Factives

Factives are a class of verbs in linguistics whose clausal complements denote propositions that are taken to be true. In sentences with factive verbs, the embedded clause is typically asserted as factual and is treated as known or established by the speaker. This contrasts with nonfactive verbs such as think or suppose, where the embedded proposition is not guaranteed to be true.

Common English examples of factive verbs include know, realize, discover, prove, demonstrate, ascertain, and be aware that. For instance, in I know that the Earth orbits the Sun, the proposition that the Earth orbits the Sun is presented as true and known to the speaker. Similar patterns hold with realize, discover, or prove: the embedded content is treated as factual within the discourse.

Semantically, factives are often described as veridical or presuppositional: the truth of the complement is entailed or presupposed by the matrix clause. This affects how truth conditions are analyzed, how negation interacts with the sentence, and how the sentence licenses inferences about the proposition in the embedded clause. In many languages, the factive property of a verb influences the choice of mood, tense, or complementizer for the embedded clause.

Cross-linguistic work shows that languages differ in how they encode factivity, with some using distinct verbal morphology, complementizers, or evidential systems to signal the assumed truth of the embedded proposition. Factives are a central topic in semantics and syntax, informing theories of belief, knowledge, evidentiality, and presupposition, and they have practical relevance for natural language processing and discourse analysis.