For most of human history, philosophers have believed that only the possession of an immaterial soul could confer free will on human beings. (There have been exceptions: the ancient Greek Stoics, for example.) This idea has fallen somewhat out of favor, but there are many theists who still hold to it. They are willing to concede that the universe we live in is an interwoven tapestry of cause and effect, but insist that we are special somehow, that we are an exemption.
If free will truly requires a magical power to exempt ourselves from the fabric of causality, the prospects of retaining it in a natural world seem dim indeed. But that consideration aside, this idea must still be considered on its own merits. The first and most important question is, how does this doctrine work? According to dualism, why do we make the decisions we do?
The classic theologian's answer is that the soul in some way inhabits our minds, directing the operation of our bodies. (Descartes, for example, thought that the interface point between soul and body was the pineal gland of the brain.) But on a closer look, this "answer" is really not an answer, because it does not explain anything at all. If there is a tiny homunculus inside each person's head, watching the input from the eyes on a screen and making the body move by pulling strings (the idea of the "ghost in the machine", or what Daniel Dennett disparagingly calls the "Cartesian theater"), then how does that homunculus' mind work? What makes it think and decide? If we cannot explain the operation of that complex organ called our mind in terms of less complex components, then there is a looming problem of infinite regression.
Furthermore, this idea leaves unanswered the question: If the soul controls all the important functions of consciousness, if all this information processing takes place elsewhere, then what is the brain for? If its only role were to control body functions, it would seem that we could do perfectly well with just a brainstem. Why do we have this massively enlarged cortex if it plays no role in our consciousness? (The proper rebuttal to the old saw that "we only use 10% of our brains" is this: Have you ever heard of someone who was shot in the head, but survived with no significant deficit because the bullet only damaged the 90% of his brain he wasn't using?)
Another dualist attempt to explain the source of free will is the doctrine of "agent causation". By this account, causes produce effects, which themselves can be causes in turn; but agents such as human beings also give rise to effects, and agents are not themselves caused by anything. As the philosopher Roderick Chisholm put it, "we have a prerogative which some would attribute only to God: each of us when we act is a prime mover unmoved. In doing what we do, we cause certain things to happen, and nothing - or no one - causes us to cause those events to happen."
Many kinds of metaphysics are obscure, but this kind seems to be intentionally obscure. Advocates of agent causation would have us believe that there simply is no cause for any of our actions - not even a reason. We just act, and the question of why has no answer. If this is the case, why are our actions so predictable? If there is no cause or reason why a person would, for example, go to work one day rather than steal a car and go on a multi-state crime spree, why do most of us so consistently do the former and not the latter? If there are no causes or reasons pushing us in one direction rather than another, every possible action should be equally probable, but this is clearly not the case.
These ideas are not solutions to the problem; they are a refusal to face the problem. And furthermore, they are not true. We know beyond any reasonable doubt that we are not unmoved movers, that we are not pure rational agents who make their decisions in a higher plane removed from earthly cause and effect.
Our thoughts and behavior demonstrably depend on the physical operation of our brains, and can be changed by physical causes that affect the way our brains work. Anesthetics shut off our consciousness, while stimulants accelerate it. Psychoactive drugs can cause or suppress hallucinations, provoke or quiet anxiety and paranoia, and affect mood, behavior and judgment. Certain genes are strongly implicated in the origin of mental disorders such as schizophrenia and OCD. Certain specific types of brain damage cause specific and predictable alterations in the way we believe, think, and decide. (For many strange and fascinating examples of this, see "A Ghost in the Machine".) Even the dualists' last redoubt, qualia, can be altered or eliminated by physical changes to the structure of the brain.
Dualism is a futile doctrine. It does not explain free will at all, rather seeks to avoid the problem by resorting to mystery; and it is contradicted by the facts. If we are to preserve the belief in free will, we need a better way to account for it - a naturalistic way, one that does not depend on a god of the gaps or on something remaining forever mysterious to us.
Some commentators, and not just dualists, would claim that this is impossible. These people believe that free will is an impossible fantasy, and now that science has revealed we live in a naturalistic universe, we should accept that we have no free will and be done with it. I do not agree.
True, I am not speaking of the mystical, dualist free will, where human beings can float free of causality and make decisions supernaturally exempt from external influence. We have every good reason to believe that that sort of free will is impossible. However, I believe it is possible to give a natural explanation of free will, one that preserves the qualities we value most - unpredictability, choice, and moral responsibility. The next three posts in this series will tackle each of these in turn.
Other posts in this series: