"Are You Living in a Computer Simulation?" is a 2003 philosophy paper by Nick Bostrom that sets out the simulation argument. The paper holds that at least one of three propositions about the future of intelligent life must be true, the third being that the inhabitants of a civilization are almost certainly living in a computer simulation.
Author: Nick Bostrom Publication: Philosophical Quarterly (2003) Vol. 53, No. 211, pp. 243–255 (first version 2001) Source: simulation-argument.com
Summary of the argument
Bostrom argues that at least one of the following propositions is true:
- The human species is very likely to go extinct before reaching a "posthuman" stage.
- Any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof).
- We are almost certainly living in a computer simulation.
From these, Bostrom draws the conclusion that the belief that there is a significant chance we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation.
The argument rests on a functionalist, substrate-independence premise: that a mind implemented on a sufficiently detailed computational substrate could have conscious experience comparable to a biological mind. More than 20 years after publication, the paper remains a canonical articulation of that functionalist-substrate-independence position, and is referenced across contemporary work on AI welfare, consciousness, and computational functionalism.
Relation to other debates
Bostrom's argument operates at the level of the consciousness ontology question — whether and on what substrate minds can exist. Lerchner's anti-computational-functionalist argument (The Abstraction Fallacy: Why AI Can Simulate But Not Instantiate Consciousness — Alexander Lerchner (Google DeepMind, March 2026)) engages directly with the functionalist premise the simulation argument depends on, taking the structurally opposed position that the premise is wrong. The Microsoft AI "seemingly conscious AI" (SCAI) framework (Seemingly Conscious AI Risks — Bariach, Schoenegger, Bhaskar, Suleyman (Microsoft AI, 2025) / We Mustn't Let AI Hack Our Empathy Circuits — Mustafa Suleyman (Nature World view, 2025)) instead sidesteps the consciousness ontology question rather than answering it.
The simulation-hypothesis tradition also informs arguments about AI Welfare / Model Welfare / Moral Patienthood: if simulated minds could count morally, then so might AI minds. The paper serves as a foundational anchor both for AI Welfare / Model Welfare / Moral Patienthood and for the philosophical-functionalism strand of the AI Consciousness debate, and as a companion to Bostrom's other AI-relevant writings (Nick Bostrom).
Relationships
- supports: AI Consciousness, AI Welfare / Model Welfare / Moral Patienthood (functionalist-premise anchor)
- contradicts: The Abstraction Fallacy: Why AI Can Simulate But Not Instantiate Consciousness — Alexander Lerchner (Google DeepMind, March 2026) (Lerchner's anti-functionalist argument is structurally opposed to the Bostrom premise)
- related: Seemingly Conscious AI Risks — Bariach, Schoenegger, Bhaskar, Suleyman (Microsoft AI, 2025), Nick Bostrom, Eric Schwitzgebel, David Chalmers
- instance-of: AI Welfare / Model Welfare / Moral Patienthood (foundational philosophical contribution)