Do advances in neuroscience threaten the idea of free will, and if so, what practical implications does this have, for instance when it comes to criminal responsibility and punishment? In a stimulating talk at the Uehiro seminar (the podcast of which is available here), Frej Klem Thomsen, assistant professor of philosophy at Roskilde University, discussed the answers that the prominent American neuroscientists Joshua Greene and Jonathan Cohen have proposed to those questions [1]. Briefly put, Greene and Cohen predict that cognitive neuroscience will make it increasingly apparent to everyone that (as some philosophers have argued centuries ago already) there is no such thing as free will as commonly understood. This, they add, will shift the approach to punishment in criminal law from the current “retributivist” one to a consequentialist one – a change they also judge desirable, on the grounds that the current approach relies on intuitions they take to be scientifically untenable.

The retributivist approach to punishment emphasizes the idea, intuitively plausible to many of us, that criminals deserve to be punished for their crimes, whereas the consequentialist approach justifies punishment by reference to its beneficial consequences for society as a whole. Thomsen summarized Greene and Cohen’s argument as follows: the commonsense view about the justification of criminal punishment is retributivist in nature, which means that it treats desert as a necessary condition of justified punishment. Desert presupposes moral responsibility, which itself presupposes free will. But as cognitive neuroscience is bringing to our attention with increasing vividness, we have good reason to think that there is no free will, because every single one of our actions is fully determined by causal chains that extend back in time beyond our individual decisions. [2] But if there is no free will, there can be no moral responsibility, and therefore no such thing as desert. Therefore, if we accept the retributivist justification of punishment, no one can ever be justifiably punished, no more than a car can deserve to be punished for refusing to start (as in this movie). From here on, we can either stick to retributivism, and conclude that punishment of any kind is never justified, or, as Greene and Cohen recommend, opt instead for a consequentialist approach to punishment that does not presuppose free will (at least as commonly understood).

One common way of responding to Greene and Cohen’s argument would be to defend a “compatibilist” view about free will. Compatibilists hold that free will is fully compatible with determinism. There are various forms of compatibilism, but for the sake of simplicity let me focus on one well-known variant of the view. On this variant, we are free to the extent that our possibilities for action are not impeded by either internal or external obstacles: e.g. it is not the case that we are paralyzed, or that someone is holding a gun to our head and ordering us to do something. Incompatibilists, by contrast, have more stringent standards for what is to count as acting freely, and as a result regard determinism and free will as incompatible. Compatibilism offers the promise of rescuing the retributivist justification of punishment against Greene and Cohen’s argument: even if, as neuroscience is said to suggest, we are never the ultimate cause of our actions, this does not challenge the reality of free will, if free will doesn’t require the falsity of determinism.

Greene and Cohen actually agree that compatibilism is the view we should prefer on pragmatic grounds, yet when it comes to finding out the truth about free will and responsibility, they think that incompatibilism is intuitively more plausible. They use the following thought experiment to support their view: imagine someone (call him Mr Puppet) whose genome, and every significant event in his life (including the way others treated him), were carefully designed in advance by a team of evil scientists. Mr Puppet ends up committing a murder, just as the scientists had intended. Greene and Cohen suggest that Mr Puppet should not be held fully responsible for the murder, since both the internal and external factors which together inexorably led him to commit it were entirely crafted by other people. But, they add, we are all in a similar situation to Mr Puppet, since our actions, too, are the result of the interaction between our genetic endowment and the environments we happen to find ourselves in. The only difference is that in our case, these things weren’t designed by a third party (unless perhaps God exists). This difference, however, changes nothing to the fact that if Mr Puppet isn’t responsible for his actions, then none of us is either. If so, contra compatibilism, determinism does undermine free will and responsibility after all.

Thomsen considered other possible replies to Greene and Cohen’s argument, with a focus on those challenging the idea that retributivism presupposes free will (in the incompatibilist sense). He argued that these replies looked unpromising. First, one might deny that desert presupposes moral responsibility. Imagine that some country runs a state lottery where the name of Andrea, a citizen of that country, is drawn as the winner, even though she is in no way responsible for this (e.g. she didn’t choose to take part in the lottery). Isn’t it nevertheless appropriate to say that she deserves the lottery prize, since her name was drawn? While accepting that it might be, Thomsen responded that what inclines us to say that Andrea deserves the prize is the idea that she is entitled to it. But in cases involving punishment, he argued, entitlement no longer seems enough for desert. For instance, if the state in question had chosen to impose instead a ten-year prison sentence on the lottery winner, we wouldn’t want to say that Andrea deserved the prison sentence, even though she had won the lottery. A second strategy discussed by Thomsen, which he referred to as “semi-compatibilism”, challenges instead the assumption that moral responsibility presupposes free will, and takes the former to be compatible with determinism, even though free will might not be. Thomsen showed, however, that semi-compatibilism seems just as vulnerable as full-fledged compatibilism to counterexamples such as that of Mr Puppet.

Considering the failure of these responses, Thomsen appears to endorse Greene and Cohen’s conclusion, according to which we should abandon the retributivist justification of punishment while still retaining, on consequentialist grounds, the practice of punishment and the notion of criminal responsibility. Thomsen thus plausibly argued that doing so would help deter offenders, reform prisoners, and secure public support for the criminal justice system, given the importance many attach to the notion of responsibility. However, this proposal raises a question: how do we retain the notion of criminal responsibility once we have established that the notions of moral responsibility and free will on which it is founded are mere illusions – especially if neuroscience makes these conclusions apparent to more and more people? One way would be to try and cash out criminal responsibility without referring to moral responsibility, e.g. by equating it with the capacity to act rationally, but Thomsen himself agrees that in the context of criminal punishment, we are not interested in rationality for its own sake but rather as a proxy for moral responsibility. The alternative would be to follow Greene and Cohen’s suggestion to embrace compatibilism about free will (at least in the context of criminal law), in spite of the objections they raise themselves against it. Yet if – as Greene and Cohen themselves believe – most of us share incompatibilist intuitions, and if incompatibilism is in fact the correct approach, it is unclear that we can reasonably be expected to endorse compatibilism on sheer consequentialist grounds. What is proposed, after all, is to keep punishing people even though no one really deserves to be punished! It would thus seem preferable if we could defend compatibilism against purported counterexamples, so that we could sincerely embrace it.

Here is one way in which we might attempt to do this in the Mr Puppet case. It seems that part of the reason why such an example is likely to elicit incompatibilist intuitions is that it is, to some extent, ambiguous. We are told that the evil scientists have scripted everything that Mr Puppet’s relatives, friends, peers etc. should say to him, and how they should treat him. Yet does this mean that they treated him in much the same way each of us was treated by his/her own relatives and friends, or that the sort of social conditioning he experienced amounted to downright manipulation, perhaps to the point of brainwashing? It may be that when reading about his case, we tend to assume the latter. Yet on this second reading, we should not conclude that we are all in a similar situation to Mr Puppet’s. Assuming that most of the people we interact with throughout our lives are not unscrupulous manipulators, the circumstances in which we are placed do not threaten our moral responsibility in the way the conditioning process Mr Puppet is subjected to threatens his. To warrant their claim that we are indeed all like Mr Puppet, Greene and Cohen ought to flesh out the example so as to make it clear that only the first reading above is appropriate. My guess is that, were they to do so, it would weaken the force of that example as a source of support for incompatibilism.

[1] In Greene, J. and Cohen, J. 2004. For the Law, Neuroscience Changes Everything and Nothing. Phil. Trans. R. Soc. Lond. B 359, 1775-85.

[2] We can leave aside here the role of quantum indeterminacies, as they simply introduce a degree of randomness that cannot salvage the commonsense understanding of free will.