Grice's theory of conversational implicature explains how listeners routinely infer meanings that go beyond what is literally said. The Cooperative Principle holds that speakers generally make their contributions relevant, truthful, appropriately informative, and clear. When an utterance appears to violate one of Grice's four maxims (Quantity, Quality, Relation, Manner), listeners infer the speaker intends an additional meaning — a conversational implicature. Unlike entailments, implicatures are cancellable: they can be retracted without contradiction.
Work through classic implicature puzzles: 'Some students passed' implicates 'not all' — but why, and how is it cancellable? Practice distinguishing implicatures from entailments by testing whether the inference survives cancellation and negation.
You have already studied linguistic pragmatics — the study of how context shapes the interpretation of utterances beyond their literal meaning. Conversational implicature is the most influential single theory within pragmatics, developed by philosopher H. P. Grice in his 1975 paper "Logic and Conversation." It answers a deceptively simple question: how do speakers routinely communicate far more than they literally say?
Grice's starting point is the observation that conversation is not a random sequence of utterances — it is a cooperative activity. Speakers generally try to make their contributions serve the conversational purpose. He called this the Cooperative Principle, and he broke it into four maxims: Quantity (be as informative as required, but not more), Quality (don't say what you believe to be false), Relation (be relevant), and Manner (be clear, brief, and orderly). These are not rules people consciously follow — they are default assumptions listeners bring to any exchange. When a contribution appears to violate one of these maxims, the listener does not conclude the speaker is being incoherent; instead, they infer that the speaker must intend an additional meaning that reconciles the apparent violation. That inferred meaning is a conversational implicature.
The classic example is scalar implicature. If someone asks "Did all the students pass?" and you reply "Some did," you have said something literally true (if at least one student passed). But by choosing "some" rather than "all" — the stronger, more informative claim — you implicate that you cannot truthfully say "all." The listener reasons: if the cooperative speaker could have said "all" and didn't, there must be a reason; the most natural reason is that "all" is false. The implicature ("not all") arises not from the meaning of "some" but from the reasoning about what a cooperative speaker would say. This is why implicatures are pragmatic rather than semantic.
The single most important technical distinction in this theory is between implicatures and entailments. Entailments are logical consequences of what a sentence literally says — they hold in every context and cannot be cancelled without contradiction. Implicatures are defeasible: they can be cancelled without contradiction when context makes the cancellation natural. "Some students passed — in fact, all of them did" is coherent because the first clause is true (all is a subset of all) and the second explicitly cancels the implicature. "John stopped smoking, but he never smoked" is not coherent because "stopped smoking" logically entails prior smoking, and you cannot cancel an entailment. Cancellability is the diagnostic test.
A further insight from Grice is that maxims can be deliberately flouted — openly violated in a way the listener is expected to notice — to generate implicatures through irony, understatement, or rhetorical effect. When someone says "Oh yes, he's a brilliant scholar" about a notoriously incompetent colleague, the obvious violation of Quality (saying something you don't believe) signals irony; the listener infers the opposite of what was said. Understanding implicature thus explains not just ordinary conversation but the mechanics of sarcasm, politeness, hedging, and rhetorical indirection that characterize sophisticated language use.