EXCERPT This is a book about human extinction. More specifically, it is a book about the history of humans thinking about human extinction. It examines how and when our species first became concerned about its ultimate fate. Because, like all important scientific, philosophical, or ethical ideas—from general relativity to gender equality—in order to become a subject of discussion and debate, this idea first had to be discovered. X-Risk reveals the untold story of the various polymaths and pioneers who made this momentous discovery. The story links contemporary debates—on topics ranging from superintelligent AIs to designer pandemics—back to the centuries-long globe-spanning drama that made them possible. Along the way we meet a range of unlikely characters including Russian princes, Romantic geologists, Victorian astrobiologists, and Marxist crystallographers. In retracing the past history of our concern for our future, we learn how today’s discussions regarding humanity’s long-term fate emerged from and grew out of the broader sweep of human history. And ultimately, retracing this history helps clarify exactly what we take our purpose as intelligent beings to be. The primary contention of the book is that human extinction is a comparatively novel idea, one that remained entirely unavailable for the greater part of our existence as a species.…