In the fall of 2023, Ilya Sutskever, OpenAI’s chief scientist, sent secret memos to three fellow-members of the organization’s board of directors. For weeks, they’d been having furtive discussions about whether Sam Altman, OpenAI’s C.E.O., and Greg Brockman, his second-in-command, were fit to run the company. Sutskever had once counted both men as friends. In 2019, he’d officiated Brockman’s weddi...