Informativeness, relevance and scalar implicature

1. Introduction The main topic of this paper is the phenomenon of scalar implicature. Typical examples are given in (1)-(4): (1) a. Bill has got some of Chomsky's papers. b. The speaker believes that Bill hasn't got all of Chomsky's papers. (2) a. There will be five of us for dinner tonight. b. There won't be more than five of us for dinner tonight. (3) a. X: I like Mary. She's intelligent and good-hearted. Y: She's intelligent. b. Y doesn't think Mary is good-hearted. (4) a. She won't necessarily get the job. b. She will possibly get the job. The idea is that, in a wide range of contexts, utterances of the sentences in (a) in each case will communicate the assumption in (b) in each case (or something closely akin to it, there being a certain amount of contextually governed variation in the speaker's propositional attitude and so the scope of the negation). These scalar inferences are taken to be one kind of (generalized) conversational implicature. As is the case with pragmatic inference quite generally, these inferences are defeasible (cancellable), which distinguishes them from entailments, and they are nondetachable, which distinguishes them from conventional implicatures. The core idea is that the choice of a weaker element from a scale of elements ordered in terms of semantic strength (that is, numbers of entailments) tends to implicate that, as far as the speaker knows, none of the stronger elements in the scale holds in this instance. The pattern is quite clear in (1) and (2), where the weak/strong alternatives are some/all and five/six respectively. In the case of (3), the stronger expression must be intelligent and good-hearted which entails intelligent; what Y's utterance implicates is that Mary does not have the two properties: intelligence and good-heartedness, so that, given the proposition expressed (Mary is intelligent) it follows, deductively, that she is not good-hearted, in Y's opinion. The example in (4) involves a scale inversion due to the negation, so that the weak/strong alternatives are not necessarily/not possibly; the negation which the scalar inference generates creates a double negation, which is eliminated giving possibly. Accounting for these sorts of examples, and more complicated scalar cases, has been, and still is, a central concern in neo-Gricean pragmatics (see references to Horn, Gazdar, Levinson, Hirschberg, Matsumoto, Welker, van Kuppevelt), but it has received relatively little attention in relevance-theoretic pragmatics. However, in the recent Postface …