Abstract: | This paper offers a defense of Davidson’s conclusion in ‘A Nice Derangement of Epitaphs’, focusing on the psychology and epistemology of language. Drawing on empirical studies in language acquisition and sociolinguistics, I problematize the traditional idealizing assumption that a person’s mental lexicon consists of two distinct parts—a dictionary, comprising her knowledge of word meanings proper, and an encyclopedia, comprising her wider knowledge of worldly affairs. I argue that the breakdown of the dictionary–encyclopedia distinction can be given a cognitive and functional explanation: facts regarding language learning and the challenges of coping with linguistically diverse environments require that dictionary and encyclopedia remain deeply integrated rather than categorically distinct dimensions of the mental lexicon. This argument provides support for a psychologized version of Davidson’s conclusion in ‘Derangement’: there is no such thing as a language, in the sense that there is no diachronically stable and uniquely specifiable object that could constitute the language which a person knows. I then apply this conclusion to the question of whether the concept of a public language—understood as a more or less stable body of conventions shared by a group of speakers—could nonetheless retain an important explanatory role in philosophy of language and linguistics. |