Scientific advancement has often upended long-cherished human beliefs. In the 17th century, the discovery that the Earth was not in fact at the center of the universe was not just difficult to fathom, it was considered a dehumanizing blow to humanity’s ego. Eventually, however, we come to embrace the new scientific knowledge – it is, for instance, now a trite fact that the Earth orbits the Sun – and we then shape our institutions accordingly. Today’s ego-shattering discovery is not cosmological, but as close to home as ever: neuroscience is increasingly reshaping the understanding of our own brains.

Advances in neuroscience have seriously put into question the notion of free will. The intuition that our conscious selves are the authors of our thoughts and of our actions, and that conscious and willful choices inform our behavior, may be more tenuous than we believe. Certain leading scientists now call this willful agency a mere illusion; they instead attribute the totality of human behavior to unconscious chemical processes. This implication – that free will may be an illusion – unsettles the notion of moral responsibility. The emerging field of Neurolaw, championed by renowned Stanford neuroscientist David Eagleman, attempts to address the judicial implications of these advances in modern neuroscience. Our system of criminal justice, he argues, ought to no longer assume the notion of free will. Instead of sentencing on the basis of culpability, it must sentence with view to risk-assessment, to the probability of recidivism, and to rehabilitation.

The emerging picture of the brain attributes decision-making to a variety of factors such as genes, environment – both in utero and during childhood – and even immediate, undetectable chemical stimuli. The brain seems to be nothing more than an innumerable series of intricate chemical reactions; nowhere in it is there a unifying “self” that directs its actions. Conscious awareness receives few or none of the factors contributing to behavior. Moreover, even consciousness itself seems not to consist of any sort of single executive entity that can be aptly labeled the “self.” In the 1980s, the psychologist Benjamin Libet famously illustrated the illusion of conscious will when he showed that a subject’s brain had decided on a particular action milliseconds before he consciously “chose” to perform that action. These findings lend credence to determinism – the philosophical position that only causal factors in accordance with physical laws determine every event, with no possible alternatives – leaving no room for human agency. Their interpretation is, of course, still controversial – the philosopher Daniel Dennett, for instance, considers free will compatible with a deterministic worldview. But even without a scientific consensus, the case against free will is strong enough, and its implications drastic enough, that it must be taken seriously.

In spite of such findings, the modern criminal justice system assumes the willful agency of the criminal, and imposes life-changing measures based on that assumption. The US Supreme Court, in United States v. Grayson, 1978, asserted that free will was a “universal and persistent’ foundation stone in our system of law,” and that determinism was “inconsistent with the underlying precepts of our criminal justice system.” In typical judicial sentences, the criminal’s culpability – that is, the level of guilt he assumes based on his intentions and circumstances – governs the severity of his sentence: the more “intentional” the crime, the more “culpable” the criminal. The degrees of murder, for instance, illustrate this kind of reasoning: first-degree murder renders the criminal more culpable than does involuntary manslaughter.

Sympathy typically grows for the criminal if some sort of cognitive dysfunction can account for his crime. Charles Whitman is a tragic example of this: in 1966, before sniping 15 people from the tower in UT Austin until shot by police, Whitman left a note requesting the examination of his brain. He described himself as overtaken by sudden aggressive urges that he could neither explain nor control. Sure enough, his autopsy revealed a large tumor pressing against his amygdala, the area of the brain responsible for aggression.

Whitman did not choose his tumor, and thus seems to us immediately less culpable. Yet the more neuroscience learns about behavior, the more difficult it is to distinguish Whitman’s case from any other. Just as he did not choose his tumor, so any given criminal does not choose his neurology. Whether the fault lies with the person or with the biology is, in Eagleman’s view, the wrong question, for increasingly those two are indistinguishable. In this view, all criminals are ultimately the victims of unlucky but predetermined circumstances – which neuroscientist Sam Harris aptly describes as a combination “of bad genes, bad parents, bad environments, and bad ideas” (Free Will, ‘Moral Responsibility’).

But even without a scientific consensus, the case against free will is strong enough , and its implications drastic enough , that it must be taken seriously. "

This argument renders criminal punishment only for the sake of ‘just retribution’ cruel and unjust. To punish someone for his neurochemistry – in other words, for his bad luck – is unethical. Criminal punishment, then, would seem defensible only if it could deter crime. There is, however, next to no evidence that it can. Punishment, therefore, can serve neither an ethical nor a practical purpose.

Incarceration, however, can still serve a practical purpose: the prevention of future crimes. Harris makes the point that “if we could incarcerate earthquakes and hurricanes for their crimes,” we would do so for the sake of public safety (Free Will, ‘Moral Responsibility’). In many cases, violent offenders pose a clear threat to the public; these criminals, even though the mere victims of their biology, should still be restrained from civil society as long as they pose a threat.

This modern understanding of our neurology leads to the conclusion that criminal sentencing must emphasize rehabilitation over punishment. About a third of incarcerated Americans suffer from mental illness; punitive sentencing cannot substitute for medical treatment. Restorative justice – a system of criminal justice that focuses on rehabilitative rather than on punitive measures for offenders – has already proven effectual. Norway’s system, for example, provides inmates with high-quality care and facilities, and offers vocational programs to prepare them for life outside prison. Whereas the US — which emphasizes punitive measures — has one of the highest rates of recidivism in the world at 60%, Norway has one of the lowest at 20%. Such a system as Norway’s creates rehabilitatees out of offenders, who then go on to contribute productively to society.

None of this is at all to say, however, that criminal intent is irrelevant to criminal sentencing. Intent is indeed relevant, but only in so far as it may predict future behavior. The key distinction is that this prediction, rather than any artificial determination of culpability, must determine a sentence.

Such predictive capabilities may seem impossible, but Neurolaw is already providing them. Eagleman is developing the science of rational sentencing, which uses indices of intent as surprisingly reliable predictors of re-offense. He employs cutting-edge technology that, by assessment of individual brains, can inform customized sentencing. Neuropsychological evaluations can estimate the likelihood of criminal re-offense to an incredible degree of accuracy, thus providing the judiciary with the ability to discriminate whom it should and should not incarcerate. One of such evaluative tools is a certain kind of video game that tests the degree of reactive aggression of violent criminals, or of inhibition of drug abusers. Its results can predict risks of re-offense with up to 95% accuracy. Another test displays images of human eyes to violent criminals, and then gauges their emotional reactions to them. Its results indicate their levels of empathy, which correlate at statistically significant rates with their likelihood of recidivism.

This sort of testing may seem dehumanizing, since it removes human judgment from the process of criminal sentencing, but Eagleman makes the point that human judgment is a much inferior predictor of criminal behavior. Human judgment is subject to all sorts of biases – longer sentences, for instance, highly correlate with the physical appearance, and with the race, of the criminal. Judges exhibit much more clemency if the sentencing occurs after they have eaten lunch. The intolerably high rates of US recidivism, moreover, are indicative of the incredibly poor judgment that the US’ criminal justice system exercises.

Neurolaw is the future. Our judicial system, on the other hand, was created by men who still believed in an immaterial soul that magically existed outside physical processes. To rid ourselves of the illusion of free will and of a substantive self, though at first glance counterintuitive, would actually help us to create a much more humane criminal justice system, and a much more just society.