--- 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.