Elon Musk really wants us to be worried about the potential danger of artificial intelligence. He just told an MIT symposium that he feels it's "our biggest existential threat," then ratcheted the hyperbole further, saying "with artificial intelligence, we're summoning the demon." He added that "HAL9000 would be... like a puppy dog," and said governments need to start regulating the development of AI sooner than later. Last August, Musk said that super-intelligent robots were "potentially more dangerous than nukes." Paranoid rantings? We doubt it -- given his track record, it's more likely that Musk knows something we don't.