The reliability of moral intuitions: A challenge from neuroscience

A recent study of moral intuitions, performed by Joshua Greene and a group of researchers at Princeton University, has recently received a lot of attention. Greene and his collaborators designed a set of experiments in which subjects were undergoing brain scanning as they were asked to respond to various practical dilemmas. They found that contemplation of some of these cases (cases where the subjects had to imagine that they must use some direct form of violence) elicited greater activity in certain areas of the brain associated with emotions compared with the other cases. It has been argued (e.g., by Peter Singer) that these results undermine the reliability of our moral intuitions, and therefore provide an objection to methods of moral reasoning that presuppose that they carry an evidential weight (such as the idea of reflective equilibrium). I distinguish between two ways in which Greene's findings lend support for a sceptical attitude towards intuitions. I argue that, given the first version of the challenge, the method of reflective equilibrium can easily accommodate the findings. As for the second version of the challenge, I argue that it does not so much pose a threat specifically to the method of reflective equilibrium but to the idea that moral claims can be justified through rational argumentation in general.