 H. P. Grice famously defended the truth-functional account, in his William James lectures, “Logic and Conversation”, delivered in 1967 (see Grice (1989); see also Thomson (1990)). There are many ways of speaking the truth yet misleading your audience, given the standard to which you are expected to conform in conversational exchange. One way is to say something weaker than some other relevant thing you are in a position to say. Consider disjunctions. I am asked where John is. I am sure that he is in the pub, and know that he never goes near libraries. Inclined to be unhelpful but not wishing to lie, I say “He is either in the pub or in the library”. My hearer naturally assumes that this is the most precise information I am in a position to give, and also concludes from the truth (let us assume) that I told him “If he’s not in the pub he’s in the library”. The conditional, like the disjunction, according to Grice, is true if he’s in the pub, but misleadingly asserted on that ground. 