Epistemic Disagreement and Practical Disagreement

It is often thought that the correct metaphysics and epistemology of reasons will be broadly unified across different kinds of reason: reasons for belief, and reasons for action. This approach is sometimes thought to be undermined by the contrasting natures of belief and of action: whereas belief appears to have the ‘constitutive aim’ of truth (or knowledge), action does not appear to have any such constitutive aim. I develop this disanalogy into a novel challenge to metanormative approaches by thinking about disagreement. The constitutive aim of belief can play a role in adjudicating epistemic disagreements for which there is no analogue in practical disagreements. Consequently, we have more reason, all else being equal, to expect convergence in epistemic judgment than in practical judgment. This represents a prima facie challenge to the metanormative theorist because the extent of (suitably specified) disagreement in an area of thought is of prima facie significance for the metaphysics of that area of thought.