**Doomsday Argument**

If humanity is assumed to grow exponentially until it ends at some point in time (“doomsday”), then it is more likely to find a randomly selected human near the end of history than at the beginning. Hence, since we are alive today we can deduce that we are close to the end of history and use Bayesian reasoning to estimate the expected remaining time. The argument (which can be applied to many other things, such as the remaining time the Earth is inhabitable) is hotly debated, and involves many subtle assumptions of probability. [The argument originated by Brandon Carter and was published by John Leslie in *The End of the World* (Routledge 1996)]