Presupposition is surely one of the most debated notions in the linguistic and philosophical literature. Historically, there are two main theoretical approaches to presuppositions. According to the first one, the semantic view, presuppositions are semantic implications, that is, truth-conditional relations between propositions and statements. In this sense, presuppositions are considered properties of sentences and a presupposed proposition is a necessary condition for the truth of the presupposing statement. In the second approach, the pragmatic view, presuppositions are not properties of sentences but rather properties of speakers or of linguistic performances given a certain context of utterance. From this view, a presupposed proposition is a condition for the felicitous utterance of the presupposing statement in a given context.

Traditionally, it is assumed that semantic presuppositions differ from classical entailments, as presuppositions, unlike classical entailments, project under negation: if we compare a context of entailment to a context of presupposition, we should see that entailments, but not presuppositions, disappear under negation. This presentation aims to propose a revision of the semantic notion of presupposition. I argue that most standard cases of presuppositions are classical entailments. Moreover, I claim that all presuppositions that are classical entailments are also pragmatic presuppositions, while not all pragmatic presuppositions are also classical entailments. I contend that factive verbs offer a paradigmatic example of this distinction, as the factivity related to know is semantic, hence a classical entailment, whereas the factivity related to regret is merely pragmatic. This claim stands in contrast to Karttunen’s (1971) well-known analysis of factive verbs and his distinction between true factives (that is, emotive factives) and semifactives (that is, cognitive factives).