The Illusion of Free Will

Neil deGrasse Tyson: What exactly do we mean when we say that a person has free will? He says there are proponents of what's called libertarian free will. On the other end of the spectrum, he says, is hard determinism or causal determinism. In theory, if we had total understanding of the universe and every event proceeding back to Big Bang, in theory, could we predict next thing everyone is going to do? De Grasse Tyson: If you can predict where Jupiter is going to be 20 years from now, I hope not.