In 1999, a young PhD candidate in philosophy named Nick Bostrom published an article in Mind entitled “The Doomsday Argument is Alive and Kicking.” The article asked whether probabilistic attempts to predict when the last human being would be born were reasonable. (They were, it argued.) The title, however, signaled something far more significant: the end of post–Cold War optimism. Human extinction was back on the menu.
In the years following the Mind article, Bostrom’s star would rise....
