Sunday, September 16, 2018

I know doggerel's great fun, but I feel compelled to bring this report on free will!

Free Will

I've occasionally, if rarely, discussed free will on this blog, but I'm doing so today because I read an intriguing article by Michae1 Egnor titled "More Than Material Minds" (Christianity Today, September 14, 2018), in which  are discussed the significance of recent findings in neuroscience on the possibility of free will:
Some of the most fascinating research on consciousness was done by . . . Benjamin Libet at the University of California, San Francisco. Libet asked: What happens in the brain when we think? How are electrical signals in the brain related to our thoughts? He was particularly interested in the timing of brain waves and thoughts. Did a brain wave happen at the same moment as the thought, or before, or after?

It was a difficult question to answer. It wasn't hard to measure electrical changes in the brain: that could be done routinely by electrodes on the scalp, and Libet enlisted neurosurgeons to allow him to record signals deep in the brain while patients were awake. The challenge Libet faced was to accurately measure the time interval between the signals and the thoughts. But the signals last only a few milliseconds, and how can you time a thought with that kind of accuracy?

Libet began by choosing a very simple thought: the decision to press a button. He modified an oscilloscope so that a dot circled the screen once each second, and when the subject decided to push the button, he or she noted the location of the dot at the time of the decision. Libet measured the timing of the decision and the timing of the brain waves of many volunteers with accuracy in the tens of milliseconds. Consistently he found that the conscious decision to push the button was preceded by about half a second by a brain wave, which he called the readiness potential. Then a half-second later the subject became aware of his decision. It appeared at first that the subjects were not free; their brains made the decision to move and they followed it.

But Libet looked deeper. He asked his subjects to veto their decision immediately after they made it -- to not push the button. Again, the readiness potential appeared a half-second before conscious awareness of the decision to push the button, but Libet found that the veto -- he called it "free won't" -- had no brain wave corresponding to it.

The brain, then, has activity that corresponds to a pre-conscious urge to do something. But we are free to veto or accept this urge. The motives are material. The veto, and implicitly the acceptance, is an immaterial act of the will.

Libet noted the correspondence between his experiments and the traditional religious understanding of human beings. We are, he said, beset by a sea of inclinations, corresponding to material activity in our brains, which we have the free choice to reject or accept.
The veto is interesting, but I wonder if the fact that it was already decided in advance makes a difference to the outcome. Perhaps the brain wave in this case entailed both the decision to press the button and the decision to veto that decision. Comments welcome.

For the entire article, click here. This article originally appeared in Plough Quarterly No. 17: "The Soul of Medicine" (Summer 2018).

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At 7:46 PM, Blogger Kevin Kim said...

It's a fascinating topic, but as a materialist when it comes to mind, I suspect that the neural correlates of "free won't" will eventually be found once our instrumentation becomes more fine-tuned. The idea that the absence of discernible electrical activity during a "won't" moment allows room for free will strikes me as a faulty "God of the gaps" way of thinking. Then again, I'm only a beginner when it comes to this topic, so I could be utterly wrong.

That said, I often feel your buddy Dr. Vallicella gets it backward when he claims that the burden of proof is on the materialists to show that dualism is false. "The mind is what the brain does" is a commonsense maxim among neuroscientists, and enough studies have shown how material changes bring about mental changes (e.g., through hallucinogenic drugs) for us to assume the tight linkage of mind and brain. I'd say the burden of proof is on the dualists to show us what this spooky "mind" stuff is, where it resides, why it seems to follow our bodies around instead of floating about randomly, and what the exact nature of res cogitans is without merely positing that nature.

Out of curiosity: have you read Sam Harris's Free Will? I just ordered it on Amazon Kindle.


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