Two souls of disjunction: deriving presupposition projection from exhaustification
There are two broad traditions addressing the semantics and pragmatics of disjunction, with little overlap: The scalar implicature literature (Sauerland 2004, a.o.) is concerned with deriving exclusive readings and ignorance inferences, and the logical environments in which they arise, while retaining inclusive disjunction as the basic meaning of natural language ``or''. The literature on dynamic semantics (Heim 1982, Beaver 2001) is largely concerned with deriving facts concerning presupposition projection (Karttunen 1973). Both approaches to disjunction seem necessary, given the data, but it is not obvious that the two are even compatible. Relatedly, dynamic semantics has been repeatedly criticized (see, e.g., Schlenker 2009,2010) because the dynamic entry for disjunction can't be derived from logical disjunction. In this talk we aim to reconcile the pragmatic and dynamic approaches to disjunction by integrating exhaustification into a dynamic framework. We'll argue that we can get away with just lifting logical disjunction, once exhaustification enters the picture. Relatedly, one of our main goals will be to boost the explanatory power of dynamic semantics (wrt. presupposition projection). We'll present evidence that this move is independently necessary from facts concerning presupposition in disjunctive sentences, which the orthodox dynamic approach is ill-equipped to handle.