Determinism and Free Will (Pt. I)

Philosopher Stephen Cave wrote in The Atlantic a few years ago that the idea that human beings have free will is dying out among scientists. The results of the experiments of neuroscientists, he argues, all seem to support the notion that at any given moment there's only one possible future. Our "choices" are determined by causes of which we may be completely unaware but which make our decisions ineluctable.

I've excerpted parts of Cave's essay below and follow the excerpts with critical comments.

Cave observes that,

In recent decades, research on the inner workings of the brain has helped to resolve the nature-nurture debate—and has dealt a further blow to the idea of free will.

Brain scanners have enabled us to peer inside a living person’s skull, revealing intricate networks of neurons and allowing scientists to reach broad agreement that these networks are shaped by both genes and environment. But there is also agreement in the scientific community that the firing of neurons determines not just some or most, but all of our thoughts, hopes, memories, and dreams.

It should be noted that the agreement to which he refers is a tacit consequence of a metaphysical assumption shared by many researchers - the assumption that there are no non-physical, non-material factors at play in the universe or in human beings. Of course, if physicalism or materialism are true then determinism follows, but there's no good reason to think that either are true and good reasons to think they're not.

He goes on to say that,

We know that changes to brain chemistry can alter behavior—otherwise neither alcohol nor antipsychotics would have their desired effects. The same holds true for brain structure: Cases of ordinary adults becoming murderers or pedophiles after developing a brain tumor demonstrate how dependent we are on the physical properties of our gray stuff.

Quite so, but it doesn't follow from the fact that changes in the physical brain cause changes in behavior that therefore the physical brain is all that's involved in behavior. A viewer can change the physical settings on his television and thereby change the image on the screen, but it would be foolish to conclude that therefore the image can be completely explained in terms of the workings of the television set.

Many scientists say that the American physiologist Benjamin Libet demonstrated in the 1980s that we have no free will. It was already known that electrical activity builds up in a person’s brain before she, for example, moves her hand; Libet showed that this buildup occurs before the person consciously makes a decision to move.

The conscious experience of deciding to act, which we usually associate with free will, appears to be an add-on, a post hoc reconstruction of events that occurs after the brain has already set the act in motion.

This is a misreading of Libet's work, a clarification of which can be read here. Libet himself believed that human beings had free will. It would've been peculiar of him to hold this view after he had proven that the view was wrong.

The challenge posed by neuroscience is more radical: It describes the brain as a physical system like any other, and suggests that we no more will it to operate in a particular way than we will our heart to beat. The contemporary scientific image of human behavior is one of neurons firing, causing other neurons to fire, causing our thoughts and deeds, in an unbroken chain that stretches back to our birth and beyond.

In principle, we are therefore completely predictable. If we could understand any individual’s brain architecture and chemistry well enough, we could, in theory, predict that individual’s response to any given stimulus with 100 percent accuracy.

If the system which produces our choices is indeed "a physical system like any other" then determinism is very probably true, but the assumption that our choices are solely the product of physical causes is an unprovable metaphysical faith-claim. If we are also possessed of an immaterial, non-physical mind or soul, as many philosophers believe, that faculty could possibly function as a locus of free choice.

The only reason for thinking that such minds don't exist is an apriori commitment to physicalism.

More on Cave's essay tomorrow.