Guardians of the Apocalypse

Rick Schwall retired seven years ago after a successful career in Silicon Valley. He says he’s a millionaire but declines to reveal where he worked or how he made his money. “I consider all of that stuff to be absolutely pointless,” he says. “What is important is that in 2006 I stumbled upon existential risk.”

For the uninitiated, existential risk is a broad term covering catastrophic events that could wipe out the human species. Some existential risk devotees agonize over nuclear wars, climate change, and virus outbreaks. Others, such as Schwall, put more energy into worrying about the potential downside of information technology. They fret about a super-powerful artificial intelligence run amok and hordes of killer nanobots. “There are a number of people who have knowledge in this field that estimate humanity’s chance at making it through this century at about 50 percent,” Schwall says. “Even if that number is way off and it’s one in a billion, that’s too high for me.”