 To work out that a particular conversational implicature is present, the hearer will rely on the following data: (1) the conventional meaning of the words used, together with the identity of any references that may be involved; (2) the Cooperative Principle and its maxims; (3) the context, linguistic or otherwise, of the utterance; (4) other items of background knowledge; and (5) the fact (or supposed fact) that all relevant items falling under the previous headings are available to both participants and both participants know or assume this to be the case. A general pattern for the working-out of a conversational implicature might be given as follows: He has said that q; there is no reason to suppose that he is not observing the maxims, or at least the Cooperative Principle [Cooperative Presumption]; he could not be doing this unless he thought that p [Determinacy]; he knows (and knows that I know that he knows) that I can see that the supposition that he thinks that p is required [Mutual Knowledge]; he has done nothing to stop me thinking that p; he intends me to think, or is at least willing to allow me to think, that p; and so he has implicated that p”. (Grice 1975: 31; my emphasis and insertions)