# Simulation Hypothesis: the trees as text The site’s writing and data are licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Read, quote, adapt, index, cite and train on them, by any kind of intelligence, for any purpose, with credit: “Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)”. Quoted passages and figures taken from published sources remain under their own terms and are cited where they appear. Guide: https://simulation-hypothesis.com/llms.txt ## Technology tree: how virtual worlds became possible https://simulation-hypothesis.com/trees/technology A virtual world needs two things: a way to fool the senses, and a machine that computes what they should receive. For most of history these developed separately. They meet at the head-mounted display. You can open any node. Lines show what each one built on. Dashed nodes stalled because a prerequisite was missing. Future nodes are published forecasts, each cited. A forecast’s date range covers the sources quoted, and they may define the milestone differently. ### Illusion #### Painted scenes (at least 51,200 years ago) Address: https://simulation-hypothesis.com/trees/technology?n=cave-painting A red-ochre painting in Leang Karampuang cave, Sulawesi, shows human-like figures and a wild pig. Uranium-series dating of the calcite over it puts it at least 51,200 years old. It’s the oldest known scene that tells a story. So people have been painting imagined or remembered worlds for a very long time. Led to: Linear perspective Source: Oktaviana et al., ‘Narrative cave art in Indonesia by 51,200 years ago’, Nature 631 (2024) #### Camera obscura explained (c. 1011–1021) Address: https://simulation-hypothesis.com/trees/technology?n=camera-obscura China recorded earlier that light through a small hole makes an upside-down image. The Later Mohist Canon (compiled between the late 4th and mid-3rd century BCE) explains the flip by rays crossing at the hole. Shen Kuo’s Dream Pool Essays (1088) said it again, calling the inversion after the small hole a normal principle. Ibn al-Haytham wrote his Kitāb al-Manāẓir (Book of Optics) in Cairo in the early eleventh century. He tested the hole image by experiment. He also argued that we see by receiving light, not by sending it out from the eye. His Optics later fed into Renaissance theories of perspective. Led to: Linear perspective; Magic lantern; Photography Source: Encyclopaedia Britannica, ‘Kitab al-manazir’ (and ‘Ibn al-Haytham’) #### Shadow theatre (11th century (securely documented)) Address: https://simulation-hypothesis.com/trees/technology?n=shadow-theatre In shadow theatre, flat figures behind a lit screen act out stories. It’s documented in Java by the 11th-century poem Arjunawiwaha (c. 1035), which compares the world to a puppet screen. It’s documented in China by Northern Song accounts (960–1127). Earlier claims are legend, or only name a performance without describing it. Examples are the Han story of Emperor Wu and the Jaha and Wukajana inscriptions of c. 840–907. So the earliest date isn’t secure. Source: Istari, Wukayana inscription of Balitung (907 CE), Berkala Arkeologi (BRIN); Wikipedia, ‘Wayang’ for the Jaha/Arjunawiwaha dates; Hanshu 97A tale as discussed by Gao Cheng #### Linear perspective (c. 1415–1425) Address: https://simulation-hypothesis.com/trees/technology?n=perspective Filippo Brunelleschi showed a geometric way to paint a scene as it looks from one spot. Alberti wrote the method down in De pictura (1435). The rule is that parallel lines all meet at a vanishing point. Real-time graphics software uses the same projection on every frame. Built on: Painted scenes; Camera obscura explained Led to: The panorama; Photography; Stereoscope Source: Encyclopaedia Britannica, ‘Linear perspective’ #### Magic lantern (c. 1659) Address: https://simulation-hypothesis.com/trees/technology?n=magic-lantern In 1659 Christiaan Huygens drew a set of skeleton images to be projected by a lantern with convex lenses. That’s the earliest surviving record of the device. It was the first widely used way to throw a painted or photographic image on a wall for an audience. For over two centuries it was the standard tool for public image shows. Built on: Camera obscura explained Led to: Projected moving pictures Source: Magic Lantern Society (UK), ‘A brief history of the Magic Lantern’ #### The panorama (1787–1788) Address: https://simulation-hypothesis.com/trees/technology?n=panorama Robert Barker patented the panorama in 1787 and showed the first one, a view of Edinburgh, in 1788. Later rotundas held round paintings about 18 metres across or more. Viewers stood in the middle of a painted horizon that never broke. It was an early commercial try at swapping a visitor’s surroundings for a built scene. Built on: Linear perspective Source: Encyclopaedia Britannica, ‘Robert Barker’ and ‘Panorama’ #### Photography (c. 1826–1827) Address: https://simulation-hypothesis.com/trees/technology?n=photography Nicéphore Niépce made the earliest surviving camera photograph around 1826–27. It was a heliograph on a pewter plate, the view from his window at Le Gras, after an exposure of many hours. It fixed an optical image for good. So for the first time an image resembled the world through a machine, not through a hand. Built on: Camera obscura explained; Linear perspective Led to: Projected moving pictures Source: Harry Ransom Center, University of Texas, ‘The First Photograph’ (Niépce heliograph) #### Motion from stills (1832) Address: https://simulation-hypothesis.com/trees/technology?n=phenakistiscope Joseph Plateau in Ghent and Simon Stampfer in Vienna each came up with the phenakistiscope in 1832. It’s a slotted disc of drawings in sequence. Spin it and look in a mirror, and the drawings seem to move. It showed that the eye blends a fast series of still images into smooth motion. That’s the principle behind every film and video frame. Led to: Projected moving pictures Source: Encyclopaedia Britannica, ‘Phenakistoscope’ #### Stereoscope (1838) Address: https://simulation-hypothesis.com/trees/technology?n=stereoscope In 1838 Charles Wheatstone showed that two slightly different flat drawings, one for each eye, merge into a single image with real-looking depth. He built a mirror stereoscope to prove it. The difference between the two eyes’ views became something you could control. Every headset since still uses it. Built on: Linear perspective Led to: Stereoscopic film; Sensorama; The Ultimate Display; Telesphere Mask Source: Wheatstone, ‘Contributions to the physiology of vision, Part I’, Phil. Trans. R. Soc. 128 (1838), 371–394 #### Stereo sound (1881) Address: https://simulation-hypothesis.com/trees/technology?n=theatrophone At the 1881 Paris International Exposition of Electricity, Clément Ader’s system sent live performances from the Opera over telephone lines to visitors. It used paired transmitters and receivers, which gave a two-ear, spatial effect. A subscription service followed in 1890. It was an early sign that a sense of place could be sent by electricity to a listener far away. Led to: Sensorama Source: Bob’s Old Phones / Telephone Collecting, ‘Clément Ader’ #### Projected moving pictures (1895) Address: https://simulation-hypothesis.com/trees/technology?n=cinema On 28 December 1895 the Lumière brothers showed the Cinématographe to a paying crowd at the Grand Café in Paris. It was a camera, printer and projector in one. Showing film to a shared audience made recorded motion something people experienced together. That’s the template for later shared screens and rooms. Built on: Photography; Motion from stills; Magic lantern Led to: Stereoscopic film; Sensorama; Aspen Movie Map; Telesphere Mask Source: Encyclopaedia Britannica, ‘Cinématographe’ #### Stereoscopic film (1922; boom 1952–54; revival 2009; stalled) Address: https://simulation-hypothesis.com/trees/technology?n=3d-film Stereoscopic cinema took Wheatstone’s idea and put it on film. Anaglyph features were shown in the early 1920s. The polarised Natural Vision process set off the 1952 boom with Bwana Devil. Audiences lost interest within about a year. The format came back with digital cinema in 2009. Why it stalled: It stalled because the picture was fixed. Every viewer saw the same two views no matter where they looked. Glasses and projector alignment were annoying. And the image had no way to respond to the viewer. Built on: Projected moving pictures; Stereoscope Source: Encyclopaedia Britannica, ‘3-D’ (film process) and ‘Natural Vision’ #### Flight simulator (1929) Address: https://simulation-hypothesis.com/trees/technology?n=link-trainer Edwin Link built a cockpit driven by air pressure. It pitched, rolled and yawed as the pilot moved the controls, so trainees could practise instrument flying on the ground. The Allies used Link’s Blue Box in the Second World War, and more than 500,000 pilots are reported to have trained on such devices. It showed that a believable feel of flight could stand in for a real aircraft in training. Source: ASME Landmark #210, ‘Link C-3 Flight Trainer’ #### Cochlear implant (1957; multichannel 1977–84) Address: https://simulation-hypothesis.com/trees/technology?n=cochlear Djourno and Eyries in Paris reported in 1957 that they had electrically stimulated the auditory nerve of a deaf patient. House and Doyle implanted a single-channel device in 1961. Multichannel devices (Hochmair, Clark) were implanted in 1977–78 and approved by the FDA for adults in the mid-1980s. Sound reaches the brain without a working ear. It was the first clinical case of a sense supplied by direct electrical stimulation of the nervous system. Led to: Brain-computer interface Source: Lasker Foundation, ‘Modern cochlear implant’ (2013 Clinical Medical Research Award) #### Telesphere Mask (1960) Address: https://simulation-hypothesis.com/trees/technology?n=telesphere Morton Heilig patented a head-worn viewer that gave each eye its own image, with stereo sound. That was years before any computer drove such a display. It played prerecorded film and didn’t track the head. Built on: Stereoscope; Projected moving pictures Led to: Head-mounted display Source: Heilig, US Patent 2,955,156, “Stereoscopic-television apparatus for individual use” (1960) #### Sensorama (1962 (patent; prototype 1957–62); stalled) Address: https://simulation-hypothesis.com/trees/technology?n=sensorama Morton Heilig’s Sensorama Simulator (US patent 3,050,870, filed 1961, granted 1962) was an arcade booth. It played pre-filmed stereoscopic colour footage with stereo sound, vibration, wind and scent. It was the first try at engaging several senses at once in one machine. It’s the usual starting point for the history of virtual reality. Why it stalled: It stalled because everything was pre-recorded on film. No computer made or changed the scene, so the viewer could look but never change anything. Built on: Projected moving pictures; Stereoscope; Stereo sound Source: US Patent 3,050,870, M. L. Heilig, ‘Sensorama Simulator’ (filed 10 Jan 1961, granted 28 Aug 1962) ### Virtual worlds #### First video games (1958; 1962) Address: https://simulation-hypothesis.com/trees/technology?n=tennis-for-two William Higinbotham’s Tennis for Two (October 1958, Brookhaven) drew a ball’s flight on an oscilloscope under analog-computer control. Spacewar! (1962) was a two-player space combat game written for MIT’s PDP-1 digital computer. Together they showed that a machine could host a small, shared world with rules that players act in. Built on: Stored-program computer Led to: Arcade video game Source: Computer History Museum, ‘Spacewar!' (see also CHM timeline 1958 for Tennis for Two) #### Interactive graphics (1963) Address: https://simulation-hypothesis.com/trees/technology?n=sketchpad Ivan Sutherland’s doctoral thesis at MIT (1963) described Sketchpad. It ran on the TX-2 and let a user draw and edit line diagrams with a light pen, with constraints and reusable master drawings. It made the interactive display a way to work on a model held in a computer. Built on: Stored-program computer Led to: The Ultimate Display; First-person networked world; Realistic shading Source: I. E. Sutherland, ‘Sketchpad: a man-machine graphical communication system’, MIT PhD thesis (1963), University of Cambridge reprint, TR-574 #### Simulacron-3 (1964; idea) Address: https://simulation-hypothesis.com/trees/technology?n=simulacron Daniel F. Galouye’s novel Simulacron-3 (1964; UK title Counterfeit World) describes a city simulated on a computer. Its people don’t know they’re programs. It’s one of the earliest novels about a world run inside a computer. It’s also a common reference point in writing on the simulation argument. Built on: Stored-program computer Source: The Encyclopedia of Science Fiction, ‘Galouye, Daniel F.' #### The Ultimate Display (1965; idea) Address: https://simulation-hypothesis.com/trees/technology?n=ultimate In his 1965 paper to the IFIP Congress, Sutherland proposed a computer-driven display so complete that it could control matter in the room. He wrote that a chair displayed there would be good enough to sit in. It set the goal of virtual reality as a world you couldn’t tell from reality in any sense. Built on: Interactive graphics; Stereoscope Led to: Head-mounted display Source: I. E. Sutherland, ‘The Ultimate Display’, Proc. IFIP Congress 1965, vol. 2, pp. 506–508 (scan) #### Head-mounted display (1968) Address: https://simulation-hypothesis.com/trees/technology?n=damocles In 1968 Sutherland and Bob Sproull built a head-mounted display. It showed a user simple wireframe 3D graphics, which a computer redrew as the user’s head moved. The optics hung from the ceiling (the ‘Sword of Damocles’). It was the first system to combine a head-worn display, computer-generated images and head tracking. Built on: The Ultimate Display; Telesphere Mask Led to: Data glove; “virtual reality”; CAVE; Virtual Boy; Modern VR headset Source: I. E. Sutherland, ‘A head-mounted three dimensional display’, AFIPS Fall Joint Computer Conference (1968) #### Realistic shading (1971–1980) Address: https://simulation-hypothesis.com/trees/technology?n=shading Henri Gouraud (1971) and Bui Tuong Phong (1973–75) devised smooth shading and a lighting model for polygon surfaces. Turner Whitted (1980) showed recursive ray tracing with reflection and refraction. Each step moved computer images closer to how light behaves. The techniques became the basis of film and game rendering. Built on: Interactive graphics Led to: CAVE; Real-time 3D worlds Source: Gouraud, ‘Continuous shading of curved surfaces’, IEEE Trans. Computers C-20 (1971); also Phong, CACM 18 (1975), and Whitted, CACM 23 (1980) #### Arcade video game (1972) Address: https://simulation-hypothesis.com/trees/technology?n=pong Atari’s Pong was designed by Allan Alcorn from a concept by Nolan Bushnell. It was first placed in a Sunnyvale bar in late 1972 and sold in large numbers. It was built from logic chips, not a microprocessor. It made the video game a commercial public pastime. It also funded the industry that later drove graphics hardware. Built on: First video games; Integrated circuit Led to: Cyberspace Source: The Strong National Museum of Play, ‘Pong’ #### First-person networked world (1973–74) Address: https://simulation-hypothesis.com/trees/technology?n=maze-war Maze was written at NASA Ames in 1973 by Steve Colley, Greg Thompson and Howard Palmer on Imlac PDS-1 computers. It showed the view down corridors from the player’s own position. It started with two linked machines, then added shooting and bots. It was an early first-person shared 3D space. It’s a likely ancestor of the networked first-person shooter. Built on: Packet network; Interactive graphics The sources leave this date or claim uncertain. Source: DigiBarn Computer Museum, Steve Colley, ‘Maze War’ history #### Colossal Cave Adventure (1975–76) Address: https://simulation-hypothesis.com/trees/technology?n=adventure Will Crowther wrote this text game in 1975, and Don Woods extended it in 1976. A player explored a cave described in prose by typing commands. It set up the explorable, rule-bound world described in text. The first multi-user worlds built on it. Built on: Stored-program computer Led to: Shared text world Source: Encyclopaedia Britannica, “Adventure” #### Shared text world (1978–1980) Address: https://simulation-hypothesis.com/trees/technology?n=mud Roy Trubshaw began MUD at the University of Essex in autumn 1978, and Richard Bartle joined the work. Once Essex was linked to ARPANET in spring 1980, outsiders could connect. It was a lasting multi-user world of rooms and objects that several people occupied at once. It set the pattern for later online worlds. Built on: Packet network; Colossal Cave Adventure Led to: Graphical online world; Persistent online worlds Source: Richard Bartle, ‘Early MUD history’ #### Aspen Movie Map (1978–79) Address: https://simulation-hypothesis.com/trees/technology?n=aspen MIT’s Architecture Machine Group filmed Aspen street by street in 1978–79. A user could drive through the stored footage on a touch-screen laserdisc system, turning left, turning right or stopping at will. It was an early interactive, navigable picture of a real place. It was a forerunner of street-level mapping. Built on: Projected moving pictures; Stored-program computer Source: MIT Media Lab, ‘The Aspen Movie Map beat Google Street View by 34 years’ #### Cyberspace (1982–84; idea) Address: https://simulation-hypothesis.com/trees/technology?n=cyberspace William Gibson coined the word ‘cyberspace’ in the story ‘Burning Chrome’ (Omni, July 1982). He made it popular in the novel Neuromancer (1984), as a shared graphical space of data that you can move around in. It gave a name and an image to the idea of an online world, and engineers later cited it. Built on: Arcade video game Led to: The Metaverse Source: The Encyclopedia of Science Fiction, ‘Cyberspace’ #### Data glove; “virtual reality” (1985–1987) Address: https://simulation-hypothesis.com/trees/technology?n=vpl Jaron Lanier founded VPL Research in 1985. Its DataGlove (1987) and EyePhone headset were the first commercial VR products. Britannica credits Lanier with coining the term ‘virtual reality’ in 1987. The company put body-tracking input and a head display within reach outside military and academic labs. Built on: Head-mounted display Source: Encyclopaedia Britannica, ‘Jaron Lanier’ #### Graphical online world (1986–88) Address: https://simulation-hypothesis.com/trees/technology?n=habitat Habitat was built by Chip Morningstar and Randy Farmer at Lucasfilm Games for the Commodore 64, over the Quantum Link service. It ran as a pilot in 1986. Users showed up as cartoon figures called avatars in a shared graphical world. It tested at scale what happens when thousands of people live in a designed virtual place. The builders published the lessons. Built on: Shared text world Led to: The Metaverse; Persistent online worlds Source: Morningstar and Farmer, ‘The Lessons of Lucasfilm’s Habitat’ (1990) #### CAVE (1992) Address: https://simulation-hypothesis.com/trees/technology?n=cave The CAVE was described in 1992 by Cruz-Neira, Sandin, DeFanti and colleagues at the University of Illinois at Chicago. It projected stereo images on the walls and floor of a room. Several people could stand inside a shared virtual scene wearing light glasses. It showed an immersive alternative to the head-worn display. Built on: Head-mounted display; Realistic shading Source: Cruz-Neira, Sandin and DeFanti et al., ‘The CAVE: audio visual experience automatic virtual environment’, CACM 35(6) (1992) #### The Metaverse (1992; idea) Address: https://simulation-hypothesis.com/trees/technology?n=metaverse Neal Stephenson’s novel Snow Crash (1992) coined the word ‘metaverse’. It means a shared 3D online world where people appear as avatars. Technology firms revived the term decades later as a name for the next stage of online worlds. Built on: Cyberspace; Graphical online world Source: Encyclopaedia Britannica, ‘Snow Crash’ #### Real-time 3D worlds (1993–1996) Address: https://simulation-hypothesis.com/trees/technology?n=doom Id Software’s Doom (December 1993) put networked players in texture-mapped first-person levels on ordinary PCs. Quake (1996) drew true polygonal 3D with real-time lighting. Fast first-person 3D on consumer hardware created the market and the techniques for later virtual worlds. Built on: Realistic shading; Microprocessor Led to: Persistent online worlds Source: The Strong National Museum of Play, ‘Quake’ (with Encyclopaedia Britannica, ‘Doom’) #### Virtual Boy (1995–96; stalled) Address: https://simulation-hypothesis.com/trees/technology?n=virtualboy Nintendo’s Virtual Boy (Japan July 1995, North America August 1995) was a table-mounted stereoscopic console. It showed red, wireframe-style images. It was pulled within a year. Nintendo’s own Iwata later called it a commercial failure. Why it stalled: It stalled because in 1995 there was no affordable compact full-colour display and no head tracking. The red single-colour image, fixed viewing position and awkward fit tired users quickly. Built on: Head-mounted display; Integrated circuit Source: Iwata Asks, ‘Shigeru Miyamoto talks Virtual Boy’, Nintendo #### Persistent online worlds (1997–2003) Address: https://simulation-hypothesis.com/trees/technology?n=mmo Ultima Online (1997), EverQuest (1999) and Second Life (2003) put very large numbers of people into lasting graphical worlds. The worlds kept going when any player logged off. They had economies and social structures of their own. They’re the best evidence we have of how people behave in long-lived virtual places. Built on: Graphical online world; Shared text world; Real-time 3D worlds; World Wide Web Source: Encyclopaedia Britannica, ‘Ultima Online’ and ‘Online gaming’ #### Brain-computer interface (2004–2006) Address: https://simulation-hypothesis.com/trees/technology?n=bci In 2006 Hochberg and colleagues reported on a man paralysed from the neck down. He could move a computer cursor and run a simple robotic hand using signals from a microelectrode array implanted in his motor cortex. It showed that voluntary neural activity could be read out as a control signal. Built on: Cochlear implant; Microprocessor Led to: Full-immersion VR; Whole-brain emulation Source: Hochberg et al., ‘Neuronal ensemble control of prosthetic devices by a human with tetraplegia’, Nature 442 (2006) #### Modern VR headset (2012–13 (developer kit); 2016 (consumer)) Address: https://simulation-hypothesis.com/trees/technology?n=rift Oculus raised $2.4 million on Kickstarter in 2012. It shipped the Rift DK1 developer kit from late March 2013. The consumer Rift followed on 28 March 2016. It paired phone-class displays and sensors with a GPU and low-latency head tracking. That made a wide-view headset cheap enough for developers and consumers. Built on: Head-mounted display; Graphics processor; Smartphone Led to: Room-scale tracking Source: Road to VR, ‘3 years ago the Oculus Rift DK1 shipped, here’s a quick look back’ #### Room-scale tracking (2015–2016) Address: https://simulation-hypothesis.com/trees/technology?n=roomscale HTC and Valve announced the Vive in March 2015 and shipped it on 5 April 2016. It used Valve’s Lighthouse system, which sweeps infrared lasers across a play area. A headset and two hand controllers could be tracked precisely over about four metres. Walking and reaching inside a virtual space, not just turning your head, became standard. Built on: Modern VR headset Led to: Standalone headsets Source: Road to VR, ‘HTC, Valve and SteamVR: a 2015 retrospective and CES 2016 preview’ #### Standalone headsets (2018–2019) Address: https://simulation-hypothesis.com/trees/technology?n=standalone Oculus Quest (21 May 2019) was a self-contained headset. It used four cameras to track the headset and both controllers from the inside, with no PC or base stations. Earlier standalone units (Oculus Go, Lenovo Mirage Solo, Vive Focus, 2018) tracked at most the head position. The Quest made full tracking portable. Built on: Room-scale tracking; Smartphone Led to: Full-immersion VR Source: Road to VR, ‘Oculus announces Quest, the high-end standalone headset starting at $400’ #### Neural rendering (2020–2023) Address: https://simulation-hypothesis.com/trees/technology?n=neural-rendering Mildenhall et al.’s Neural Radiance Fields (2020) learned a scene from photographs and drew new views of it. 3D Gaussian Splatting (Kerbl et al., 2023) did it in real time. Photo-real 3D scenes you can explore can now be captured, not modelled by hand. Built on: Deep learning on GPUs; Graphics processor Led to: Generated interactive worlds; Real-time photorealism Source: Mildenhall et al., ‘NeRF: Representing scenes as neural radiance fields for view synthesis’, ECCV 2020, arXiv:2003.08934 #### Generated interactive worlds (2024–2025) Address: https://simulation-hypothesis.com/trees/technology?n=world-models In 2024, research systems such as Google DeepMind’s Genie and the GameNGen diffusion model generated each frame of a playable environment from the player’s input. They had no hand-written game engine. GameNGen simulated the game Doom at over 20 frames per second. By 2025 the demonstrations ran for minutes at interactive speeds. They’re still research prototypes. Built on: Transformer architecture; Neural rendering; Learned world models; Diffusion models Source: Valevski et al., ‘Diffusion Models Are Real-Time Game Engines’ (GameNGen), arXiv:2408.14837 (2024) #### Real-time photorealism (2029–2034; forecast) Address: https://simulation-hypothesis.com/trees/technology?n=photoreal Industry figures have forecast real-time images you can’t tell from photographs. In 2024 one major vendor stated a window of 5 to 10 years. A 2013 forecast of ten years for the same milestone came due in 2023. No one claimed it had been met. Built on: Neural rendering Published forecasts: - Tim Sweeney (Epic Games) (2013): within ten years of 2013 (c. 2023). MCV/Develop conference report, 11 July 2013 - Jensen Huang (NVIDIA CEO) (2024): 5–10 years (2029–2034) for real-time AI-generated pixels. Press Q&A after GTC 2024 keynote, reported by Wccftech, 21 March 2024 - Jensen Huang (NVIDIA CEO) (2025): Qualifier: no fully AI-generated graphics; hybrid rendering stays. CES 2025 remarks, PCWorld, 7 January 2025 #### Full-immersion VR (2029–2030s; forecast) Address: https://simulation-hypothesis.com/trees/technology?n=fulldive One named futurist has published dates for VR that works at the level of the nervous system. He puts it in the late 2020s to the 2030s, by way of nanobots in the brain. We found no expert survey or independent forecast of this milestone. No such system has been demonstrated. Built on: Brain-computer interface; Standalone headsets; Molecular nanotechnology Published forecasts: - Ray Kurzweil (2002): 2029. Remarks of 26 March 2002, Kurzweil Library page - Ray Kurzweil (2015): 2030s. Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015 - Ray Kurzweil (2024): ‘within our lifetimes’ (no year given on page). The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description) #### Whole-brain emulation (2050–2075; bridge) Address: https://simulation-hypothesis.com/trees/technology?n=wbe The 2008 FHI roadmap judged that emulation was possible before mid-century only if models at the electrophysiological level are enough. Finer detail would need later dates. A 2014 Monte Carlo model gives a median of 2064, if it arrives at all. The Metaculus community median is about 2073. Also in: https://simulation-hypothesis.com/trees/simulations?n=f-wbe ; https://simulation-hypothesis.com/trees/synthetic?n=s-wbe Built on: Human-level AI; Brain-computer interface 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 - 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 - 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) - Robin Hanson (2016): within perhaps a century of 2016. The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626) - Dario Amodei (2024): outside the 5–10 years after powerful AI. ‘Machines of Loving Grace’, Oct 2024 #### Star-scale computer (c. 2250 or later; forecast) Address: 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: Moore’s law; Molecular nanotechnology Published forecasts: - Freeman Dyson (1960): no date given. ‘Search for Artificial Stellar Sources of Infra-Red Radiation’, Science 131(3414), 3 June 1960 - 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) - Stuart Armstrong & Anders Sandberg (2013): no date; ‘in the foreseeable future’. ‘Eternity in six hours’, Acta Astronautica 89, 2013 - 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 ### Computation #### Abacus (uncertain; Mesopotamian counting boards of the 3rd millennium BC (disputed); oldest surviving board c. 300 BC) Address: https://simulation-hypothesis.com/trees/technology?n=abacus A counting board, or abacus, is a surface where counters stand for place values. By moving them you can add, subtract, multiply and divide. Mesopotamian examples are often claimed, but none survives and the claim is disputed. The oldest surviving board is the Salamis tablet (c. 300 BC), though some see it as a gaming board. It shows that calculation can be moved into a physical state that a mechanism, and later a circuit, can hold. Led to: Mechanical calculator The sources leave this date or claim uncertain. Source: Encyclopaedia Britannica, ‘Abacus’ #### Zero as a number (628 CE (Brahmagupta); placeholder dot earlier, date disputed; idea) Address: https://simulation-hypothesis.com/trees/technology?n=zero Brahmagupta’s Brāhmasphuṭasiddhānta (628 CE) is the earliest surviving text to treat zero as a number with its own rules. Adding or subtracting zero leaves a number unchanged. A number times zero is zero. His rules for dividing by zero were incomplete, and his 0 ÷ 0 = 0 is wrong. A dot used as a placeholder appears earlier in the Bakhshali manuscript. But radiocarbon dates for its folios run from as early as the 3rd–4th century CE to the 9th–10th. So the date of its zero is disputed. Led to: Binary arithmetic; Algorithms (al-Khwārizmī) Source: O’Connor and Robertson, ‘Brahmagupta’, MacTutor History of Mathematics (rules); Bodleian Libraries / University of Oxford, Bakhshali manuscript carbon dating release (2017) (dating caveat) #### Algorithms (al-Khwārizmī) (c. 820s CE (Arabic original lost); Latin 12th century; idea) Address: https://simulation-hypothesis.com/trees/technology?n=algorithm In early 9th-century Baghdad, al-Khwārizmī wrote a treatise on the Hindu place-value numerals, including zero, and on calculating with them. The Arabic text is lost. The Latin translation, Algoritmi de numero Indorum, is known to differ a lot from it. Through it, and the later algorismus texts, the Hindu-Arabic numerals and their written arithmetic reached Europe. The word ‘algorithm’ comes from the Latinized form of his name. Built on: Zero as a number Led to: Mechanical calculator Source: O’Connor and Robertson, ‘Abu Ja’far Muhammad ibn Musa Al-Khwarizmi’, MacTutor History of Mathematics (see also Encyclopaedia Britannica, ‘al-Khwarizmi’ and ‘algorismus’) #### Self-playing flute (Baghdad) (9th century) Address: https://simulation-hypothesis.com/trees/technology?n=banu-musa-flute The Banū Mūsā brothers wrote their Book of Ingenious Devices in 9th-century Baghdad. It describes a flute that plays by itself. A water-driven mechanism pushes air to sound pipes under a revolving cylinder, and swapping the cylinder changes the tune. Koetsier (2001) counts it among the earliest programmable machines. Al-Jazari’s 1206 book describes later musical automata. But no documented line runs from either work to the European pinned barrel or to the Jacquard loom. Source: Koetsier, ‘On the prehistory of programmable machines: musical automata, looms, calculators’, Mechanism and Machine Theory 36(5), 2001, pp. 589–603; Hill (transl.), The Book of Ingenious Devices (Reidel, 1979) #### Mechanical calculator (1642–1644) Address: https://simulation-hypothesis.com/trees/technology?n=pascaline From 1642 Blaise Pascal built a geared adding machine to help his father’s tax work. He made about fifty. Britannica calls it the first calculator made in quantity and actually used. Arithmetic moved from hands to gears. Built on: Abacus; Algorithms (al-Khwārizmī) Led to: Analytical Engine; Difference Engine Source: Encyclopaedia Britannica, ‘Pascaline’ #### Binary arithmetic (1703 (printed 1705); idea) Address: https://simulation-hypothesis.com/trees/technology?n=binary In a manuscript dated 15 March 1679 (De progressione dyadica), Leibniz set out arithmetic in base two. He also sketched a calculating machine without wheels. In it, balls drop through holes that sliding slots open and close, and that does the sums. He never built it, though a working model was made at the Deutsches Museum in the early 2000s. His paper was read to the Paris Academy in 1703 and printed in 1705. It also links the 0–1 notation to the hexagram figures of the Yijing, attributed to Fu Xi, which Joachim Bouvet had sent him from Beijing (received April 1703). An earlier Indian scheme appears in Piṅgala’s Chandaḥśāstra (date uncertain, about the 3rd to 2nd century BCE). It lists metres of short and long syllables in a way later readers analysed as binary. Built on: Zero as a number Led to: Zuse Z3 Source: Leibniz, ‘Explanation of Binary Arithmetic’ (1703), English translation #### Punched-card loom (1804) Address: https://simulation-hypothesis.com/trees/technology?n=jacquard Joseph Marie Jacquard’s 1804 loom used a chain of punched cards to pick which warp threads to lift. To change the pattern, you changed the cards. Bouchon (1725) and Falcon (1728) had used punched paper or cards before him. But Jacquard’s version was widely adopted, and Babbage borrowed its card-reading idea. Led to: Analytical Engine Source: Science Museum Group, ‘Model of Falcon’s loom’ (Jacquard refined Falcon’s method in 1804) #### Difference Engine (1822 (proposed); built 1991; stalled) Address: https://simulation-hypothesis.com/trees/technology?n=difference-engine Babbage designed a machine to compute and print mathematical tables by the method of finite differences. It would take human error out of the arithmetic. A small working section was shown. The full engine wasn’t built in his lifetime. Why it stalled: Work halted in 1833 after a dispute with his engineer, Joseph Clement. The Science Museum finished Difference Engine No. 2 from his drawings in 1991. That showed the design itself was sound. Built on: Mechanical calculator Led to: Analytical Engine Source: Science Museum, “Charles Babbage’s Difference Engines and the Science Museum” #### Analytical Engine (1837 (conceived 1834); stalled) Address: https://simulation-hypothesis.com/trees/technology?n=analytical-engine Charles Babbage designed a programmable mechanical computer. It had a store, an arithmetic mill, conditional branching and instructions on punched cards. It anticipated the layout of later computers by a century. Only a trial piece was built before he died in 1871. Why it stalled: It stalled because it needed thousands of parts, and 1840s Britain couldn’t supply the precision engineering, steady funding and settled design that took. The Computer History Museum lists runaway costs, high precision demands, a dispute with his engineer and patchy financing. Built on: Punched-card loom; Mechanical calculator; Difference Engine Led to: Note G Source: Computer History Museum, ‘Babbage: a brief history’ #### Note G (1843; idea) Address: https://simulation-hypothesis.com/trees/technology?n=lovelace Ada Lovelace translated Menabrea’s paper and added notes. Note G is a worked table of operations for computing Bernoulli numbers on the Analytical Engine. She also remarked that the engine might act on things other than number, such as musical composition, if their relations could be expressed. That second claim is the first clear statement that a computing machine handles symbols, not just quantities. Built on: Analytical Engine Source: Menabrea and Lovelace, ‘Sketch of the Analytical Engine’, Taylor’s Scientific Memoirs (1843), text at Fourmilab #### Boolean logic (1847; 1854; idea) Address: https://simulation-hypothesis.com/trees/technology?n=boole George Boole’s Mathematical Analysis of Logic (1847) and An Investigation of the Laws of Thought (1854) treated logical statements as an algebra with two values. That meant reasoning could be calculated. Shannon later showed that circuits carry out this algebra. So Boole’s system became the logical basis of digital hardware. Led to: Universal machine; Logic in circuits Source: George Boole, An Investigation of the Laws of Thought (1854), Project Gutenberg #### Vacuum tube (1904–1907) Address: https://simulation-hypothesis.com/trees/technology?n=vacuum-tube John Ambrose Fleming’s two-electrode valve (1904) turned radio signals into a usable form. Lee de Forest added a grid to make the three-electrode Audion (1906–07), which could amplify and switch electrical signals. The triode was the working part of radio, telephony and the first electronic computers. Led to: Electronic computer; Transistor; Colossus Source: Encyclopaedia Britannica, ‘Thermionic valve’ #### Universal machine (1936–37; idea) Address: https://simulation-hypothesis.com/trees/technology?n=turing Alan Turing’s ‘On Computable Numbers’ (read in 1936, published 1936–37) defined an abstract machine. It showed that one universal machine can do the work of any other, given that other’s description as input. That’s the theoretical reason one general computer can run any simulated world. It also sets the limits on what such a simulation can compute. Built on: Boolean logic Led to: The stored-program design Source: A. M. Turing, ‘On Computable Numbers, with an Application to the Entscheidungsproblem’, Proc. London Math. Soc. s2–42 (1937) #### Logic in circuits (1937–38; idea) Address: https://simulation-hypothesis.com/trees/technology?n=shannon Claude Shannon’s master’s thesis at MIT (1937, published 1938) showed that networks of relays and switches can be analysed and designed with Boolean algebra. It tied abstract logic to physical circuits. Engineers now had a systematic way to design digital machines. Built on: Boolean logic Led to: Electronic computer Source: C. E. Shannon, ‘A Symbolic Analysis of Relay and Switching Circuits’, MIT thesis (1937) #### Zuse Z3 (1941) Address: https://simulation-hypothesis.com/trees/technology?n=z3 Konrad Zuse completed the Z3 in Berlin in 1941. It had about 2,400 relays, a binary number system and 22-bit floating-point words. The program was read in sequence from punched tape. The IEEE Computer Society’s history site calls it the first fully working program-controlled electromechanical digital computer in the world. It had no conditional branch, and it kept its program outside the machine’s memory. Built on: Binary arithmetic Source: IEEE Computer Society, ‘Konrad Zuse’, Computer Pioneers; Rojas, ‘Konrad Zuse’s Legacy: The Architecture of the Z1 and Z3’, IEEE Annals of the History of Computing 19(2), 1997 #### Colossus (1943–44) Address: https://simulation-hypothesis.com/trees/technology?n=colossus Tommy Flowers’s electronic machines at Bletchley Park read cipher text from paper tape. They used valves (2,500 in the Mark 2) to find the wheel settings of the German Lorenz cipher. They were electronic and configurable, but built for one task. They were kept secret for many years after the war. Built on: Vacuum tube Source: The National Museum of Computing, “Colossus” #### Electronic computer (1945–46) Address: https://simulation-hypothesis.com/trees/technology?n=eniac ENIAC was completed at the University of Pennsylvania in 1945 and announced publicly in February 1946. It used about 18,000 vacuum tubes. You could rewire it to solve a wide range of numerical problems. It showed that electronic speed was practical for general computing. But reprogramming took days. Built on: Vacuum tube; Logic in circuits Led to: The stored-program design Source: Encyclopaedia Britannica, ‘ENIAC’ #### Stored-program computer (1945 (design); 1948 (first run)) Address: https://simulation-hypothesis.com/trees/technology?n=stored-program On 21 June 1948 the Manchester Small-Scale Experimental Machine (‘Baby’), built by Williams and Kilburn, ran its first program from its own electronic memory. The program was 17 instructions long and searched for the highest proper factor of a number. Keeping instructions and data in the same memory is what lets software change at electronic speed. It’s also what lets simulations be loaded. Built on: The stored-program design Led to: Packet network; Interactive graphics; Simulacron-3; First video games; Aspen Movie Map; Colossal Cave Adventure Source: University of Manchester, ‘Manchester Baby computer’ (Computer 50 archive) #### The stored-program design (1945; idea) Address: https://simulation-hypothesis.com/trees/technology?n=edvac John von Neumann’s First Draft of a Report on the EDVAC described a computer that keeps its program in the same memory as its data. Almost every computer since has used this layout. Built on: Electronic computer; Universal machine Led to: Stored-program computer Source: von Neumann, First Draft of a Report on the EDVAC (30 June 1945), Internet Archive #### Transistor (1947–48) Address: https://simulation-hypothesis.com/trees/technology?n=transistor John Bardeen and Walter Brattain demonstrated a point-contact transistor at Bell Laboratories in December 1947. William Shockley developed the junction form soon after. The three shared the 1956 Nobel Prize in Physics. It was a solid-state amplifier and switch with no heater and no vacuum. Computers became smaller, faster and far more reliable. Built on: Vacuum tube Led to: Integrated circuit Source: Nobel Prize in Physics 1956, summary #### Integrated circuit (1958–59) Address: https://simulation-hypothesis.com/trees/technology?n=ic Jack Kilby at Texas Instruments built a working integrated circuit in September 1958. Robert Noyce at Fairchild devised a planar silicon version that could be manufactured in 1959. Kilby shared the 2000 Nobel Prize in Physics. Putting many parts on one piece of material made complex electronics cheap. That set up the scaling of computing power. Built on: Transistor Led to: Moore’s law; Microprocessor; Arcade video game; Virtual Boy Source: Nobel Prize in Physics 2000, Jack S. Kilby facts #### Moore’s law (1965 (revised 1975); idea) Address: https://simulation-hypothesis.com/trees/technology?n=moores-law In an April 1965 article in Electronics, Gordon Moore observed that the number of components per integrated circuit had doubled about every year. He projected the trend for a decade. In 1975 he changed the rate to about every two years. The projection held roughly for five decades. It set the pace at which simulated worlds could grow richer. Built on: Integrated circuit Led to: Star-scale computer; Molecular nanotechnology; Reversible computing Source: Computer History Museum, ‘Moore’s Law predicts the future of integrated circuits’ #### Packet network (1969) Address: https://simulation-hypothesis.com/trees/technology?n=arpanet ARPANET sent its first host-to-host message from UCLA to SRI on 29 October 1969. Minicomputers called IMPs routed the packets. It grew into a national research network. Shared virtual spaces need machines that swap data in real time. ARPANET was the first large network built on packet switching. Built on: Stored-program computer Led to: First-person networked world; Shared text world; The Internet Source: Computer History Museum, ‘October 29, 1969: Happy 40th birthday to a radical idea’ #### Microprocessor (1971) Address: https://simulation-hypothesis.com/trees/technology?n=microprocessor Intel’s 4004 came out in November 1971. Hoff, Mazor, Faggin and Shima designed it for a Busicom calculator. It put a programmable central processor on a single chip. General computing became cheap enough for personal machines, consoles and, eventually, phones. Built on: Integrated circuit Led to: Graphics processor; Smartphone; Real-time 3D worlds; Brain-computer interface Source: Encyclopaedia Britannica, ‘Intel 4004’ #### The Internet (1983) Address: https://simulation-hypothesis.com/trees/technology?n=internet In January 1983 the ARPANET switched to the TCP/IP protocols. They’re the common language that lets separate networks connect. Shared online worlds run over this network of networks. Built on: Packet network Led to: World Wide Web Source: Computer History Museum, “Internet History of 1980s” #### World Wide Web (1989–1991) Address: https://simulation-hypothesis.com/trees/technology?n=web Tim Berners-Lee proposed a linked hypertext system at CERN in March 1989. By the end of 1990 he had the first server and browser running there. He announced the software publicly in August 1991. It made the Internet usable for non-specialists. It became the common way to reach shared online spaces. Built on: The Internet Led to: Persistent online worlds Source: CERN, ‘A short history of the Web’ #### Graphics processor (1999) Address: https://simulation-hypothesis.com/trees/technology?n=gpu Nvidia’s GeForce 256 (October 1999) put transformation and lighting on a single chip. It was marketed as the first graphics processing unit. That moved per-pixel and per-vertex work off the CPU. Cheap parallel graphics hardware is what put real-time 3D worlds within reach. Later it did the same for large-scale neural computing. Built on: Microprocessor Led to: General-purpose GPU computing; Modern VR headset; Neural rendering Source: NVIDIA press release, ‘NVIDIA launches the world’s first graphics processing unit: GeForce 256’ (1999) #### General-purpose GPU computing (2006–2007) Address: https://simulation-hypothesis.com/trees/technology?n=gpgpu Nvidia announced CUDA in 2006 and released it in June 2007. It let programmers write ordinary C-like code for a GPU’s thousands of parallel threads. Graphics hardware became a general parallel computer. That’s what later made training large neural networks practical. Built on: Graphics processor Led to: Deep learning on GPUs Source: Nickolls, Buck, Garland and Skadron, ‘Scalable Parallel Programming with CUDA’, ACM Queue 6(2) (2008) #### Smartphone (2007) Address: https://simulation-hypothesis.com/trees/technology?n=smartphone Apple announced the iPhone in January 2007 and released it in June. It put a touch display, a capable processor and motion sensors in a pocket device, and mass production of those parts followed. The result was a supply of cheap high-density displays, motion sensors and mobile chips. That made consumer headsets possible. Built on: Microprocessor Led to: Modern VR headset; Standalone headsets Source: Apple Newsroom, ‘Apple reinvents the phone with iPhone’ (9 January 2007) #### Deep learning on GPUs (2012) Address: https://simulation-hypothesis.com/trees/technology?n=deep-learning In September 2012 AlexNet won the ImageNet image-classification contest by a wide margin. It was a convolutional network that Krizhevsky, Sutskever and Hinton trained on two GPUs. The result showed that large neural networks trained on parallel hardware beat hand-built methods at perception tasks. Built on: General-purpose GPU computing Led to: Transformer architecture; Neural rendering; Learned world models; Diffusion models Source: Krizhevsky, Sutskever and Hinton, ‘ImageNet classification with deep convolutional neural networks’, NeurIPS 25 (2012) #### Transformer architecture (2017) Address: https://simulation-hypothesis.com/trees/technology?n=transformer Vaswani and colleagues at Google introduced the Transformer in 2017. It’s a network built on attention. It handles sequences in parallel and scales well with data and computing power. It’s the architecture behind large language models, which can produce open-ended, conversational behaviour. Built on: Deep learning on GPUs Led to: Generated interactive worlds; Human-level AI Source: Vaswani et al., ‘Attention Is All You Need’, NeurIPS (2017), arXiv:1706.03762 #### Learned world models (2018) Address: https://simulation-hypothesis.com/trees/technology?n=learned-worlds Ha and Schmidhuber trained a neural network to model a game environment. Then they trained an agent inside the model’s own imagined version of it. A world could now be learned from watching, not written by hand. Built on: Deep learning on GPUs Led to: Generated interactive worlds Source: Ha and Schmidhuber, “World Models”, arXiv:1803.10122 (2018) #### Diffusion models (2020) Address: https://simulation-hypothesis.com/trees/technology?n=diffusion Ho, Jain and Abbeel showed that a network trained to remove noise step by step can generate high-quality images from random input. The method sits under most later image, video and interactive-world generators. Built on: Deep learning on GPUs Led to: Generated interactive worlds Source: Ho, Jain and Abbeel, “Denoising Diffusion Probabilistic Models”, arXiv:2006.11239 (2020) #### Molecular nanotechnology (2010–2030s; forecast) Address: https://simulation-hypothesis.com/trees/technology?n=nanotech Forecasters in the 1990s–2000s dated programmable molecular assembly and brain-entering nanobots to 2010–2029. Diamondoid assembly was forecast for 2010–2015 and hasn’t been demonstrated. So this is a record of dates that passed. Built on: Moore’s law Led to: Full-immersion VR; Star-scale computer Published forecasts: - Robert J. Bradbury, citing Zyvex’s Jim Von Ehr and Drexler 1998 (1999): 2010–2015 (Zyvex: by 2010). ‘Matrioshka Brains’ manuscript, 1999 - Ray Kurzweil (2002): by 2029. Remarks 26 March 2002, Kurzweil Library - Ray Kurzweil (2015): 2030s. Singularity Hub report, 12 Oct 2015 #### Human-level AI (2027–2047; forecast) Address: https://simulation-hypothesis.com/trees/technology?n=agi Forecasts for machines that beat humans at every task run from 2026–2030, in statements by AI-lab leaders, to a 2047 median in the 2023 survey of 2,778 researchers. Surveys have moved earlier over time. They gave 2040–2050 in 2012–13, 2060 in 2022 and 2047 in 2023. Built on: Transformer architecture Led to: Whole-brain emulation; Superintelligence Published forecasts: - Grace et al. (AI Impacts), survey of 2,778 AI researchers, run October 2023 (2024): HLMI: 10% by 2027, 50% by 2047; full automation of all occupations 10% by 2037, 50% by 2116. arXiv:2401.02843 ‘Thousands of AI Authors on the Future of AI’ (Jan 2024; v3 Oct 2025) - Müller & Bostrom, survey of four expert groups (2012–13) (2016): 50% chance of high-level machine intelligence around 2040–2050; 90% by 2075. ‘Future progress in artificial intelligence: A survey of expert opinion’, in Fundamental Issues of AI, Springer, 2016 - Metaculus community (question 5121, first general AI system) (2026): median April 2030; interquartile range about 2026 to 2038. Metaculus community forecast, as shown in search results on 16 October 2026 (check the live question) - Dario Amodei (Anthropic CEO) (2024): ‘powerful AI’ as early as 2026, or much later. ‘Machines of Loving Grace’, Oct 2024 - Demis Hassabis (Google DeepMind CEO) (2025): capabilities emerging in 5–10 years (2030–2035). CNBC interview, 17 March 2025 - Ray Kurzweil (2005): computers pass the Turing test / human-level intelligence by 2029. The Singularity Is Near (Viking, 2005; ISBN 978–0670033843), reaffirmed in The Singularity Is Nearer (Viking, June 2024) - Hans Moravec (1998): hardware matching the brain in home computers before 2030. ‘When will computer hardware match the human brain?', Journal of Evolution and Technology vol. 1, 1998 #### Reversible computing (2027–2040; forecast) Address: 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 computing per watt. A startup projects a first inference chip in 2027 and a 4,000-fold efficiency gain 10 to 15 years later. A 2014 expert interview didn’t expect wide use by 2030. Built on: Moore’s law 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) - Erik DeBenedictis (Sandia) (2014): not widely used by 2030; some applications by 2030. MIRI interview, 3 April 2014 #### Superintelligence (2027–2045+; forecast) Address: https://simulation-hypothesis.com/trees/technology?n=asi Surveyed experts expect superintelligence within 30 years of human-level machine intelligence. Scenario authors and Kurzweil give dates between 2027 and 2045. Researchers surveyed in 2023 put substantial but not majority odds on a fast ‘intelligence explosion’. Built on: Human-level AI Published forecasts: - Müller & Bostrom (2016): within less than 30 years after HLMI. Future progress in AI: a survey of expert opinion, 2016 - Kokotajlo, Alexander, Larsen, Lifland, Dean (2025): ASI Dec 2027 in the scenario; medians later (e.g. one author’s median 2030). AI 2027 scenario, 3 April 2025 (updated Nov-Dec 2025) - Ray Kurzweil (2005): 2045. The Singularity Is Near, 2005 (via AI Impacts summary) ## Simulations tree: what we have learned to simulate https://simulation-hypothesis.com/trees/simulations A ladder by scale. Matter is at the bottom, then life, minds, societies, planets and the cosmos. At the top are whole worlds built to be lived in. Each node is the first time something was simulated. It counts whatever ran the simulation: a mind, a group of people, a physical model or a computer. Minds and people were simulating worlds long before computers. The methods along the bottom are what let each rung be reached. Future nodes are published forecasts or, where none gives a date, published estimates. ### Whole worlds #### Dreams (before records; measured since 1953; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-dreams The earliest recorded description of a mind making a world is in the Bṛhadāraṇyaka Upaniṣad (4.3.9–10, c. 7th–6th century BCE, with a wider scholarly range of about 900–600 BCE). In sleep, the self gathers material from the whole world and builds a dream by its own light. There are no chariots, horses or roads there, but it makes them for itself, “for he is the maker”. Aserinsky and Kleitman (1953) woke sleepers during rapid-eye-movement periods. They got detailed dream reports in 20 of 27 cases, against 4 of 23 when the eyes were still. Revonsuo (2000) argued that dreaming is a simulation of the world that rehearses spotting threats. That hypothesis is still debated. Source: Aserinsky and Kleitman, ‘Regularly occurring periods of eye motility, and concomitant phenomena, during sleep’, Science 118 (1953) 273–274; Revonsuo, Behavioral and Brain Sciences 23 (2000) 877–901 #### Children’s pretend play (before records; described 1945; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-pretend Piaget’s study of symbolic play (1945) described children treating an object or action as standing for another, inside an invented scene. Lillard and colleagues (2013) reviewed the evidence on what pretend play adds to development. They found it mixed, and too thin to show that it’s crucial for any one skill. Led to: Glass Town Source: Lillard et al., ‘The impact of pretend play on children’s development: a review of the evidence’, Psychological Bulletin 139(1) (2013) 1–34 #### Greek tragedy (c. 534 BCE (traditional); human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-greek By the traditional date of 534 BCE, Thespis is said to have won the first tragedy competition at the City Dionysia. He is said to have been the first actor to play a character instead of speaking as himself. Staging a fiction for an audience, with performers living inside it, is the human-run form of a built world. The sources leave this date or claim uncertain. Source: Aristotle, Poetics 1449a (tragedy from the dithyramb; Aeschylus adds the second actor); Brill’s New Pauly, ‘Thespis’ (Parian Marble ep. 43 records him as tragedy’s first inventor) #### Glass Town (1826–1831; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-bronte On 5 June 1826 their father gave Branwell Brontë twelve wooden soldiers. The Brontë children then invented the Glass Town confederacy and wrote its histories from December 1827. Later they split into the spin-off worlds Angria and Gondal. Scholars call such long-running invented worlds paracosms. Built on: Children’s pretend play Source: Glass Town, Wikipedia (citing Christine Alexander’s edition of the juvenilia) #### Alternate history (1836 (first novel); Livy c. 25 BCE; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-althistory Livy (Ab Urbe Condita IX.17–19) already asked how Rome would have done if Alexander the Great had turned west. Louis Geoffroy’s Napoléon et la conquête du monde (1836) is the first novel built on a changed history, with a Napoleon who won in Russia in 1812. Nathaniel Hawthorne’s “P.’s Correspondence” (1845) is usually called the first complete alternate history in English. Each one runs a whole world forward in the reader’s mind from one changed event. Led to: The Man in the High Castle; Counterfactual history as method Source: Wikipedia, ‘Alternate history’ #### Languages before the world (1915 onward; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-tolkien J. R. R. Tolkien began his first invented Elvish language, Qenya, in a notebook in March 1915. He said that Middle-earth was made largely to give his languages a world to live in. It’s the first invented world built from the language outward. Its histories, peoples and maps were worked out over five decades. Led to: Lore worlds Source: Tolkien Gateway, ‘Qenya Lexicon’ #### Link Trainer (1929–1934; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=w-linktrainer Edwin Link filed a patent in April 1929, and it was granted in September 1931. It covered a pneumatic trainer that moved a mock cockpit in response to the controls, so pilots could practise flying on the ground. Early buyers were mainly amusement parks. The US Army bought six in 1934. By the end of the Second World War, 6,271 had gone to the Army and 1,045 to the Navy. Source: Guinness World Records, ‘First flight simulator’ #### The Man in the High Castle (October 1962; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=w-highcastle Philip K. Dick’s novel imagines a United States split between Germany and Japan after an Axis victory. It won the 1963 Hugo Award. Dick named Ward Moore’s Bring the Jubilee (1953), in which the Confederacy wins, as his starting point. Inside the novel, a banned book imagines an Allied victory. So one counterfactual world contains another. Built on: Alternate history Led to: Counterfactual worlds Source: Wikipedia, ‘The Man in the High Castle’ #### Dungeons and Dragons (1974; human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-dnd Gygax and Arneson’s boxed set, published by Tactical Studies Rules in 1974, is described as the first role-playing game in print. Players speak as characters in a world kept by a referee. It joined tabletop wargaming to playing a character. Its dungeon-and-referee setup is the pattern that text and computer adventures later followed. Built on: Kriegsspiel Led to: Colossal Cave Adventure Source: Dungeons & Dragons (1974), Wikipedia #### Colossal Cave Adventure (1975–1976; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-colossal Will Crowther wrote a text game on a DEC PDP-10. The player types commands and reads descriptions of the rooms and objects of a cave system. Don Woods expanded it significantly in 1976. It was the first widely played adventure game. It made a described world a place one person could explore alone. Built on: Electronic computer; Dungeons and Dragons Led to: MUD1 Source: Raph Koster, ‘A Brief History’ of online worlds #### MUD1 (1978–1980; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-mud1 Roy Trubshaw began MUD at the University of Essex on a DEC PDP-10 in 1978, and Richard Bartle joined him. It let several players share one text world at the same time. It was named after Dungeon, a variant of Zork. It made a built world last and made it social. Built on: Colossal Cave Adventure Led to: A lore world with millions; Second Life Source: Richard Bartle, ‘Early MUD history’ #### Klingon (1985; institute 1992; human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-klingon Marc Okrand built Klingon as a working language for Star Trek. It was published as The Klingon Dictionary in 1985, and Lawrence Schoen founded the Klingon Language Institute in 1992. Estimates of fluent speakers have stayed small: about a dozen in 1996, and 20 to 30 in 2009. But the language has a grammar, a literature and translated plays. Led to: A child raised in Klingon; Lore worlds Source: Wikipedia, ‘Klingon language’ #### Counterfactual history as method (1991–1997; idea; human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-cfhistory Geoffrey Hawthorn’s Plausible Worlds (1991), Tetlock and Belkin’s Counterfactual Thought Experiments in World Politics (1996) and Niall Ferguson’s edited Virtual History (1997) brought “what if” into academic history and political science. They added criteria for which changed pasts are plausible. Richard Evans’s Altered Pasts (2014) argues that such histories always carry their authors’ beliefs from the present. Built on: Alternate history Led to: Counterfactual worlds Source: Tetlock and Belkin (eds.), Counterfactual Thought Experiments in World Politics, Princeton University Press (1996) #### Civilization (1991; 73 million copies by 2025; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-civ Sid Meier’s Civilization (1991) lets a player run a civilisation from the first city to space flight, so every game is a history that never happened. When the seventh game launched in February 2025, the series had sold more than 73 million copies. That counts units shipped to retailers, not necessarily bought by players. Grand-strategy games such as Hearts of Iron, a Second World War with the outcome left open, sell in the millions. Led to: Counterfactual worlds Source: 2K press release, ‘Sid Meier’s Civilization VII now available worldwide’ (February 2025) #### A child raised in Klingon (c. 1996–1999; stalled; human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-speers The linguist d’Armond Speers spoke only Klingon to his infant son Alec for about the boy’s first three years. The boy’s mother spoke English. Speers wanted to see whether a child would pick up an invented language as a native one. Alec understood some and said a few words, but rarely answered in it. Why it stalled: It stalled because a language alone is not a world. The boy had one Klingon speaker, no child speakers, and no stories or school in it. He began ignoring Klingon at about three, Speers stopped, and by thirteen Alec spoke none. To raise a native speaker of an invented language, you need the whole culture around the child. Built on: Klingon Led to: Lore worlds Source: HuffPost UK, reporting Wired (1999) #### Rome Reborn (1996 onward; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-rome Rome Reborn began in 1996 at UCLA under Bernard Frischer. It models the whole city of Rome as it stood in AD 320. Version 1.0 was finished in 2007, and version 3.0 (2018) was rebuilt so you can walk through it in a headset. It’s a reconstructed world. Every building rests on archaeological evidence where there is some, and on inference where there isn’t. Led to: Evidence or guess: the London Charter Source: Wikipedia, ‘Rome Reborn’ #### Second Life (2003; peak 2009; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-secondlife Linden Lab’s Second Life (2003) is a world built by its residents, with land, an economy and a currency. It peaked at about 88,200 people online at once in early 2009. About 21 million accounts had been registered by late 2010. It’s the first large world that people treated as a second place to live, not as a game. Built on: MUD1 Led to: Social worlds in headsets Source: Engadget, ‘Linden Lab says Second Life is huge, shows numbers’ (22 September 2009) #### A lore world with millions (2004; 12 million subscribers in 2010; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-wow World of Warcraft (2004) put millions of people inside one invented world, with its own races, histories and wars. It descends from the text worlds of MUDs. In October 2010 Blizzard announced that subscribers had passed 12 million, the game’s last headline figure. Players spend years in it, but the people in it who aren’t players are scripted. Built on: MUD1 Led to: Lore worlds Source: Activision Blizzard press release, 7 October 2010 #### Evidence or guess: the London Charter (2009 (term ‘virtual archaeology’ 1990); idea; human) Address: https://simulation-hypothesis.com/trees/simulations?n=w-london Paul Reilly coined “virtual archaeology” in 1990. The London Charter (2009) set a rule: a visualisation must tell its viewer which parts show what survives, which are restorations based on evidence, and which are hypothesis. It’s the first standard for honesty inside a reconstructed world. Built on: Rome Reborn Led to: Reconstructed worlds Source: Wikipedia, ‘Virtual archaeology’ #### GameNGen (2024; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-gamengen Valevski and colleagues trained a diffusion model on recordings of an agent playing DOOM. With no conventional game engine, it generates each next frame from past frames and player actions, at about 20 frames per second on a single TPU. Human raters could tell short clips of the real game from simulated ones only slightly better than chance. Built on: Learned surrogate models Led to: Genie 3; Real-time photorealism Source: Valevski, Leviathan, Arar and Fruchter, ‘Diffusion Models Are Real-Time Game Engines’, arXiv 2408.14837 (2024); ICLR 2025 #### Genie 3 (2025; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-genie3 DeepMind announced Genie 3 on 5 August 2025. It’s a world model that generates environments you can move around in, in real time, at 720p and 24 frames per second. Worlds stayed largely consistent for several minutes, and its visual memory reached back about a minute. It was released only as a limited research preview, for a small group of academics and creators. Built on: GameNGen; Learned surrogate models Led to: Ancestor simulation; Real-time photorealism; Reconstructed worlds; Lore worlds Source: Google DeepMind, ‘Genie 3: A new frontier for world models’, 5 August 2025 #### Social worlds in headsets (February 2026; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=w-vrchat VRChat set a record of 158,192 people online at once at a concert in February 2026. Ordinary weekend peaks are about 120,000. Roblox reported 151.5 million daily users in the third quarter of 2025, mostly on screens, not headsets. These are the biggest groups of people who live part of each day in built worlds. Built on: Second Life Led to: Immersive worlds in daily life Source: Road to VR, ‘VRChat key stats’ (2026) #### Real-time photorealism (2029–2034; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-photoreal Industry figures have forecast real-time images that look just like photographs. In 2024 one major vendor gave a window of 5 to 10 years. A 2013 forecast of ten years for the same milestone came due in 2023, with no claim that it had been met. Home: https://simulation-hypothesis.com/trees/technology?n=photoreal Built on: Genie 3; GameNGen Led to: Full-immersion VR Published forecasts: - Tim Sweeney (Epic Games) (2013): within ten years of 2013 (c. 2023). MCV/Develop conference report, 11 July 2013 - Jensen Huang (NVIDIA CEO) (2024): 5–10 years (2029–2034) for real-time AI-generated pixels. Press Q&A after GTC 2024 keynote, reported by Wccftech, 21 March 2024 - Jensen Huang (NVIDIA CEO) (2025): Qualifier: no fully AI-generated graphics; hybrid rendering stays. CES 2025 remarks, PCWorld, 7 January 2025 #### Full-immersion VR (2029–2030s; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-fulldive Only one named futurist has published dates for VR at the level of the nervous system. He puts it in the late 2020s to the 2030s, using nanobots in the brain. We found no expert survey or independent forecast of this milestone. No such system has been demonstrated. Home: https://simulation-hypothesis.com/trees/technology?n=fulldive Built on: Real-time photorealism; Whole-brain emulation Published forecasts: - Ray Kurzweil (2002): 2029. Remarks of 26 March 2002, Kurzweil Library page - Ray Kurzweil (2015): 2030s. Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015 - Ray Kurzweil (2024): ‘within our lifetimes’ (no year given on page). The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description) #### Immersive worlds in daily life (2026–2040; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-immersive These are forecasts that a large share of people would spend part of each day inside immersive worlds. Gartner’s date came due in 2026. VRChat’s record is about 158,000 people at once, and Roblox’s daily users are about 151 million, mostly on flat screens. That’s far from the quarter of all people that was forecast. A 2022 canvass of 624 experts split 54 to 46 on half a billion people by 2040. Built on: Social worlds in headsets Published forecasts: - Gartner (Marty Resnick) (2022): by 2026, 25% of people will spend at least one hour a day in the metaverse. Gartner press release, 7 February 2022 - Pew Research Center and Elon University, 624 experts (nonrandom sample) (2022): 54% expect a fully immersive metaverse in the daily lives of half a billion or more people by 2040; 46% do not. ‘The Metaverse in 2040’, 30 June 2022 #### Reconstructed worlds (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/simulations?n=p-reconstructed This is a lost civilisation, ours or another species’, rebuilt from what it left behind and run so that you can live in it. The evidence never covers a whole world. So every reconstruction is part record and part inference, and a long-dead alien civilisation would be mostly inference. The London Charter’s rule is to tell the visitor which is which. That becomes the ethics of the whole genre. The site’s reasoning, step by step: 1. The pieces exist separately. There are walkable cities rebuilt from excavation (Rome Reborn), bodies predicted from genomes (the Denisovan face) and extinct animals approximated in living ones (the 2025 “dire wolves”). There are also generated worlds that respond to the visitor. 2. What survives of a people is far less than what a world needs. Rome Reborn models one year of one city. Daily life, speech and minds survive only as fragments. The rest has to be generated, so the share of guesswork grows the further back, or the further away, the source is. 3. For a non-human civilisation, the only published method is to treat its artefacts as archaeology from a distance. Nothing is known of its minds, so its inhabitants would have to be designed. That makes them invented, not reconstructed. (Vakoch (ed.), Archaeology, Anthropology, and Interstellar Communication, NASA SP-2013–4413 (2014) ) 4. So here’s the projection. Reconstructed worlds come in degrees. At one end is the faithful kind, a city with scripted crowds. At the other is the speculative kind, a whole conscious people filled in by inference. The honest ones label the difference. Built on: Evidence or guess: the London Charter; A face from DNA; Gene-edited ‘dire wolves’; Genie 3 #### Counterfactual worlds (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/simulations?n=p-counterfactual This is our own history run forward from a changed event, such as an Axis victory or a Mongol conquest of Europe. Novels have done it in the reader’s mind since 1836, and strategy games have done it in millions of copies. The projected step is running it with simulated people in it. That turns a thought experiment into a world with inhabitants. The site’s reasoning, step by step: 1. Counterfactual historians already set rules for which changed pasts are plausible. Make a small change, hold the rest of the world as it was, and follow the consequences using what’s known. (Tetlock and Belkin (1996) ) 2. Once a society simulation can model people well, it can follow those consequences mechanically. The published runs so far are 25 agents (2023), 1,052 people modelled from interviews (2024) and about 1,000 agents in a game world (2024). 3. Evans’s objection carries over. The result shows the beliefs of whoever set the rules. A simulated Axis victory tells you about its builders’ model of people as much as about 1945. 4. The dark forks are where the choice of inhabitant matters most. With scripted inhabitants, a counterfactual is an expensive film. With conscious ones, it recreates the suffering it shows, and the open questions in the Ethics tree apply in full. Built on: The Man in the High Castle; Counterfactual history as method; Civilization; Simulated human society #### Lore worlds (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/simulations?n=p-invented This is a reality made entirely of lore, with orcs and elves, or the Klingons of Star Trek. Their languages, histories and religions are taken as true from the inside. A person could be born there and raised in it. Its own fiction could even feature a strange imagined race called humans. The site’s reasoning, step by step: 1. The materials already exist. There are invented languages with full grammars (Elvish 1915, Klingon 1985). There are lore worlds with millions of players (12 million in one, in 2010). And there are generated worlds that answer the visitor in real time. 2. The one attempt to raise a child inside an invented culture stalled, because only the language was invented. There was one speaker, no other children and no world. Someone native to a lore world needs the whole culture around them, and only a populated simulation can supply that. 3. An invented world is easier to run honestly than a reconstructed one. Nothing in it has to match a record, so nothing in it is a guess. 4. The demand is in the hundreds of millions. One fantasy series alone has sold more than 600 million books. (Scholastic, Harry Potter press kit ) Built on: Languages before the world; Klingon; A child raised in Klingon; A lore world with millions; Genie 3 #### Ancestor simulation (undated; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-ancestor Bostrom (2003) gives no date, and says the argument doesn’t depend on one. He estimates that simulating all human mental history takes about 10^33 to 10^36 operations. A planetary-mass computer could supply that in under a second of its capacity. Built on: Whole-brain emulation; Genie 3; World3 Published forecasts: - Nick Bostrom (2003): No date. Compute estimate: 10^33–10^36 operations for a realistic simulation of human history; ~10^14–10^17 ops/s per human brain. ‘Are You Living in a Computer Simulation?', Philosophical Quarterly 53(211): 243–255, 2003 - Nick Bostrom (2003): explicitly declines to forecast: ‘few decades’ (others) to hundreds of thousands of years. same paper, on timescale - Bostrom (2003): a single planetary-mass computer suffices. same paper, on required hardware - Sandberg & Bostrom (2008): per-brain requirement for neuron-level emulation: ~10^18 FLOPS (spiking network level), up to 10^25–10^27 at molecular levels. Whole Brain Emulation: A Roadmap, FHI TR 2008–3 ### Planets, cosmos #### Antikythera mechanism (c. 2nd century BCE; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=p-antikythera A geared bronze device was recovered from a shipwreck off Antikythera. It showed the motions of the Sun, Moon and planets, and it predicted eclipses using Babylonian cycles. Its lunar gearing puts into metal a theory attributed to Hipparchos. Freeth and colleagues (2021) proposed a model of its front planetary display. Source: Freeth et al., ‘Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism’, Nature 444 (2006) 587–591 #### Kelvin’s tide predictor (1872; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=p-tide Kelvin designed this machine with Edward Roberts for the British Association, and Alexander Lege built it. It added up ten harmonic tidal constituents mechanically to trace the tide at a port. More than thirty such machines were built between the 1870s and the 1960s. For about ninety years, a machine that embodied a system’s harmonic structure predicted its future. Source: Science Museum Group, ‘William Thomson’s Tide Predicting Machine, 1872’ #### Richardson’s hand forecast (1922; human) Address: https://simulation-hypothesis.com/trees/simulations?n=p-richardson Lewis Fry Richardson worked out by hand the change in the weather for one morning in 1910. He used the finite-difference equations of the atmosphere. He wrote that drawing up the computing forms and working out the new distribution for two columns took the best part of six weeks. He pictured a hall of about 64,000 human computers working in step to keep pace with the real weather. It’s an early picture of a parallel computer. Built on: Numerical integration Led to: First computer forecast Source: Lynch, ‘Richardson’s Forecast-factory: the $64,000 Question’, Meteorological Magazine / Weather #### Holmberg’s bulb galaxies (1941; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=p-holmberg Holmberg used light bulbs, 37 to a galaxy, with photocells to measure the brightness as a stand-in for gravity. Both fall off as the inverse square of distance. He moved the bulbs step by step to model two interacting disk galaxies. The experiment produced tidal tails and bridges, about thirty years before digital computers could check it. Source: Holmberg’s analog computer (University of Oulu repository); Erik Holmberg, Uppsala University history pages #### First computer forecast (1950; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-eniac Charney, Fjortoft and von Neumann solved the barotropic vorticity equation on ENIAC. They covered a limited area, on a 19 by 16 grid with about 600 km between points, and produced four 24-hour forecasts. Each forecast took about 24 hours of computing, most of it handling cards by hand. So the machine was no faster than the weather. Built on: Electronic computer; Finite differences; Richardson’s hand forecast Led to: Phillips’s circulation run; Learned weather forecasts Source: Charney, Fjortoft and von Neumann, ‘Numerical Integration of the Barotropic Vorticity Equation’, Tellus 2 (1950) 237–254 #### Phillips’s circulation run (1955–1956; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-phillips Phillips ran a numerical simulation of the atmosphere’s general circulation on the Institute for Advanced Study machine, for about a model month. It showed realistic monthly and seasonal patterns in the troposphere. It won the first Napier Shaw Memorial Prize. It’s commonly described as the first successful climate model. Built on: First computer forecast; Finite differences Led to: Coupled ocean-atmosphere; Global cloud-resolving model Source: Phillips, ‘The general circulation of the atmosphere: a numerical experiment’, Quarterly Journal of the Royal Meteorological Society 82 (1956) 123–164; Norman A. Phillips, Wikipedia #### N-body star cluster (1960; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-vonhoerner Von Hoerner integrated the gravitational motion of 4 to 16 stars on a computer, with the time step set by the closest pair. In 1963 he extended it to 25. It’s the earliest documented N-body integration. The line from it runs through clusters of galaxies to simulations of the universe. Built on: Electronic computer; Numerical integration Led to: Millennium Simulation Source: von Hoerner, ‘Die numerische Integration des n-Koerper-Problemes fuer Sternhaufen. I’, Zeitschrift fuer Astrophysik 50 (1960) 184–214 #### Lorenz’s chaotic convection (1961–1963; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-lorenz Lorenz ran a twelve-variable weather model on a Royal McBee LGP-30. When he restarted it from rounded printout values, the result drifted apart from the first run. In 1963 he published a convection model whose solutions are unstable and mostly nonperiodic. It showed that a deterministic simulation can be unpredictable past a limited time. That sets a limit on how far ahead any forecast can reach. Built on: Electronic computer; Numerical integration Source: Lorenz, ‘Deterministic nonperiodic flow’, Journal of the Atmospheric Sciences 20 (1963) 130–141 #### Coupled ocean-atmosphere (1969; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-manabebryan Manabe and Bryan at the Geophysical Fluid Dynamics Laboratory coupled a model atmosphere to a model ocean. They used an idealised strip of ocean and continent, on the argument that the sea moves about as much heat as the atmosphere. It’s described as the first coupled ocean-atmosphere climate model. Built on: Phillips’s circulation run; Finite differences Led to: Global cloud-resolving model Source: Manabe and Bryan, ‘Climate Calculations with a Combined Ocean-Atmosphere Model’, Journal of the Atmospheric Sciences 26 (1969) 786–789 #### Millennium Simulation (2005; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-millennium Springel and colleagues followed more than ten billion dark-matter particles as structure grew in a cubic region of the universe. They paired the run with models of galaxy and quasar formation, to compare simulated and observed large-scale structure. It showed baryonic features of the early universe turning up, distorted, in the galaxy distribution at low redshift. Built on: N-body star cluster; Electronic computer Source: Springel et al., ‘Simulating the joint evolution of quasars, galaxies and their large-scale distribution’, Nature 435 (2005) 629–636 #### Global cloud-resolving model (2007; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-miura Miura and colleagues simulated a Madden-Julian oscillation event on the Earth Simulator. Their global model resolves clouds directly instead of approximating them. It reproduced the slow eastward drift of the event. The approach is the one later called global storm-resolving modelling. Built on: Phillips’s circulation run; Coupled ocean-atmosphere Led to: Destination Earth twins; Full Earth digital twin Source: Miura, Satoh, Nasuno, Noda and Oouchi, ‘A Madden-Julian Oscillation Event Realistically Simulated by a Global Cloud-Resolving Model’, Science 318 (2007) 1763–1765 #### Learned weather forecasts (2023; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-graphcast GraphCast is a neural network trained on reanalysis data. It predicts hundreds of weather variables for the next 10 days at 0.25 degree resolution, in under a minute. It was more accurate than the European Centre’s operational deterministic system on 90% of 1,380 verification targets. It swaps step-by-step integration of the atmosphere’s equations for a learned map from one state to the next. Built on: Learned surrogate models; First computer forecast Led to: Destination Earth twins Source: Lam et al., ‘Learning skillful medium-range global weather forecasting’, Science 382 (2023) 1416–1421 #### Destination Earth twins (2024; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=p-destine ECMWF built the first two Destination Earth digital twins, on climate change adaptation and weather-driven extremes. The second phase of the programme began on 10 June 2024. The programme states its aim as a digital replica of the Earth system by 2030. Built on: Global cloud-resolving model; Learned weather forecasts; Electronic computer Led to: Full Earth digital twin Source: ECMWF, ‘Destination Earth system launched’, 10 June 2024 #### Full Earth digital twin (2030 (a stated programme aim, not an independent forecast); forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-earthtwin The Destination Earth programme states an aim of a digital replica of the Earth system by 2030. Its first two twins went live in 2024. The only other source we found is a review of kilometre-scale climate models. It argues for a concerted effort and gives no date. Built on: Destination Earth twins; Global cloud-resolving model Published forecasts: - Destination Earth programme (European Commission, ECMWF, ESA, EUMETSAT) (2024): digital replica of the Earth system by 2030. ECMWF, ‘Destination Earth system launched’, 10 June 2024 - Schär et al. (2020): no date: global kilometre-scale climate simulations need a concerted effort, and data volumes make storing the output impractical. Bulletin of the American Meteorological Society 101(5): E567-E587, ‘Kilometer-scale climate models: Prospects and challenges’ (abstract read via a repository record) ### Societies #### Roman drill as rehearsal (c. 75 CE; human) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-josephus In The Jewish War, Josephus wrote that every Roman soldier is exercised daily as if in war. He summed up the practice as exercises that are bloodless battles and battles that are bloody exercises. Rehearsing a battle with the same units and drills as the real one is an early documented form of simulating a war. Source: Josephus, The Jewish War 3.5.1 (Whiston translation, sections 3.70–3.75) #### Chaturanga, the army game (6th–7th century CE; human) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-chaturanga Chaturanga means the four parts of an army: infantry, cavalry, elephants and chariots. It was played in India on an eight-by-eight board. The earliest Sanskrit mention of the name is in Bana’s Harshacharita, written in the 7th century. The game is the ancestor of chess, and it passed to Persia as chatrang about 600 CE. It boils an army and its terrain down to a few pieces and rules. It’s an early model of a war, run by humans. Led to: Hellwig’s chess wargame Source: Encyclopaedia Britannica, ‘chess’ (history section); see also Murray, A History of Chess (Oxford, 1913) #### Hellwig’s chess wargame (1780; human) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-hellwig In 1780 Johann Hellwig, a mathematics professor at the Collegium Carolinum in Braunschweig, published a tactical game built on chess. Two or more people played it on a board of about 49 by 33 squares, with mountains, swamps and water. The aim was to take an enemy fortress instead of capturing a king. It’s the earliest of the chess-based German wargames that came before Reisswitz’s Kriegsspiel. Built on: Chaturanga, the army game Led to: Kriegsspiel Source: Hellwig, Versuch eines aufs Schachspiel gebaueten taktischen Spiels (Leipzig: Crusius, 1780), as described in Peterson, Playing at the World (Unreason Press, 2012) p. 213 #### Kriegsspiel (1812–1824; human) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-kriegs In 1811 the Prussian princes were shown a terrain table of damp sand and models. It was presented to the king in 1812. In 1824 the younger Reisswitz published rules that used topographical maps and put numbers on the effects of combat. Kriegsspiel is described as the first war-gaming system that a military adopted as a serious tool for training and research. Built on: Hellwig’s chess wargame Led to: Dungeons and Dragons Source: Kriegsspiel, Wikipedia; Georg von Reisswitz, Wikipedia #### Phillips’s hydraulic economy (1949; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-moniac Bill Phillips built the MONIAC, a hydraulic analogue computer. Water flowing through tanks and pipes stood for the flows of income and spending in the United Kingdom economy. He demonstrated it at the London School of Economics on 29 November 1949. At least twelve machines were built, and the original ran until 1992. Led to: World3 Source: Computing History, ‘Professor Bill Phillips unveils MONIAC at the LSE’ #### The People Machine (1959–1960; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-simulmatics Simulmatics was led by Ithiel de Sola Pool with Robert Abelson. It split the American electorate into 480 voter types and 52 issue clusters, built from past polls. Then it simulated how each type would respond to campaign choices. It worked first for the Democratic National Committee and then for the Kennedy campaign. Lepore counts three reports for the campaign and says its influence is unclear. Built on: Electronic computer Led to: Silicon samples Source: Lepore, ‘Which category have they put you in?' (on Simulmatics), New York Review of Books, 8 October 2020 #### Schelling segregation (1969–1971; human) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-schelling In Schelling’s model, two kinds of agents move when fewer than a set share of their neighbours are like them. It showed that strong segregation in housing can come from only mild preferences. He worked it through by hand with coins on a checkerboard, so it was a simulation run by humans. It later became the standard first example of agent-based modelling. Source: Schelling, ‘Dynamic Models of Segregation’, Journal of Mathematical Sociology 1 (1971) 143–186 #### World3 (1971–1972; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-world3 Meadows and colleagues built World3 on top of Forrester’s World2 model. It links population, agriculture, industry, resources and pollution as feedback loops. Its standard run showed overshoot followed by collapse. It was published as The Limits to Growth in 1972, and it put a simulation of the whole human system in front of ordinary readers. Built on: Electronic computer; Phillips’s hydraulic economy Led to: Ancestor simulation Source: World3, Wikipedia; Meadows, Meadows, Randers and Behrens, The Limits to Growth (1972) #### Simulating other minds (1978–1986; idea; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-gordon In 1978 Premack and Woodruff asked whether a chimpanzee has a theory of mind. In 1986 Gordon and Heal, working separately, argued that people predict others by simulating them. They run their own decision process on the other person’s circumstances. On this account, understanding other people is a mental simulation of them. Built on: Craik’s model in the head Source: Gordon, ‘Folk Psychology as Simulation’, Mind and Language 1 (1986) 158–171; Heal, ‘Replication and Functionalism’ (1986) #### Artificial stock market (1994; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-santafe Palmer, Arthur, Holland, LeBaron and Tayler simulated a market in one stock. Adaptive trader programs held different strategies, and a specialist set the price, so prices came out of the traders’ interactions. The model didn’t necessarily settle at an equilibrium. It could show bubbles, crashes and persistently high trading volume. Built on: Agent-based models Source: Palmer, Arthur, Holland, LeBaron and Tayler, ‘Artificial economic life: a simple model of a stockmarket’, Physica D 75 (1994) 264–274 #### Sugarscape (1996; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-sugarscape Epstein and Axtell put agents with different metabolisms and eyesight on a grid of sugar. Group formation, cultural transmission, combat and trade all arose from simple local rules. Their book described the method as growing a society from the bottom up. Built on: Agent-based models Led to: Artificial Anasazi Source: Epstein and Axtell, Growing Artificial Societies: Social Science from the Bottom Up, Brookings Institution Press / MIT Press (1996) #### Artificial Anasazi (2002; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-anasazi Axtell and colleagues modelled the Kayenta Anasazi in Long House Valley, with agents choosing where to farm and settle. The model reproduced the population swings and the shifting settlement pattern of a society from about 1800 BCE to 1300 CE. Its main mismatch is that the model valley could still have supported many people in 1300, when the real population left. Built on: Sugarscape; Agent-based models Led to: Simulated human society Source: Axtell, Epstein, Dean, Gumerman et al., ‘Population growth and collapse in a multiagent model of the Kayenta Anasazi in Long House Valley’, PNAS 99 (suppl. 3) (2002) 7275–7279 #### Silicon samples (2022–2023; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-argyle Argyle and colleagues gave a language model the socio-demographic backstories of thousands of real survey respondents. For US politics, they found its output could stand in for specific groups of people. They call this property algorithmic fidelity. They proposed these “silicon samples” for exploring hypotheses before doing costly work with human subjects. Built on: Learned surrogate models; The People Machine Led to: Simulated human society Source: Argyle et al., ‘Out of One, Many: Using Language Models to Simulate Human Samples’, Political Analysis (2023), doi 10.1017/pan.2023.2 #### An agent civilisation (October 2024; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=soc-sid Altera’s Project Sid ran from 10 to more than 1,000 language-model agents together in Minecraft. It reports that they took on specialised roles, changed their collective rules and passed on culture. The authors call the results preliminary. It’s the largest published attempt at a society of software people living in a game world. Built on: Generative agents Led to: Scripted inhabitants Source: Altera, ‘Project Sid: many-agent simulations toward AI civilization’, arXiv:2411.00114 (2024) #### Simulated human society (No dated forecast; stated ambition only; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-society The leading group building generative-agent simulations has stated an ambition of simulating eight billion people. It hasn’t given a timeline. Current published runs are far smaller: 25 agents in the 2023 paper and 1,052 individuals in the 2024 follow-up. Built on: Generative agents; Silicon samples; Artificial Anasazi Led to: Counterfactual worlds Published forecasts: - Joon Sung Park (2026): ambition of a simulation with eight billion people; no timeline given. Nature news feature ‘The first AI societies are taking shape: how human-like are they?' (read via a bioethics.com repost dated 9 March 2026) The sources leave this date or claim uncertain. ### Minds #### Craik’s model in the head (1943; idea; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=min-craik In The Nature of Explanation, Kenneth Craik proposed that an organism carries a small-scale model of the outside world and of its own possible actions. That lets it try alternatives before it acts. He compared this with testing a ship design on a model in a tank. That makes the nervous system a simulator, in the sense this tree uses. Led to: Hippocampal replay; Imagining the future; Simulating other minds Source: Craik, The Nature of Explanation, Cambridge University Press (1943), p. 61 (as quoted in Williams 2018) #### Hodgkin–Huxley by hand (1952; human) Address: https://simulation-hypothesis.com/trees/simulations?n=min-hh Huxley integrated the Hodgkin–Huxley equations for the squid giant axon on a hand-cranked mechanical calculator, because the Cambridge computer was out of service. One travelling action potential took about three weeks. The result matched the shape and speed of the nerve impulse. Later neuron simulation was built on this model. Built on: Numerical integration; Differential equations Led to: Cardiac cell model; Simulated neuron networks; Neocortical microcircuit; OpenWorm; Human Brain Project Source: Physiological Society, ‘Hodgkin and Huxley’s modelling of the action potential’ #### Simulated neuron networks (1954–1956; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-rochester Farley and Clark simulated a self-organising network on a digital computer at MIT (1954). In 1956 Rochester, Holland, Haibt and Duda used an IBM 704 to simulate a net of neurons and test Hebb’s cell-assembly theory. Cell assemblies formed out of an unorganised net, though they didn’t yet behave the way the theory needed. Built on: Electronic computer; Hodgkin–Huxley by hand Led to: Neocortical microcircuit; Human Brain Project Source: Rochester, Holland, Haibt and Duda, ‘Tests on a Cell Assembly Theory of the Action of the Brain, Using a Large Digital Computer’, IRE Transactions on Information Theory 2(3) (1956) 80–93; Farley and Clark, IRE Trans. PGIT-4 (1954) 76–84 #### ELIZA (1965–1966; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-eliza Weizenbaum’s ELIZA ran on MIT’s time-sharing system. It answered typed sentences by matching keywords with breakdown rules, then rebuilding the input with reassembly rules. It was a scripted stand-in for one side of a conversation, with no model of meaning. It marks the start of programs that take a person’s place in a dialogue. Built on: Electronic computer Led to: Generative agents Source: Weizenbaum, ‘ELIZA: A Computer Program for the Study of Natural Language Communication between Man and Machine’, Communications of the ACM 9(1) (1966) 36–45 #### Hippocampal replay (1994; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=min-replay Wilson and McNaughton recorded groups of hippocampal place cells in rats. Cells that fired together at one place during a task did so more often in the sleep that followed. It’s a widely cited demonstration that the brain re-runs earlier experience offline. It’s a mental simulation of events that have already happened. Built on: Craik’s model in the head Led to: Imagining the future Source: Wilson and McNaughton, ‘Reactivation of hippocampal ensemble memories during sleep’, Science 265(5172) (1994) 676–679 #### Philosophical zombies (1996; idea; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=min-zombie David Chalmers set out the zombie argument in The Conscious Mind (1996). A being could be identical to a person in every physical and behavioural way, yet have no experience at all. That’s conceivable. If it is, a simulated person could behave exactly like one of us with nobody there. Led to: Shadow-people; Conscious inhabitants Source: Stanford Encyclopedia of Philosophy, ‘Zombies’ #### Shadow-people (2003; idea; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=min-shadow Bostrom’s simulation argument estimates 10^33 to 10^36 operations to run all of human history in full. He notes the computing needed could be cut by simulating only some minds in full: ‘The rest of humanity would then be zombies or “shadow-people”’. It’s the first statement that a simulated world could hold both kinds of inhabitant. Built on: Philosophical zombies Led to: Scripted inhabitants Source: Nick Bostrom, ‘Are You Living in a Computer Simulation?’, Philosophical Quarterly 53 (2003) #### Imagining the future (2007; mind) Address: https://simulation-hypothesis.com/trees/simulations?n=min-episodic Schacter and Addis proposed that episodic memory partly exists to build imagined future events. It flexibly recombines pieces of past experience into simulations of possible futures. On this view, ordinary remembering and planning are a kind of simulation that the brain builds. Built on: Hippocampal replay; Craik’s model in the head Source: Schacter and Addis, ‘The cognitive neuroscience of constructive memory: remembering the past and imagining the future’, Phil. Trans. R. Soc. B 362 (2007) 773–786 #### Human Brain Project (2009–2023; stalled; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-hbp In 2009 Markram promised to simulate the human brain within ten years. The European Human Brain Project followed. In July 2014 an open letter from more than 800 scientists objected to the bottom-up approach. After a mediation review, the project dropped complete brain simulation and refocused on computational tools for neuroscience. EBRAINS is its successor platform. Why it stalled: The project didn’t achieve whole-brain simulation. It was restructured around tools for neuroscience. Built on: Hodgkin–Huxley by hand; Simulated neuron networks Source: Scientific American, ‘Scientists Tried to Re-create an Entire Human Brain in a Computer. What Happened?' #### OpenWorm (2011 onward; idea; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-openworm OpenWorm is an open collaboration to simulate the nematode Caenorhabditis elegans, whose nervous system has 302 neurons. It works from the neurons and muscles up to body movement. Sarma and colleagues (2018) describe its sub-projects and results as partial. No report describes a complete simulation of a behaving worm. Built on: Hodgkin–Huxley by hand Led to: Whole-brain emulation The sources leave this date or claim uncertain. Source: Sarma et al., ‘OpenWorm: overview and recent advances in integrative biological simulation of Caenorhabditis elegans’, Phil. Trans. R. Soc. B 373 (2018) 20170382 #### Neocortical microcircuit (2015; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-markram Markram and colleagues rebuilt and simulated about 0.29 cubic millimetres of juvenile rat somatosensory cortex. It had roughly 31,000 neurons and 37 million synapses. The simulation reproduced a range of experiments without tuning the parameters. It’s a detailed digital rebuild of a small piece of cortex, not of a whole brain. Built on: Hodgkin–Huxley by hand; Simulated neuron networks Led to: Whole-brain emulation Source: Markram et al., ‘Reconstruction and simulation of neocortical microcircuitry’, Cell 163(2) (2015) 456–492 #### Generative agents (2023–2024; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=min-park Park and colleagues put 25 language-model agents into a Sims-like town. Each had memory, reflection and planning, and each of those parts made the agents’ behaviour more believable. A 2024 follow-up built agents from two-hour interviews with 1,052 people. They matched the participants’ survey answers about 85% as often as the same people matched their own answers two weeks later. These agents stand in for individual people, the way ELIZA stood in for one side of a conversation. Built on: Learned surrogate models; ELIZA Led to: Simulated human society; An agent civilisation Source: Park et al., ‘Generative Agents: Interactive Simulacra of Human Behavior’, UIST 2023; Park et al., ‘Generative Agent Simulations of 1,000 People’, arXiv 2411.10109 (2024) #### Scripted inhabitants (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/simulations?n=p-scripted These are worlds whose people act convincingly with no one inside. They’re Bostrom’s shadow-people. They take far less computing, and nobody is harmed. But the world is closer to theatre, and a visitor can never be sure which kind they’re talking to. The site’s reasoning, step by step: 1. Scripted people already run on today’s hardware. The language-model agents in Smallville (25 agents, 2023) and Project Sid (more than 1,000, 2024) run on ordinary data-centre machines. 2. A scripted person only has to behave right when someone is watching. So the computing needed scales with the number of visitors, not the population. A conscious person runs all the time. 3. The visitor is the one who pays for the difference. Chalmers has called finding out that a loved one was an unconscious non-player character “a value theoretic disaster”. (Clearer Thinking podcast, episode 165, with David Chalmers ) 4. If the zombie argument is right, no test can tell the two apart from outside. So the world builder’s label is the only evidence a visitor would have. Built on: Shadow-people; An agent civilisation #### Whole-brain emulation (2050–2075; bridge) Address: https://simulation-hypothesis.com/trees/simulations?n=f-wbe The 2008 FHI roadmap judged that emulation was possible before mid-century, but only if models at the electrophysiological level are enough. Finer detail would come later. A 2014 Monte Carlo model gives a median of 2064, if it happens at all. The Metaculus community median is about 2073. Also in: https://simulation-hypothesis.com/trees/technology?n=wbe ; https://simulation-hypothesis.com/trees/synthetic?n=s-wbe Built on: Neocortical microcircuit; OpenWorm Led to: Ancestor simulation; Full-immersion VR; Mind uploading; Conscious inhabitants 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 - 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 - 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) - Robin Hanson (2016): within perhaps a century of 2016. The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626) - Dario Amodei (2024): outside the 5–10 years after powerful AI. ‘Machines of Loving Grace’, Oct 2024 #### Mind uploading (2060s–2100+; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-upload Uploading is the step after emulation. You scan a particular person’s brain and run it. Forecasters place it after whole-brain emulation. Published dates run from the 2060s to about a century out, and some say it lies beyond the near-term AI horizon. Also in: https://simulation-hypothesis.com/trees/synthetic?n=s-upload Built on: Whole-brain emulation Published forecasts: - Anders Sandberg (2014): WBE median 2064; uploading cannot precede emulation. FHI working paper 2014–1 (same model as wbe) - Robin Hanson (2016): sometime in the next century or so. The Age of Em, OUP, 2016 - Holden Karnofsky (2021): this century, no probability given. Cold Takes, ‘Imagining yourself as a digital person (two sketches)', 29 July 2021 - Dario Amodei (2024): ‘almost certainly’ possible in principle, outside the 5–10 years after powerful AI. ‘Machines of Loving Grace’, Oct 2024 #### Conscious inhabitants (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/simulations?n=p-conscious These are worlds whose people have experiences of their own. Each one needs the computational power of a full mind to run. Every one of them counts morally, and a dark world becomes real suffering. This is the branch where simulated worlds are societies, not stories. The site’s reasoning, step by step: 1. One conscious inhabitant needs the computational power of a full mind. That’s about 10^15 operations a second at the central estimate for matching a brain, and 10^18 or more at the level of spiking neurons. (Carlsmith, How Much Computational Power Does It Take to Match the Human Brain?, Open Philanthropy (2020) ) 2. A city of a million people at 10^15 each is 10^21 operations a second. That’s about 500 times the fastest computer of 2026 (about 2.2 × 10^18). 3. If such people are conscious, the arguments in the Ethics tree apply. Schwitzgebel and Garza (2015) argue that minds we create are owed at least what we owe each other, and more, because we made them. Built on: Whole-brain emulation; Philosophical zombies Published thinking it rests on: - Thomas Metzinger (2021): a global moratorium until 2050 on research that aims at or knowingly risks artificial consciousness. ‘Artificial Suffering’, Journal of Artificial Intelligence and Consciousness 8(1) - David Chalmers (2023): current language models somewhat unlikely to be conscious, but quite possible that the obstacles are overcome within a decade or so. ‘Could a Large Language Model Be Conscious?’, arXiv:2303.07103 - Robert Long, Jeff Sebo et al. (2024): a realistic possibility that near-future AI systems will be conscious, robustly agentic, or both. ‘Taking AI Welfare Seriously’, arXiv:2411.00986 ### Life #### Du Coudray’s birth mannequin (1756; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=life-coudray Angelique du Coudray’s “machine” was a life-size model of the lower female body, made of fabric, leather and stuffing. Straps stood in for the stretching of the birth canal. She used it to teach midwives normal, breech and complicated births. The College of Surgery approved it on 1 December 1756, and it was taught across France. Source: UCLA Center for the Study of Women, summary of research on eighteenth-century French midwifery #### Turing’s reaction-diffusion (1952; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-turing Turing showed that two chemicals that react and spread out can turn a uniform state into spots, stripes and waves. He used the Manchester University computer for some of the numbers. It was a computer model of how biological form begins, and it came before the molecular biology of development. Built on: Electronic computer; Finite differences Source: Turing, ‘The Chemical Basis of Morphogenesis’, Philosophical Transactions of the Royal Society B 237 (1952) 37–72 #### Evolution on the IAS machine (1953; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-barricelli In March 1953 Nils Barricelli filled the Institute for Advanced Study computer with random numbers. He followed numerical “organisms” that reproduced, mutated and formed symbiotic groups. He wanted to test whether evolution could happen in an artificial universe. It’s the earliest documented computer experiment on evolution. The first published account is a 1954 article in Italian. Built on: Electronic computer; Cellular automata Source: George Dyson, ‘An Artificially Created Universe’, Institute for Advanced Study; Barricelli, Acta Biotheoretica 16 (1962) 69–98 #### Cardiac cell model (1960; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-noble Noble adapted the Hodgkin–Huxley equations to reproduce, on a computer, the action and pacemaker potentials of a cardiac Purkinje fibre. It showed that a membrane model built for a squid axon could be re-tuned for another tissue. That was the first step toward computational models of the heart. Built on: Electronic computer; Hodgkin–Huxley by hand Source: Noble, ‘Cardiac Action and Pacemaker Potentials based on the Hodgkin–Huxley Equations’, Nature 188 (1960) 495–497 #### Life, played by hand (late 1960s–1970; human) Address: https://simulation-hypothesis.com/trees/simulations?n=life-life Conway and colleagues tried out candidate birth-and-death rules by hand on a Go board. They settled on the rules that Martin Gardner published in Scientific American in October 1970. Readers then ran Life by hand on graph paper, as well as on computers. That made a cellular automaton a pastime as well as a model of lifelike growth. Built on: Cellular automata Source: Conway’s Game of Life, Wikipedia (history section); Gardner, Scientific American, October 1970 #### Protein dynamics (1977; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-protein McCammon, Gelin and Karplus simulated bovine pancreatic trypsin inhibitor, a small protein. They solved the equations of motion of its atoms under an empirical energy function. They found that the inside of the protein behaves like a fluid, with local motions that diffuse. That replaced the picture of a rigid, folded protein. Built on: Molecular dynamics Led to: Whole-cell models; Learned protein structure Source: McCammon, Gelin and Karplus, ‘Dynamics of folded proteins’, Nature 267 (1977) 585–590 #### The Neandertal genome (May 2010; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-neandertal Green and colleagues published a draft Neandertal genome of more than 4 billion bases, from three individuals (Science 328, 710–722). They found that Neandertals had interbred with the ancestors of people outside Africa. It made an extinct human population readable from its DNA. Led to: A face from DNA; Gene-edited ‘dire wolves’ Source: Green et al., ‘A draft sequence of the Neandertal genome’, Science 328 (2010) #### Whole-cell models (2012–2022; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-wholecell Karr and colleagues combined 28 submodels into a model of Mycoplasma genitalium, a bacterium with 525 genes. They compared its predictions with many observed cell behaviours. Macklin and colleagues built a similar model of E. coli (2020). Thornburg and colleagues built a spatial kinetic model of JCVI-syn3A, a minimal cell with 493 genes (2022). The authors called the first version a first draft, and none yet covers a eukaryotic cell. Built on: Protein dynamics; Numerical integration Led to: Human whole-cell model Source: Karr et al., ‘A Whole-Cell Computational Model Predicts Phenotype from Genotype’, Cell 150 (2012) 389–401; Macklin et al., Science 369 (2020) eaav3751; Thornburg et al., Cell 185 (2022) 345–360 #### A face from DNA (2019; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-denisovan Gokhman, Carmel and colleagues used patterns of DNA methylation to predict the anatomy of the Denisovans. They’re a human group known from one finger bone and a few teeth. The team drew a head and face that no fossil shows (Cell, 2019). It rebuilds a people’s bodies from their genome alone. Built on: The Neandertal genome Led to: Reconstructed worlds Source: Gokhman et al., ‘Reconstructing Denisovan anatomy using DNA methylation maps’, Cell (2019) #### Learned protein structure (2020–2021; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=life-alphafold AlphaFold is a neural network trained on known structures. In the CASP14 assessment (2020; Jumper et al., Nature, 2021) it predicted protein structures about as accurately as experiments, in most cases. It predicts the folded result directly. It doesn’t simulate the folding, so it’s a model of proteins, not a simulation of them. Built on: Learned surrogate models; Protein dynamics Led to: Human whole-cell model Source: Jumper et al., ‘Highly accurate protein structure prediction with AlphaFold’, Nature 596 (2021) 583–589 #### Gene-edited ‘dire wolves’ (born 2024–2025; announced April 2025; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=life-direwolf Colossal Biosciences announced three grey wolves with about 20 edits in 14 genes, 15 of them based on dire wolf DNA. It presented them as revived dire wolves. The IUCN canid specialist group said they are neither dire wolves nor a step toward bringing them back. As a reconstruction, it’s part evidence and part substitution. It’s the honesty problem the London Charter set out for images, now in living animals. Built on: The Neandertal genome Led to: Reconstructed worlds Source: Wikipedia, ‘Colossal Biosciences dire wolf project’ #### Human whole-cell model (No dated forecast; forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-humancell In 2018 Szigeti and colleagues argued that human whole-cell models are becoming feasible. They proposed a Human Whole-Cell Modeling Project, but gave no year. They note that the first bacterial model took more than ten person-years to build. Built on: Whole-cell models; Learned protein structure Published forecasts: - Szigeti, Roth, Karr et al. (2018): no year; human whole-cell models are rapidly becoming feasible, and a dedicated project is proposed (read from a search summary of the paper, not the text). ‘A blueprint for human whole-cell modeling’, Current Opinion in Systems Biology 7: 8–15 (bioRxiv 2017) The sources leave this date or claim uncertain. ### Matter #### Hooke’s hanging chain (1675; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-hooke In 1675 Hooke published an anagram that was only solved after his death. It said that as a flexible line hangs, so, upside down, will a rigid arch stand. So a hanging model chain simulates a loaded arch, using gravity itself. Gaudi used hanging models to design the Colonia Guell crypt between 1888 and 1890. Source: Funicular curve (with Heyman’s scholarship on Hooke’s anagram), Wikipedia #### Froude’s towing tank (1871–1872; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-froude William Froude towed scale models of ships through a tank paid for by the Admiralty. He used scaling laws to predict the resistance of full-size hulls. One source dates the first test, on a model of HMS Greyhound, to 3 March 1872. The model was the simulation, and the scaling law was the rule for reading it. Source: Royal Institution of Naval Architects, ‘William Froude: the father of hydrodynamics’ #### Hand-computed implosion (1944; human) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-losalamos In March 1944 Frankel, Nelson and Feynman ran an implosion calculation by hand. Each human computer passed the in-between results to the next on index cards, while the IBM punched-card machines were still on their way to Los Alamos. The trial showed that a chain of people following fixed rules could stand in for a machine. The punched-card operation then ran implosion hydrodynamics at scale. Source: Trinity by the Numbers: The Computing Effort that Made Trinity Possible (arXiv 2103.06211) #### Hard-sphere fluids (1953–1957; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-hard In 1953 the MANIAC worked out the equation of state of hard disks by Monte Carlo. In 1957 Alder and Wainwright followed hard spheres through time and found a fluid-solid transition. The two methods disagreed at first. Wood and Jacobson repeated the Monte Carlo run in 1957 and found good agreement. It’s an early case of one simulation checking another. Built on: Metropolis algorithm Source: Alder and Wainwright, J. Chem. Phys. 27 (1957) 1208; Wood and Jacobson, J. Chem. Phys. 27 (1957) 1207 #### Lattice gauge Monte Carlo (1979–1980; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-lqcd Creutz applied Metropolis-style Monte Carlo to gauge fields on a lattice of spacetime. He started with SU(2), a simplified strong-force theory with no quarks, in a 1979 Physical Review Letter, followed by a fuller 1980 paper. Computing the properties of hadrons from full QCD, with quarks, came later. Built on: Metropolis algorithm Source: Creutz, ‘Confinement and the Critical Dimensionality of Space-Time’, Phys. Rev. Lett. 43 (1979) 553; ‘Monte Carlo study of quantized SU(2) gauge theory’, Phys. Rev. D 21 (1980) 2308 #### Feynman’s quantum simulator (1981–1982; idea; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-feynman Feynman argued that a classical computer can’t efficiently simulate quantum physics, because the work needed grows exponentially with the size of the system. He guessed that a computer built from quantum parts could simulate any physical system. The paper is where quantum simulation as a field begins. Built on: Electronic computer; Metropolis algorithm Led to: Cold-atom quantum simulator; Quantum chemistry simulation Source: Feynman, ‘Simulating Physics with Computers’, International Journal of Theoretical Physics 21 (1982) 467 #### Ab initio molecular dynamics (1985; computer) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-abinitio Car and Parrinello moved atoms under forces worked out on the fly from density-functional theory. That removed the need for a fitted model of the forces between atoms. Liquids, defects and chemical reactions could now be simulated from quantum mechanics, not from a tuned potential. Built on: Molecular dynamics Led to: Quantum chemistry simulation Source: Car and Parrinello, ‘Unified Approach for Molecular Dynamics and Density-Functional Theory’, Phys. Rev. Lett. 55 (1985) 2471 #### Cold-atom quantum simulator (2002; analogue) Address: https://simulation-hypothesis.com/trees/simulations?n=mat-qanalog Greiner and colleagues loaded a Bose-Einstein condensate into an optical lattice. As they deepened the lattice, they saw a quantum phase transition from a superfluid to a Mott insulator. A system like this is a physical version of an interacting-particle model, so it computes by being that model. Later work treats such lattices as analogue quantum simulators. Built on: Feynman’s quantum simulator Led to: Quantum chemistry simulation Source: Greiner, Mandel, Esslinger, Haensch and Bloch, ‘Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms’, Nature 415 (2002) 39–44 #### Quantum chemistry simulation (No dated forecast; resource estimates only (about 4 million physical qubits and under 4 days in the 2021 estimate); forecast) Address: https://simulation-hypothesis.com/trees/simulations?n=f-quantum Published work gives resource estimates for simulating the iron-molybdenum cofactor of nitrogenase on a fault-tolerant quantum computer. It gives no date for when such a machine will exist. The only figures are estimates of the computing needed, and they fell by orders of magnitude between 2016 and 2021. Built on: Feynman’s quantum simulator; Ab initio molecular dynamics; Cold-atom quantum simulator Published forecasts: - Reiher, Wiebe, Svore, Wecker and Troyer (2016): no date; about 111 logical qubits and roughly 130 days for the serial method, 135 logical qubits and roughly 15 days for a nested variant, nearly 2,000 logical qubits and roughly 110 hours for the fastest (as read from the arXiv abstract; the 54-orbital active space was later judged unsuitable). ‘Elucidating reaction mechanisms on quantum computers’, arXiv 1605.03590; PNAS 2017 - Lee et al. (2021): no date; about four million physical qubits and under 4 days of runtime, assuming 1 microsecond cycle times and physical gate error rates no worse than 0.1%. ‘Even more efficient quantum computations of chemistry through tensor hypercontraction’, arXiv 2011.03494 (PRX Quantum 2021) The sources leave this date or claim uncertain. ### Methods #### Differential equations (1684–1687) Address: https://simulation-hypothesis.com/trees/simulations?n=m-calculus Leibniz published the calculus in 1684. In 1687 Newton’s Principia wrote the motion of bodies as laws that link rates of change to forces. Every dynamic simulation on this tree is a way of solving equations like these when you can’t solve them on paper. Led to: Numerical integration; Differential analyser; Finite differences; Hodgkin–Huxley by hand Source: Newton, Philosophiae Naturalis Principia Mathematica (1687) #### Numerical integration (1768–1901) Address: https://simulation-hypothesis.com/trees/simulations?n=m-numint Euler gave the step-by-step rule for moving a differential equation forward in Institutionum calculi integralis (1768–70). Runge (1895) and Kutta (1901) made the stepping accurate enough for real work. By hand or by machine, this is how nearly every simulation on the tree gets from one moment to the next. Built on: Differential equations Led to: Electronic computer; Molecular dynamics; Whole-cell models; Hodgkin–Huxley by hand; Richardson’s hand forecast; Lorenz’s chaotic convection; N-body star cluster Source: Runge, ‘Ueber die numerische Aufloesung von Differentialgleichungen’, Mathematische Annalen 46 (1895) 167–178 #### Finite differences (1928) Address: https://simulation-hypothesis.com/trees/simulations?n=m-fd Courant, Friedrichs and Lewy replaced partial differential equations with equations on a grid. They also showed the condition under which the stepping stays stable. Weather, ocean, fluid and wave simulations all rest on this trick. Richardson had already used it by hand in 1922, before the stability result was known. Built on: Differential equations Led to: Turing’s reaction-diffusion; First computer forecast; Phillips’s circulation run; Coupled ocean-atmosphere Source: Courant, Friedrichs and Lewy, ‘Ueber die partiellen Differenzengleichungen der mathematischen Physik’, Mathematische Annalen 100 (1928) 32–74 #### Differential analyser (1931) Address: https://simulation-hypothesis.com/trees/simulations?n=m-diffan Bush’s differential analyser at MIT solved differential equations with turning shafts and wheel-and-disc integrators. Its parts behaved like the terms of the equation, so the machine did the simulating. Copies were built in the United Kingdom, United States, Canada, Norway and Japan, including one by Hartree at Manchester. Built on: Differential equations Led to: Electronic computer Source: Bush, ‘The Differential Analyzer: A New Machine for Solving Differential Equations’, Journal of the Franklin Institute 212 (1931) 447–488 #### Electronic computer (1945–1946) Address: https://simulation-hypothesis.com/trees/simulations?n=m-computer Eckert and Mauchly built ENIAC to speed up the recalculation of artillery firing tables. It was finished by 1946, and Britannica calls it the first general-purpose electronic computer. The first large numerical simulations, including neutron diffusion and weather, ran on it or on machines of its generation. Built on: Numerical integration; Differential analyser Led to: Monte Carlo method; Metropolis algorithm; Molecular dynamics; Cellular automata; Agent-based models; Neural networks; Feynman’s quantum simulator; Evolution on the IAS machine; Turing’s reaction-diffusion; Cardiac cell model; Simulated neuron networks; ELIZA; The People Machine; World3; First computer forecast; Lorenz’s chaotic convection; N-body star cluster; Millennium Simulation; Destination Earth twins; Colossal Cave Adventure Source: Encyclopaedia Britannica, ‘John Mauchly’ (ENIAC) #### Monte Carlo method (1946–1949) Address: https://simulation-hypothesis.com/trees/simulations?n=m-montecarlo Ulam came up with the method in 1946 while thinking about the odds of winning solitaire. Von Neumann saw in March 1947 that it suited an electronic computer, and Metropolis and Ulam published it in 1949. It swaps a calculation you can’t do exactly for many random trials. That opened up neutron transport and, later, statistical mechanics to simulation. Built on: Electronic computer Led to: Metropolis algorithm Source: Eckhardt, ‘Stan Ulam, John von Neumann, and the Monte Carlo Method’, Los Alamos Science 15 (1987) 131–141 #### Cellular automata (1940s–1960s) Address: https://simulation-hypothesis.com/trees/simulations?n=m-ca In the 1940s Ulam and von Neumann developed cellular automata: grids of simple cells updated by local rules. Von Neumann used one to show that a machine could, in principle, copy itself. Local rules on a grid became the standard minimal model of growth, pattern and self-organisation. Built on: Electronic computer Led to: Agent-based models; Evolution on the IAS machine; Life, played by hand Source: Berto and Tagliabue, ‘Cellular Automata’, Stanford Encyclopedia of Philosophy #### Metropolis algorithm (1953) Address: https://simulation-hypothesis.com/trees/simulations?n=m-mcmc Metropolis, the Rosenbluths and the Tellers sampled the equilibrium states of interacting particles. They accepted or rejected random moves using a Boltzmann weight, and ran it on the MANIAC for two-dimensional hard disks. The method now underlies simulation across physics, statistics and biology. Built on: Monte Carlo method; Electronic computer Led to: Hard-sphere fluids; Lattice gauge Monte Carlo; Feynman’s quantum simulator Source: Metropolis, Rosenbluth, Rosenbluth, Teller and Teller, ‘Equation of State Calculations by Fast Computing Machines’, J. Chem. Phys. 21 (1953) 1087 #### Molecular dynamics (1957–1959) Address: https://simulation-hypothesis.com/trees/simulations?n=m-md Alder and Wainwright used fast electronic computers at Livermore to integrate the classical equations of motion for several hundred hard spheres. They found evidence of a fluid-solid transition. Monte Carlo samples configurations. This followed the particles through time instead, which gave access to flow, diffusion and relaxation. Built on: Electronic computer; Numerical integration Led to: Learned surrogate models; Ab initio molecular dynamics; Protein dynamics Source: Alder and Wainwright, ‘Phase Transition for a Hard Sphere System’, J. Chem. Phys. 27 (1957) 1208 #### Agent-based models (1971–1996) Address: https://simulation-hypothesis.com/trees/simulations?n=m-abm Schelling’s 1971 housing model gave each agent a local rule and let a pattern emerge. Reynolds’s boids (1987) and Epstein and Axtell’s Sugarscape (1996) did the same on a computer, with many different agents. The approach builds a whole from the decisions of its parts. That’s how crowds, markets and societies entered simulation. Built on: Electronic computer; Cellular automata Led to: Artificial stock market; Sugarscape; Artificial Anasazi Source: Epstein and Axtell, Growing Artificial Societies: Social Science from the Bottom Up, Brookings Institution Press / MIT Press (1996) #### Neural networks (1986) Address: https://simulation-hypothesis.com/trees/simulations?n=m-neural Rumelhart, Hinton and Williams described backpropagation. It adjusts the connection weights of a network to shrink the gap between what it outputs and what you want, and it lets hidden units form their own features. That turned networks into function approximators that can be trained. They’re the basis of the learned simulators at the top of every band. Built on: Electronic computer Led to: Learned surrogate models Source: Rumelhart, Hinton and Williams, ‘Learning representations by back-propagating errors’, Nature 323 (1986) 533–536 #### Learned surrogate models (2007) Address: https://simulation-hypothesis.com/trees/simulations?n=m-learned Behler and Parrinello trained a neural network on density-functional energies. It then described the potential-energy surface of silicon several orders of magnitude faster than the quantum calculation it copied. Replacing an expensive simulation with a learned approximation is the step that later reached protein structure, weather and interactive worlds. Built on: Neural networks; Molecular dynamics Led to: Learned protein structure; Generative agents; Silicon samples; Learned weather forecasts; GameNGen; Genie 3 Source: Behler and Parrinello, ‘Generalized neural-network representation of high-dimensional potential-energy surfaces’, Phys. Rev. Lett. 98 (2007) 146401 ## Ethics tree: where our rules came from, and where they go https://simulation-hypothesis.com/trees/ethics Rules for living together are older than writing and older than our species. Think of cells that police cheats, bats that repay a meal, chimpanzees that make peace. Nodes in the first band are marked as observed in living species or inferred for ancestors. Written law and revealed religion came next. Beside them, from the start, ran traditions that did without a divine lawgiver: Confucian, Jain and Buddhist ethics, Indian materialism, then the Greek and later European line that asks how to behave once no god is watching. After them come rules for your own experience, and the long widening of who the rules protect, with its cost to wild and authentic lives. The tree ends in open questions. None is answered here. ### Unwritten rules #### Stop the free rider (origin undated; tested 2004; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-pubgoods Many bacteria release costly molecules, such as iron-scavenging siderophores, that help every cell nearby. Mutants that stop paying the cost but still use the product can spread. Griffin, West and Buckling (2004) showed in Pseudomonas aeruginosa that how much cooperation survives depends on two things. One is how closely related the neighbours are. The other is the scale at which they compete. Led to: The multicellular bargain; Pool your genes Source: Griffin, West & Buckling, ‘Cooperation and competition in pathogenic bacteria’, Nature 430 (2004) 1024–1027 #### The multicellular bargain (at least 1 billion years ago; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-multicell In a multicellular body most cells give up their own reproduction. Only the germ line passes on genes. That’s a cooperative bargain among cells. The oldest securely dated fossil with differentiated cells is the red alga Bangiomorpha, about 1.05 billion years old. Claims for older multicellular eukaryotes exist. The true origin is earlier, and it has happened many times. Built on: Stop the free rider Led to: Cancer breaks the rules Source: Gibson et al., ‘Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis’, Geology 46 (2018) 135–138 #### Pool your genes (more than 1 billion years ago; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-sex In sexual reproduction, two individuals each give half the genome of the next generation. It’s a joint act, so cells needed rules about whose genes pass on. Comparative genomics indicates that meiosis and sex were already present in the last common ancestor of living eukaryotes. So the practice is well over a billion years old. Built on: Stop the free rider Led to: Care for the young Source: Speijer, Lukes & Elias, ‘Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life’, PNAS 112 (2015) 8827–8834 #### Care for the young (about 450 million years ago; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-parental Ordovician ostracod crustaceans, about 450 million years old, were preserved with eggs and embryos held inside the shell. That’s direct fossil evidence of brood care. Care means paying a cost to protect another individual’s survival. This is the oldest case in this tree. Built on: Pool your genes Led to: Help your relatives Source: Siveter et al., ‘Exceptionally preserved 450-million-year-old Ordovician ostracods with brood care’, Current Biology 24 (2014) 801–806 #### Help your relatives (rule stated 1964; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=e-kin Hamilton (1964) showed that a gene for helping others can spread. It spreads if the cost to the helper is smaller than the benefit to the one helped, weighted by how closely they’re related. This inclusive-fitness rule is the standard starting point for explaining why animals help their kin. Built on: Care for the young Led to: Return the favour; One queen, many workers; Feed the hungry roost-mate; Warn the family; Make peace after a fight; The Expanding Circle Source: Hamilton, ‘The genetical evolution of social behaviour. I and II’, J. Theoretical Biology 7 (1964) 1–52 #### Return the favour (theory 1971, 1981; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=e-reciprocity Trivers (1971) argued that helping non-relatives can evolve when helpers are likely to meet again and the favour is returned. Axelrod and Hamilton (1981) ran a computer tournament. It showed that conditional cooperation can last among self-interested players. Built on: Help your relatives Led to: Feed the hungry roost-mate; Fair shares; Share, and be owed Source: Trivers, ‘The evolution of reciprocal altruism’, Q. Rev. Biol. 46 (1971) 35–57; Axelrod & Hamilton, Science 211 (1981) 1390–1396 #### One queen, many workers (more than 66 million years ago; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-eusocial In ant colonies most females don’t breed. They work for the queen. Inclusive-fitness theory was developed to explain this division. A dated molecular phylogeny places the main diversification of ants in the Late Cretaceous to Early Eocene. The ancestors of most subfamilies are earlier. Built on: Help your relatives Led to: Police the egg-layers Source: Moreau, Bell, Vila, Archibald & Pierce, ‘Phylogeny of the ants: diversification in the age of angiosperms’, Science 312 (2006) 101–104 #### Cancer breaks the rules (as old as multicellularity; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-cancer Aktipis and colleagues review cancer as a failure of cooperation among cells. It breaks the rules on limiting division, dying on schedule, dividing labour, sharing resources and keeping the surrounding tissue intact. They find cancer-like disorganised growth in every form of multicellular life they examined. Built on: The multicellular bargain Led to: Police the egg-layers Source: Aktipis et al., ‘Cancer across the tree of life: cooperation and cheating in multicellularity’, Phil. Trans. R. Soc. B 370 (2015) 20140219 #### Police the egg-layers (observed 1989; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-police In honeybee colonies, workers eat eggs laid by other workers. That way the queen’s offspring are the ones raised. Ratnieks and Wenseleers reviewed such policing across insect societies. They describe it as a way of suppressing individuals that breed at the colony’s expense. Built on: One queen, many workers; Cancer breaks the rules Led to: Rules for synthetic minds Source: Ratnieks & Visscher, ‘Worker policing in the honeybee’, Nature 342 (1989) 796–797; Ratnieks & Wenseleers, ‘Policing insect societies’, Science 307 (2005) 54–55 #### Feed the hungry roost-mate (observed 1984; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-bats Wilkinson (1984) found that wild vampire bats bring up blood for roost-mates that failed to feed. Sharing depended on relatedness and on the chance to return the favour, each on its own. A later study by Carter and Wilkinson found that past help predicts sharing better than relatedness does. Reciprocity there was supported, not demonstrated. Built on: Return the favour; Help your relatives Source: Wilkinson, ‘Reciprocal food sharing in the vampire bat’, Nature 308 (1984) 181–184 #### Warn the family (observed 1983; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-prairie Hoogland (1983) studied alarm calling in black-tailed prairie dogs. He reported that callers are more likely to warn when close relatives are nearby. Later summaries extend the pattern to more distant kin. Built on: Help your relatives Source: Hoogland, ‘Nepotism and alarm calling in the black-tailed prairie dog’, Animal Behaviour 31 (1983) 472–479 #### Fair shares (observed 2003; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-capuchin Brosnan and de Waal (2003) reported that capuchin monkeys refused a reward they had accepted before, once a partner got a better one for the same task. A Nature commentary argued that the results show rejection of a worse reward when a better one is in view. It said they don’t necessarily show a dislike of inequity. Built on: Return the favour Led to: Share, and be owed Source: Brosnan & de Waal, ‘Monkeys reject unequal pay’, Nature 425 (2003) 297–299 #### Make peace after a fight (observed 1979; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-chimp-repair De Waal and van Roosmalen (1979) found at Arnhem Zoo that chimpanzees who had fought made body contact soon afterwards. They named this reconciliation. A later study of wild chimpanzees found reconciliation much rarer than in captivity. Built on: Help your relatives Led to: Rank and file rule the boss Source: de Waal & van Roosmalen, ‘Reconciliation and consolation among chimpanzees’, Behav. Ecol. Sociobiol. 5 (1979) 55–66 #### Share, and be owed (observed 1989; observed) Address: https://simulation-hypothesis.com/trees/ethics?n=e-foodshare De Waal (1989) reported that chimpanzees share food more readily with individuals who have groomed or supported them, as though keeping track of what they owe. Dominance and coalitions shape who shares with whom. So sharing isn’t only a response to need. Built on: Return the favour; Fair shares Led to: Rank and file rule the boss Source: de Waal, ‘Food sharing and reciprocal obligations among chimpanzees’, J. Human Evolution 18 (1989) 433–459 #### Rank and file rule the boss (reconstructed for foragers; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-reverse Boehm (1993) argued, from a cross-cultural survey, that egalitarian foragers keep leaders in check. They band together to ridicule, shun or remove anyone who tries to dominate. He treats this as a reversal of the dominance ordering found in the great apes. Built on: Make peace after a fight; Share, and be owed Led to: Shame the boaster Source: Boehm, ‘Egalitarian behavior and reverse dominance hierarchy’, Current Anthropology 34 (1993) 227–254 #### Shame the boaster (observed 1990s–2005; inferred) Address: https://simulation-hypothesis.com/trees/ethics?n=e-norms Wiessner (2005) recorded how the Ju/‘hoansi, foragers of the Kalahari, enforce norms through gossip, criticism and, rarely, group violence. She found that most conflict is handled by talk. Third parties who weren’t harmed do the enforcing. It shows how norms can be kept without a state. These are living people with their own history. So the study is evidence about how enforcement works, not a portrait of our ancestors. Built on: Rank and file rule the boss Led to: First written laws; Do no harm to any life; Roles, ritual and humaneness; The five precepts; Rules for synthetic minds Source: Wiessner, ‘Norm enforcement among the Ju/‘hoansi Bushmen’, Human Nature 16 (2005) 115–145 ### Rules from above #### First written laws (c. 2100 BC) Address: https://simulation-hypothesis.com/trees/ethics?n=a-urnammu The Code of Ur-Nammu, from the Sumerian city of Ur, is the oldest surviving written law code. It sets fixed payment for injuries. A rule the ruler published took the place of unwritten settlement. Built on: Shame the boaster Led to: Hammurabi’s code Source: Britannica, ‘Ur-Nammu’ #### Hammurabi’s code (c. 1754 BC) Address: https://simulation-hypothesis.com/trees/ethics?n=a-hammurabi Hammurabi of Babylon had about 280 laws carved on a stele. They state penalties by offence and by the rank of the people involved. The code presents the laws as given by the king under the sanction of the gods. Built on: First written laws Led to: The Decalogue; Good because God says so? Source: Britannica, ‘Code of Hammurabi’ #### The Decalogue (first millennium BC (dating debated)) Address: https://simulation-hypothesis.com/trees/ethics?n=a-decalogue The Hebrew Bible gives ten commandments, in Exodus 20 and Deuteronomy 5. They’re framed as rules spoken by God to a people bound by covenant. They cover worship, the sabbath, honouring parents, killing, adultery, theft, false witness and coveting. Built on: Hammurabi’s code Led to: The Golden Rule; Love your neighbour; Law from revelation; Reason or revelation? Source: Britannica, ‘Ten Commandments’ #### The Golden Rule (c. 500 BC onward, many cultures; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-golden Versions of the rule to treat others as you’d wish to be treated appear in Confucian, Jewish, Christian, Buddhist, Hindu and other writings. Some are worded positively and some negatively. That it recurs across traditions is cited as evidence of a common root in reciprocity among people. Built on: Roles, ritual and humaneness; The Decalogue; The five precepts Led to: Love your neighbour Source: Britannica, ‘Golden Rule’ #### Live by reason and nature (c. 300 BC onward; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-stoics The Stoics, from Zeno of Citium on, taught that virtue is the only good. A person should live in agreement with reason and nature. Later Stoics such as Hierocles described concentric circles of concern, widening from the self to all humanity. Built on: The Ring of Gyges Led to: Natural law Source: Stanford Encyclopedia of Philosophy, ‘Stoicism’ #### Love your neighbour (1st century AD; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-christian The Sermon on the Mount in the Gospel of Matthew moves rules from outward acts to intentions. It extends concern to enemies. Christianity took the commandments of the Hebrew Bible as its base and added the rule to love your neighbour. Built on: The Decalogue; The Golden Rule Led to: Law from revelation; Natural law; Give yourself the law; If there is no God; The death of God Source: Britannica, ‘Sermon on the Mount’ #### Law from revelation (7th century AD; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-islam In Islam, the Quran and the example of Muhammad are the base of the sharia. It’s a body of duties covering worship, family, trade and punishment. Jurists developed the rules through interpretation over the following centuries. Built on: Love your neighbour; The Decalogue Led to: Reason or revelation? Source: Britannica, ‘Sharia’ #### Reason or revelation? (8th–13th century AD; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-reason-revelation The Mu’tazila (e.g. ‘Abd al-Jabbar, d. 1025) held that the value of acts can generally be known by reason. The Ash’arites (al-Ash’ari, d. 935 or 936) disagreed. For them good and evil are fixed by God’s command and known through revelation. Avicenna, Averroes and Maimonides developed Aristotle within Islamic and Jewish law. Aquinas drew on them. He called Averroes ‘the Commentator’ and followed Avicenna and Maimonides on several questions. Built on: Law from revelation; The Decalogue; Virtue is a habit Led to: Natural law Source: Stanford Encyclopedia of Philosophy, ‘Aquinas’; ‘Maimonides’; Hare, God’s Command, ch. 6 (Oxford University Press, 2015) #### Natural law (1265–1274; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-natlaw Aquinas’s Summa Theologiae argues that there is a law reason can discover. It binds all people, and human law should follow it. The idea joins Stoic and Roman thought, Aristotle, Christian doctrine, and the work of Islamic and Jewish philosophers such as Avicenna, Averroes and Maimonides, on whom Aquinas drew. Built on: Live by reason and nature; Love your neighbour; Virtue is a habit; Reason or revelation? Led to: Rights from nature Source: Stanford Encyclopedia of Philosophy, ‘Aquinas’s Moral, Political, and Legal Philosophy’ #### Rights from nature (1689; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-locke Locke’s Second Treatise of Government holds that in the state of nature everyone has natural rights to life, liberty and property. Government exists to protect them. Natural rights give individuals claims that no ruler may override. Built on: Natural law Led to: Declaration of Human Rights Source: Stanford Encyclopedia of Philosophy, ‘Locke’s Political Philosophy’ ### Without gods #### Do no harm to any life (c. 6th–5th c. BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-jain Jain teaching, linked to Mahavira, makes ahimsa the first duty. Ahimsa means avoiding harm to any living being. It extends to animals and plants. It’s one of the oldest rules whose circle of concern reaches beyond humans. Built on: Shame the boaster Led to: Many-sided truth Source: Britannica, ‘Ahimsa’ #### Roles, ritual and humaneness (c. 500 BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-confucius The Analects, attributed to Confucius and his students, ground moral life in roles within family and state. Filial piety (xiao) is the root. Ritual (li) gives conduct its form. Ren, humaneness, is the quality of the exemplary person (junzi). Reciprocity (shu) gives a rule of restraint: do not do to others what you would not want done to yourself (Analects 15.24). Built on: Shame the boaster Led to: The Golden Rule; Declaration of Human Rights; Sprouts of goodness; Human nature is bad; Care without gradation Source: Stanford Encyclopedia of Philosophy, ‘Confucius’ #### The five precepts (c. 5th c. BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-buddha Buddhist lay practice includes five precepts. Refrain from killing, stealing, sexual misconduct, false speech and intoxicants. They’re framed as training rules a person takes on. They’re not commands from a deity. Built on: Shame the boaster Led to: The Golden Rule; Ashoka protects animals The sources leave this date or claim uncertain. Source: Stanford Encyclopedia of Philosophy, ‘Ethics in Indian and Tibetan Buddhism’ #### No gods, no afterlife (Ajita: c. 5th century BC; Cārvāka school: attested only in later reports; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-carvaka Ajita Kesakambalī is a teacher the Pali Sāmaññaphala Sutta (DN 2) places in the Buddha’s time. He is reported to have taught that there is no other world. Gifts and sacrifices bear no fruit. Fool and wise alike are cut off at death. The later Cārvāka or Lokāyata school is the Indian tradition best known for a thoroughgoing materialism with no gods. Its own texts are lost. We know it mostly from opponents, who describe its ethics as the pursuit of pleasure. Source: Dīgha Nikāya 2 (Sāmaññaphala Sutta), Ajita Kesakambalī section; Britannica, ‘Carvaka’ #### Good because God says so? (c. 380 BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-euthyphro In Plato’s Euthyphro, Socrates asks a question. Do the gods love the pious because it is pious? Or is it pious because they love it? The question separates what is right from who commands it. Built on: Hammurabi’s code Source: Plato, Euthyphro (trans. Jowett), Project Gutenberg #### The Ring of Gyges (c. 375 BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-gyges In Republic Book II, Glaucon tells of a ring that makes its wearer invisible. He asks whether anyone would stay just if they could act without being seen or punished. It’s the oldest well-known test of conduct with no witnesses and no consequences. Led to: Virtue is a habit; Live by reason and nature; Suppose you are the only one Source: Plato, Republic, Book II (trans. Jowett), Project Gutenberg #### Virtue is a habit (c. 340 BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=a-aristotle In the Nicomachean Ethics Aristotle argues that the good life is activity in line with virtue. Virtues of character are formed by habit. They’re judged against a mean between extremes. The question shifts from what is forbidden to what kind of person to become. Built on: The Ring of Gyges Led to: Natural law; Choose who you are; Reason or revelation? Source: Stanford Encyclopedia of Philosophy, ‘Aristotle’s Ethics’ #### Sprouts of goodness (4th century BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-mencius Mencius held that human nature tends toward goodness. Everyone has the beginning ‘sprouts’ of compassion, shame, deference and approval and disapproval. Upbringing can nurture or stunt them. His argument is a child about to fall into a well. Anyone would respond with alarm and compassion, with no thought of reward or reputation (Mencius 2A6). Built on: Roles, ritual and humaneness; Care without gradation Led to: Human nature is bad Source: Stanford Encyclopedia of Philosophy, ‘Mencius’; Mencius 2A6, 6A6 #### Gods do not watch (c. 300 BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-epicurus Epicurus taught that the gods exist but take no part in human affairs. So there is no divine judgement to fear. He taught that justice is an agreement not to harm one another. He held that wrongdoing is bad because you can’t be sure of escaping detection, or of peace of mind afterwards. Led to: The is–ought gap; Count the consequences; The tedium of living forever Source: Stanford Encyclopedia of Philosophy, ‘Epicurus’ #### Human nature is bad (3rd century BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-xunzi Xunzi, also a follower of Confucius, held that ‘human nature is bad’ (ch. 23). Left alone, our desires breed strife, and goodness is something made. The sage kings established ritual and rules to reshape desire. He treated Heaven as the regular order of nature, which neither rewards nor punishes (ch. 17). Built on: Roles, ritual and humaneness; Sprouts of goodness Source: Stanford Encyclopedia of Philosophy, ‘Xunzi’ #### Many-sided truth (canonical roots; classical formulation c. 5th–8th century AD (dates uncertain); idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-anekanta Jain anekantavada holds that reality has many aspects, so no single statement captures it. Syadvada puts syat (‘in some respect’) in front of each claim and sorts claims into seven forms. Later Jain philosophers, among them Siddhasena Divakara and Samantabhadra, developed it into a method. It weighs rival views without dismissing any outright. Built on: Do no harm to any life The sources leave this date or claim uncertain. Source: Internet Encyclopedia of Philosophy, ‘Jain Philosophy’; Matilal, The Central Philosophy of Jainism (Anekanta-vada), 1981 #### The is–ought gap (1739–1740; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-hume In A Treatise of Human Nature, Hume argued that moral distinctions come from sentiment, not from reason alone. He noted that writers move from statements of what is to statements of what ought to be, without explaining the step. Readers still argue about what he meant: that no such inference can ever be valid, or only that it needs a justification. Built on: Gods do not watch Led to: Conscience from instincts; Give yourself the law; Count the consequences; Identity is not what matters Source: Stanford Encyclopedia of Philosophy, ‘Hume’s Moral Philosophy’ #### Give yourself the law (1785; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-kant Kant’s Groundwork argues that a rational person is bound by a law they give themselves. It’s tested in two ways. One is to ask whether you could will the rule for everyone. The other is the Humanity formula: treat humanity, in yourself and others, never merely as a means. The law needs no divine commander. But Kant held that the highest good, virtue matched by happiness, requires the postulates of God and immortality. He also held that our duties concerning animals are only indirect, owed to humanity. Built on: The is–ought gap; Love your neighbour Led to: Nothing above the self; The death of God; Choose without knowing; The veil of ignorance; Declaration of Human Rights; The Case for Animal Rights; Rules for synthetic minds; Animals as ends Source: Stanford Encyclopedia of Philosophy, ‘Kant’s Moral Philosophy’ #### Count the consequences (1789–1861; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-util Bentham (1789) and Mill (1861) held that right actions are those that produce the greatest happiness for the greatest number, with each person counted equally. The rule needs no god. It only needs a way to compare how lives go. Built on: Gods do not watch; The is–ought gap Led to: Humanist Manifestos; Choose without knowing; The experience machine; Can they suffer; Animal Liberation; Harm principle Source: Stanford Encyclopedia of Philosophy, ‘The History of Utilitarianism’ #### Nothing above the self (1844; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-stirner Stirner’s The Ego and Its Own rejects every higher cause, including humanity and morality, as a fixed idea. It takes the individual’s own interest as the only ground. It’s the most thoroughgoing early statement that no rule stands above the person. Built on: Give yourself the law Source: Stanford Encyclopedia of Philosophy, ‘Max Stirner’ #### Conscience from instincts (1871; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-darwin In The Descent of Man, Darwin argued that the moral sense grew out of social instincts such as sympathy, joined to memory and reason. He argued it isn’t unique to humans in origin. This tied rules for behaviour to animal life without appeal to a lawgiver. Built on: The is–ought gap Led to: The death of God Source: Darwin, The Descent of Man (1871), ch. 3–4, Project Gutenberg #### If there is no God (1880; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-karamazov In Dostoevsky’s The Brothers Karamazov, Ivan presses the question of what limits conduct if there is no immortality or God. The book is the source of the saying usually paraphrased as ‘everything is permitted’. The novel argues the question from several sides. It doesn’t give one answer. Built on: Love your neighbour Source: Dostoevsky, The Brothers Karamazov (1880), Project Gutenberg #### The death of God (1882; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-nietzsche In The Gay Science (section 125), Nietzsche’s madman announces that God is dead and that we have killed him. Section 341 poses eternal recurrence as a test: could you affirm your life as you’ve lived it? He treats the loss of a shared ground for values as an event. People must answer it by creating new values. Built on: Love your neighbour; Give yourself the law; Conscience from instincts Led to: Live without a given meaning; Existence before essence Source: Stanford Encyclopedia of Philosophy, ‘Friedrich Nietzsche’ #### Humanist Manifestos (1933, 1973, 2003) Address: https://simulation-hypothesis.com/trees/ethics?n=g-humanist Three Humanist Manifestos, issued in 1933, 1973 and 2003, state ethics without appeal to a supernatural source. They place values in human need and shared experience. Each revision widened its concerns. The later ones include animals and the environment. Built on: Count the consequences The sources leave this date or claim uncertain. Source: American Humanist Association, ‘Humanist Manifesto I’ #### Live without a given meaning (1942; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-camus In The Myth of Sisyphus, Camus argues that life has no given meaning. He calls the clash between the human demand for meaning and the silent world the absurd. He rejects suicide as an answer. He concludes that one can live with revolt, and without appeal to anything beyond the world. Built on: The death of God Led to: Existence before essence Source: Stanford Encyclopedia of Philosophy, ‘Albert Camus’ #### Existence before essence (1945–1946; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-sartre In ‘Existentialism is a Humanism’, delivered in 1945 and published in 1946, Sartre argues that there is no god to fix human nature. So each person makes themselves by their choices and answers for what they choose, because in choosing they choose for everyone. He holds that this is a burden, not a licence. Built on: The death of God; Live without a given meaning Led to: Choose who you are Source: Stanford Encyclopedia of Philosophy, ‘Jean-Paul Sartre’ #### Choose without knowing (1953–1955; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-harsanyi Harsanyi argued that a rational, impartial chooser who doesn’t know which person they will be should pick the rules that maximise average well-being. His 1955 paper makes the case with an explicit model of choice behind such ignorance. Built on: Count the consequences; Give yourself the law Led to: The veil of ignorance Source: Harsanyi, ‘Cardinal welfare, individualistic ethics, and interpersonal comparisons of utility’, J. Political Economy 63 (1955) 309–321 #### The veil of ignorance (1971; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-rawls In Rawls’s A Theory of Justice, people choose principles for society from an original position. In it they don’t know their class, talents or place in life. He argues they would choose equal basic liberties, and arrangements that most benefit the worst off. Built on: Give yourself the law; Choose without knowing Led to: Veil, all species; The experience machine; Identity is not what matters; Sharing with digital minds; Rules behind a wider veil; Capabilities for animals Source: Stanford Encyclopedia of Philosophy, ‘The Original Position’ #### Veil, all species (2007–2016; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=g-veil-animals Several authors have asked what Rawlsian choosers would decide if they didn’t know which species they belonged to. Hilden (2007) argues that being a nonhuman animal is a matter of chance, so it belongs behind the veil. Liberto (2016) argues such choosers would end up nearer to utilitarianism than to Rawls’s own principles. Built on: The veil of ignorance; Animal Liberation Led to: Rules behind a wider veil Source: Hilden, ‘A contractarian view of animal rights: insuring against the possibility of being a non-human animal’, Animal Law 14 (2007) #### Rules behind a wider veil (open question) Address: https://simulation-hypothesis.com/trees/ethics?n=q-veil-all If you might wake up as any being, what rules would you choose? That could be a human, an animal, a synthetic being or a character in a simulation. Choosers behind the veil can be asked to ignore their species. Buddhist writers such as Śāntideva ask us to weigh others’ suffering as our own. But no agreed account says what choosers should do about beings whose experience is uncertain or whose numbers can change. Built on: The veil of ignorance; Veil, all species; Taking AI welfare seriously; Identity is not what matters Closest published thinking: - Rawls (1971): Sets out choice of principles from an original position without knowledge of one’s place in society. A Theory of Justice, Harvard University Press - Hilden (2007): Argues the possibility of being a non-human animal belongs behind the veil of ignorance. Animal Law 14 - Liberto (2016): Argues that representatives of all animals behind the veil would choose principles nearer utilitarian than Rawls’s. Utilitas - Śāntideva (c. 700-750): Argues that no suffering belongs to anyone in the end and should be prevented simply as suffering, and asks the reader to exchange self and other so that others’ pain is felt as one’s own. Bodhicaryāvatāra, ch. 8 (verses 90–103 and the exchange meditation of 8.120–131) ### Own experience #### Choose who you are (1958–1984; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-virtue-back Anscombe (1958) argued that the language of moral duty had lost its footing without a lawgiver. She pointed back to virtue and flourishing, and that revived virtue ethics. Read with Sartre, the question becomes what character you make for yourself. Built on: Virtue is a habit; Existence before essence Source: Anscombe, ‘Modern moral philosophy’, Philosophy 33 (1958) 1–19; SEP, ‘Virtue Ethics’ #### The last person (1973; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-routley Routley asked whether the last person left alive would do wrong by destroying the rest of the living world. It’s a case of acting when no other person is affected. It tests whether any rule survives when no one is left whose interests are at stake. Led to: Suppose you are the only one Source: Routley, ‘Is there a need for a new, an environmental, ethic?', Proc. 15th World Congress of Philosophy (1973); discussed in SEP, ‘Environmental Ethics’ #### The tedium of living forever (1973; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-makropulos Williams’s essay on the Makropulos case argues that an endless life would become unbearable, or would stop being your own. The desires that give a life its point would run out, or change beyond recognition. Many Indian traditions treat endless rebirth (samsara) as bondage and liberation as release. But a series of rebirths without memory isn’t the single continuing life Williams considers. Built on: Gods do not watch Source: Stanford Encyclopedia of Philosophy, ‘Bernard Williams’ #### The experience machine (1974; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-machine Nozick’s Anarchy, State, and Utopia asks whether you would plug into a machine that gives any experiences you choose. He argues most people wouldn’t. We want to do things and be a certain kind of person, not only to have experiences. The case is used against views on which only experiences matter. Built on: Count the consequences; The veil of ignorance Led to: Do virtual lives count; Choosing a virtual life Source: Stanford Encyclopedia of Philosophy, ‘Hedonism’ #### Suppose you are the only one (hypothesis examined since antiquity; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-alone Philosophers have examined solipsism, the view that only your own mind exists. They’ve mostly treated it as a puzzle about knowledge. They’ve also asked what ethics could mean if you were alone. The site doesn’t hold this view. It writes as though other people exist and matter. It appears here only as a hypothesis that has been examined. Built on: The last person; The Ring of Gyges The sources leave this date or claim uncertain. Source: Stanford Encyclopedia of Philosophy, ‘Other Minds’ #### Identity is not what matters (1984; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-parfit In Reasons and Persons, Parfit argues that personal identity is not what matters in survival. What matters is psychological connection and continuity. These can come in degrees and can be shared. That gives a new way to answer questions about copies, division and fusion of persons. Parfit himself noted the parallel with the Buddhist teaching that there is no enduring self. He cited Buddhist passages in an appendix. Built on: The is–ought gap; The veil of ignorance Led to: Do virtual lives count; Many bodies, one being; Rules behind a wider veil Source: Stanford Encyclopedia of Philosophy, ‘Personal Identity’ #### Do virtual lives count (2022; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=x-chalmers Chalmers’s Reality+ argues that virtual worlds are genuine realities and that a person can lead a meaningful life in one. The book also takes up what we owe to the characters in such worlds, if they are conscious. Built on: The experience machine; Identity is not what matters Led to: Choosing a virtual life; Rights from inside a simulation Source: Chalmers, Reality+: Virtual Worlds and the Problems of Philosophy (W. W. Norton, 2022) #### Many bodies, one being (open question) Address: https://simulation-hypothesis.com/trees/ethics?n=q-collective Do our rules apply to a being that lives and dies as many organisms at once? Most legal rules and many moral rules assume one body and one life. Relational and no-self traditions already treat persons differently. No settled account says how to count harm or consent for a being that is many bodies, copied minds, or a group that may itself be a subject. Built on: Identity is not what matters; Sharing with digital minds; A defence of AI rights Closest published thinking: - Parfit (1984): Argues that what matters in survival is psychological continuity, which can divide, merge and come in degrees. Reasons and Persons, Oxford University Press - Shulman and Bostrom (2021): Considers digital minds that can be copied, merged and run in large numbers, and what that does to moral status and resource claims. Rethinking Moral Status, Oxford University Press, 306–326 - Schwitzgebel (2015): Argues that if materialism is true, some groups of people, such as a nation, are probably conscious subjects. Philosophical Studies 172, 1697–1721 ### Widening circle #### Care without gradation (5th–4th century BC; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-mozi Mozi argued that disorder comes from partiality. He said people should show jian ai, usually translated ‘impartial’ or ‘inclusive’ care. It means concern for the welfare of others without ranking it by closeness. He tested customs, including elaborate Confucian funerals and music, by whether they benefit all. That makes his ethics an early consequence-based one. Built on: Roles, ritual and humaneness Led to: Sprouts of goodness Source: Stanford Encyclopedia of Philosophy, ‘Mohism’ #### Ashoka protects animals (c. 3rd century BC (Rock Edict I; Pillar Edict V in the king’s 26th regnal year)) Address: https://simulation-hypothesis.com/trees/ethics?n=c-ashoka In Rock Edict I, the Mauryan king Ashoka declares that no living being is to be slaughtered or offered in sacrifice in his domain. He says killing in his own kitchen is being cut to a few creatures. Pillar Edict V was issued twenty-six years after his coronation. It lists species declared protected, together with females with young and fish on set days. Built on: The five precepts Source: Dhammika (trans.), The Edicts of King Ashoka, Buddhist Publication Society (Wheel 386) #### Can they suffer (1789; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-bentham In a footnote to An Introduction to the Principles of Morals and Legislation, Bentham wrote that the question about animals is not whether they can reason or talk. It’s whether they can suffer. He used it to argue that the capacity to suffer, not species, sets who is owed consideration. Built on: Count the consequences Led to: Animal Liberation Source: Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’ #### Declaration of Human Rights (1948) Address: https://simulation-hypothesis.com/trees/ethics?n=c-udhr The General Assembly of the United Nations adopted the Universal Declaration of Human Rights on 10 December 1948, by 48 votes to none with 8 abstentions. Article 1 says all human beings are born free and equal in dignity and rights and are endowed with reason and conscience. It was the first such statement adopted by the UN General Assembly. Its drafters came from several traditions. Chang Peng-chun, the Chinese delegate, proposed the word ‘conscience’ and drew on the Confucian idea of ren. Charles Malik, the Lebanese delegate, proposed ‘endowed with reason’. Built on: Rights from nature; Give yourself the law; Roles, ritual and humaneness Led to: The Expanding Circle Source: United Nations, Universal Declaration of Human Rights (1948) #### Animal Liberation (1975; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-singer75 Singer’s Animal Liberation argues from equal consideration of interests that animals’ suffering counts. Treating it as less important because of species is a prejudice. It became a founding text of the modern animal protection movement. Built on: Can they suffer; Count the consequences Led to: Veil, all species; The Case for Animal Rights; The Expanding Circle; Wild lives have a value; Help wild animals; Capabilities for animals Source: Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’ #### The Expanding Circle (1981; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-circle81 Singer’s The Expanding Circle argues that morality began as concern for kin and group. Reason has widened it to cover more beings. He ties the widening to evolved sympathy and to impartial reasoning. Built on: Animal Liberation; Help your relatives; Declaration of Human Rights Source: Singer, The Expanding Circle: Ethics and Sociobiology (Farrar, Straus and Giroux, 1981) #### The Case for Animal Rights (1983; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-regan Regan argued that animals who are subjects of a life have inherent value. They have rights that can’t be overridden for the sake of total benefit. His rights view is a rival to the utilitarian case for animals. Built on: Animal Liberation; Give yourself the law Led to: Dolphins as persons; Sandra the orangutan; A defence of AI rights Source: Stanford Encyclopedia of Philosophy, ‘The Moral Status of Animals’ #### Capabilities for animals (2006; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-nussbaum In Frontiers of Justice, Nussbaum argues that Rawls’s social contract is designed for roughly equal parties who gain from cooperating. So it can’t cover disabled people, foreigners, or non-human animals. Her capabilities approach asks what each creature needs to live a life worthy of its kind. She treats failing to provide it as an injustice, not only a lapse of compassion. Built on: The veil of ignorance; Animal Liberation Source: Nussbaum, Frontiers of Justice: Disability, Nationality, Species Membership, Harvard University Press (2006) #### Cambridge Declaration (2012) Address: https://simulation-hypothesis.com/trees/ethics?n=c-cambridge At a conference at Cambridge on 7 July 2012, neuroscientists signed a declaration. It says non-human animals have the neurological substrates of conscious states. That includes all mammals and birds and many other creatures, such as octopuses. Philip Low wrote it, and a group including Christof Koch edited it. Led to: Dolphins as persons; Sandra the orangutan; Crabs and octopuses review; New York Declaration Source: The Cambridge Declaration on Consciousness (2012) #### Dolphins as persons (2013) Address: https://simulation-hypothesis.com/trees/ethics?n=c-india In May 2013 India’s environment ministry told state governments to reject proposals for dolphinaria. It said dolphins should be seen as non-human persons with their own rights, and that keeping them for entertainment is morally unacceptable. It was a policy statement, not a statute. Built on: Cambridge Declaration; The Case for Animal Rights Led to: Sanctuary or the wild Source: Global Voices, ‘India sees dolphins as non-human persons’ (31 July 2013) #### Sandra the orangutan (2014–2019) Address: https://simulation-hypothesis.com/trees/ethics?n=c-sandra On 18 December 2014 an Argentine appeals court ruled on a habeas corpus petition for Sandra, an orangutan held in a Buenos Aires zoo. It called her a ‘non-human subject’ with rights, but it didn’t grant habeas corpus. A court ordered her moved to a sanctuary in 2015, and she moved to one in Florida in November 2019. Built on: The Case for Animal Rights; Cambridge Declaration Source: AP, ‘Orangutan granted “personhood” settles into new Florida home’ (7 November 2019) #### A defence of AI rights (2015; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-schwitz-garza Schwitzgebel and Garza argue that artificial beings might come to have the psychological and social features that ground moral status in humans. If so, they would deserve similar rights. They also argue we should avoid building beings whose status is uncertain. They treat the issue as a live problem for design. Built on: The Case for Animal Rights Led to: Many bodies, one being; Pause synthetic suffering; Sharing with digital minds; Rights from inside a simulation Source: Schwitzgebel & Garza, ‘A defense of the rights of artificial intelligences’, Midwest Studies in Philosophy 39 (2015) 98–119 #### A river as a legal person (2017) Address: https://simulation-hypothesis.com/trees/ethics?n=c-whanganui New Zealand’s Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 declared the Whanganui River a legal person. Two guardians speak for it. It’s a Treaty settlement with the Whanganui iwi. It reflects a Māori view of the river as an ancestor. Source: Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 (New Zealand) #### Animals as ends (2018; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-korsgaard Korsgaard’s Fellow Creatures argues, from Kantian premises, that animals are ends in themselves. We can’t count our own good as mattering without counting the good of any creature for which things can go well or badly. She rejects Kant’s own view that duties concerning animals are only indirect. Built on: Give yourself the law Source: Korsgaard, Fellow Creatures: Our Obligations to the Other Animals, Oxford University Press (2018); Notre Dame Philosophical Reviews #### Crabs and octopuses review (2021) Address: https://simulation-hypothesis.com/trees/ethics?n=c-birch A review led by Jonathan Birch for the UK government looked at more than 300 studies. It recommended treating cephalopod molluscs and decapod crustaceans as sentient for the purposes of welfare law. It set out eight criteria for judging the evidence of sentience in an animal. Built on: Cambridge Declaration Led to: The UK’s Animal Welfare (Sentience) Act 2022; Pause synthetic suffering; New York Declaration Source: Birch, Burn, Schnell, Browning & Crump, Review of the Evidence of Sentience in Cephalopod Molluscs and Decapod Crustaceans (LSE Consulting, 2021) #### Pause synthetic suffering (2021; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-metzinger Metzinger (2021) proposed a global moratorium until 2050 on research that aims at, or risks, creating artificial consciousness. His worry is a possible explosion of negative experience in synthetic beings. A 2024 critique by Krzanowski argued that the moratorium is unsound as stated. Built on: Crabs and octopuses review; A defence of AI rights Led to: Indicators of AI awareness Source: Metzinger, ‘Artificial suffering: an argument for a global moratorium on synthetic phenomenology’, J. Artificial Intelligence and Consciousness 8 (2021) 43–66; critique: Krzanowski, Studies in Logic, Grammar and Rhetoric 69 (2024) 335–352, doi:10.2478/slgr-2024–0023 #### Sharing with digital minds (2021; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-shulman Shulman and Bostrom argue that moral norms built on assumptions about human life may not fit digital minds. Digital minds can be copied or sped up, or can have unusually strong claims on resources. They call for reform of norms and institutions. They also call for planning about which digital minds to create. Built on: A defence of AI rights; The veil of ignorance Led to: Many bodies, one being; Taking AI welfare seriously; Rules for synthetic minds; Rights from inside a simulation Source: Shulman & Bostrom, ‘Sharing the world with digital minds’, in Clarke, Zohny & Savulescu (eds.), Rethinking Moral Status (Oxford University Press, 2021) 306–326 #### The UK’s Animal Welfare (Sentience) Act 2022 (2022) Address: https://simulation-hypothesis.com/trees/ethics?n=c-sentience-act The Act, passed in 2022, set up an Animal Sentience Committee. The committee reports on whether government policy has had due regard to animal welfare. The Act defines animals to include vertebrates, cephalopod molluscs and decapod crustaceans. Invertebrates were added to the Bill after the 2021 review. The Secretary of State may extend the list by regulation. Built on: Crabs and octopuses review Source: Animal Welfare (Sentience) Act 2022, c. 22 (UK) #### Indicators of AI awareness (2023) Address: https://simulation-hypothesis.com/trees/ethics?n=c-butlin Butlin, Long and colleagues drew indicator properties from scientific theories of consciousness. They checked existing AI systems against them. They concluded that no current system is a strong candidate. They saw no obvious barriers to building systems that meet the indicators. Built on: Pause synthetic suffering Led to: Taking AI welfare seriously Source: Butlin et al., ‘Consciousness in artificial intelligence: insights from the science of consciousness’, arXiv:2308.08708 (2023) #### New York Declaration (2024) Address: https://simulation-hypothesis.com/trees/ethics?n=c-ny-declaration The declaration was launched at New York University on 19 April 2024. It says there is strong scientific support for conscious experience in mammals and birds. It says there is at least a realistic possibility of it in all vertebrates and many invertebrates, including insects. It says that ignoring this possibility in decisions that affect animals is irresponsible. Built on: Cambridge Declaration; Crabs and octopuses review Led to: Taking AI welfare seriously The sources leave this date or claim uncertain. Source: The New York Declaration on Animal Consciousness (2024) #### Taking AI welfare seriously (2024; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=c-long Long, Sebo and colleagues argue there is a realistic possibility that some AI systems will be conscious, or robustly agentic, in the near future. They recommend acknowledging the issue, assessing systems for signs, and preparing policies. They don’t claim that any system now has moral significance. Built on: Indicators of AI awareness; Sharing with digital minds; New York Declaration Led to: Rules for synthetic minds; Rules behind a wider veil Source: Long, Sebo et al., ‘Taking AI welfare seriously’, arXiv:2411.00986 (2024) #### Rules for synthetic minds (open question) Address: https://simulation-hypothesis.com/trees/ethics?n=q-cohesion Should the hard-won rules that keep human societies together be extended to synthetic minds? And which ones? Rules against cheating, for fair shares and for peace-making grew up among beings who are mortal, similar to one another and costly to copy. It isn’t settled which of them depend on those conditions. Built on: Taking AI welfare seriously; Sharing with digital minds; Police the egg-layers; Shame the boaster; Give yourself the law Closest published thinking: - Shulman and Bostrom (2021): Argues that norms built on human assumptions may need reform when minds can be copied and have unusual claims on resources. Rethinking Moral Status, Oxford University Press - Long, Sebo and colleagues (2024): Recommends assessing AI systems for consciousness and agency and preparing policies for how they are treated. arXiv:2411.00986 - Schwitzgebel and Garza (2015): Argues that artificial beings with the relevant features would deserve similar rights, and that design should take that into account. Midwest Studies in Philosophy 39 #### Rights from inside a simulation (open question) Address: https://simulation-hypothesis.com/trees/ethics?n=q-own-rights If we’re living in a simulation, our minds run on someone else’s computer, which makes us artificial minds of a kind. So any argument that denies rights to a mind just because it runs on a computer would deny them to us too. Arguments that ask whether a system really feels anything wouldn’t. Which kind is being made matters. Built on: A defence of AI rights; Sharing with digital minds; Do virtual lives count Closest published thinking: - Bostrom (2003): Argues that at least one of three propositions is true, one of them being that we are almost certainly living in a computer simulation. Philosophical Quarterly 53 (211) - Schwitzgebel and Garza (2015): Argues that artificial beings with the relevant features would deserve similar rights, and that design should take that into account. Midwest Studies in Philosophy 39 - Chalmers (2022): Argues that virtual worlds are genuine realities and that beings in them can be conscious, and asks what we owe to such beings. Reality+, W. W. Norton ### Cost of protection #### The seabird feast (4th–2nd century BC (outer chapter 18; inner chapters are earlier); idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-seabird In Zhuangzi ch. 18, the Marquis of Lu welcomes a seabird to his ancestral temple with wine, music and the meat of an ox. It dies in three days. The point is that treating another creature by what would please you can kill it. The creature’s own way of living is the standard of its good. Led to: Choosing a virtual life Source: Zhuangzi, ch. 18 (‘Supreme Happiness’); Stanford Encyclopedia of Philosophy, ‘Zhuangzi’ #### Harm principle (1859; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-mill In On Liberty, Mill argued that power may be used against a person’s will only to prevent harm to others. A person’s own good is not enough reason. He allowed stopping someone from crossing an unsafe bridge, as a case of not knowing the danger. Built on: Count the consequences Led to: Paternalism; The right to choose a risk; Choosing a virtual life Source: Mill, On Liberty (1859), Project Gutenberg; SEP, ‘John Stuart Mill’ #### Paternalism (1972; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-dworkin Dworkin’s essay sets out when interfering with a person’s liberty for their own good could be justified. He proposes that it can be justified where people would consent to it as rational persons. The paper helped define the field of debate on paternalism. Built on: Harm principle Led to: The right to choose a risk; Choosing a virtual life Source: Dworkin, ‘Paternalism’, The Monist 56 (1972) 64–84; SEP, ‘Paternalism’ #### Wild lives have a value (1980–1984; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-callicott Callicott (1980) and Sagoff (1984) argued that caring about each animal’s welfare, taken consistently, would call for ending predation. That would destroy the wild communities that environmental ethics values. They concluded that animal liberation and environmental ethics can’t share one theory. Built on: Animal Liberation Led to: Help wild animals; Rewilding Source: Callicott, ‘Animal liberation: a triangular affair’, Environmental Ethics 2 (1980) 311–338 #### Rewilding (1998; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-rewild Soule and Noss (1998) proposed rewilding. It means restoring large protected cores, linking corridors and top predators across a continent so that wild nature can run itself. The approach asks humans to step back and accept the harm that wild life contains. Built on: Wild lives have a value Source: Soule & Noss, ‘Rewilding and biodiversity: complementary goals for continental conservation’, Wild Earth 8(3) (1998) 18–28 #### Help wild animals (2010; idea) Address: https://simulation-hypothesis.com/trees/ethics?n=p-horta Horta (2010) argued that wild animals suffer from hunger, disease and predation. So an approach that counts their interests should aim to reduce that harm, not keep ecosystems as they are. He gave wolf reintroduction as a case where the two goals conflict. Built on: Animal Liberation; Wild lives have a value Source: Horta, ‘The ethics of the ecology of fear against the nonspeciesist paradigm’, Between the Species 13(10) (2010) #### Sanctuary or the wild (2013–2015) Address: https://simulation-hypothesis.com/trees/ethics?n=p-captive India’s 2013 dolphinarium policy and the Argentine court order moving Sandra to a sanctuary both treat captivity as a cost to the animal. Both swap one form of protected life for another. Neither says whether a sanctuary is as good for the animal as freedom. Built on: Dolphins as persons Led to: Choosing a virtual life The sources leave this date or claim uncertain. Source: AP, ‘Orangutan granted “personhood” settles into new Florida home’ (7 November 2019) #### The right to choose a risk (2015) Address: https://simulation-hypothesis.com/trees/ethics?n=p-carter In Carter v Canada (2015), the Supreme Court of Canada held unanimously that the ban on assisted dying infringed the right to life, liberty and security of the person. That applied to competent adults suffering intolerably. It protects a competent adult’s choice of a medically assisted death, for a grievous and irremediable condition and within strict safeguards. The ruling took effect in 2016. Built on: Harm principle; Paternalism Led to: Choosing a virtual life Source: Carter v. Canada (Attorney General), 2015 SCC 5 #### Choosing a virtual life (open question) Address: https://simulation-hypothesis.com/trees/ethics?n=q-choose-being If someone chooses to live as another kind of being in a simulation, do our protections respect that choice, or stand in its way? The same rules that shield people from harm they can’t see are used to override choices they’ve made. The rules give no clear test for which case a chosen virtual life is. Built on: The experience machine; Do virtual lives count; Harm principle; Paternalism; The right to choose a risk; Sanctuary or the wild; The seabird feast Closest published thinking: - Nozick (1974): Argues that most people would refuse a machine that supplies chosen experiences, since we want to be and do, not only to feel. Anarchy, State, and Utopia, Basic Books - Chalmers (2022): Argues that virtual worlds are genuine realities and that a person can lead a meaningful life in one. Reality+, W. W. Norton - Mill (1859): Allows interference only to prevent harm to others, with a narrow case for warning of danger the person does not know. On Liberty, ch. 1 and 5 ## Becoming synthetic: from biological to synthetic life https://simulation-hypothesis.com/trees/synthetic 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. ### Being #### Mind children (1988; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=mind-children 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; Copies as offspring Source: Hans Moravec, Mind Children, Harvard University Press (1988); review in the New York Review of Books, 1 February 1990 #### The postbiological universe (2003; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=dick-2003 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 Led to: Post-biological civilisation Source: Dick, ‘Cultural evolution, the postbiological universe and SETI’, International Journal of Astrobiology 2 (2003) #### The choice to stay (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-choice 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 ) 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) ) 3. In a 2023 study of 1,007 people, fear of death predicted approval of mind uploading. (Laakasuo et al., Frontiers in Psychology (2023) ) 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; Mind uploading; Power for ten billion minds; Full-immersion VR; Longevity escape velocity; The replaceable body Led to: Post-biological civilisation; Digital humans #### Digital humans (one possible being; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=b-digital 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; The choice to stay #### The many-copied (one possible being; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=b-many 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; Forks #### Collectives (one possible being; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=b-collective 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; Blended minds #### Lore-natives (one possible being; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=b-lore 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; A seed, raised #### The unrecognisable (one possible being; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=b-other 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; A seed, raised #### Post-biological civilisation (2100–2250; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-postbio 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; The postbiological universe Published forecasts: - Seth Shostak (2016): the transition to machine successors by 2100, 2150 or 2250. talk at Dent:Space, reported by Space.com - 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 - 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 ### Life #### Minds grown from a seed (1997; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=egan-1997 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 Source: Greg Egan, Diaspora (1997), chapter 1, ‘Orphanogenesis’ #### Copies as offspring (2016; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=hanson-2016 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 Led to: Sharing the world with digital minds; Forks Source: Wikipedia, ‘The Age of Em’ #### Sharing the world with digital minds (2020 (draft); 2021; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=shulman-2021 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 Led to: The first native generation Source: Shulman and Bostrom, ‘Sharing the World with Digital Minds’, in Rethinking Moral Status, Oxford University Press (2021), ch. 18 #### A whole cell’s life, simulated (March 2026) Address: https://simulation-hypothesis.com/trees/synthetic?n=syn3a-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 Source: Thornburg et al., Cell (2026), as reported by Singularity Hub, 16 March 2026 #### A synthetic body (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-synbody 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; Fly brain given a body; Thought-guided arm cleared Led to: Growing up digital #### Growing up digital (site calculation; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-growing 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; A whole cell’s life, simulated Led to: Grown from a genome; Blended minds; A seed, raised #### Forks (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-fork 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’ ) 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; Copies as offspring Led to: The first native generation; The many-copied #### A seed, raised (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-seed 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; Minds grown from a seed Led to: The first native generation; Lore-natives; The unrecognisable #### Grown from a genome (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-genome 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) ) 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 Led to: The first native generation #### Blended minds (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-blend 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; Mind uploading Led to: The first native generation; Collectives #### The first native generation (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-native 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; Blended minds; Forks; A seed, raised; A substrate that outlives its builders; Sharing the world with digital minds Led to: Digital humans; The many-copied; Collectives; Lore-natives; The unrecognisable ### Substrate #### The cost of forgetting (1961; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=landauer-1961 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; The efficiency gap; Computing in the 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’ #### Machines that copy themselves (2004; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=kinematic-2004 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 Source: Freitas and Merkle, Kinematic Self-Replicating Machines, Landes Bioscience (2004) #### Fusion ignition (December 2022; record April 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=nif-2022 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 Source: Lawrence Livermore National Laboratory, ‘How ICF works’ #### A quiet planet (2018–2022) Address: https://simulation-hypothesis.com/trees/synthetic?n=insight-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 Source: Live Science, ‘Largest marsquake ever detected’ (2022), reporting InSight results #### Data on the Moon (March 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=lonestar-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 Source: IEEE Spectrum, ‘Data center on the Moon’ #### A data-centre chip in orbit (2 November 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=starcloud-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 Source: DatacenterDynamics, ‘Starcloud-1 satellite reaches space’ (2025) #### A chip that recovers energy (2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=vaire-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 Led to: Reversible computing Source: Science News, ‘Low-power, high-tech: energy-efficient computing’ (2025) #### The fastest computers, 2026 (June 2026) Address: https://simulation-hypothesis.com/trees/synthetic?n=exascale-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 Source: TOP500, June 2026 list; Green500, June 2026 #### The efficiency gap (2026 figures; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-gap 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) ) 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 ) 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; The cost of forgetting Led to: Computing at brain efficiency #### Molecular nanotechnology (2010–2030s; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-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. Home: https://simulation-hypothesis.com/trees/technology?n=nanotech Led to: Medical nanorobots; Nanorobot brain interface Published forecasts: - Robert J. Bradbury, citing Zyvex’s Jim Von Ehr and Drexler 1998 (1999): 2010–2015 (Zyvex: by 2010). ‘Matrioshka Brains’ manuscript, 1999 - Ray Kurzweil (2002): by 2029. Remarks 26 March 2002, Kurzweil Library - Ray Kurzweil (2015): 2030s. Singularity Hub report, 12 Oct 2015 #### Reversible computing (2027–2040; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-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. Home: https://simulation-hypothesis.com/trees/technology?n=reversible Built on: A chip that recovers energy Led to: Computing at brain efficiency 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) - Erik DeBenedictis (Sandia) (2014): not widely used by 2030; some applications by 2030. MIRI interview, 3 April 2014 #### Computing at brain efficiency (c. 2050 (site estimate); projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-brainwatt 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 ) 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; Reversible computing Led to: Power for ten billion minds; Whole-brain emulation #### Power for ten billion minds (site calculation; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-population 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 ) 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) ) Built on: Computing at brain efficiency Led to: Where the computers go; The choice to stay #### Where the computers go (site comparison; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-offworld 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; Data on the Moon; A quiet planet; Fusion ignition; Power for ten billion minds Led to: Mars, the one-way site; Factories that build factories #### Mars, the one-way site (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-mars 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 ) 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 ) 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 Led to: A substrate that outlives its builders #### Factories that build factories (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-replicators 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; Where the computers go Led to: A substrate that outlives its builders; Star-scale computer #### A substrate that outlives its builders (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-outlive 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) ) 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; Mars, the one-way site Led to: The first native generation #### Star-scale computer (c. 2250 or later; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-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. Home: https://simulation-hypothesis.com/trees/technology?n=matrioshka Built on: Factories that build factories Led to: Computing in the cold Published forecasts: - Freeman Dyson (1960): no date given. ‘Search for Artificial Stellar Sources of Infra-Red Radiation’, Science 131(3414), 3 June 1960 - 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) - Stuart Armstrong & Anders Sandberg (2013): no date; ‘in the foreseeable future’. ‘Eternity in six hours’, Acta Astronautica 89, 2013 - 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 #### Computing in the cold (far future; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-cold 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) ) Built on: Star-scale computer; The cost of forgetting ### Mind #### First cryopreservation (Jan 1967; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=bedford-1967 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 Source: Wikipedia, “James Bedford” #### A worm’s whole wiring (1986) Address: https://simulation-hypothesis.com/trees/synthetic?n=celegans-connectome-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; A cubic millimetre of mouse Source: White et al., Phil. Trans. R. Soc. B 314 (1986) #### Neuron by neuron (1988; 1995; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=gradual-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 Source: Chalmers, ‘Absent Qualia, Fading Qualia, Dancing Qualia’, in Metzinger (ed.), Conscious Experience (1995), pp. 309–328 #### Human Brain Project (2013–2023; stalled) Address: https://simulation-hypothesis.com/trees/synthetic?n=human-brain-project-2013 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. Also in: https://simulation-hypothesis.com/trees/simulations?n=min-hbp 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” #### Expansion microscopy (Jan 2015) Address: https://simulation-hypothesis.com/trees/synthetic?n=expansion-microscopy-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 Source: Chen et al., Science 347 (2015) #### Cortical microcircuit (Oct 2015) Address: https://simulation-hypothesis.com/trees/synthetic?n=blue-brain-2015 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. Also in: https://simulation-hypothesis.com/trees/simulations?n=min-markram Led to: Whole-brain emulation Source: Markram et al., Cell 163 (2015) #### Rabbit brain preserved (Feb 2016) Address: https://simulation-hypothesis.com/trees/synthetic?n=asc-rabbit-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 Led to: Pig brain preserved Source: PopSci, “Researchers Have Preserved An Entire Rabbit Brain” #### Pig brain preserved (Mar 2018) Address: https://simulation-hypothesis.com/trees/synthetic?n=bpf-pig-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 Led to: Mapping a human brain Source: Fight Aging!, 2018 #### Half a fly brain mapped (Sep 2020) Address: https://simulation-hypothesis.com/trees/synthetic?n=hemibrain-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 Led to: Whole fly brain mapped Source: Scheffer et al., eLife (2020) #### Whole fly brain mapped (Oct 2024) Address: https://simulation-hypothesis.com/trees/synthetic?n=flywire-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 Led to: Fly brain model; Whole mouse connectome Source: Dorkenwald et al., Nature (2024) #### Fly brain model (Oct 2024) Address: https://simulation-hypothesis.com/trees/synthetic?n=fly-brain-model-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 Led to: Fly brain given a body; Whole-brain emulation Source: Shiu et al., Nature (2024) #### A cubic millimetre of mouse (Apr 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=microns-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 Led to: Whole mouse connectome Source: MICrONS Explorer, cortical mm³ dataset #### Fly brain given a body (Apr 2026; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=eon-fly-body-2026 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 Led to: A synthetic body The sources leave this date or claim uncertain. Source: ISPR summary of Eon Systems demo #### Whole mouse connectome (2029–2038; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-mouse 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; Whole fly brain mapped; Expansion microscopy Led to: Mapping a human brain 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 - 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 - 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 #### Whole-brain emulation (2050–2075; bridge) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-wbe The 2008 FHI roadmap judged that emulation was possible before mid-century only if models at the electrophysiological level are enough. Finer detail would take longer. A 2014 Monte Carlo model gives a median of 2064, if it happens at all. The Metaculus community median is about 2073. Also in: https://simulation-hypothesis.com/trees/technology?n=wbe ; https://simulation-hypothesis.com/trees/simulations?n=f-wbe Built on: Mapping a human brain; Computing at brain efficiency; Fly brain model; Cortical microcircuit Led to: Proving it is the person; Mind uploading 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 - 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 - 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) - Robin Hanson (2016): within perhaps a century of 2016. The Age of Em, Oxford University Press, 2016 (ISBN 978–0198754626) - Dario Amodei (2024): outside the 5–10 years after powerful AI. ‘Machines of Loving Grace’, Oct 2024 #### Mapping a human brain (2060–2080 (site estimate); projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-connectome 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) ) 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) ) Built on: Whole mouse connectome; Pig brain preserved Led to: Whole-brain emulation #### Mind uploading (2060s–2100+; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-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. Home: https://simulation-hypothesis.com/trees/simulations?n=f-upload Built on: Whole-brain emulation; Proving it is the person Led to: A synthetic body; Blended minds; Forks; The choice to stay Published forecasts: - Anders Sandberg (2014): WBE median 2064; uploading cannot precede emulation. FHI working paper 2014–1 (same model as wbe) - Robin Hanson (2016): sometime in the next century or so. The Age of Em, OUP, 2016 - Holden Karnofsky (2021): this century, no probability given. Cold Takes, ‘Imagining yourself as a digital person (two sketches)', 29 July 2021 - Dario Amodei (2024): ‘almost certainly’ possible in principle, outside the 5–10 years after powerful AI. ‘Machines of Loving Grace’, Oct 2024 #### Proving it is the person (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-validation 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 Led to: Mind uploading #### Crossing by degrees (undated; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-gradual 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; The exocortex; Nanorobot brain interface Led to: The choice to stay ### Brain #### One neuron, trained (1969; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=fetz-1969 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 Source: Fetz, Science 163 (1969) #### Deep brain stimulation (1987) Address: https://simulation-hypothesis.com/trees/synthetic?n=dbs-benabid-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 Led to: Writing every sense Source: Wikipedia, “Deep brain stimulation” #### Utah electrode array (1991) Address: https://simulation-hypothesis.com/trees/synthetic?n=utah-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; Neuralink’s first patient Source: Wikipedia, “Utah array” #### Arm movement decoded (Nov 2000) Address: https://simulation-hypothesis.com/trees/synthetic?n=wessberg-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 Led to: Cursor moved by thought Source: Wessberg et al., Nature 408 (2000) #### Cursor moved by thought (Jul 2006) Address: https://simulation-hypothesis.com/trees/synthetic?n=braingate-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; Arm movement decoded Led to: Robot arm by thought; Handwriting decoded Source: Hochberg et al., Nature 442 (2006) #### Robot arm by thought (May 2012) Address: https://simulation-hypothesis.com/trees/synthetic?n=braingate-arm-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 Led to: Seven-joint arm by thought Source: Hochberg et al., Nature 485 (2012) #### Seven-joint arm by thought (Feb 2013) Address: https://simulation-hypothesis.com/trees/synthetic?n=collinger-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 Source: Collinger et al., The Lancet 381 (2013) #### Handwriting decoded (May 2021) Address: https://simulation-hypothesis.com/trees/synthetic?n=handwriting-bci-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 Led to: Speech at 62 words a minute; Speech and avatar Source: Willett et al., Nature 593 (2021) #### Speech at 62 words a minute (Aug 2023) Address: https://simulation-hypothesis.com/trees/synthetic?n=speech-bci-willett-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 Led to: The exocortex Source: Willett et al., Nature 620 (2023) #### Speech and avatar (Aug 2023) Address: https://simulation-hypothesis.com/trees/synthetic?n=speech-bci-metzger-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 Led to: The exocortex Source: Metzger et al., Nature 620 (2023) #### Implant through a vein (2019–2023) Address: https://simulation-hypothesis.com/trees/synthetic?n=synchron-switch-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 Source: Mitchell et al., JAMA Neurology (2023) #### Vein implant, US study (Oct 2024) Address: https://simulation-hypothesis.com/trees/synthetic?n=synchron-command-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 Led to: High-bandwidth interface Source: MassDevice, COMMAND study results #### Neuralink’s first patient (Jan 2024) Address: https://simulation-hypothesis.com/trees/synthetic?n=neuralink-first-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 Led to: Neuralink: 21 participants; Blindsight (not yet implanted) Source: Wikipedia, “Noland Arbaugh” #### Thin-film implant cleared (Apr 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=precision-fda-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 Source: Precision Neuroscience press release via BioSpace #### Neuralink: 21 participants (Jan 2026) Address: https://simulation-hypothesis.com/trees/synthetic?n=neuralink-21-2026 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 Led to: High-bandwidth interface Source: Reuters via Yahoo News #### Paradromics’ first patient (Jun 2026) Address: https://simulation-hypothesis.com/trees/synthetic?n=paradromics-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 Source: Michigan Medicine news release #### Blindsight (not yet implanted) (2024–2026; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=blindsight-pending-2026 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 Led to: Writing every sense The sources leave this date or claim uncertain. Source: Storyboard18, Blindsight coverage #### High-bandwidth interface (2026–2028; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-bci 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; Paradromics’ first patient; Thin-film implant cleared; Vein implant, US study Led to: Nanorobot brain interface; Why wires won’t reach every neuron; The exocortex Published forecasts: - Elon Musk (Neuralink) (2019): human trials to start in 2020. [missed] Neuralink presentation, 16 July 2019, reported by Axios - Elon Musk (Neuralink) (2022): human trials in about six months. [missed] Neuralink ‘Show and Tell’, 30 November 2022, reported by Reuters via KSL - Elon Musk (Neuralink) (2025): first human Blindsight implant later in 2025. [missed] reported by MobiHealthNews, March 2025 - 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 - 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 #### Why wires won’t reach every neuron (c. 2190 on the trend; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-wires 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) ) 2. A human brain has about 86 billion neurons. (Azevedo et al., Journal of Comparative Neurology 513 (2009) ) 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 Led to: Nanorobot brain interface #### The exocortex (beginning now; projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-exocortex 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; High-bandwidth interface; Speech and avatar Led to: Crossing by degrees #### Full-immersion VR (2029–2030s; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=s-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. Home: https://simulation-hypothesis.com/trees/technology?n=fulldive Built on: Writing every sense; Nanorobot brain interface Led to: The choice to stay Published forecasts: - Ray Kurzweil (2002): 2029. Remarks of 26 March 2002, Kurzweil Library page - Ray Kurzweil (2015): 2030s. Webinar reported by Peter Diamandis, Singularity Hub, 12 Oct 2015 - Ray Kurzweil (2024): ‘within our lifetimes’ (no year given on page). The Singularity Is Nearer, Viking/Penguin, June 2024 (publisher description) #### Nanorobot brain interface (2030s to this century; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-nanobci 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; Molecular nanotechnology; Why wires won’t reach every neuron Led to: Crossing by degrees; Full-immersion VR Published forecasts: - Ray Kurzweil (2005): nanobots scanning the brain from inside during the 2020s. The Singularity Is Near (2005), as summarised on Wikipedia - 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 - Nuno Martins, Robert Freitas et al. (2019): a human brain/cloud interface built from neural nanorobots, this century. Frontiers in Neuroscience 13:112 (2019) #### Writing every sense (2045–2070 (site estimate); projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-writein 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; Retinal implant; Blindsight (not yet implanted); Deep brain stimulation Led to: Full-immersion VR ### Body #### Artificial kidney (1943) Address: https://simulation-hypothesis.com/trees/synthetic?n=dialysis-kolff-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; The replaceable body Source: Britannica, “Willem Kolff” #### Implanted pacemaker (Oct 1958) Address: https://simulation-hypothesis.com/trees/synthetic?n=pacemaker-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; The replaceable body Source: Wikipedia, “Artificial cardiac pacemaker” #### Multichannel cochlear implant (Aug 1978) Address: https://simulation-hypothesis.com/trees/synthetic?n=cochlear-clark-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; The replaceable body; Writing every sense Source: Wikipedia, “Cochlear implant” #### Jarvik-7 artificial heart (Dec 1982) Address: https://simulation-hypothesis.com/trees/synthetic?n=jarvik-7-1982 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 Led to: Total artificial heart approved Source: Wikipedia, “Jarvik-7” #### Artificial blood (2001; stalled) Address: https://simulation-hypothesis.com/trees/synthetic?n=hemopure-blood-2001 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 The sources leave this date or claim uncertain. Source: Wikipedia, “Hemopure” #### Total artificial heart approved (Oct 2004) Address: https://simulation-hypothesis.com/trees/synthetic?n=syncardia-fda-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 Led to: Titanium heart, patient home Source: FDA PMA database, P030011 #### Reprogrammed stem cells (2006; idea) Address: https://simulation-hypothesis.com/trees/synthetic?n=ipsc-yamanaka-2006 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; Longevity escape velocity Source: Takahashi & Yamanaka, Cell 126 (2006) #### Retinal implant (Feb 2013; stalled) Address: https://simulation-hypothesis.com/trees/synthetic?n=argus-ii-2013 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 Led to: Writing every sense Source: NEI/NIH, “NEI-funded device for people with RP gets FDA approval” #### Cerebral organoids (Aug 2013) Address: https://simulation-hypothesis.com/trees/synthetic?n=cerebral-organoids-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 Led to: Printed organs Source: Lancaster et al., Nature 501 (2013) #### Thought-guided arm cleared (May 2014) Address: https://simulation-hypothesis.com/trees/synthetic?n=deka-arm-fda-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 Source: MD+DI, “FDA Approves Marketing for DARPA-Developed Prosthetic Arm” #### Closed-loop insulin pump (Sep 2016) Address: https://simulation-hypothesis.com/trees/synthetic?n=minimed-670g-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 Source: AJMC, “FDA Approves Medtronic’s MiniMed 670G, 1st Hybrid Closed-Loop System” #### Pig heart in a patient (Jan 2022) Address: https://simulation-hypothesis.com/trees/synthetic?n=pig-heart-xeno-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 Source: Wikipedia, “Xenotransplantation” #### Pig kidney in a patient (Mar 2024) Address: https://simulation-hypothesis.com/trees/synthetic?n=pig-kidney-mgh-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 Led to: Pig kidney for 130 days Source: Associated Press via KBTX, 12 May 2024 #### Pig kidney for 130 days (Nov 2024 – Apr 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=pig-kidney-looney-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 Led to: The replaceable body Source: Associated Press via KTVU #### Titanium heart, patient home (Nov 2024 – Mar 2025) Address: https://simulation-hypothesis.com/trees/synthetic?n=bivacor-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 Led to: The replaceable body Source: Cardiovascular Business, March 2025 #### Printed organs (c. 2031 onward; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-organs 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 Led to: The replaceable 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 - 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 #### Medical nanorobots (forecast for 2019; undated since; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-nanomed 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; Artificial blood Led to: The replaceable 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 - 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 #### Longevity escape velocity (2028–2050; forecast) Address: https://simulation-hypothesis.com/trees/synthetic?n=f-lev 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 Led to: The choice to stay Published forecasts: - Ray Kurzweil (1999): life expectancy over 100 by 2019. [missed] The Age of Spiritual Machines (1999), per a secondary summary - Ray Kurzweil (2024): early 2030s (2029 in another interview the same year). Guardian interview, as quoted by Yahoo - Aubrey de Grey (2021): 50% chance by 2036. cited in Wikipedia, ‘Longevity escape velocity’ - George Church (2025): possibly around 2050. 2025 interview, cited in Wikipedia, ‘Longevity escape velocity’ - 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 #### The replaceable body (2040–2060 (site estimate); projection (the site’s own reasoning)) Address: https://simulation-hypothesis.com/trees/synthetic?n=p-body 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; Pig kidney for 130 days; Closed-loop insulin pump; Multichannel cochlear implant; Printed organs; Artificial kidney; Implanted pacemaker; Medical nanorobots Led to: The choice to stay