The Presuppositions of Soft Triggers are Obligatory Scalar Implicatures

Presupposition triggers can be divided in two groups, ‘soft’ and ‘hard,’ based on whether the presuppositions they give rise to are easily defeasible and whether they project uniformly in quantificational sentences (Abusch 2002, 2010, Charlow 2009). Recently, two ideas have been put forward in the literature in connection to this problem. First, soft triggers should be thought of as non-presuppositional items associated with lexical alternatives (Abusch 2002, 2010). Second, the projection behavior of presuppositions can be accounted for by a theory based on scalar implicatures (Chemla 2009a, Chemla 2010). In this paper, building on these two ideas, I propose a scalar approach to the presuppositions of soft triggers. The contribution of the proposal is twofold. First, I propose a theory of soft presuppositions as scalar implicatures that provides an account of their behaviour in quantificational sentences that makes more accurate predictions than Chemla’s (2009a), Chemla’s (2010) and Abusch’s (2010) proposals and other non-alternative-based theories that I am aware of. Second, I develop an account of the differences between soft and hard presuppositions, on the one hand, and the similarities between soft presuppositions and scalar implicatures, on the other. Finally, the proposed approach also reduces the pattern of presupposition suspension to independent principles needed in the theory of scalar implicatures.