Is mind an illusion? When we introspect, are we merely passive observers of a process over which we have no real influence? If so, what are the implications for the science of mental function?
For millennia, theologians first and now philosophers and neuroscientists have tried to free us from the conundrum of determinism. Whether you believe in an all-powerful god, or in the ultimate, brute reality of molecules and energy, it takes some fancy philosophical footwork to convince yourself that you are truly the captain of your own ship.
I want to return to the question in more detail later, but right now my aim is to show how the conundrum of free will versus determinism makes it essential to resist the idea that neuroscience will ultimately solve all of our psychiatric problems.
Free will has been a thorny philosophical question for ages; what has it to do with mental illness? Two things, really. First, the sense that one does not have free will-that one's thoughts and actions are driven by something beyond one's own psyche, soul, consciousness, mind, will, or what have you-is very odd, and suggests a serious mental illness like schizophrenia or obsessive compulsive disorder.
Second, the fact that we experience free will, whether or not it is true, makes it a core phenomenon of mental life, and something that must be contended with if one is to develop a biologically coherent psychological account of mental life and mental illness symptoms.
What's the scientific alternative to free will? Mind is a complex function, like weather, or an ecosystem. In the best of scientific circumstances, we might have a powerfully predictive model. Suppose we did have such a model, into which one could plug an array of input variables-data about a person's genetic makeup, temperamental disposition, behavioral conditioning, major life events. Your model could, perhaps, generate a highly probable prediction of the outcome of some mental function, but we haven't explained away free will.
Determinism is meaningless to the individual. If your model predicted that I would choose a tuna sandwich over a ham sandwich for lunch, and you told me this, I might choose ham simply to demonstrate my independence. Even a reliable statistical model for behavior could only predict the behavior of a population, not an individual. Nine people out ten might pick up a quarter on the sidewalk, but if we are interested in what makes one person bend over to pick up this quarter, today, on this sidewalk, and another person to forego it, statistical models do not get us there.
Psychiatrists are concerned with individuals, and in psychiatry the ability to understand an individual's motivations and vulnerabilities can mean life or death. The knowledge that 9837 out of 10,000 people would not kill themselves under a given set of circumstances is less likely to help you deter a suicide than is an intimate knowledge of the forces that drive the patient in your office, right now, towards or away from suicide today.
The philosophical question of free will is yet another reason it is safe to assume that psychiatry is still very much in need of a scientific foundation in psychology, which does take the individual mind as its subject matter, and not just neuroscience, which looks at brain functioning in general.