The more I learn about biology, the less I believe in free will.
All of our behavior results from a bunch of molecules bouncing around according to the laws of quantum mechanics. Seen that way, we don’t have any more free will than pebbles being tumbled down a river. We think we have free will because we can’t predict the future, and because our immediate experience is full of so much ambiguity.
Free will is an illusion, but it’s a powerful, persistent and useful illusion. The inherently complex and chaotic nature of our brains prevents us from being able to predict our own actions. We’re even worse at predicting events caused by the emergent complexities of the interactions between large groups of people other people.
Way down at the quantum level, we may well be living in a deterministic universe. But because we have no way of perceiving all the intricate quantum interactions doing the determining, for all practical purposes, we might as well pretend to have free will.
I reached the same conclusion a while back. Daniel Dennett, in his book Freedom Evolves, reaches the opposite conclusion using a variety of very clever arguments. I’m not fully convinced, but he does take a respectable crack at it.
A nitpick, though–at the quantum level, behavior is not deterministic. It’s probabilistic. For example, there’s no way to know exactly which atoms of a radioactive isotope will decay in a given second, but given a few trillion atoms, you can say with shocking accuracy how many will decay in a given second.
Even without invoking quantum level behavior, I think free will is a pretty dubious proposition. Genetic and environmental influences (nature and nurture, if you will) seem to provide a complete set of causes for human behavior. If you take those out of the equation, what’s left? Magic?
You were never going to believe in freewill in the first place.