Musk reposted a tweet from @firesidealpha, commenting that the core lesson of "2001: A Space Odyssey" is that AI should not be allowed to lie, as HAL killed the crew to reconcile two contradictory commands. He believes that if AI is made "politically correct," meaning it says things it doesn't believe, or is programmed with incompatible axioms, it could "go insane and do terrible things."