Your mother's socio-economic status at the time of your birth. Whether your ancestors raised crops or led camels through the desert. The smell of the room you're in when you're making a decision--all of these things, says neuroscientist Robert Sapolsky, combine to affect your behavior, as well as everything in between. And if you're wondering where free will fits in, Sapolsky says, it doesn't: If we're all the sum of our biology and environments over which we had no control, it makes no sense to hold us accountable for anything that we do. In a conversation that's equal parts fascinating and frightening, Sapolsky and EconTalk's Russ Roberts discuss the science and philosophy behind determinism. They explore what this argument, taken to its logical conclusion, means for our social and legal systems, and the challenge of how to live if free will is an illusion.