Traditionally, the dominant theory of metaphor has taken the form of saying that metaphor is a matter of using a word with a figurative meaning, that is, a meaning which deviates from standard, literal, meaning. The present article challenges the assumption on which such a characterization rests: that there are standard meanings for words fixed by conventions normative for our use of words. It argues that the most sophisticated defense of such a conception of meaning - that of David Lewis - gives an account of convention that cannot be coherently applied to the case of language and which misdescribes the phenomena of language. The fluidity and flexibility exhibited in our normal literal uses of words is such that to say that a meaning deviates from past meanings assigned to a word registers no contrast between the metaphorical use of words and the literal. Hence if we contrast the literal and the metaphorical, we must do it in some other way than by talking about what happens to the meanings of words. (LLBA 2001, vol. 35, n. 5)