This paper argues that at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a “posthuman” stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation. It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation. A number of other consequences of this result are also discussed.
"The Simulation Argument is perhaps the first interesting argument for the existence of a Creator in 2000 years." - David Pearce (exaggerated compliment)
"Thank you so much, Dr. Bostrom. You have proved that my psychiatrist was wrong all along." - Anonymous correpondent (misfiring compliment)