The Simulation Hypothesis: Are We Living in a Computer Program?
The idea that our reality might be a computer simulation run by a more advanced civilization. It was set out formally by philosopher Nick Bostrom in 2003. It is a philosophical argument, not an established scientific finding.
Verdict: Unproven. The sources below do not establish this claim. That is not the same as proving it false. How we rate stories
The Story
The idea that the world might be an illusion is ancient. In 2003 the philosopher Nick Bostrom gave it a modern, statistical form.
His argument runs roughly like this. If civilizations can reach a stage where they can run detailed simulations of their ancestors, and if they choose to run many of them, then simulated minds would vastly outnumber real ones. So at least one of three things must be true: civilizations almost never reach that stage, they almost never run such simulations, or we are almost certainly living in one.
'This is not a scientific question; there is no objective way to test it.' — Simon Duan, Scientific American
The idea spread far beyond philosophy. At the 2016 Isaac Asimov Memorial Debate at the American Museum of Natural History, scientists argued it out on stage. Some floated possible physical tests. Others, like physicist Lisa Randall, rejected the probabilities underlying it.
Critics say the hypothesis cannot be tested, which places it outside science. For now it remains an unproven philosophical idea: a thought experiment, not a discovery.
Origins
In 'Are You Living in a Computer Simulation?' (Philosophical Quarterly, 2003), philosopher Nick Bostrom argued that 'at least one' of three propositions is true. One of them is that we are almost certainly living in a computer simulation.
The Claims
- Advanced civilizations could run vast numbers of simulated worlds, so we are most likely in one of them.
- The laws of physics might reveal 'code' underlying reality.
Key Evidence
- Bostrom's paper presents a formal probabilistic argument. Its conclusion is that we should accept at least one of three options, not that we are definitely simulated.
- According to Scientific American, physicist James Gates said at the 2016 Isaac Asimov Memorial Debate that evidence of spacetime made of discrete points, such as signatures in cosmic rays, 'would convince me as a physicist.'
The Evidence Against
- At the same debate, Harvard physicist Lisa Randall said the statistical argument is 'just not based on well-defined probabilities,' Scientific American reports.
- In a 2024 Scientific American opinion piece, Simon Duan wrote that 'this is not a scientific question; there is no objective way to test it.'
- No experiment has found evidence that reality is simulated.
Documents & Sources
- AcademicNick Bostrom, 'Are You Living in a Computer Simulation?' Philosophical Quarterly (2003) (PDF) simulation-argument.com ↗
- NewsAre We Living in a Computer Simulation? (Scientific American, 2016) scientificamerican.com ↗
- NewsStop Asking If the Universe Is a Computer Simulation, by Simon Duan (Scientific American, opinion) scientificamerican.com ↗
Each link was checked for availability on Oct. 27, 2026. Links open in a new tab.