If one wants to go hunting for fossilized remains, they need not look further than the United States legal system. Based upon what amounts to medieval precedents from English common law, our present legal code is so out of step with decades of neuroscientific findings as to be rendered almost ridiculous.

While it would take nothing short of a complete overhaul to bring our legal system up to date with neuroscience, a premise cogently argued by Dr. David Eagleman in his article for The Atlantic “The Brain on Trial,” there are signs science is beginning to penetrate the anachronistic outer shell of the US Supreme Court. Last week the Supreme Court ruled that a 2012 precedent banning mandatory sentences of life without parole for juvenile killers must be applied retroactively. This would potentially allow hundreds of American children convicted of homicide to be rehabilitated and rejoin society.

At the heart of the Supreme Court decision was the scientific evidence that the human brain does not reach full maturation until well into one’s early 20s. Prior to that, humans are biased towards serial risk taking, as every observant parent will readily attest. These findings make it clear that teenage killers aren’t playing with the same deck of cards as adults and the law needs to reflect.

While this is intuitively sensible to many of us, it nonetheless required a landslide of scientific evidence to overturn the old sentencing pattern. This serves to illustrate just how stodgy and antiquated a legal system we are living with. But change it must, for as science marches on and the gap between legal tenet and scientific understanding continues to grow, we will increasingly bump up against a discontinuity between the two. This gap is only tenable up unto a point, and all the evidence suggests we’re quickly approaching that juncture.

For those curious to peer into the looking glass and see what legal reform is likely to take place as a result of neuroscience, there are several indicators that can point in the correct direction. To explore these, let’s dive into the strange world of neuroscience as it applies to criminal tendencies. Many of the most interesting cases in neuroscience involve lesions to the brain with resulting changes in behavior. The history of the discipline is littered with examples like that of Phineas P. Gage, a railroad construction foreman who lost a large portion of the frontal lobe due to a gruesome job accident. One of the most surprising results of the accident were the changes to his personality, transforming him from a mild mannered householder into a bawdy and brawling miscreant.

Today, neuroscience has established without a shadow of doubt that small, almost invisible lesions to the brain can have a drastic impact on behavior, deeply calling into question old notions of criminal culpability. A person who otherwise appears normal may unwittingly be suffering from a brain disorder that has a profound impact on their decision making.

Take the case of a man referred to in the scientific literature as Alex. In 2000, Alex suddenly developed an overwhelming appetite for child pornography. Hitherto, he had been a normal and by all accounts wholesome member of society. He could not account for this new and insatiable desire, but it quickly landed him in front of a judge. On the night before he was to report for prison sentencing, he experienced a terrible headache and submitted himself to the hospital. Here he was found to possess a massive tumor in his orbitofrontal cortex. When the tumor was removed, his unusual sexual proclivities disappeared and he returned to being the devoted husband and householder of before.

These examples are not cited in order to dismiss culpability, but rather as a basis for suggesting that as neuroscience unravels the causes for many criminal tendencies, the entire thrust of the legal system will shift away from a paradigm of punishment for volitional acts to one based on treatment and rehabilitation. Even as I write, neuroscience continues to roll back the curtain on what constitutes a volitional act with the result that it looks increasingly nonsensical to ask whether a crime was the result of our biology or our free will. The most recent evidence indicates the two are inextricably linked. As such, the idea of personal culpability for a bad behavior becomes a dicey proposition.

David Eagleman explores this, writing for The Atlantic, “It is problematic to imagine yourself in the shoes of someone breaking the law and conclude, ‘Well, I wouldn’t have done that’—because if you weren’t exposed to in utero cocaine, lead poisoning, and physical abuse, and he was, then you and he are not directly comparable. You cannot walk a mile in his shoes.” While this brings us perilously close to the ancient debate over free will, we don’t have to answer that definitively in order to realize the old legal paradigm no longer applies.

Even if it turns out we have some ultimate say over a particular behavior, it is clear that both our environment and genetic factors prime our decisions in ways we have little control over. Take a Tourettes patient as an example: Today we would think it foolish to punish them for their outbursts, knowing they have little control over that behavior. However, this somewhat enlightened viewpoint is only a result of our modern understanding of the ailment. In the past, Tourettes patients were treated little better than criminals.

The difference turns out to hinge on what science can tell us about the underlying cause of the behavior. In the past, we punished what we could not understand, and not having the requisite scientific knowledge to fathom genetic and neurobiological differences, we applied common and frequently brutal punishments. Sadly, we are little changed from that era, with the differences in today’s legal system being more one of degree than substance. We still punish people alike when we cannot understand the individual causes of their behavior. But just as we now know better than to treat an adult and a child alike under law when there are obvious differences in the way their brains are functioning, the same can be applied between adults when we begin to unravel the neurological differences between them.

Looking towards the future, recent changes in medicine suggest a similar path is in store for the legal system. The genomics revolution is ushering in an era of personalized medicine, in which treatments are formulated based on each person’s unique genetic code. The neuroscientific revolution demands a similar paradigm shift towards personalized justice based upon each person’s unique brain development.

The analogy is an apt one, for as we understand more about the underlying causes of criminal behavior, the legal system will likely transform from a methodology of punishment to one of prescription – treating criminals more like sick patients who deserve rehabilitation rather than isolation and guilt.

Just as today we look back on the witch trials perpetrated by our ancestors as hopelessly barbaric, it is almost certain our descendants will view our present legal system as similarly backward and scary. But until then, it is the responsibility of the populace to push for the kind of reforms that will bring our legal machinery in line with current levels of neuroscientific understanding.