# Are we living in a simulation? > There is no evidence that we are. Nick Bostrom's 2003 argument shows only that one of three possibilities must hold, and most versions of the simulation hypothesis make no testable predictions. A more productive idea is that the universe computes without an outside programmer: physical law behaves like information processing. That version can be tested against data. Author: Mikhail Savchenko Updated: 2026-09-26 Canonical: https://neuralcosmology.com/en/answers/is-the-universe-a-simulation Locale: en Translations: en, ru, pt, es License: CC-BY-4.0 (https://creativecommons.org/licenses/by/4.0/) --- ## Bostrom's argument in plain terms Nick Bostrom's paper "Are You Living in a Computer Simulation?" (*Philosophical Quarterly*, 2003) makes a narrower claim than its reputation: one of three statements is almost certainly true. 1. Nearly all civilisations at our stage go extinct before they can run realistic simulations of minds. 2. Nearly all civilisations that can run them choose not to. 3. We are almost certainly living in a simulation, because simulated minds would vastly outnumber original ones. Which one is true depends on numbers nobody knows. The argument is logically neat and empirically empty until those numbers can be estimated. ## Why the hypothesis is hard to test A perfect simulation would reproduce physics exactly, so no experiment inside it could tell the difference. Any test has to assume an imperfect simulation with some specific shortcut. The best-known proposal is by Silas Beane, Zohreh Davoudi and Martin Savage (2012). If the simulation runs on a space-time grid, like today's lattice calculations of quantum chromodynamics, the grid would impose a maximum energy and a preferred set of directions. The highest-energy cosmic rays would then arrive in a slightly non-uniform pattern tied to the grid's axes. No such pattern has been seen. That rules out only this particular kind of simulation. Other suggested "glitches", from quantum measurement to the speed of light as a processing limit, are analogies. They explain known physics after the fact without predicting anything new. ## Simulated versus computational The simulation hypothesis bundles two different ideas: - **The universe is computational.** Its laws describe how information is transformed. This needs no outside computer. - **Someone is running it.** There is a simulator, a programmer and a purpose. This adds an agent for which we have no evidence. The first idea has a long scientific history: Konrad Zuse's *Calculating Space* (1969), John Wheeler's "it from bit" (1989), Rolf Landauer's argument that information is physical, Seth Lloyd's view of the universe as a quantum computer, and Stephen Wolfram's hypergraph models (2020). It can be turned into mathematics, and mathematics can be tested. The second idea is what makes the simulation hypothesis popular and what makes it untestable. ## The testable version The research programme on this site takes the first idea and drops the second. It treats the universe as a network that processes information, closer to Vanchurin's world-as-a-neural-network model than to a video game, and asks what that predicts for something measurable. Its preprint builds such a network as working code, the Sixth language, and derives from it complexity results, correspondences with known models of distributed computation and a substrate-language version of the standard dark-energy estimate, each with falsifiers stated in advance. The novel Bugs Academy plays the simulation idea out as fiction: a debugger who treats physical anomalies as bugs. The non-fiction The Celestial Code keeps to what can be measured. ## Bottom line Nobody knows whether we are in a simulation, and most forms of the idea cannot be tested. The part worth keeping is the claim that physics is information processing, because it leads to models that can be checked against data. ## FAQ ### What is Bostrom's simulation argument? In 2003 Nick Bostrom argued that at least one is true: almost no civilisations reach the ability to run detailed simulations of their ancestors; almost none that can, choose to; or we are almost certainly living in such a simulation. It is an argument about probabilities, not evidence that we are simulated. ### Can the simulation hypothesis be tested? Only specific versions. Beane, Davoudi and Savage (2012) showed that a universe simulated on a space-time lattice could leave a signature in the angular distribution of the highest-energy cosmic rays. No such signature has been found. ### What is digital physics? The family of ideas that the universe is fundamentally computational: Konrad Zuse's Calculating Space (1969), John Wheeler's “it from bit” (1989), Seth Lloyd's quantum-computing universe and Stephen Wolfram's hypergraph models (2020). ### Is the Neural Cosmology programme a simulation theory? No. It does not assume a simulator. It proposes that the universe processes information like a network and builds that idea as working code with falsifiers stated in advance.