On May 25, 2015, Sam Altman sent an email to Elon Musk proposing a “Manhattan Project for A.I.” He envisioned a Silicon Valley research lab that would build enormously powerful artificial intelligence and share it with the rest of the world “via some sort of nonprofit.” Mr. Musk replied that evening, saying the idea was “probably worth a conversation.” Before the end of the year, the two tech entrepreneurs founded a nonprofit they called OpenAI, which would go on to launch the global A.I. boom