Are You Living in a Computer Simulation?

TL;DR — Bostrom’s trilemma: at least one of three propositions about posthuman civilisations and ancestor simulations must be true.

⬇ Download the archived copy — kept here so the document survives its source going dark. Explicitly free / author-released / CC.

Philosophical Quarterly (2003) Vol. 53, No. 211, pp. 243–255; first version 2001.

The argument is a trilemma, not a claim — and that is the part popular retellings drop. At least one of the following is true: the human species very likely goes extinct before reaching a posthuman stage; any posthuman civilisation is extremely unlikely to run significant numbers of ancestor simulations; or we are almost certainly living in one.

Fourteen pages, and the reasoning is a straightforward indifference-principle argument once the setup is granted. The most-recommended philosophy paper in either thread.

Where this came from

• Will Manidis’s “most underrated PDF” thread

Recommended 3 separate times across the sources above.

14 pages. A copy is archived locally against link rot; the header links the original source.