Does free will exist?
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.