Expressivism - the sophisticated contemporary incarnation of the noncognitivist research program of Ayer, Stevenson, and Hare - is no longer the province of metaethicists alone. Its comprehensive view about the nature of both normative language and normative thought has also recently been applied to many topics elsewhere in philosophy - including logic, probability, mental and linguistic content, knowledge, epistemic modals, belief, the a priori, and even quantifiers.
Yet the semantic commitments of expressivism are still poorly understood and have not been very far developed. As argued...