--- 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: