1. It is widely assumed that there is some form of logical tension between the idea that everything that happens happens of necessity and the idea that people are sometimes responsible for what they do. If there is such a tension, it ought to be possible to characterise the notions of ‘necessity’ and ‘responsibility’ in a way such that the incompatibility is transparent.

Some insist that it is a philosophical confusion to suppose that there is any kind of tension between the thought that an action was necessary – the thought that, given her circumstances, the individual could not have done other than she did – and the thought that she is fully responsible for her action. Thus, Susan Wolf asks us to compare a woman who simply could not leave a child to drown ‘because her understanding of the situation is so good and her moral commitment so strong’ with another who, her moral commitment being weaker, could leave the child to drown but in fact does jump in to save him. It is clear, Wolf argues, that the first woman is fully responsible for her action, in just the sense in which the second is, even though she could not have done other than she did. I will return to Wolf 's case. The point I want to draw from it now is that the form of ‘necessity’ that Wolf highlights is different from that which philosophers generally have in mind when they see a conflict between ‘responsibility’ and ‘necessity’. We might speak of a contrast between a necessity of reasons and causal necessity. Whether or not that way of making the contrast is entirely satisfactory, my question is: how are we to characterise this other – the causal – notion of necessity in a way that brings out the supposed tension with the idea of responsibility?

To see that there is work to be done here, we could consider the constant conjunction account of causality associated with Hume. If one thinks that this account is of the right general form, even if requiring significant modification in its details, one might well conclude (as Hume himself does) that there is no tension between the thought that a particular action was completely causally determined and the idea that the individual is rightly held responsible for it.