A presupposition is a proposition that a speaker or writer treats as already accepted as true within a given context, so that the utterance can function without explicitly asserting it. The parameters of a presupposition are: (1) it is backgrounded rather than foregrounded in communication, (2) it survives negation — if the main claim is denied, the presupposition remains intact, (3) it is a precondition for the utterance to have relevance or truth-aptness at all. A presupposition persists through teaching, discourse conventions, and the structured use of language across communities. Unlike an assertion, a presupposition is not directly accountable for falsity; it hides inside the architecture of the statement itself, which is why presuppositions are the hardest things to challenge in argument.
[formal: praesumptio | substrate: mind | horizon: hours | explicit: no | epoch: 0.01]