Lawmaker Steals Leather Pants: Brain May Be Responsible, Lawyer Says
The title of this post is an edited version of a headline that appeared this week at ABC news. The story behind it is that a Californian politician named Mary was caught shoplifting, and her lawyer says that her impaired judgment may have been caused by a benign brain tumour.
We can accept that in principle, a brain tumour could undermine Mary’s moral responsibility and excuse her actions, because we now know that tumours can press on parts of the brain and prevent them functioning properly – causing all kinds of unusual thoughts and behaviours. And Mary could hardly be held responsible for her having a brain tumour. She didn’t choose to have it; it just happened to her.
But if we leave the word “tumour” out of the headline, as I did, we are apt to be surprised by the result. Suppose that Mary never had a brain tumour. Then the thought that Mary’s brain on its own might have absolved her of responsibility by causing the action strikes us as exceedingly odd. Why?
First, perhaps this sounds odd because we are tempted to identify Mary with her brain. I don’t think that’s very plausible, though – most of us are not even slightly tempted to think that Mary is less than two kilos in weight and enclosed within a bony skull.
As a second guess, perhaps we think Mary must be responsible because we think that Mary is in control of what her brain does. But how is this possible? It seems more accurate to say that Mary’s brain is in control of what Mary does. We might be in the grip of a dualistic picture of the mind according to which Mary herself is an immaterial mind or soul that has causal influence over her brain. But this theory is not scientifically plausible, and it is hard to imagine what this immaterial substance could be, and how such immaterial substances could fit into and interact with the naturalistic universe. Many of us are convinced that dualism is false, yet it still seems obvious to us that Mary cannot be excused merely by showing that her brain caused the action.
Perhaps we instead reflect that all our actions are caused by our brains, and that we know that people are responsible for at least some of their actions, so it follows that the fact that a person’s brain caused her action cannot absolve her of responsibility.
But now consider what the brain is: it is, essentially, a biological machine; 100 billion nerve cells living in a chemical soup and firing electrical impulses at each other. And in years to come, as neuroscience improves and expands our knowledge of the brain, we may reach the stage where your lawyer will be able to explain any particular criminal misjudgement as a result of this-or-that chemical overdose or deficit, this-or-that badly routed synapse, the growth of this-or-that cell, or – perhaps – this-or-that quantum random occurrence.
How will we respond to these future lawyers? What’s the difference between the idea that this-or-that bit of your brain (albeit perhaps a microscopic bit) made you irrational, and the idea that a large tumour made you irrational? A tumour is not some alien invader: it is a proliferation of your own cells. Is it, then, size that matters here? Surely not!
It seems inconsistent to accept the tumour excuse but not the others. The odds are high that neuroscience will one day force us to radically revise the way we think about responsibility and the criminal law. Perhaps we will no longer accept that tumours in our brains can provide us with excuses – or perhaps we will cease to believe in personal responsibility altogether.