Search for free will pits scientists against philosophers

Our actions may be fully caused and determined by events that precede our very existence, but not all causes are alike. Josef Grunig/Flickr

For most of the last couple of centuries, philosophers have had the question of free will largely to themselves (prior to that date, the distinction between philosophy and the natural sciences was less clear). In recent years, however, scientists have begun to investigate free will, as they understand it.

There have been a number of experiments aimed at showing that free will doesn’t exist; more generally, some scientists have seen the success of science in explaining human behaviour as evidence against the existence of free will. For the most part, philosophers have been unimpressed since the kind of free will scientists typically deny we have isn’t the kind of free will that has been the subject of philosophical debate.

No philosopher believes that if free will is real, human behaviour is unpredictable. The majority of them believe that free will consists in some kind of power to guide one’s behaviour in the light of reasons. They expect this power to be explicable in scientific terms: the product of complex brains like ours and nothing supernatural or spooky.

Contra the scientists, most philosophers don’t even believe that free will requires indeterminism (the idea that not all events are completely determined by a preceding cause) in the laws of nature or in our brains.

In response to philosophical criticism of their work, scientists have sometimes replied that it’s not the philosopher’s conception of free will that matters: it’s the ordinary conception. They’re interested in what people in the street believe: after all, it’s ordinary people who, for instance, sit on juries in criminal trials.

This response has not impressed philosophers either, because the scientists haven’t usually bothered to gather data on what ordinary people believe, while philosophers, increasingly, have been investigating just this topic. In the past year or so, we have several times been witness to the bizarre spectacle of scientists insisting that they know what ordinary people think without checking, while the philosophers cite data!

Because the scientists don’t investigate what philosophers mean by free will, philosophers haven’t welcomed their contributions. Recently, however, scientists have turned their attention to a new topic: not the existence of free will, but what the effects of denying the existence of free will might be. This research built on previous work, by Kathleen Vohs and Jonathan Schooler and by Roy Baumeister and colleagues.

In the earlier studies, it was found that giving participants passages that denied the existence of free will led to more cheating on a subsequent test, and less helpful behaviour, compared to participants who read neutral passages. But there was a potential problem with the studies.

The passage used (from the Nobel prize winning scientist, Francis Crick) did not merely deny the existence of free will, it mocked the idea. Most people believe in free will so it might be that having one’s cherished notions mocked caused the behaviour observed, rather than the denial of free will itself.

In the recent study by Rigoni and colleagues, the passages the participants read avoided these problems. Rather than mocking free will, the passages asserted that determinism was true and therefore all actions are determined (controls got neutral passages to read). Then belief in free will was measured, and participants performed a number of tasks.

The most important of these was the free decision task: subjects saw a ball roll down a ramp, and were instructed to stop it (by pressing a button) on some trials. The subjects who got the determinism passages professed a less strong belief in free will. They also pressed the button stopping the ball less often. They were also less likely to judge that early decisions made to press the button were the result of their choices.

Rigoni and colleagues suggest that their free will manipulation was causally involved in the difference in button pressing. Subjects who have lower levels of belief in free will are less likely to exert the effort required to press the button. There’s good independent evidence that the mental acts of deciding and initiating actions are effortful. So, the suggestion is not implausible. However, I want to register two points.

The first is that though the passages used were an improvement on earlier attempts, we still don’t know whether it’s denying free will that causes the behavioral effects. Though it’s still unclear whether people believe that determined actions are unfree, it does seem as though ordinary people have a deterministic theory regarding free will (the debate is about how ordinary people judge individual actions, not about their theories). It may be that denying a cherished claim produced the effect, rather than anything specific to free will.

The second point is more philosophical. Recall that many philosophers believe that free will is the power to respond to reasons. The experiment actually demonstrates just the kind of point these philosophers aim to make. Our actions may be fully caused and determined by events that precede our very existence, but not all causes are alike. It wasn’t the laws of nature that caused these participants to conclude that inhibiting their responses wasn’t worth the effort, it was their beliefs.

The experiment may have provided data that people have a theory that free will is inconsistent with determinism, but at the same time it provided evidence in favour of the philosophical theory that what matters for free will is our response to put beliefs, not the causal structure of the universe.

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