Richard discusses the classic philosophical problem of free will --- that is, the question of whether we human beings decide things for ourselves, or are forced to go one way or another. He distinguishes between two different worries. One worry is that the laws of physics, plus facts about the past over which we have no control, determine what we will do, and that means we're not free. Another worry is that because the laws and the past determine what we'll do, someone smart enough could know what we would do ahead of time, so we can't be free. He says the second worry is much worse than the first, but argues that the second doesn't follow from the first.