Philosophy of Law Spring 2022

Modern Incompatibilism


Pay attention to the title: For the Law, Neuroscience Changes Nothing and Everything. There are going to be two sides to this: an argument for the conclusion that neuroscience changes nothing and an argument for the conclusion that it changes everything.

Greene and Cohen contend that the law is superficially compatibilist. The law only requires the capacity for rational behavior as a condition of criminal liability. That is compatible with the causal determination of our actions. You can be rational and have your actions causally determined at the same time. So, on the face of it, nothing that we can learn from neuroscience would directly contradict anything that the law says. That is why the title of their article starts with “For the Law, Neuroscience Changes Nothing.”

However, Greene and Cohen argue, we accept this superficially compatibilist rationality condition for incompatibilist reasons. They claim that we think of the rational person as a non-physical mind, distinct from the physical brain (the view that mind and brain are distinct entities is called dualism). They think we believe that a rational person can be held responsible because we think reason is free from the constraints of physical causation. The brain, by contrast, is subject to causal determination just like every other physical thing.

Neuroscience, according to Greene and Cohen, will undermine this dualist picture of persons by explaining more and more of our behavior as the product of physical causes. As a result, they believe, we will abandon the retributivist parts of our practices of punishment. The retributive ideal is that punishment is reserved for the guilty: those who freely chose to do bad things. Neuroscience, they believe, will show that no one freely chooses anything and so punishment for retributive reasons makes no sense.

In place of retributivism, they believe, we will take up a consequentialist approach to antisocial behavior. They think this is a good thing because they view consequentialism as the more humane approach to punishment. Because they believe that neuroscience will lead us to fundamentally rethink the purposes of the criminal justice system, they end the title of their article with the word “everything,” as in: “For the Law, Neuroscience Changes Nothing and Everything.” So really, in their opinion, neuroscience will change everything.

Mr. Puppet

Greene and Cohen claim to show that we are tacitly incompatibilists with their example of Mr. Puppet. The idea is that Mr. Puppet would not be held responsible for his actions because they were so clearly formed by the scientist. But, they reason, if we aren’t willing to hold Mr. Puppet responsible for behavior that was caused, we should not hold anyone responsible for their behavior. Why? Everyone’s behavior is caused!

It seems to me that this is their main argument, so we will probably discuss it for some time. We are supposed to think that Mr. Puppet is not responsible and that, in turn, is supposed to show that we are incompatibilists. Without Mr. Puppet, I don’t see that they have another way of showing that people are implicitly incompatibilists.

Main Points

  1. Why the law is at least superficially compatibilist.
  2. Why the law is actually incompatibilist, according to Greene and Cohen.
  3. Why Greene and Cohen think neuroscience will move us towards consequentialism.
  4. The case of Mr. Puppet.


Greene, Joshua, and Jonathan Cohen. 2004. “For the Law, Neuroscience Changes Nothing and Everything.” Philosophical Transactions of the Royal Society 359 (1451): 1775–85.