What is (In)coherence?

Recent work on rationality has been increasingly attentive to “coherence requirements”, with heated debates about both the content of such requirements and their normative status (e.g., whether there is necessarily reason to comply with them). Yet there is little to no work on the metanormative status of coherence requirements. Metaphysically: what is it for two or more mental states to be jointly incoherent, such that they are banned by a coherence requirement? In virtue of what are some putative requirements genuine and others not? Epistemologically: how are we to know which of the requirements are genuine and which aren’t? This paper tries to offer an account that answers these questions. On my account, the incoherence of a set of attitudinal mental states is a matter of its being (partially) constitutive of the mental states in question that, for any agent that holds these attitudes jointly, the agent is disposed, when conditions of full transparency are met, to give up at least one of the attitudes.