Nov 25, 2006

NewScientist at 50: Patricia Churchland on free will

NewScientist often features humorous little pieces on "nominative determinism," the idea that your name can control your destiny.

It's not quite perfect. Consider Patricia Churchland, a neurophilosopher who isn't exactly friendly to a theistic worldview, since she espouses "eliminative materialism," the idea that the mind is matter, and that's all that matters.

In her contribution to NewScientist's 50th anniversary special, she explains how this affects traditional notions of free will. She begins by asking us to consider a tumor that turns an otherwise normal man into a pedophile: not just a hypothetical, but as reported in a 2003 article from the Archives of Neurology.
A middle-aged Virginian man with no history of any misdemeanour began to stash child pornography and sexually molest his 8-year-old stepdaughter. Placed in the court system, his sexual behaviour became increasingly compulsive. Eventually, after repeatedly complaining of headaches and vertigo, he was sent for a brain scan. It showed a large but benign tumour in the frontal area of his brain, invading the septum and hypothalmus - regions known to regulate sexual behaviour.

After removal of the tumour, his sexual interests returned to normal. Months later, his sexual focus on young girls rekindled, and a new scan revealed that bits of tissue missed in the surgery had grown into a sizeable tumour. Surgery once again restored his behavioural profile to "normal".
Churchland uses this extreme case to test the limits of the libertarian conception of uncaused free will, which she ultimately dismisses, writing,
...choices are made by brains, and brains operate causally; that is, they go from one state to the next as a function of antecedent conditions. Moreover, though brains make decisions, there is no discrete brain structure or neural network which qualifies as "the will" let alone a neural structure operating in a causal vacuum. The unavoidable conclusion is that a philosophy dedicated to uncaused choice is as unrealistic as a philosophy dedicated to a flat Earth.
Instead, Churchland advocates a framework of moral responsibility based on "self-control."
Unlike free will, self-control is a concept that we can usefully apply to other animals.... Through reinforcement, my dog has learned to lie quietly when the local squirrel taps the screen door for peanuts; a hungry chimpanzee will reach for a banana only if he knows the alpha male cannot see it, but will suppress the desire otherwise. Ulysses famously bound himself to the mast of his ship to avoid seduction by the sirens...

Self-control also allows us to make sense of difficult cases where free will is unhelpful....

...[E]ventually we will understand, at least in general terms, the neurobiological profile of a brain that has normal levels of control, and how it differs from a brain that has compromised control.
In other words, retributive justice can operate without a traditional view of totally free choice. We use the apparatus of the state to limit those who can't limit themselves. (Hobbes would proud.)

Lastly, Churchland answers those who criticize reductionism from aesthetic grounds.
In essence, the self is a construction of the brain; a real, but brain-dependent organisational network for monitoring body states, setting priorities and, within the brain itself, creating the separation between inner world and outer world....

Is one cheapened by this neuroscientific knowledge? I think not. Self-esteem and self-worth are wholly compatible with realising that brains make us what we are.... [T]he beauty, intricacy and sophistication of the neurobiological machine that makes me "me" is vastly more fascinating and infinitely more awesome than the philosophical conception of the brain-free soul that somehow, despite the laws of physics, exercises its free will in a causal vacuum. Each of us is a work of art, sculpted first by evolution, and second by experience in the world. With experience and reflection one's social perception matures, and so also does the level of autonomy. Aristotle called it wisdom.

No comments: