The Argument from Moral Responsibility

There is a familiar argument for the falsity of determinism, an argument that proceeds from the claim that agents are morally responsible. A number of authors have challenged the soundness of this argument. I pose a different challenge, one that grants its soundness. The challenge is that, given certain plausible assumptions, one cannot know the conclusion of this argument on the basis of knowing its premises. That is, one cannot know that determinism is false on the basis of this argument even if agents are in fact morally responsible and moral responsibility is in fact incompatible with determinism. A slightly different version of the challenge tells also against the claim that one can be justified in believing that determinism is false on the basis of the argument, so that the challenge cannot be evaded by a retreat to an epistemic position weaker than knowledge. I compare my challenge to the challenge posed by the external world sceptic, and argue that there are asymmetries between these challenges that make it reasonable to accept the former and reject the latter. I close by considering the prospects for developing an epistemology of moral responsibility that is adequate to answer the challenge.