presupposition: one construct, many systems

In the philosophy of language, a presupposition is a condition that must hold for a statement to have a normal truth value at all: "the present King of France is bald" presupposes that there is a present King of France, and if there is none the question of truth or falsity does not arise in the usual way. Strawson's On referring argued, against Russell, that such existence conditions are presupposed rather than asserted, so their failure yields not falsity but a truth-value gap. The referent is a background condition on meaningful assertion, diagnosed by its survival under negation, and it is the same core construct that linguistics later made its own.[1]

Unit

A precondition that must hold for a sentence to take a truth value

Recovery means

Not applicable

Measured by

Diagnosed by whether the backgrounded condition survives negation and whether its failure produces a truth-value gap

In linguistic pragmatics, a presupposition is background information an utterance treats as already taken for granted by the speakers, as "John stopped smoking" presupposes that John used to smoke, and this backgrounded content characteristically survives negation and questioning. Stalnaker's Presuppositions recast the notion in terms of the common ground: what the speakers mutually accept as given at that point in the conversation. It is the same construct as the logician's, here realized as a condition on the discourse context rather than on the sentence in isolation, measured by projection tests and common-ground behavior.[2]

Unit

Content an utterance treats as already shared in the common ground

Recovery means

Not applicable

Measured by

Tested by projection behaviour, survival under negation and questioning, and accommodation into the common ground