Structure and conventions

Wayne Davis's Meaning, Expression and Thought argues that linguistic meaning is conventional use to express ideas. An obvious problem with this proposal is that complex expressions that have never been used are nonetheless meaningful. In response to this concern, Davis associates conventions of use not only with linguistic expressions but also with the modes in which such expressions can combine into larger expressions. I argue that such constructive conventions are in conflict with the principle of compositionality (as it is usually understood) and that (at least in the cases Davis considers) they are unnecessary for semantic explanations.