Part of the philosophy of language of the 20th century is marked by a shift from the view of language as a tool of representing the world to its view as a means of interacting with the world. This shift is common to the later Wittgenstein, to pragmatists and neopragmatists including Brandom, and also to Chomsky and his school. The claim of the paper is that though the Chomskyans have offered an admirably elaborated theory of syntax adequate to the interactive view of language, they failed to develop a comparably adequate notion of semantics; and that it is Brandom‘s approach which, though prima facie much more speculative and much less scientific, paves the way to a semantic theory which an ‘interactivist’ should endorse.