The goal of this paper is to explore the presuppositionality of factive verbs, with special emphasis on the verbs know and regret. The hypothesis put forward here is that the factivity related to know and the factivity related to regret are two different phenomena, as the former is a semantic implication that is licensed by the conventional meaning of know, while the latter is a purely pragmatic phenomenon that arises conversationally. More specifically, it is argued that know is factive in (...) the sense that it both entails and presupposes p, while regret is factive in the sense that it only presupposes p. In a recent article, Hazlett, 497–522, 2010) shows with authentic examples how know is used non-factively in ordinary language, and he observes in these examples, as he says, “a threat to Factivity.” I argue that non-factive uses of factive verbs, such as know and regret, far from being a threat to factivity, show that, on the one hand, know is ambiguous between a factive and a non-factive sense; on the other hand, in the case of regret, the presupposition of factivity has to be intended as a merely pragmatic implication which can be suspended by the speaker herself. (shrink)