 A possible way out is to regard  (15)  not as a pragmatic rule, but rather as a semantic rule, couched in a dynamic notion of interpretation. This was most prominently proposed in Heim 1983b, following Karttunen 1973. Karttunen distinguishes global contexts, which are contexts relative to which the current sentence is evaluated, from local contexts, which are contexts relative to which the current clause (or potentially some sub-clausal entity) is interpreted. The idea now is that a rule like  (15)  can express the semantics of and. In  (15),  \(C\) is the global context. A crucial part of the semantics of conjunction is that the local context for \(S\)2 is the update of the global context with \(S\)1. Thus, there is no presupposition in  (14)  simply because of the dynamic semantics of and. All we need to account for the lack of presupposition in  (16)  is to come up with a semantics for disjunction in which the local context for the second disjunct has already been updated with the negation of the first disjunct; see Krahmer and Muskens 1996 for such an account that also captures interactions between (double) negation and anaphora.