Modern compatibilism

Notes for Thursday, December 4, 2014

Main points

Morse’s article falls into two parts. In the first part, he tries to show that the law’s assumptions about human behavior are compatible with causal determination. Since that is so, identifying causes of criminal behavior at the neurological level should not change anything about the legal standards for criminal liability. In the second part, he tackles neurological experiments that, he believes, genuinely threaten to undermine the law’s assumptions about the conditions under which we can be punished for our behavior.

The law’s compatibilism

The law recognizes excuses for behavior that violates the criminal law. People who do not meet the standards of rationality cannot be punished for their actions.

What does it mean to be rational? The main component, according to Morse, concerns knowledge: rational people understand what the law requires and the nature of their own behavior (2010, 842).

The law also recognizes external compulsion or coercion as an excuse. Those who break the law with a gun to their heads are excused even though they do not suffer from defects in their rationality. (Quite the contrary.)

This raises a question about what is sometimes called “internal” compulsion. Cases of internal compulsion involve people who cannot control their behavior. They do what they know to be wrong for reasons that, they maintain, are out of their control. Is internal compulsion an excuse and, if so, why? Morse treats these cases as defects of rationality. The idea seems to be that they involve an inability to control one’s behavior in the light of what one knows to be right. So you can know what the law is and what your behavior involves but still suffer from a lack of rationality if you can’t bring your knowledge to bear on your actions.

To illustrate cases of internal compulsion, I mentioned two specific cases. One involves a man who had surgery to relieve the symptoms of epilepsy and the other a man with recurring brain tumors. In both cases, the physical insults to their brains seem to have caused their clearly illegal behavior.

We were mostly reluctant to hold them responsible for their actions. A significant number of us were willing to hold them responsible for acting to do something about their condition. If they knew they were behaving wrongly and could not control themselves, they should have seen a doctor. (The fact that the man in the first case did not was cited by the prosecutor who sent him to prison.)

Suppose you think something like this: “they weren’t responsible for their behavior; it was the physical condition of their brains that made them do what they did.” That’s certainly my initial reaction. Then you face a question: what about everyone else? It’s always the physical conditions of our brains that makes us do the things we do. If they aren’t responsible for what they did, how are any criminals responsible for their crimes?

The threat to folk psychology

Morse is not worried by that sort of question. What really worries Morse is the possibility that neuroscience will displace what he calls “folk psychology.” When we employ folk psychology, we explain people’s behavior as the product of their beliefs, desires, and intentions. Morse believes the law assumes folk psychology is accurate and that beliefs, desires, and intentions really do explain why people do the things they do. So if neuroscience displaces folk psychology in the way that the physical sciences have displaced folk physics, one of the assumptions the law relies on would have been shown to be false. That is what Morse worries about.

We spent a fair amount of time talking about the experiments done by Benjamin Libet (Libet 1999). These seem to show that the brain starts acting before the person is consciously aware of having decided to act. That suggests that the intention to act is not the cause of our actions: it happens after the brain takes the first steps to cause an action.

We talked very briefly about Libet’s idea that the conscious self can “veto” the brain’s decision to act as well as some of Morse’s criticisms of Libet’s work.

I ended with a suggestion that both Libet and Morse were wrong in assuming that folk psychology requires us to be conscious of our beliefs, desires, and intentions. I myself rarely explicitly think through exactly what I believe, desire, and intend before acting. But I have no doubt that my actions reflect those things. For example, I do not explicitly think “I would like some coffee now” each morning, much less “and I believe that I will get it if I put the kettle on the stove.” Nonetheless I think that those beliefs and desires explain why I put the kettle on the stove every morning.

What I’m suggesting is that the electrical activity that Libet’s experiment identified was the intention to move the hand. It’s just that the subjects were not consciously aware of intending to do that for several microseconds. If that’s right, Libet’s experiments do not threaten to displace the folk psychological concepts of belief, desire, and intention.


Libet, Benjamin. 1999. “Do We Have Free Will?” Journal of Consciousness Studies 6 (8–9): 47–57.

Morse, Stephen J. 2010. “Scientific Challenges to Criminal Responsibility.” In Philosophy of Law, edited by Joel Feinberg, Jules Coleman, and Christopher Kutz, 9th ed., 839–53. Wadsworth.

This page was written by Michael Green for Seminar on Punishment, Philosophy 185B, Fall 2014. It was posted December 9, 2014.
Seminar on Punishment