Study Shows Neuroscience Doesn't Threaten Our Conception of Free Will

Friday, 19 September 2014 - 4:42PM
Friday, 19 September 2014 - 4:42PM

One of the most significant questions in philosophy is that of the potential incompatibility between predeterminism and free will. The so-called paradox of free will originated in theological arguments, in which philosophers such as Thomas Aquinas discussed whether humans can have free will in light of God's omniscience. In other words, if God knows everything we're going to do, then it seems that our actions are already set in stone, and therefore we have no choice in the matter. There are several arguments in favor of the compatibility of free will and determinism; arguably the most interesting being Aquinas's assertion that God knows everything we're going to do in the future because He is unstuck in time Slaughterhouse Five-style, and so the future is as knowable to Him as the present, regardless of whether we make choices or not. 


Modern-day philosophy is essentially concerned with the same question, with neuroscience serving the same function as an omniscient deity. Philosophers and civilians alike worry that the more we come to understand the human brain, the more we can predict human behavior based solely on brain activity. If we can glean future behavior through interactions between neurons, then all behavior could potentially be predicted, which seems to be incompatible with our conception of free will. The sect of philosophy that holds the belief that people will eventually reject free will in light of future neuroscientists' ability to perfectly predict our behavior are called "willusionists." 


But now, a study from experimental philosopher Eddy Nahmias of Georgia State University apparently contradicts the willusionists' theory. Nahmias posed the question to 278 people: if, in the future, neuroimaging technology reaches a level of sophistication at which scientists would be able to perfectly predict all of a person's decisions, then does that person still have free will? In the specific story, the person's name was Jill, and she was fitted with a neural cap that predicts all of her actions with 100% accuracy, including her votes in political elections. 92% of respondents believed that Jill was still acting on her own free will. 


From the paper: "Most people seem to understand free will in a way that is not threatened by perfect prediction based on neural information, suggesting that they believe that just because 'my brain made me do it,' that does not mean that I didn't do it of my own free will."


"This paper breaks new ground," says Joshua Knobe, a philosopher at Yale University. "But this study suggests that whatever it is that we find threatening to free will, it isn't neuroscience."


Nahmian (somewhat condescendingly) concluded that "people's understanding of free will is minimally metaphysical." "People don't have detailed metaphysical views about what underlies free will," said Nahmias. "What people care about is that their own conscious reasoning makes a difference to their behaviour – and nothing in neuroscience suggests it doesn't."


In my humble opinion, these conclusions don't necessarily follow from the study. People may very well have "metaphysical views" of free will, but simply have reasons to believe that prediction of behavior does not threaten it. Jill's story did not focus on the causation of her behavior, but almost solely on the prediction. If the story had instead posed the question, "If Jill's every behavior is determined by interactions between neurons in her brain," then the results may have turned out differently. This way, it just seems like the neural cap is predicting behaviors from factors that could very well be correlation rather than direct causation. This interpretation of the results is only reinforced by the fact that most of the respondents felt that Jill was not acting of her own free will if the neural cap manipulated her decisions. If the question is posed in a way that threatens causation of behavior, rather than unknowability, then our conception of free will is also threatened.


Some may argue that this does demonstrate that people have a less sophisticated view of free will, if they don't understand that absolute predictability is more akin to a machine than the popular conception of a human. But it may make more sense to focus on agency rather than unpredictability. For example, a recent UC Davis study showed that "arbitrary states in the brain can influence apparently voluntary decisions." In other words, the decisions that seem unpredictable, irrational, inherently human, may very well be the product of random fluctuations in the brain. But if the person's "self" is not responsible for the decision, but rather a biological determinism, then it doesn't seem to matter very much whether the behavior is predictable or not.

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