Karttunen logic for presupposition projection

Presuppositions of complex sentences are empirically distinguished from the propo-sitional contexts that render a sentence coherent. This distinction is at the heart of theprovisoproblemfor presupposition projection. Here we show that Karttunen’sinference-basedap-proach in his proposals from the early 1970s can be used to directly avoid the proviso problem.Inference-based projection is different from trivalent accounts or satisfaction-based methods indistinguishing presuppositions from admittance conditions on contexts. This distinction is usedwithin a new propositional fragment, whose rules for updating local contexts and satisfying pre-suppositions are explained using the same Incrementality principle of previous accounts, butwithout any of the additional assumptions that have been used to tackle the proviso problem.