Doomsday Argument

The Doomsday Argument is an application of the Anthropic Principle and anthropic reasoning to the estimation of humanity's future duration. It uses self-sampling — the assumption that you are a random observer drawn from all humans who will ever exist — to argue that your birth rank provides probabilistic information about the total number of humans who will ever live.\n\nThe argument was developed by Brandon Carter and popularized by John Leslie and Nick Bostrom. It connects to broader debates in probability theory about the reference class problem and in cosmology about whether observer selection effects should constrain our estimates of existential risk. Critics dispute whether the self-sampling assumption is valid, whether the reference class of "observers" can be defined independently of the conclusion, and whether the argument conflates epistemic probability with objective frequency. The Doomsday Argument is less a settled result than a stress test for the foundations of anthropic reasoning.\n\n\n