Presumptive Meanings: The theory of generalized conversational implicature

Levinson's book presents a theory of generalized conversational implicature (GCI), and makes the central claim that this theory necessitates a "new view of the architecture of the theory of meaning" (p. 9). Levinson claims that to account for GCI (and other types of presumptive meanings, or preferred interpretations), it is necessary to distinguish a new level of utterance-type meaning from sentence-meaning and speaker-meaning: "This level is to capture the suggestions that the use of an expression of a certain type generally or normally carries, by default" (p. 71). The book belongs to the genre of linguistic argumentation. Expanding upon the Gricean notion of GCI (Grice 1975), the author provides numerous examples of GCI and classifies them into three categories, each category representing a different licensing heuristic. Then he discusses the implications of the theory: first, for the interface between semantics and pragmatics, and second, for syntactic theory. Throughout the presentation, the author addresses in great detail potential objections and counterarguments from alternative theories of meaning. According to the author, GCIs are defeasible inferences triggered by the speaker's choice of utterance form and lexical items because of three heuristics mutually assumed by speaker and hearer. The heuristics, which can be related to Grice's maxims, are these: