 Jerrold Katz and Paul Postal (1991, pp. 516–7) did claim that adequate linguistic theory should, inter alia, explain why, if John killed Bill is true, then so is Bill is dead. However, as David Israel (1991) pointed out in reply: “there are facts about English, about what propositions are expressed by certain utterances, and then there is a non-linguistic fact: that one proposition entails another” (p. 571). Utterances of sentences are one thing; the propositions (or thoughts) many different sentences may express, quite another, and the two shouldn’t be confused: