The concept of conversational implicature is due to the work of Paul Grice, and in particular to his paper "Logic and Conversation," which was delivered in 1967 and instantly became highly influential, although it was not published until 1975. A key goal of this paper was to defend the traditional logical understanding of connectives like and against what he saw as the excesses of ordinary language philosophy. He did this by drawing a sharp distinction between what is strictly speaking said and what is conversationally implicated. Consider sentence (1), below.

(1) Amanda and Beau fell in love and got married.

An utterance of (1) will typically suggest that the falling in love preceded the marriage. However, if and has its bare logical meaning, (1) may be true even if the marriage was initially loveless. According to Grice, (1) might indeed be true under these circumstances—because, strictly speaking, and contributes no more than...