Will advances in neuroscience radically transform criminal law? Stephen Morse believes they won't. To the extent neuroscience merely gives us a fuller picture of brain mechanisms, he argues, it ought not affect the law because the law does not require us to be the ultimate physical cause of our behavior. Provided we have no excusing condition like insanity, the law deems us responsible for our actions because, Morse writes, “the law’s official position” is “that conscious, intentional, rational, and uncompelled agents may properly be held responsible.”
Morse defends a compatibilist view of free will. He believes that even if all of our actions are caused by our brains which in turn were caused by states of the universe before we were born, we can still be morally responsible for our actions. And some of Morse's writing imply the view that the law itself takes a compatibilist stance toward free will.
While the law is generally consistent with compatibilism, I argue that the law is also consistent with another view about free will that we can call soul-based libertarianism. On this view, we can be morally responsible for our actions provided that they emanate from non-physical souls. In other words, the law may treat our choices as somehow special, occurring outside the boundaries of the natural world. Indeed, the law was crafted over centuries with contributions from thousands of people. For a long portion of that history, lawmakers likely held some version of a libertarian view about free will.
The Supreme Court of Michigan may have reflected a libertarian worldview in the nineteenth-century case of Maher v. People. The court sought to determine which provocative circumstances, like adultery, should mitigate what would otherwise be murder to a less severe conviction for manslaughter. The court said that the circumstances need only have the natural tendency to create a heated emotional state because it need not be “such a provocation as must, by the laws of the human mind, produce such an effect with the certainty that physical effects follow from physical causes; for then the individual could hardly be held morally accountable.” In other words, if a person’s behavior is caused in the way that one physical entity causes another physical effect, then he cannot be held morally or legally accountable at all. While the statement in Maher could perhaps be given a compatibilist interpretation, at least taken literally, it seems to deny responsibility for mechanistic actions that follow with certainty from physical effects.
One case hardly generalizes to the entire corpus of law. Still, the criminal law was largely devised by people who held libertarian views like those in Maher. When, if ever, did the law change its position? Some empirical evidence, though it is controversial, suggests that most people naturally hold libertarian views, even today. Here is the key point: Questions about free will go back centuries. But whatever your view about free will, the law may have its own view. To the extent we're unlikely to resolve questions about free will to everyone's satisfaction, the law's default position takes on increasing importance. While I hardly think the law takes a clear stance on the issue, to the extent that purposive analysis is appropriate, the law may well be vested with soul-based libertarian inclinations.
Lastly, to a much greater degree than compatibilism, soul-based libertarianism actually is threatened as neuroscience becomes more powerful and comprehensive. The better neuroscience becomes, and, as Greene and Cohen suggest, the easier it is for us to visualize neuroscientific mechanisms, the less we will be inclined to rely on souls to understand human behavior. Consider a judge who believes that all people act because of first-moving decisions they make in their souls. Such a judge may start to question whether someone really has “intent” to kill when the judge subsequently comes to understand intentions in mechanistic terms. Thus, if the law has soul-based libertarian roots, it is indeed vulnerable to advances in neuroscience (and other sciences) that continually remind us that we are mechanistic cogs in the universe.
(This post is adapted from the recently-published article, Will There Be a Neurolaw Revolution?, and was originally posted at Prawfsblawg.)