The Weekly Newsletter of MIT Linguistics

Ling-Lunch 11/8 - Giuseppe Ricciardi (Harvard)

Speaker: Giuseppe Ricciardi (Harvard)

Title: “She must be mad” Really? Must? Epistemic must statements are felt “weak” because they are usually false [work with Edward Gibson and Rachel A. Ryskin]
Date and time: Thursday, 11/8, 12:30-1:50pm
Location: 32-D461
Two main hypotheses have been proposed in the literature about the semantics of epistemic ‘must’. The Strong Must Hypothesis (von Fintel & Gillies, 2010) and the Weak Must Hypothesis (Karttunen, 1972; Kratzer, 1981; Lassiter, 2017). Lassiter (2016) offers an experiment whose results support the Weak Must Hypothesis. I argue that Lassiter (2016)’s task is invalid for testing participants’ competence about truth-conditions of statements and I show that if one modifies Lassiter’s task so that participants understand it as a truth-value task then the results support the Strong Must Hypothesis over the Weak Must Hypothesis. Moreover, Lassiter (2016) offers some weak uses of epistemic ‘must’ derived from a corpus. I discuss these examples as well and challenge their status as piece of evidence supporting the Weak Must Hypothesis.
Overall, I argue for the following claim: the weakness observed since Karttunen (1972) with respect to epistemic ‘must’ statements is not due to their being true in weak contexts but to their being systematically falsely uttered in weak contexts. To account for such systematicity, I propose that epistemic ‘must’ statements are often used hyperbolically.