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Tuesday, November 17, 2015

Is Free Will Better than Cats?

Jaroslav Flegr, a Czech scientist, has argued for decades that a surprisingly large number of people have been infected by a parasite carried by certain cats that causes toxoplasmosis. He believes the parasite remains dormant in people’s brains even after symptoms of acute infection disappear and subtly affects brain function for years to come.  As one journalist describes Flegr’s views, the “parasite may be quietly tweaking the connections between our neurons, changing our response to frightening situations, our trust in others, how outgoing we are, and even our preference for certain scents.”  The parasite may also “contribute[] to car crashes, suicides, and mental disorders such as schizophrenia”  in ways that may be killing “at least a million people a year.” 

Flegr’s views have started to receive increased attention from mainstream researchers.  But whether or not he is right, his research raises the following question: Suppose a person is, without fault, infected by a parasite that alters his brain function. Assume it doesn’t make him insane or even diagnosably mentally ill, but it changes his personality in ways that make him more careless, impulsive, aggressive, and tempted by criminal behavior. Should we hold him responsible for crimes he would not have committed but for the parasitic infection?

On one view, he should not be held fully responsible because he is not responsible for being infected and, had he not been infected, he would not have engaged in criminal behavior. Indeed, if you or I were infected, we might have engaged in the very same behavior. And, one might argue, you and I would not deserve punishment for behaviors caused by an unforeseen and unwanted infection.

On another view, we all act in ways determined by features of ourselves for which we are not responsible. Most notably, we have limited, if any, control over our genes and the environments in which we were raised. So another powerful intuition pushes us in the other direction. Merely being subject to the causal influence of factors beyond our control cannot excuse our conduct because then none of us would be responsible for anything. And surely you and I are sometimes responsible, one might argue, as when we deserve credit for our brave and heroic deeds.

Here’s one possible explanation of why those with parasite-infected brains seem less-than-fully responsible: the more we know about the “mechanistic” causes of a person’s behavior—the causes of a person’s actions framed in terms of the movement of particles or the firing of synapses (and so on)—the less inclined we are to hold the person fully responsible. I call this the “reduced responsibility” reaction. Knowledge of mechanistic causation frequently weakens our intuitions that a person is responsible, even when the mechanistic causes are unrelated to traditional excusing conditions like duress or insanity. 

So, for example, one might have a reduced responsibility reaction sparked by growing evidence that preschool lead exposure especially from car exhaust explains much of the soaring crime rates from the 1960s through the 1980s.  Or one might have such a reaction to causal stories of antisocial behavior sparked by debilitating migraines or severe premenstrual symptoms. Detailed explanations of the physiological causes of behavior sometimes reduce ascriptions of responsibilities even when traditional excusing conditions are irrelevant.

Yet those who subscribe to the scientific, mechanistic view of the universe should find the reduced responsibility reaction unreliable as a general matter. If the world is mechanistic, some mechanism explains every human action. Whether we happen to know the mechanistic causes of a person’s action is irrelevant to the person's actual level of responsibility.  Nevertheless, the reduced responsibility reaction may explain why the debate about free will has persisted for centuries: Our intuitions point us to a conclusion that lacks a sound theoretical justification.

Leading theories of free will address the reduced responsibility reaction in opposite ways. One approach, which we can call free will skepticism, says that the reduced responsibility reaction doesn’t go far enough. If knowledge of a partial causal back story reduces our ascriptions of responsibility to some degree, then a full causal back story ought to eliminate our attributions of responsibility entirely, whether we know the back story or not. In other words, one might conclude that free will doesn't really exist and that we ought not hold people morally responsible. Returning to the parasite that causes toxoplasmosis, the free will skeptic would say that those infected are not responsible for the behavior the parasite causes them to take because none of us are ever genuinely responsible for our actions. There may still be good reasons to punish people or detain them, but their responsibility for their actions is not one of them.

Alternatively, one might say that the reduced responsibility reaction itself goes too far. If partial knowledge of a causal back story inclines us to reduce ascriptions of responsibility, such reactions cannot be trusted for they imply that full causal knowledge would eliminate attributions of responsibility entirely. And responsibility plays such an important role in our daily lives that we ought not dismiss it too quickly. According to a "compatibilist's" description of the toxoplasmosis hypothetical, we should determine the details of the parasitic infection. Does it interfere with the human host’s rationality? Does it create urges that are impossible for him to resist? To the compatibilist, the mere fact that the parasite causes a person to take actions that he would otherwise resist is irrelevant to the person’s responsibility, so long as the parasite leaves intact his ability to reason, decide in accordance with his values, or satisfy some other compatibilist criterion that purportedly allows us to identify a choice with a particular person rather than just the motion of particles in his brain.

All of this is a prelude to my view (see here) that the free will debate isn't just an important philosophical issue. It's one for which the law may have its own perspective. (Adapted from Free Will as a Matter of Law; see also Will There Be a Neurolaw Revolution?) (Here's the dated reference in the title of the post.)

Posted by Adam Kolber on November 17, 2015 at 04:05 AM | Permalink

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