Factivity and Factualness

Predicates exhibit different behavior when it comes to whether or not they introduce a presupposition in their embedded complement. These contrasts are best described in terms of factivity: factive verbs (e.g. regret, know) project a presupposition throughout different types of syntactic environments; semi-factives (e.g. discover, learn) project it in some contexts but not in others; whereas non-factive predicates (e.g. think, believe, say) are not presuppositional at all. In addition to different types of predicates, presupposition-triggering is also contingent on other natural-language phenomena, such as pragmatic conventional implicatures or syntactic complementizer selection, among others. As a final word, it should be reiterated that the concept of presupposition and the area of factivity more generally remain controversial topics in the literature and a definitive theory of these phenomena at the interface of semantics, pragmatics and syntax still remains elusive.