Presupposition

Presupposition is an implicit background assumption that must be true for a sentence to be appropriate or meaningful. It is not part of the statement’s asserted content, but rather a condition that the utterance relies on. Presuppositions are often considered to be background information that speakers take for granted, and they can influence how a sentence is interpreted in context. They can arise from various linguistic forms and constructions, making certain ideas seem pre-existing before any explicit claim is evaluated.

Common triggers include verbs and phrases that imply a change of state, such as stop, continue, or quit (for example, “Jane stopped smoking” presupposes that Jane used to smoke). Definite descriptions and certain factive verbs also trigger presuppositions (for instance, “The king of France is bald” suggests that there exists a king of France). Other examples involve constructions with “the former,” “the author of,” or iterative expressions that presuppose a prior situation or fact.

A key point is the distinction between presupposition and entailment. An utterance’s truth conditions describe what is asserted, whereas presuppositions are background assumptions that may persist under negation or questioning. In many theories, presuppositions are treated as part of the common ground or as context-change potential, and they may be canceled or reinforced by discourse, depending on the situation. They are a central topic in semantics and philosophy of language, where researchers study how presuppositions are triggered, projected through negation, and managed in dynamic contexts.

In practice, understanding presupposition helps explain how speakers convey information efficiently, how readers and listeners fill in implicit facts, and how misinterpretations can arise in communication. It also informs natural language processing and information extraction efforts that must reason about background assumptions.