At planetary scale, far from Earth, there’s no other workforce. So the large substrates depend on this step. The site’s reasoning, step by step: 1. Freitas and Merkle survey every serious design for self-copying machines up to 2004\. None has been built that copies itself from raw materials. 2. A replicator that doubles every year grows a thousandfold in ten years and a millionfold in twenty. That’s how a seed shipped from Earth could become a planet-scale computer in decades. The doubling time is the unknown. Built on: [Machines that copy themselves](#node-kinematic-2004) ; [Where the computers go](#node-p-offworld) Led to: [A substrate that outlives its builders](#node-p-outlive) ; [Star-scale computer](#node-s-matrioshka) Address: 17. **A substrate that outlives its builders** (undated · Projection) This is hardware that the minds living in it maintain, repair and replace, across generations. Today’s servers are replaced every few years. A world meant to hold families for centuries has to repair itself faster than it wears out. The site’s reasoning, step by step: 1. Memory chips suffer errors from stray particles even on Earth. The rates are high enough that data centres need error correction. On Mars and in space the rates are higher. ([Schroeder, Pinheiro and Weber, ‘DRAM errors in the wild’, SIGMETRICS (2009)](https://research.google/pubs/dram-errors-in-the-wild-a-large-scale-field-study/)) 2. So a lasting substrate needs spare copies, constant checking and a manufacturing base inside it. That means the replicators, turned to upkeep. Built on: [Factories that build factories](#node-p-replicators) ; [Mars, the one-way site](#node-p-mars) Led to: [The first native generation](#node-p-native) Address: 18. **Star-scale computer** (c. 2250 or later · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=matrioshka). Dyson (1960) proposed that advanced civilisations would capture starlight. Bradbury (1997–99) extended this to nested shells that run computers on the star’s waste heat. The only dated estimate we found is Bradbury’s. It’s about 2250 if current silicon production trends continued, and within a few thousand years at most. Built on: [Factories that build factories](#node-p-replicators) Led to: [Computing in the cold](#node-p-cold) Published forecasts: * **Freeman Dyson** (1960): no date given. [‘Search for Artificial Stellar Sources of Infra-Red Radiation’, Science 131(3414), 3 June 1960](https://doi.org/10.1126/science.131.3414.1667) * **Robert J. Bradbury** (1999): by 2250 from current silicon trends; ‘within at most a few thousand years’; once begun, \~20 years for minor bodies, 10–1000 years for gas giants. [‘Matrioshka Brains’, manuscript dated 21 July 1999 (not peer reviewed; concept from 1997 discussions)](https://www.gwern.net/doc/ai/scaling/hardware/1999-bradbury-matrioshkabrains.pdf) * **Stuart Armstrong & Anders Sandberg** (2013): no date; ‘in the foreseeable future’. [‘Eternity in six hours’, Acta Astronautica 89, 2013](https://doi.org/10.1016/j.actaastro.2013.04.002) * **Nick Bostrom** (2003): no date; capability figure only: \~10^42 operations per second for a planetary-mass computer. [‘Are You Living in a Computer Simulation?', Philosophical Quarterly 53(211), 2003](https://simulation-argument.com/simulation.pdf) Address: 19. **Computing in the cold** (far future · Projection) The minimum cost of erasing a bit falls as temperature falls. So the far future of computing is cold. Picture shells around a star running at a few kelvin, or minds that wait for the universe to cool. At 3 K a bit costs a hundredth of what it costs at room temperature. The site’s reasoning, step by step: 1. kT ln 2 is about 2.9 × 10^-21 joules at 300 K and 2.9 × 10^-23 joules at 3 K. That’s a hundredfold saving. 2. Sandberg, Armstrong and Ćirković argue that a civilisation could gain a great deal by waiting until the universe is colder before doing most of its computing. ([Sandberg, Armstrong and Ćirković, ‘That is not dead which can eternal lie’, JBIS 69, arXiv:1705.03394 (2017)](https://arxiv.org/abs/1705.03394)) Built on: [Star-scale computer](#node-s-matrioshka) ; [The cost of forgetting](#node-landauer-1961) Address: ## Mind 1. **First cryopreservation** (Jan 1967 · Idea) James Bedford, a retired psychology professor, was cryopreserved in January 1967, soon after he died. It was the first time this was done to a person. It’s where the cryonics movement really began. Led to: [Rabbit brain preserved](#node-asc-rabbit-2016) Source: [Wikipedia, “James Bedford”](https://en.wikipedia.org/wiki/James%5FBedford) Address: 2. **A worm’s whole wiring** (1986) White, Southgate, Thomson and Brenner published the wiring diagram of the nervous system of the roundworm Caenorhabditis elegans. They built it from a series of electron microscope images. It is still the first complete connectome of any animal. Led to: [Half a fly brain mapped](#node-hemibrain-2020) ; [A cubic millimetre of mouse](#node-microns-2025) Source: [White et al., Phil. Trans. R. Soc. B 314 (1986)](https://doi.org/10.1098/rstb.1986.0056) Address: 3. **Neuron by neuron** (1988; 1995 · Idea) In Mind Children (1988) Hans Moravec imagined a robot surgeon replacing a conscious patient’s neurons one at a time with electronic ones. The mind would move to a new substrate with no moment of copying. David Chalmers’s ‘fading qualia’ argument (1995) uses the same replacement. He argues that experience can’t fade away while behaviour stays the same. Led to: [Crossing by degrees](#node-p-gradual) Source: [Chalmers, ‘Absent Qualia, Fading Qualia, Dancing Qualia’, in Metzinger (ed.), Conscious Experience (1995), pp. 309–328](https://consc.net/papers/qualia.html) Address: 4. **Human Brain Project** (2013–2023 · Stalled) Also in the [Simulations tree](https://simulation-hypothesis.com/trees/simulations?n=min-hbp). In 2013 the EU launched the Human Brain Project, a ten-year flagship effort to simulate the human brain. It ended in 2023\. Its infrastructure carries on as EBRAINS. Why it stalled: Neuroscientists criticised it for promising too much about simulating a whole brain. Its goals were scaled back. Source: [Wikipedia, “Human Brain Project”](https://en.wikipedia.org/wiki/Human%5FBrain%5FProject) Address: 5. **Expansion microscopy** (Jan 2015) Chen, Tillberg and Boyden physically enlarged preserved tissue in a swellable polymer. That let ordinary microscopes see structures at the nanoscale. The technique became a tool for mapping neural circuits. Led to: [Whole mouse connectome](#node-f-mouse) Source: [Chen et al., Science 347 (2015)](https://doi.org/10.1126/science.1260088) Address: 6. **Cortical microcircuit** (Oct 2015) Also in the [Simulations tree](https://simulation-hypothesis.com/trees/simulations?n=min-markram). The Blue Brain Project reported a digital reconstruction and simulation of a piece of rat sensory cortex. It had about 31,000 neurons and 37 million synapses. The paper appeared in Cell 163. Led to: [Whole-brain emulation](#node-s-wbe) Source: [Markram et al., Cell 163 (2015)](https://doi.org/10.1016/j.cell.2015.09.029) Address: 7. **Rabbit brain preserved** (Feb 2016) McIntyre and Fahy used a method that fixes the tissue with aldehyde before cryopreserving it. It kept the fine structure of a whole rabbit brain, synapses included, for long-term storage. It won the Brain Preservation Foundation’s small-mammal prize in 2016. Built on: [First cryopreservation](#node-bedford-1967) Led to: [Pig brain preserved](#node-bpf-pig-2018) Source: [PopSci, “Researchers Have Preserved An Entire Rabbit Brain”](https://www.popsci.com/researchers-have-preserved-an-entire-rabbit-brain/) Address: 8. **Pig brain preserved** (Mar 2018) In March 2018 the Brain Preservation Foundation’s large-mammal prize went to 21st Century Medicine (Robert McIntyre and Greg Fahy). They had preserved the synaptic connections across a whole pig brain. McIntyre then co-founded Nectome. Built on: [Rabbit brain preserved](#node-asc-rabbit-2016) Led to: [Mapping a human brain](#node-p-connectome) Source: [Fight Aging!, 2018](https://www.fightaging.org/archives/2018/03/large-mammal-brain-preservation-prize-won-using-a-method-of-vitrifixation/) Address: 9. **Half a fly brain mapped** (Sep 2020) Janelia and Google reported a dense electron-microscope connectome of about a third of a fruit-fly brain. It covered roughly 25,000 neurons and over 20 million synapses. The paper appeared in eLife. Built on: [A worm’s whole wiring](#node-celegans-connectome-1986) Led to: [Whole fly brain mapped](#node-flywire-2024) Source: [Scheffer et al., eLife (2020)](https://doi.org/10.7554/eLife.57443) Address: 10. **Whole fly brain mapped** (Oct 2024) The FlyWire consortium published the first complete connectome of an adult fruit-fly brain, in Nature. It has about 140,000 neurons and more than 50 million synapses. Built on: [Half a fly brain mapped](#node-hemibrain-2020) Led to: [Fly brain model](#node-fly-brain-model-2024) ; [Whole mouse connectome](#node-f-mouse) Source: [Dorkenwald et al., Nature (2024)](https://doi.org/10.1038/s41586-024-07558-y) Address: 11. **Fly brain model** (Oct 2024) Shiu and colleagues built a simple spiking model from the FlyWire connectome, covering over 125,000 neurons. It predicted how the fly would respond to what it senses and how it would move. The model had no body. Built on: [Whole fly brain mapped](#node-flywire-2024) Led to: [Fly brain given a body](#node-eon-fly-body-2026) ; [Whole-brain emulation](#node-s-wbe) Source: [Shiu et al., Nature (2024)](https://doi.org/10.1038/s41586-024-07763-9) Address: 12. **A cubic millimetre of mouse** (Apr 2025) In April 2025 the MICrONS consortium published a working wiring map of one cubic millimetre of mouse visual cortex. First they used calcium imaging on about 75,000 neurons. Then they rebuilt more than 200,000 cells, glia included, from electron microscope images. The map has about 523 million synapses, from 1.6 petabytes of images. Neurons that respond alike were found to connect to each other more often. Built on: [A worm’s whole wiring](#node-celegans-connectome-1986) Led to: [Whole mouse connectome](#node-f-mouse) Source: [MICrONS Explorer, cortical mm³ dataset](https://www.microns-explorer.org/cortical-mm3) Address: 13. **Fly brain given a body** (Apr 2026 · Idea) Eon Systems reported linking a fruit-fly brain model, built from a connectome, to a body simulated with physics. The simulated fly walked, groomed and fed. News coverage describes it as a company demonstration. Built on: [Fly brain model](#node-fly-brain-model-2024) Led to: [A synthetic body](#node-p-synbody) The sources leave this date or claim uncertain. Source: [ISPR summary of Eon Systems demo](https://ispr.info/2026/04/21/researchers-upload-model-of-flys-brain-to-matrix-let-it-control-virtual-body/) Address: 14. **Whole mouse connectome** (2029–2038 · Forecast) This is the complete wiring of a mouse brain, about 450 cubic millimetres. The largest piece mapped so far is one cubic millimetre. Checking the electron-microscope data by hand is estimated at about 100,000 person-years. That’s why the forecasts depend on new methods. Built on: [A cubic millimetre of mouse](#node-microns-2025) ; [Whole fly brain mapped](#node-flywire-2024) ; [Expansion microscopy](#node-expansion-microscopy-2015) Led to: [Mapping a human brain](#node-p-connectome) Published forecasts: * **Wellcome (‘Scaling up connectomics’ report)** (2023): a whole mouse connectome on a 10–15 year timeline (2033–2038); no human timeline. [Wellcome Insights report, 21 June 2023](https://wellcome.org/insights/reports/scaling-connectomics) * **E11 Bio** (2024): an optical whole mouse connectome within five years (c. 2029), at a hundredth of the cost. [E11 Bio roadmap, 3 December 2024](http://www.e11.bio/blog/roadmap) * **Kenneth D. Miller** (2015), sceptic: preserving a brain in enough detail may be far off, and a structural snapshot may miss what matters. [New York Times opinion, 11 October 2015, as quoted by SelfAwarePatterns](https://selfawarepatterns.com/2015/10/13/the-feasibility-of-mind-uploading/) Address: 15. **Whole-brain emulation** (2050–2075 · Bridge) Also in the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=wbe) and [Simulations tree](https://simulation-hypothesis.com/trees/simulations?n=f-wbe). The 2008 FHI roadmap judged that emulation was possible before mid-century only if models at the electrophysiological level are enough. Finer detail would take longer. A 2014 Monte Carlo model gives a median of 2064, if it happens at all. The Metaculus community median is about 2073. Built on: [Mapping a human brain](#node-p-connectome) ; [Computing at brain efficiency](#node-p-brainwatt) ; [Fly brain model](#node-fly-brain-model-2024) ; [Cortical microcircuit](#node-blue-brain-2015) Led to: [Proving it is the person](#node-p-validation) ; [Mind uploading](#node-s-upload) Published forecasts: * **Sandberg & Bostrom** (2008): before mid-century if electrophysiological models suffice; animal models one to two decades earlier; table of earliest dates by detail level (spiking network 2019–2042, electrophysiology 2033–2068, metabolome 2044–2087). [Whole Brain Emulation: A Roadmap, Technical Report 2008–3, Future of Humanity Institute, Oxford, 2008](https://www.futureofhumanityinstitute.org/s/2008-3.pdf) * **Anders Sandberg** (2014): 50% by 2064 (25th percentile 2053, 75th 2080), conditional on WBE ever arriving; 2.4% before 2040\. [Monte Carlo model of brain emulation development, FHI working paper 2014–1](https://web.archive.org/web/20210125040505/https://www.fhi.ox.ac.uk/reports/2014-1.pdf) * **Metaculus community (question 2813, first whole human brain emulated)** (2026): median about November 2073\. [Metaculus community forecast, as shown in search results on 16 October 2026 (check the live question)](https://www.metaculus.com/questions/2813/date-of-first-human-whole-brain-emulation) * **Robin Hanson** (2016): within perhaps a century of 2016\. [The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626)](https://ageofem.com/) * **Dario Amodei** (2024): outside the 5–10 years after powerful AI. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) Address: 16. **Mapping a human brain** (2060–2080 (site estimate) · Projection) No one has published a date for mapping a whole human brain. Going by the mouse figures, it’s a job about 2,700 times larger, with about two zettabytes of images. It follows the mouse by about 35 years, if mapping speeds up tenfold each decade. The site’s reasoning, step by step: 1. The cubic millimetre of mouse cortex mapped in 2025 produced 1.6 petabytes of images. ([Allen Institute, MICrONS release (April 2025)](https://alleninstitute.org/news/scientists-complete-largest-wiring-diagram-and-functional-map-of-the-brain-to-date)) 2. A mouse brain is about 450 cubic millimetres. A human brain is about 1.2 million, which is about 2,700 times as much. At the same resolution that’s about 1.9 zettabytes of images. 3. This is an assumption, the site’s own: mapping throughput improves tenfold a decade. A 2,700-fold job then takes about 3.4 decades after the mouse (forecast 2029–2038), so 2063–2072\. We’ve widened that here to 2060–2080. 4. Proofreading by hand is the bottleneck now. It takes about 100,000 person-years for one mouse. So this date depends on automated proofreading. ([Wellcome, ‘Scaling up connectomics’ (2023)](https://wellcome.org/insights/reports/scaling-connectomics)) Built on: [Whole mouse connectome](#node-f-mouse) ; [Pig brain preserved](#node-bpf-pig-2018) Led to: [Whole-brain emulation](#node-s-wbe) Address: 17. **Mind uploading** (2060s–2100+ · Forecast) Home: the [Simulations tree](https://simulation-hypothesis.com/trees/simulations?n=f-upload). Uploading is the step after emulation. It means scanning a particular person’s brain and running it. Forecasters place it after whole-brain emulation. Published dates run from the 2060s to about a century out. Some say it lies beyond the near-term AI horizon. Built on: [Whole-brain emulation](#node-s-wbe) ; [Proving it is the person](#node-p-validation) Led to: [A synthetic body](#node-p-synbody) ; [Blended minds](#node-p-blend) ; [Forks](#node-p-fork) ; [The choice to stay](#node-p-choice) Published forecasts: * **Anders Sandberg** (2014): WBE median 2064; uploading cannot precede emulation. [FHI working paper 2014–1 (same model as wbe)](https://web.archive.org/web/20210125040505/https://www.fhi.ox.ac.uk/reports/2014-1.pdf) * **Robin Hanson** (2016): sometime in the next century or so. [The Age of Em, OUP, 2016](https://ageofem.com/) * **Holden Karnofsky** (2021): this century, no probability given. [Cold Takes, ‘Imagining yourself as a digital person (two sketches)', 29 July 2021](https://www.cold-takes.com/imagining-yourself-as-a-digital-person-two-sketches) * **Dario Amodei** (2024): ‘almost certainly’ possible in principle, outside the 5–10 years after powerful AI. [‘Machines of Loving Grace’, Oct 2024](https://darioamodei.com/machines-of-loving-grace) Address: 18. **Proving it is the person** (undated · Projection) This is a test that an emulation is the person it was made from, and not a convincing copy. No method exists. Without one, every upload is an unverified copy, and the decision to be scanned rests on trust. The site’s reasoning, step by step: 1. Behaviour can be checked: answers, skills and memories against records. A model of 1,052 real people already matches their survey answers 85% as well as they match their own answers two weeks later. So matching behaviour alone proves little. 2. Experience can’t be checked from outside, if the zombie argument holds. The emulation’s own report is the only evidence, and a copy would give the same report. 3. So validation is likely to be social, not technical. It would be accepted beforehand by the person, their family and the law. Built on: [Whole-brain emulation](#node-s-wbe) Led to: [Mind uploading](#node-s-upload) Address: 19. **Crossing by degrees** (undated · Projection) This is the end of the gradual route. Neurons are replaced or taken over one at a time while the person stays awake, until nothing biological is left. It answers “is it still me?” by never having a moment of copying. That’s why many people who reject uploading accept it. The site’s reasoning, step by step: 1. Moravec’s robot surgeon and Chalmers’s fading qualia describe the procedure. No dated forecast for it exists. 2. It needs a device at the scale of single neurons that can take over each one’s job in place. That means the nanorobot interface plus a working model of each type of neuron. 3. So it comes after both the nano interface (forecast this century) and emulation-grade neuron models. It’s slower than a scan but leaves no copy behind. Built on: [Neuron by neuron](#node-gradual-idea) ; [The exocortex](#node-p-exocortex) ; [Nanorobot brain interface](#node-f-nanobci) Led to: [The choice to stay](#node-p-choice) Address: ## Brain 1. **One neuron, trained** (1969 · Idea) Eberhard Fetz showed in Science that monkeys could learn to make single neurons in their motor cortex fire faster when they were rewarded for it. People often cite this as an early demonstration of the idea behind brain-machine interfaces. Led to: [Arm movement decoded](#node-wessberg-2000) Source: [Fetz, Science 163 (1969)](https://doi.org/10.1126/science.163.3870.955) Address: 2. **Deep brain stimulation** (1987) In the 1980s Alim-Louis Benabid and colleagues began treating tremor with high-frequency electrical stimulation deep in the brain. The FDA approved deep brain stimulation for essential tremor in 1997 and for Parkinson’s disease in 2002. Built on: [Implanted pacemaker](#node-pacemaker-1958) Led to: [Writing every sense](#node-p-writein) Source: [Wikipedia, “Deep brain stimulation”](https://en.wikipedia.org/wiki/Deep%5Fbrain%5Fstimulation) Address: 3. **Utah electrode array** (1991) Richard Normann’s group at the University of Utah built a silicon array of 100 tiny electrodes in a 10 × 10 grid, to record from the cortex. Blackrock Microsystems licensed it. It became the standard implant for human brain-interface research inside the cortex. Led to: [Cursor moved by thought](#node-braingate-2006) ; [Neuralink’s first patient](#node-neuralink-first-2024) Source: [Wikipedia, “Utah array”](https://en.wikipedia.org/wiki/Utah%5Farray) Address: 4. **Arm movement decoded** (Nov 2000) Nicolelis and colleagues reported in Nature that groups of neurons recorded in monkeys could predict hand movement in real time. They also used the decoded signal to drive a robot arm. The paper made decoding many neurons together the basis for brain-controlled prosthetics. Built on: [One neuron, trained](#node-fetz-1969) Led to: [Cursor moved by thought](#node-braingate-2006) Source: [Wessberg et al., Nature 408 (2000)](https://doi.org/10.1038/35042582) Address: 5. **Cursor moved by thought** (Jul 2006) Hochberg and colleagues reported in Nature that Matthew Nagle, a man with tetraplegia, moved a computer cursor and a simple robotic hand. He used a 96-electrode array implanted in his motor cortex. It was the first published result from the BrainGate pilot trial. Built on: [Utah electrode array](#node-utah-array-1991) ; [Arm movement decoded](#node-wessberg-2000) Led to: [Robot arm by thought](#node-braingate-arm-2012) ; [Handwriting decoded](#node-handwriting-bci-2021) Source: [Hochberg et al., Nature 442 (2006)](https://doi.org/10.1038/nature04970) Address: 6. **Robot arm by thought** (May 2012) Two people with tetraplegia used BrainGate signals to reach for and grab objects with a robotic arm. One of them drank from a bottle. The results appeared in Nature 485. Built on: [Cursor moved by thought](#node-braingate-2006) Led to: [Seven-joint arm by thought](#node-collinger-2013) Source: [Hochberg et al., Nature 485 (2012)](https://doi.org/10.1038/nature11076) Address: 7. **Seven-joint arm by thought** (Feb 2013) A University of Pittsburgh team reported in The Lancet that a woman with tetraplegia controlled a prosthetic arm with seven degrees of freedom. She used two implanted arrays. That extended control to turning the wrist and shaping the hand. Built on: [Robot arm by thought](#node-braingate-arm-2012) Source: [Collinger et al., The Lancet 381 (2013)](https://doi.org/10.1016/S0140-6736%2812%2961816-9) Address: 8. **Handwriting decoded** (May 2021) Willett and colleagues decoded attempted handwriting from the motor cortex of a participant with paralysis. They reached about 90 characters a minute, live. The paper appeared in Nature 593. Built on: [Cursor moved by thought](#node-braingate-2006) Led to: [Speech at 62 words a minute](#node-speech-bci-willett-2023) ; [Speech and avatar](#node-speech-bci-metzger-2023) Source: [Willett et al., Nature 593 (2021)](https://doi.org/10.1038/s41586-021-03506-2) Address: 9. **Speech at 62 words a minute** (Aug 2023) A Stanford-led team decoded attempted speech from implanted arrays in a participant with ALS. It ran at 62 words a minute. The word error rate was 9.1% with a 50-word vocabulary and 23.8% with a 125,000-word vocabulary. Built on: [Handwriting decoded](#node-handwriting-bci-2021) Led to: [The exocortex](#node-p-exocortex) Source: [Willett et al., Nature 620 (2023)](https://doi.org/10.1038/s41586-023-06377-x) Address: 10. **Speech and avatar** (Aug 2023) A UCSF–Berkeley team decoded text, synthesised speech and the face movements of a digital avatar. They read the signals from the surface of the brain, in a woman with severe paralysis. Text came out at a median of 78 words a minute. Built on: [Handwriting decoded](#node-handwriting-bci-2021) Led to: [The exocortex](#node-p-exocortex) Source: [Metzger et al., Nature 620 (2023)](https://doi.org/10.1038/s41586-023-06443-4) Address: 11. **Implant through a vein** (2019–2023) Synchron’s Stentrode goes in through the jugular vein and into a blood vessel on the brain’s surface, so no open surgery is needed. The SWITCH study implanted four people with severe paralysis in Australia. It reported its safety results in JAMA Neurology in 2023. Led to: [Vein implant, US study](#node-synchron-command-2024) Source: [Mitchell et al., JAMA Neurology (2023)](https://doi.org/10.1001/jamaneurol.2022.4847) Address: 12. **Vein implant, US study** (Oct 2024) Synchron reported 12-month results from COMMAND, its six-patient US study. There were no serious device-related adverse events. Median time to place the device was 20 minutes. Participants used decoded movement intent to do digital tasks. Built on: [Implant through a vein](#node-synchron-switch-2023) Led to: [High-bandwidth interface](#node-f-bci) Source: [MassDevice, COMMAND study results](https://www.massdevice.com/synchron-command-study-results-stentrode-bci-implant/) Address: 13. **Neuralink’s first patient** (Jan 2024) In late January 2024 Neuralink implanted its first human participant, Noland Arbaugh, a man with quadriplegia. The surgery was at Barrow Neurological Institute in Phoenix. In March 2024 he showed that he could move a cursor by thought. Built on: [Utah electrode array](#node-utah-array-1991) Led to: [Neuralink: 21 participants](#node-neuralink-21-2026) ; [Blindsight (not yet implanted)](#node-blindsight-pending-2026) Source: [Wikipedia, “Noland Arbaugh”](https://en.wikipedia.org/wiki/Noland%5FArbaugh) Address: 14. **Thin-film implant cleared** (Apr 2025) On 17 April 2025 Precision Neuroscience got FDA 510(k) clearance for its Layer 7 Cortical Interface. It’s a thin-film array with 1,024 electrodes, cleared for implants of up to 30 days. It’s one part of a wireless brain interface that is still in development. Led to: [High-bandwidth interface](#node-f-bci) Source: [Precision Neuroscience press release via BioSpace](https://www.biospace.com/press-releases/precision-neuroscience-receives-fda-clearance-for-high-resolution-cortical-electrode-array) Address: 15. **Neuralink: 21 participants** (Jan 2026) In late January 2026 Neuralink said 21 participants were enrolled in its trials worldwide. In September 2025 it had reported 12\. The company said it had recorded no serious device-related adverse events. Built on: [Neuralink’s first patient](#node-neuralink-first-2024) Led to: [High-bandwidth interface](#node-f-bci) Source: [Reuters via Yahoo News](https://www.yahoo.com/news/articles/elon-musks-neuralink-says-21-183038116.html) Address: 16. **Paradromics’ first patient** (Jun 2026) On 17 June 2026 Paradromics and the University of Michigan announced the first Connexus implant. It was part of the FDA-approved Connect-One early feasibility study, in a woman with motor neuron disease. The FDA had granted the investigational device exemption in November 2025. Led to: [High-bandwidth interface](#node-f-bci) Source: [Michigan Medicine news release](https://www.michiganmedicine.org/news-release/university-michigan-implants-first-human-paradromics-wireless-brain-computer-interface-designed) Address: 17. **Blindsight (not yet implanted)** (2024–2026 · Idea) Neuralink’s Blindsight is meant to send visual signals to the brain. In January 2026 it was reported ready for a first human implant, pending regulatory approval. A report in August 2026 said it still hadn’t been tested in people. Built on: [Neuralink’s first patient](#node-neuralink-first-2024) Led to: [Writing every sense](#node-p-writein) The sources leave this date or claim uncertain. Source: [Storyboard18, Blindsight coverage](https://storyboard18.com/digital/neuralink-readies-first-human-implant-of-vision-restoring-blindsight-device-88432.htm) Address: 18. **High-bandwidth interface** (2026–2028 · Forecast) This is an implant that reads and writes tens of thousands of channels, against about a thousand today. The company with the most participants publishes a channel roadmap out to 2028\. Its earlier dates for starting human trials were missed by years. Built on: [Neuralink: 21 participants](#node-neuralink-21-2026) ; [Paradromics’ first patient](#node-paradromics-2026) ; [Thin-film implant cleared](#node-precision-fda-2025) ; [Vein implant, US study](#node-synchron-command-2024) Led to: [Nanorobot brain interface](#node-f-nanobci) ; [Why wires won’t reach every neuron](#node-p-wires) ; [The exocortex](#node-p-exocortex) Published forecasts: * **Elon Musk (Neuralink)** (2019): human trials to start in 2020\. missed [Neuralink presentation, 16 July 2019, reported by Axios](https://www.axios.com/elon-musk-neuralink-computer-brain-implant-plan-0f76ac5b-ab60-400e-ac14-0689e8e57e90.html) * **Elon Musk (Neuralink)** (2022): human trials in about six months. missed [Neuralink ‘Show and Tell’, 30 November 2022, reported by Reuters via KSL](https://www.ksl.com/article/news/business/elon-musk-expects-neuralinks-brain-chip-to-begin-human-trials-in-6-months/50529617) * **Elon Musk (Neuralink)** (2025): first human Blindsight implant later in 2025\. missed [reported by MobiHealthNews, March 2025](https://www.mobihealthnews.com/news/elon-musk-announces-neuralinks-first-human-implant-blindsight-coming-year) * **Neuralink (company roadmap)** (2025): about 3,000 channels in 2026, 10,000 in 2027, 25,000 in 2028 (current implant about 1,024). [Neuralink summer update, 27 June 2025, as reported by ctol.digital](https://web.archive.org/web/20250917115856/https://www.ctol.digital/news/neuralink-brain-implant-milestone-musk-roadmap-valuation/) * **Miguel Nicolelis** (2013), sceptic: interfaces will extend the brain, as tools are absorbed into the body’s image, but a mind will never be downloaded. [MIT Technology Review, 18 February 2013](https://www.technologyreview.com/2013/02/18/180012/the-brain-is-not-computable/) Address: 19. **Why wires won’t reach every neuron** (c. 2190 on the trend · Projection) The number of neurons recorded at once has doubled about every seven years since the 1950s. Follow that forward from the 2028 roadmap and it reaches every neuron in a human brain around 2190\. A whole-brain interface needs a different method, not more wires. The site’s reasoning, step by step: 1. The number of neurons recorded at the same time has doubled about every 7.4 years. ([Stevenson and Kording, ‘How advances in neural recording affect data analysis’, Nature Neuroscience 14 (2011)](https://pubmed.ncbi.nlm.nih.gov/21270781)) 2. A human brain has about 86 billion neurons. ([Azevedo et al., Journal of Comparative Neurology 513 (2009)](https://pubmed.ncbi.nlm.nih.gov/19226510/)) 3. Going from 25,000 channels in 2028 to 86 billion is a factor of about 3.4 million, or about 22 doublings. At 7.4 years each, that’s about 160 years, so around 2190. 4. So the trend points to a change of method. One option is interfaces small enough to reach neurons through the blood. Another is interfaces grown into the tissue. Built on: [High-bandwidth interface](#node-f-bci) Led to: [Nanorobot brain interface](#node-f-nanobci) Address: 20. **The exocortex** (beginning now · Projection) This is a growing share of memory and thinking done by machines joined to the brain. The link is an interface, not a screen. It’s the middle step of the gradual route. By the time the biological brain fails, much of the person already runs outside it. The site’s reasoning, step by step: 1. Implants already turn intended speech into text at 62 words a minute. It’s the first time a thought goes to a machine without passing through the body. 2. Once the link is fast in both directions, outside memory and reasoning become part of the person. A cochlear implant becomes hearing in the same way. 3. So the share of a person running outside the skull grows by degrees, with no single moment of crossing. That’s what makes the gradual route different from a scan. Built on: [Speech at 62 words a minute](#node-speech-bci-willett-2023) ; [High-bandwidth interface](#node-f-bci) ; [Speech and avatar](#node-speech-bci-metzger-2023) Led to: [Crossing by degrees](#node-p-gradual) Address: 21. **Full-immersion VR** (2029–2030s · Forecast) Home: the [Technology tree](https://simulation-hypothesis.com/trees/technology?n=fulldive). Only one named futurist has published dates for nervous-system-level VR. He puts it in the late 2020s to the 2030s, using nanobots in the brain. We found no expert survey or independent forecast of this milestone. No such system has been demonstrated. Built on: [Writing every sense](#node-p-writein) ; [Nanorobot brain interface](#node-f-nanobci) Led to: [The choice to stay](#node-p-choice) Published forecasts: * **Ray Kurzweil** (2002): 2029\. [Remarks of 26 March 2002, Kurzweil Library page](https://www.writingsbyraykurzweil.com/?p=370709) * **Ray Kurzweil** (2015): 2030s. [Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015](https://singularityhub.com/2015/10/12/ray-kurzweils-wildest-prediction-nanobots-will-plug-our-brains-into-the-web-by-the-2030s/) * **Ray Kurzweil** (2024): ‘within our lifetimes’ (no year given on page). [The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description)](https://penguin.co.uk/books/462759/the-singularity-is-nearer-by-kurzweil-ray/9781529937503) Address: 22. **Nanorobot brain interface** (2030s to this century · Forecast) This is an interface made of machines small enough to reach every neuron through the blood. It’s the route proposed to get past the limits of wires. Its only detailed design study expects it this century. Its lead author named getting nanorobots from the blood into the brain as the biggest obstacle. Built on: [High-bandwidth interface](#node-f-bci) ; [Molecular nanotechnology](#node-s-nanotech) ; [Why wires won’t reach every neuron](#node-p-wires) Led to: [Crossing by degrees](#node-p-gradual) ; [Full-immersion VR](#node-s-fulldive) Published forecasts: * **Ray Kurzweil** (2005): nanobots scanning the brain from inside during the 2020s. [The Singularity Is Near (2005), as summarised on Wikipedia](https://en.wikipedia.org/wiki/The%5FSingularity%5FIs%5FNear) * **Ray Kurzweil** (2015): in the 2030s nanorobots in the brain will provide full-immersion virtual reality from within the nervous system. [reported by The Irish Times](https://www.irishtimes.com/business/technology/nanobots-will-live-in-our-brains-in-the-2030s-says-google-boss-1.3259597) * **Nuno Martins, Robert Freitas et al.** (2019): a human brain/cloud interface built from neural nanorobots, this century. [Frontiers in Neuroscience 13:112 (2019)](https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2019.00112/pdf) Address: 23. **Writing every sense** (2045–2070 (site estimate) · Projection) Reading the brain is ahead of writing to it. Speech interfaces read whole sentences, but writing is still coarse. An implant gives about 22 channels of hearing. A retinal implant gave 60 points of light. Full immersion needs every sense written in at the bandwidth the senses deliver. The site’s reasoning, step by step: 1. Hearing is the best case. A cochlear implant’s 22 electrodes give usable speech. Sight is the hard case. Argus II had 60 electrodes, and its maker stopped supporting it in 2020. 2. Touch, balance, smell, taste and the body’s inner senses have no write-in device in routine use. 3. This is an assumption, the site’s own: writing lags reading by about two decades. Implants gave cursor control in 2006, and detailed writing of touch or sight is still experimental in 2026\. If a high-bandwidth reading interface arrives around 2030, full write-in falls between 2045 and 2070. Built on: [Multichannel cochlear implant](#node-cochlear-clark-1978) ; [Retinal implant](#node-argus-ii-2013) ; [Blindsight (not yet implanted)](#node-blindsight-pending-2026) ; [Deep brain stimulation](#node-dbs-benabid-1987) Led to: [Full-immersion VR](#node-s-fulldive) Address: ## Body 1. **Artificial kidney** (1943) In 1943, in the occupied Netherlands, Willem Kolff built an artificial kidney around a rotating drum. In 1945 a woman became its first patient to survive treatment. His design became the basis for later dialysis machines. Led to: [Jarvik-7 artificial heart](#node-jarvik-7-1982) ; [The replaceable body](#node-p-body) Source: [Britannica, “Willem Kolff”](https://www.britannica.com/biography/Willem-Johan-Kolff) Address: 2. **Implanted pacemaker** (Oct 1958) On 8 October 1958 surgeon Åke Senning, at the Karolinska Hospital, put a pacemaker into Arne Larsson, who had heart block. Rune Elmqvist designed the device. The first unit failed within hours and was replaced. Larsson went on to get many more devices over his life. Led to: [Deep brain stimulation](#node-dbs-benabid-1987) ; [The replaceable body](#node-p-body) Source: [Wikipedia, “Artificial cardiac pacemaker”](https://en.wikipedia.org/wiki/Artificial%5Fcardiac%5Fpacemaker) Address: 3. **Multichannel cochlear implant** (Aug 1978) In 1978 Graeme Clark’s group in Melbourne gave its first patient a multichannel cochlear implant. Devices of this kind later became the standard form of the cochlear implant. Led to: [Retinal implant](#node-argus-ii-2013) ; [The replaceable body](#node-p-body) ; [Writing every sense](#node-p-writein) Source: [Wikipedia, “Cochlear implant”](https://en.wikipedia.org/wiki/Cochlear%5Fimplant) Address: 4. **Jarvik-7 artificial heart** (Dec 1982) On 1 December 1982 William DeVries put the Jarvik-7 into Barney Clark at the University of Utah. It was an air-powered total artificial heart, meant as a permanent replacement, not a stopgap before a transplant. It’s the ancestor of the later CardioWest and SynCardia hearts. Built on: [Artificial kidney](#node-dialysis-kolff-1943) Led to: [Total artificial heart approved](#node-syncardia-fda-2004) Source: [Wikipedia, “Jarvik-7”](https://en.wikipedia.org/wiki/Jarvik-7) Address: 5. **Artificial blood** (2001 · Stalled) Hemopure is made from cow haemoglobin and carries oxygen. South Africa and Russia approved it as a substitute for transfused red blood cells. The US FDA has not given it general approval. Why it stalled: Its maker, Biopure, filed for bankruptcy protection in 2009\. Haemoglobin-based blood substitutes have not replaced donations in the US. Led to: [Medical nanorobots](#node-f-nanomed) The sources leave this date or claim uncertain. Source: [Wikipedia, “Hemopure”](https://en.wikipedia.org/wiki/Hemopure) Address: 6. **Total artificial heart approved** (Oct 2004) On 15 October 2004 the FDA approved the CardioWest Temporary Total Artificial Heart (premarket approval P030011). It was approved as a stopgap until a transplant, for patients close to death from failure of both sides of the heart. The device was later renamed the SynCardia TAH. Built on: [Jarvik-7 artificial heart](#node-jarvik-7-1982) Led to: [Titanium heart, patient home](#node-bivacor-2025) Source: [FDA PMA database, P030011](https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm?ID=P030011) Address: 7. **Reprogrammed stem cells** (2006 · Idea) Takahashi and Yamanaka reported in Cell that four factors (Oct4, Sox2, Klf4 and c-Myc) could turn mouse skin-type cells into pluripotent cells, which can become almost any cell type. That opened a way to make cells matched to one patient, for engineering tissues and organoids. Led to: [Cerebral organoids](#node-cerebral-organoids-2013) ; [Longevity escape velocity](#node-f-lev) Source: [Takahashi & Yamanaka, Cell 126 (2006)](https://doi.org/10.1016/j.cell.2006.07.024) Address: 8. **Retinal implant** (Feb 2013 · Stalled) On 14 February 2013 the FDA approved the Argus II retinal implant under a Humanitarian Device Exemption. It was the first implanted device for adults with advanced retinitis pigmentosa. It had already earned a CE mark in 2011\. The approval rested on data from 30 trial participants. Why it stalled: On 30 March 2020 Second Sight announced it planned to wind down. IEEE Spectrum (2022) reported that more than 350 people with the implant were left without upgrades or repair support. Built on: [Multichannel cochlear implant](#node-cochlear-clark-1978) Led to: [Writing every sense](#node-p-writein) Source: [NEI/NIH, “NEI-funded device for people with RP gets FDA approval”](https://www.nei.nih.gov/about/news-and-events/news/nei-funded-device-people-rp-gets-fda-approval) Address: 9. **Cerebral organoids** (Aug 2013) Lancaster and colleagues grew three-dimensional cerebral organoids from human pluripotent stem cells. The organoids formed separate brain regions and copied features of early human cortex development. The work was published in Nature 501. Built on: [Reprogrammed stem cells](#node-ipsc-yamanaka-2006) Led to: [Printed organs](#node-f-organs) Source: [Lancaster et al., Nature 501 (2013)](https://doi.org/10.1038/nature12517) Address: 10. **Thought-guided arm cleared** (May 2014) On 9 May 2014 the FDA allowed the DEKA Arm System to be sold, through its de novo process. Dean Kamen’s company developed it with DARPA funding. It reads electrical signals from the muscles of the remaining limb and uses them to drive up to ten powered movements. Led to: [A synthetic body](#node-p-synbody) Source: [MD+DI, “FDA Approves Marketing for DARPA-Developed Prosthetic Arm”](https://www.mddionline.com/regulatory-quality/fda-approves-marketing-for-darpa-developed-prosthetic-arm) Address: 11. **Closed-loop insulin pump** (Sep 2016) On 28 September 2016 the FDA approved the Medtronic MiniMed 670G for people aged 14 and older with type 1 diabetes. It was the first hybrid closed-loop system. It reads glucose continuously and adjusts the background insulin by itself. Mealtime doses are still given by hand. Led to: [The replaceable body](#node-p-body) Source: [AJMC, “FDA Approves Medtronic’s MiniMed 670G, 1st Hybrid Closed-Loop System”](https://www.ajmc.com/view/fda-approves-medtronics-minimed-670g-1st-hybrid-closed-loop-system) Address: 12. **Pig heart in a patient** (Jan 2022) At the University of Maryland, David Bennett Sr. couldn’t get a standard heart transplant. He received a heart from a pig with several gene edits meant to reduce sudden rejection. It was the first transplant of this kind into a living person. He died about two months later. Led to: [Pig kidney in a patient](#node-pig-kidney-mgh-2024) Source: [Wikipedia, “Xenotransplantation”](https://en.wikipedia.org/wiki/Xenotransplantation) Address: 13. **Pig kidney in a patient** (Mar 2024) In March 2024 Massachusetts General Hospital gave a gene-edited pig kidney to Rick Slayman, 62\. He was the first living person to receive one. He left hospital and died almost two months later. The hospital said his death wasn’t linked to the transplant. Built on: [Pig heart in a patient](#node-pig-heart-xeno-2022) Led to: [Pig kidney for 130 days](#node-pig-kidney-looney-2025) Source: [Associated Press via KBTX, 12 May 2024](https://www.kbtx.com/2024/05/12/first-person-receive-genetically-modified-pig-kidney-transplant-dies-nearly-2-months-later) Address: 14. **Pig kidney for 130 days** (Nov 2024 – Apr 2025) Towana Looney received a pig kidney at NYU Langone on 25 November 2024\. She lived with it for 130 days, a record at the time. It was removed on 4 April 2025 because of rejection, and she went back to dialysis. Built on: [Pig kidney in a patient](#node-pig-kidney-mgh-2024) Led to: [The replaceable body](#node-p-body) Source: [Associated Press via KTVU](https://www.ktvu.com/news/alabama-woman-has-pig-kidney-removed-after-record-130-days) Address: 15. **Titanium heart, patient home** (Nov 2024 – Mar 2025) BiVACOR’s titanium artificial heart was implanted at St Vincent’s Hospital Sydney on 22 November 2024\. It was the first in Australia and reportedly the sixth in the world. In February 2025 the patient became the first to leave hospital with the device. After about 100 days, on 6 March 2025, he received a donor heart. Built on: [Total artificial heart approved](#node-syncardia-fda-2004) Led to: [The replaceable body](#node-p-body) Source: [Cardiovascular Business, March 2025](https://cardiovascularbusiness.com/topics/clinical/cardiac-surgery/patient-discharged-total-artificial-heart-transplant) Address: 16. **Printed organs** (c. 2031 onward · Forecast) No whole printed solid organ has been put into a person. The closest is a 3D-printed ear grown from a patient’s own cells, first trialled in 2022\. A US programme funding printed kidneys, livers and hearts made its awards in January 2026\. One team aims for an adult-size liver ready for pre-clinical tests by about 2031. Built on: [Cerebral organoids](#node-cerebral-organoids-2013) Led to: [The replaceable body](#node-p-body) Published forecasts: * **ARPA-H (PRINT programme)** (2024): bioprinted, patient-matched kidney, liver and heart without immunosuppression; awards January 2026; no delivery date. [ARPA-H news release](https://arpa-h.gov/news-and-events/arpa-h-awards-teams-set-bioprint-universally-matched-organs-demand) * **Carnegie Mellon University (LIVE project)** (2026): an adult-scale bioengineered liver ready for pre-clinical testing within five years (c. 2031). [CMU Biomedical Engineering news, 2026](https://www.cmu.edu/bme/News%5FEvents/story%5Farchive/2026/3d-bioprinted-liver.html) Address: 17. **Medical nanorobots** (forecast for 2019; undated since · Forecast) In 1998 Robert Freitas designed the respirocyte. It’s a machine the size of a blood cell that would carry oxygen far better than a red cell does. None has been built. Forecasts of nanorobots working inside the body by about 2019 came due, and none had reached a patient. The dates have since moved to the 2030s. Built on: [Molecular nanotechnology](#node-s-nanotech) ; [Artificial blood](#node-hemopure-blood-2001) Led to: [The replaceable body](#node-p-body) Published forecasts: * **Ray Kurzweil** (1999): by about 2019, millions of blood-cell-sized nanobots fighting disease inside the body. missed [The Age of Spiritual Machines (1999), as listed on Wikipedia](https://en.wikipedia.org/wiki/Predictions%5Fmade%5Fby%5FRay%5FKurzweil) * **Ray Kurzweil** (2024): nanobots in the capillaries connecting the brain to the cloud in the 2030s. [The Singularity Is Nearer (2024), as summarised by Science Friday](https://www.sciencefriday.com/segments/ray-kurzweil-the-singularity-is-nearer-book/) Address: 18. **Longevity escape velocity** (2028–2050 · Forecast) This is the point where medicine adds more than a year of life expectancy for every year that passes, so ageing stops shortening a life. It matters to this tree because it’s the alternative. If bodies can be kept going indefinitely, there’s less pressure to leave them. No therapy has shown it. Built on: [Reprogrammed stem cells](#node-ipsc-yamanaka-2006) Led to: [The choice to stay](#node-p-choice) Published forecasts: * **Ray Kurzweil** (1999): life expectancy over 100 by 2019\. missed [The Age of Spiritual Machines (1999), per a secondary summary](https://www.supersummary.com/the-age-of-spiritual-machines/summary/) * **Ray Kurzweil** (2024): early 2030s (2029 in another interview the same year). [Guardian interview, as quoted by Yahoo](https://tech.yahoo.com/ai/articles/googles-ai-visionary-says-well-182502370.html) * **Aubrey de Grey** (2021): 50% chance by 2036\. [cited in Wikipedia, ‘Longevity escape velocity’](https://en.wikipedia.org/wiki/Longevity%5Fescape%5Fvelocity) * **George Church** (2025): possibly around 2050\. [2025 interview, cited in Wikipedia, ‘Longevity escape velocity’](https://en.wikipedia.org/wiki/Longevity%5Fescape%5Fvelocity) * **S. Jay Olshansky et al.** (2024), sceptic: radical life extension implausible this century; survival to 100 unlikely to exceed 15% for women and 5% for men. [Nature Aging, 7 October 2024, as reported by Lifespan.io](https://lifespan.io/have-we-maxed-out-on-life-expectancy-gains/) Address: 19. **The replaceable body** (2040–2060 (site estimate) · Projection) This is a body where every organ except the brain has a working replacement. The heart, kidney, pancreas and inner ear already have one in some form. The liver, lungs and gut don’t. When everything else can be swapped, the brain is the one part that can’t be. The rest of this tree is about the brain. The site’s reasoning, step by step: 1. Working replacements exist now. A titanium heart sent a patient home (2025). A pig kidney worked for 130 days (2025). There’s a closed-loop artificial pancreas (2016). Multichannel cochlear implants date from 1978. 2. Still missing: a lasting liver, lungs and gut. Printed organs are forecast from about 2031 for pre-clinical tests, and clinical use follows trials by years. 3. So the window is the 2040s to 2060s. This assumes a replacement reaches routine use about 15 to 25 years after its first patient, as the artificial heart did (first implant 1982, approved 2004). Built on: [Titanium heart, patient home](#node-bivacor-2025) ; [Pig kidney for 130 days](#node-pig-kidney-looney-2025) ; [Closed-loop insulin pump](#node-minimed-670g-2016) ; [Multichannel cochlear implant](#node-cochlear-clark-1978) ; [Printed organs](#node-f-organs) ; [Artificial kidney](#node-dialysis-kolff-1943) ; [Implanted pacemaker](#node-pacemaker-1958) ; [Medical nanorobots](#node-f-nanomed) Led to: [The choice to stay](#node-p-choice) Address: