The Weekly Newsletter of MIT Linguistics

LF Reading Group 11/18 - Frank Staniszewski (MIT)

Speaker: Frank Staniszewski (MIT)
Title: Polarity sensitive weak necessity modals
Time: Wednesday, November 18th, 1pm – 2pm

Abstract: I develop a new analysis of ‘weak necessity’ modals ‘should’ and ‘supposed to’ that is motivated by novel observations of weaker than expected meanings in some environments. For example, ’supposed to’ in (1a) gives rise to a meaning that can be paraphrased as the weaker modal statement in (1b).

(1) A: Can you please pick up a book for me at the office?
      B: I don’t know… Are we supposed to be back on campus without a Covid test?
      B′: I don’t know… Are we allowed to be back on campus without a Covid test?

I argue that this and other evidence of weak readings shows that these modal verbs exhibit a type of variable force. They express universal force in positive sentences and existential force under negation. The analysis will build on an analogy with free-choice disjunction that assumes a basic weak meaning that strengthens in upward-entailing environments (Fox 2007; Bassi & Bar-Lev 2016).  I hypothesize that the precise distribution of the strengthened readings is governed by the polarity-sensitive nature of the modals (cf. Iatridou Zeijlstra 2013; Homer 2015).  In particular, I argue that the polarity sensitivity of the modals is the result of the association of their domains with a covert even-like operator (cf. Lahiri 1998; Crnič 2014, 2019  for NPI ‘any’).

This hypothesis makes intricate predictions about the range of readings that should be observed in various logical environments that I show to be borne out. It predicts that the modals should receive strong interpretations in positive sentences, and weak readings in negative sentences. For environments that contain both negative and positive components, such as the question in (1), and in the scope of non-monotonic quantifiers, two possible readings are predicted: one in which the positive component strengthens, and the negative component remains weak, and another in which both components remain weak, and the contribution of the covert ’even’ results in strong constraints on the discourse context. I discuss the logic of these predictions, and also argue that the analysis provides a natural link between polarity sensitivity and ‘weak necessity’ modals.