by Ashutosh Jogalekar
The Doomsday Scenario, also known as the Copernican Principle, refers to a framework for thinking about the death of humanity. One can read all about it in a recent book by science writer William Poundstone. The principle was popularized mainly by the philosopher John Leslie and the physicist J. Richard Gott in the 1990s; since then variants of it have have been cropping up with increasing frequency, a frequency which seems to be roughly proportional to how much people worry about the world and its future.
The Copernican Principle simply states that the probability of us existing at a unique time in history is small because we are nothing special. We therefore must exist roughly close to half the period of our existence. Using Bayesian statistics and the known growth of population, Gott and others then calculated lower bounds for humanity’s future existence. Referring to the lower bound, their conclusion is that there is a 95% chance that humanity will go extinct in 9120 years.
The Doomsday Argument has sparked a lively debate on the fate of humanity and on different mechanisms by which the end will finally come. As far as I can tell, the argument is little more than inspired numerology and has little to do with any rigorous mathematics. But the psychological aspects of the argument are far more interesting than the mathematical ones; the arguments are interesting because they tell us that many people are thinking about the end of mankind, and that they are doing this because they are fundamentally pessimistic. This should be clear by how many people are now talking about how some combination of nuclear war, climate change and AI will doom us in the near future. I reject such grim prognostications because they are mostly compelled by psychological impressions rather than by any semblance of certainty. Read more »