Dan Sperber & Deirdre Wilson (1990) Rhetoric and relevance. In D. Wellbery & J. Bender (eds.), The Ends of Rhetoric: History, Theory , Practice (Stanford University Press), 140-155.

“…If relevance theory is right, then it offers a solution to the rhetorician’s dilemma, a way of being precise about vagueness, of making literal claims about metaphors and ironies, without abandoning any of the Romantics’ intuitions. However, rhetoricians could not adopt this solution without jeopardizing the very foundations of rhetoric. For what this solution implies is that metaphor and irony are ordinary exploitations of basic processes of verbal communication, rather than devices based on codified departures from the ordinary use of language. Moreover metaphor and irony exploit quite different basic processes and are more closely related, the former to loose talk, the latter to a variety of echoic uses, than to one another. The very notion of a trope is better dispensed with. If so, then rhetoric has no subject matter to study, or to teach…”  [PDF version]