Ignorance inferences in the presence of presuppositions

Abstract

This paper investigates the interplay between presupposition triggers and implicatures, focusing on filtering disjunctions, cases where the presupposition of a disjunct is met by the negation of the other. Empirically, these disjunctions behave like standard disjunctions, yielding typical ignorance and distributive inferences. The main contribution of this work is to show that, in many theories of these inferences, the ordinariness of filtering disjunctions comes as a suprise. Nearly all neo-Gricean and grammatical theories expect that the presence of a presupposition trigger should affect the inferences obtained, contrary to fact. We propose very speculatively a question-based approach to these inferences which would explain why presuppositions seem to have no effect in these cases.