Don’t Put the Brain on Trial

Contemporary proponents of scientism, the view that the empirical sciences and mathematics are, in principle, capable of offering an exhaustive account of reality, are increasingly honest in advocating public policies that are merely the logical working out of their reductive accounts of human nature. For example, in addition to this essay published by the National Academy of Sciences (an excellent response to which can be found here), David Eagleman, a neuroscientist at Baylor College of Medicine, now argues in a recent article in The Atlantic, “The Brain on Trial,” for a “more biologically informed jurisprudence.” Specifically, Eagleman argues that a “forward-thinking legal system” will respond to neuroscience’s increasing capacity to demonstrate the illusory nature of free will by developing “customized rehabilitation” for criminal behavior.

Eagleman’s proposed rehabilitation of the criminal justice system is bad public policy for at least three reasons. First, it is based on conclusions not supported by the examples he cites as evidence. Second, it fails to recognize science’s limitations in explaining human behavior. Third, it ultimately dehumanizes in seeking to be humane. In short, scientism makes for bad philosophy, and even worse public policy.

Eagleman uses several cases in which criminals were found to have brain abnormalities in order to support his case against free will. As a paradigmatic example, Eagleman points to Charles Whitman, a 25-year-old who in 1966 took the lives of innocent strangers from the University of Texas Tower in Austin, as well as those of his wife and mother. An autopsy of Whitman’s brain revealed a tumor, which, according to Eagleman, accounted for Whitman’s self-reported experience of being “a victim of many unusual and irrational thoughts.”

The details of Whitman’s case—one from which Eagleman generalizes—are nuanced and do not support Eagleman’s portrait of the killer as hostage to neuro-abnormality. Eagleman claims that Whitman’s tumor was compressing the amygdala, a region of the brain known to be involved in fear and anger, and suggests that this tumor was principally responsible for Whitman’s homicidal actions. However, in animal studies, damage to the amygdala typically produces a less aggressive animal; formerly wild creatures become tame. In humans, amygdala damage can lead to difficulties in reading emotion in others, but it does not typically cause aggression. If certain parts of a cat’s hypothalamus are damaged, the cat does become more aggressive, as part of its “fight or flight” response. We might speculate that the tumor damaged just that spot in Whitman’s brain. But in the rare cases in which humans have suffered damage parallel to that of the hissing cats, the emotions they typically report are fear and agitation, not anger.

As importantly, the pathologist who performed Whitman’s autopsy denied that the tumor had anything to do with Whitman’s behavior or headaches. The autopsy report describes the tumor, but claims “no correlation to psychosis.” The Governor requested a medical investigation, and a team of seven pathologists examined the evidence, including the tumor and parts of the brain, and concluded that “the data obtained provide no evidence that this man had a clinical neurological abnormality, and there is no evidence from the pathological reports that the tumor interrupted pathways leading to detectable neurological signs.”

Although Eagleman describes Whitman’s personal life prior to his killing spree as “unremarkable,” implying that the tumor turned a well-adjusted Boy Scout leader into a killer, by all accounts, Whitman had a troubled personal life. His father was harsh and abusive, and Whitman was distraught at his parents’ recent separation. Several years before the murders, he was court-martialed by the Marines. Although Whitman’s suicide note does describe his feeling that he does not really understand himself and his violent impulses, and requests an autopsy to look for physical causes of his mental turmoil, he also offers reasons for killing his wife. He describes himself as uncertain about which reason is the most compelling, and this part of the letter is quoted by Eagleman: “I cannot rationaly [sic] pinpoint any specific reason for doing this.” But Whitman goes on:

I don’t know whether it is selfishness, or if I don’t want her to have to face the embrassment [sic] my actions would surely cause her. At this time, though, the prominent reason in my mind is that I truly do not consider this world worth living in, and am prepared to die, and I do not want to leave her to suffer alone in it. I intend to kill her as painlessly as possible.

Whitman goes on to say that his reasons for killing his mother were similar. He had witnessed her being regularly beaten by his father, who prevented her from ever enjoying life. In another letter, Whitman expresses distress at having killed his mother, but explains that he had either sent her to heaven or, if there is no such thing, ended her great suffering. He writes, “I am truly sorry that this is the only way I could see to relieve her sufferings but I think it was best. Let there be no doubt in your mind I loved that woman with all my heart. If there exists a God let him understand my actions and judge me accordingly.”

Whitman’s own account of his actions does not give the impression that he flew into a murderous rage as a result of a storm of uncontrollable emotion. Neither does it give the impression that he lacked empathy or all sense of right and wrong. He describes his murders as a form of euthanasia. He does also describe fighting violent impulses and irrational thoughts, but doesn’t understand himself to have given in to them. He understood himself to be making a choice. Like all choices, it was influenced by a complex mix of factors, but despite Eagleman’s assertion to the contrary, Whitman’s case does not stand as particularly strong evidence for neurological determinism of criminal behavior.

As we noted above, Eagleman believes that we can extrapolate from cases like Whitman’s, which he claims are “not uncommon,” to brain-behavior links generally. He alleges that as neuroscience improves, we are increasingly able to “detect more [brain] problems, and link them more easily to aberrant behavior.” However, as our own brief analysis of Whitman’s case makes clear, easily “linking” Whitman’s tumor to his killing spree is not as simple as Eagleman would have his readers believe. Thus, the generalized picture of mere brain states as causally sufficient conditions for behavior is doubtful. That Eagleman would have us believe in the simplicity of the brain-behavior link is evidence both of his failure to appreciate the complexity of the science at hand and his presupposition that the presence of a neurophysiological explanation for human action is a sufficient condition for showing that it is involuntary.

The latter assumption figures prominently in Eagleman’s case against free will. By pointing to the physical behavioral patterns of individuals who suffer from Tourette’s syndrome, Eagleman argues that the exercise of free will is neither necessary nor sufficient for action. But this is entirely beside the point. Almost no one believes that the exercise of free will is either necessary or sufficient for mere action. Rather, free will is traditionally understood as demarcating the boundaries between voluntary and involuntary action. Eagleman seems aware of this in conceding that the “crux of the question is whether all of your actions are fundamentally on autopilot” (i.e., involuntary), but he simply begs the question in asserting that “there is no meaningful distinction between a person’s biology and his decision-making.”

The net result of Eagleman’s rejection of human freedom is to propose “new rehabilitative strategies” for criminal behavior based on a sophisticated form of biofeedback therapy he calls “the prefrontal workout.” The details of this particular rehabilitation need not detain us here. However, two things are worth noting. First, this type of biofeedback is on solid footing from a neurophysiological perspective. For example, meditation has been shown to increase activity in the frontal lobes and also to increase self-regulation. Second, Eagleman’s proposed use of this therapy is ironically inconsistent with his effort to downplay the role of free will. The success of such therapies (as his own example of cessation from cigarette smoking makes clear) depends precisely upon the comprehensive volition of the patient to modify behavior overall as well as his immediate volition to control each impulsive craving during the therapy itself. In the absence of such volition, it seems unclear how such treatment could ever be effective.

This is precisely what makes Eagleman’s proposed use of the judicial system so dangerous—a danger presaged in C.S. Lewis’s “The Humanitarian Theory of Punishment.” Lewis rightly pointed out that as humane as “mending” a criminal may sound, such “sentences,” when issued by “the expert ‘penologist’ (let barbarous things have barbarous names)” and enforced by the power of the state, tend ultimately to dehumanize. Lewis explains, “[t]o be ‘cured’ against one’s will and cured of states which we may not regard as disease is to be put on a level with those who have not yet reached the age of reason or those who never will; to be classed with infants, imbeciles, and domestic animals.” More ominously, Lewis observed that the threat intensifies when the state is corrupt. “For if crime and disease are to be regarded as the same thing,” writes Lewis, “it follows that any state of mind which our masters choose to call ‘disease’ can be treated as crime; and compulsorily cured.”

Eagleman insists that “we can build a legal system more deeply informed by science, in which we will continue to take criminals off the streets, but we will customize sentencing, leverage new opportunities for rehabilitation, and structure between incentives for good behavior.” But if the science that informs jurisprudence is merely scientism, presupposing a grossly oversimplified picture of human nature (i.e., human beings = genes + environment), we risk reforming our legal system at the cost of our humanity.

Though imperfect, the fundamental principles of our traditional system of justice demonstrate deep respect for the inherent dignity of human beings. The traditional system rests on a presumption that human beings enjoy a measure of free (i.e., voluntary) agency sufficient to hold them morally accountable for their criminal acts. Moreover, it already affords enough flexibility to accommodate cases in which criminal behavior is demonstrably involuntary. The wholesale replacement of our traditional system, as envisioned by Eagleman, would treat human behavior as though it resulted from merely involuntary neurological spasms. Such a system of “justice” would render the concept of desert meaningless and reduce human beings to mere biological machines. In our view, an imperfect system that acknowledges the dignity of human nature is better than a perfect system that treats human beings like plants; penalties are preferable to neurological greenhouses.