In social science generally and linguistics specifically, the cooperative principle describes how people achieve effective conversational communication in common social situations—that is, how listeners and speakers act cooperatively and mutually accept one another to be understood in a particular way. As phrased by Paul Grice, who introduced it in his pragmatic theory,Make your 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....e need first to get clear on the character of Grice's maxims. They are not sociological generalizations about speech, nor they are moral prescriptions or proscriptions on what to say or communicate. Although Grice presented them in the form of guidelines for how to communicate successfully, I think they are better construed as presumptions about utterances, presumptions that we as listeners rely on and as speakers exploit). In social science generally and linguistics specifically, the cooperative principle describes how people achieve effective conversational communication in common social situations—that is, how listeners and speakers act cooperatively and mutually accept one another to be understood in a particular way. As phrased by Paul Grice, who introduced it in his pragmatic theory, Though phrased as a prescriptive command, the principle is intended as a description of how people normally behave in conversation. Jeffries and McIntyre describe Grice's maxims as 'encapsulating the assumptions that we prototypically hold when we engage in conversation'. The cooperative principle is divided into four maxims of conversation, called the Gricean maxims. These four maxims describe specific rational principles observed by people who follow the cooperative principle in pursuit of effective communication. Applying the Gricean maxims is a way to explain the link between utterances and what is understood from them. With respect to this maxim, Grice writes, 'Though the maxim itself is terse, its formulation conceals a number of problems that exercise me a good deal: questions about what different kinds and focuses of relevance there may be, how these shift in the course of a talk exchange, how to allow for the fact that subjects of conversations are legitimately changed, and so on. I find the treatment of such questions exceedingly difficult, and I hope to revert to them in later work.' These maxims are to be understood as describing the assumptions listeners normally make about the way speakers talk, rather than prescriptions for how one ought to talk. Philosopher Kent Bach writes: Often the addressee of an utterance can add to the overt, surface meaning of a sentence by assuming the speaker has obeyed the maxims. Such additional meanings, if intended by the speaker, are called conversational implicatures. For example, in the exchange A will assume that B obeyed the maxim of relation. But B's answer is only relevant to A if the gas station is open; so it has the implicature 'The gas station is open.' Grice did not, however, assume that all people should constantly follow these maxims. Instead, he found it interesting when these were not respected, namely either flouted (with the listener being expected to be able to understand the message) or violated (with the listener being expected to not note this). Flouting means that the circumstances lead us to think that the speaker is nonetheless obeying the cooperative principle, and the maxims are followed on some deeper level, again yielding a conversational implicature. The importance is in what was not said. For example, answering 'It's raining' to someone who has suggested playing a game of tennis only disrespects the maxim of relation on the surface; the reasoning behind this utterance is normally clear to the interlocutor. It is possible to flout a maxim and thereby convey a different meaning than what is literally said. Often in conversation, a speaker flouts a maxim to produce a negative pragmatic effect, as with sarcasm or irony. One can flout the maxim of quality to tell a clumsy friend who has just taken a bad fall that her gracefulness is impressive and obviously intend to mean the complete opposite. Likewise, flouting the maxim of quantity may result in ironic understatement, the maxim of relevance in blame by irrelevant praise, and the maxim of manner in ironic ambiguity. The Gricean maxims are therefore often purposefully flouted by comedians and writers, who may hide the complete truth and choose their words for the effect of the story and the sake of the reader's experience.