One of Bernard Williams' most influential themes has been the claim that there are only “internal” reasons. It is an important element in his moral philosophy, constituting, in particular, the main thrust in a striking critique of “modern morality,” a critique that has interesting affinities with that of Nietzsche. Yet despite the very extensive discussion this theme has produced, it also has been surprisingly elusive. Critics have found it hard to pin down the difference between “internal” and “external” reasons, and even harder to get clear about what bearing the claim that there are only internal reasons has on modern morality. What is it about this thing that Williams wishes to reject?

Here we shall set ourselves a twofold aim: to examine (§§1–3) Williams' argument for “internalism” – the thesis that there are only internal reasons – and to assess (§§4–6) what bearing internalism has on modern moral ideas, or on modern ideas about the nature of the moral.

Williams often seems to weave his internalism into a Humean model of practical reasons – a model that has struck many philosophers as unconvincing, and indeed seriously misleading. However I shall suggest that Hume's conception of practical reasons is neither the only possible starting point, nor the best starting point, for Williams' questions about morality – notably, about the scope of blame.