Implicature and Grice's Maxims

The field of pragmatics studies how speakers communicate meaning beyond the literal sense of their words. As Birner frames it, understanding what someone meant requires knowing not only the meaning of the words (semantics) and how they are combined (syntax), but also who spoke and in what context. People routinely mean more than they say, and addressees must infer the rest.

A traditional way of dividing semantics from pragmatics rests on truth conditions. To know the meaning of a sentence, in truth-conditional terms, is to know what the world would have to be like for it to be true. If a meaningful element affects truth conditions, it is treated as semantic; if it does not, it is treated as pragmatic. The sentence There's one piece of pizza left is true just in case one piece of pizza remains. Adding stress, as in There's one piece of pizza left, produces an extra inference that something other than pizza is available to eat, yet the truth conditions are unchanged. That additional, real-but-non-truth-conditional meaning is pragmatic. Researchers have long recognized this divide as too simplistic, but it remains a useful starting point.

The foundational account of pragmatic inference comes from Paul Grice (1975). Grice proposed the cooperative principle: "Make your conversational contribution such as is required, at the stage at which it occurs, by the accepted purpose or direction of the talk exchange in which you are engaged." This principle is broken down into four maxims: quantity (give the appropriate amount of information), quality (say what you believe to be true), relation (be relevant), and manner (be clear). In ordinary communication, interlocutors implicitly assume that others are following these maxims.

These shared expectations give rise to implicatures. A conversational implicature is an inference made on the basis of the specific context in which a statement occurs, and which may be canceled. It contrasts with entailment, which always holds. A common type is the scalar implicature. The sentence Some of the kids went to the park invites the inference that not all of them did, even though the semantics of some requires only two or more. Likewise Most of the kids went to the park implies that not all went, although most semantically means only more than half. Grice explains this through the maxim of quantity: had the speaker been able to say all, they would have.

Maxims can also be flouted deliberately to convey additional meaning. In 1 Kings 18:27, Elijah taunts the prophets of Baal by suggesting their god may be relieving himself or otherwise occupied. Elijah knows this is false, and his audience knows he knows. By flouting the maxim of quality, he communicates not merely that Baal is not listening but that the whole enterprise is ridiculous. The rhetorical force comes precisely from the shared assumption that speakers normally observe the cooperative principle.

Finally, a conventional implicature is a non-truth-conditional aspect of meaning tied to particular words. Unlike a conversational implicature, it is constant and not cancelable; unlike an entailment, it does not affect truth conditions. The classic example is but. The kids want to go outside, but it is raining differs in meaning from the same sentence with and, yet both propositions remain equally true either way. The contrastive meaning contributed by but is a conventional implicature.