“Free will” is an illusion. What you do is determined by the structure of your nervous system and the sensory signals that go into it.

You don’t believe that? To begin with, what happens when you itch? You scratch. Even if you had sensory inputs in the past that told you not to scratch, and you remember that you shouldn’t scratch, you eventually scratch.

Maybe that doesn’t count because it’s just a reflex action that bypasses your mind, and you still have free will for more complicated actions. But think about addiction: people smoke when they know they shouldn’t, do drugs when they don’t want to, eat more than they know they should, and so on. They go to places where they are allowed to smoke, they go out of their way to contact drug dealers, they open the refrigerator. These are not simple reflex actions. They are “willful” acts, driven by something beyond our “will.”

Think about it: where would “free will” come from? Your mind, your consciousness, is a physiological process going on in your brain. The structure and function of the brain are determined by two basic factors: genetic patterns we inherit, and learning from what we experience. Heredity and environment; there’s nothing else.

When you “decide” to do something, processes go on inside your brain that depend on how your brain was formed by heredity and environment. These processes cause muscles to contract so that your facial expression changes, you make noises that we call speech, your hands, arms, and legs move so you can go places and make things happen.

For example: Charles Darwin, as a result of the structure and function of his brain and the opportunities available to him, traveled as ship’s naturalist on the Beagle. His observations on that voyage caused processes in his brain that resulted years later in the publication of the Origin of Species.

The implications for “moral responsibility” are not at all clear to me. Obviously, somebody who habitually violates the law is just someone whose brain is not working the way it should. But I don’t know whether such a brain could be reshaped into a more acceptable form, and if it could, whether “punishment” or “treatment” would be the best way to do it.

And of course there’s the complication that whether we punish or treat criminals depends solely on the structure and function of our own brains.