Post-truth The semantics and pragmatics of saying "what you believe to be false"
Grice's first maxim of quality says "do not say what you believe to be false", but we often do. We tell lies ("I did not have sexual relations with that woman"), we deceive (e.g. by lying by implicature), we bullshit ("Trade wars are easy to win"), we make up stories ("When Harry Potter first came to Hogwarts …"), we pretend (Kids playing: "You were Batgirl and I was Wonder Woman"), or we use irony ("Losing the key was very smart!"). In all such speech acts there is a clear sense in which we're not, or at least not literally, speaking the truth. Clinton did have a sexual affair, trade wars are probably not easy to win, there is no Hogwarts, the kids are no superheroes, losing keys is not smart. On the other hand, except in (typical cases of) lying, these speech acts also convey something true: Harry did go to Hogwarts in the well-known series of novels, the kids are superheroes in their play, and the attitude which speakers intend to communicate with their bullshit or irony may be true as well.
Semantics has typically focused on idealized cooperative conversation, where every assertion contributes to a lofty shared truth-seeking endeavor in order to establish a common ground of shared beliefs between speaker and hearer. However, since the phenomena like the above all run counter to this idea, their explanation is usually left to pragmatics, philosophy, or literary theory. And while Grice's other maxims have gained a lot of attention and sparked entire research traditions (quantity implicatures, relevance theory, Horn's division of pragmatic labor and Levinson's M-principle), the role of the quality maxim remained a bit underexplored in linguistic semantics and pragmatics.