Mark Zuckerberg, Elon Musk and the Feud Over Killer Robots

Mr. Musk's fears of A.I., distilled to their essence, were simple: If we create machines that are smarter than humans, they could turn against us. Let's for once, he was saying to the rest of the tech industry, consider the unintended consequences of what we are creating before we unleash it on the world. Neither Mr. Musk nor Mr. Zuckerberg would talk in detail about the dinner, which has not been reported before, or their long-running A.I. debate. The creation of "superintelligence" -- the name for the supersmart technological breakthrough that takes A.I. to the next level and creates machines that not only perform narrow tasks that typically require human intelligence (like self-driving cars) but can actually outthink humans -- still feels like science fiction. But the fight over the future of A.I. has spread across the tech industry.