Diagnosing the presuppositional properties of scalar implicatures

Existing accounts of scalar implicatures (SIs) treat them as post-semantic inferences (Grice, 1975) or as part of the asserted meaning (Chierchia et al., 2012), but these views have recently been challenged based on evidence that in certain environments, SIs behave like presuppositions (Bassi et al., 2021). In this paper, we provide additional evidence for the presuppositional approach by showing that SIs are sensitive to constraints on presupposition accommodation (Heim, 2015; Doron and Wehbe, 2022). In addition, we show that even when the implicature trigger is embedded in a downward-entailing environment and the implicature does not strengthen the overall meaning, we can detect the contribution of a presuppositional implicature. We take this to provide evidence against both the Gricean perspective and the assertive exh perspective.