On the Free Choice Potential of Epistemic and Deontic Modals

A number of constructions in various languages display a different behavior in the scope of epistemic and deontic modals. For example, the German indefinite determiner irgendein gives rise to different inferences under the two kinds of modals (Aloni and Port 2010; Kratzer and Shimoyama 2002). Furthermore, while the Romanian determiner vreun is licensed under epistemic modals, but not under deontic modals (Fălăuş 2009), concessive scalar particles like Slovenian magari are licensed under deontic modals but not under epistemic ones (e.g. Crnič¸, 2011b). Although seemingly a diverse set of observations, there is a curious commonality in the proposed explanations for the relevant data: all of the three case studies independently assume that deontic and epistemic modals have different free choice (FC) potential, in the sense that these modals differ in the way that they license so-called FC-inferences. We consider FC-inferences to be inferences of the form in (1b) and (2b) associated with either existentials or disjunctions under modals, as in (1a) and (2a) respectively: (1) a.☐∃x: ϕ(x) b. ◇∃x: ϕ(x) c. ∀x: ◇ϕ(x) (2) a. ☐(p1 ∨ p2 ∨ … pn) b. ◇(p1 ∨ p2 ∨. .. pn) c. ∀i ∈ {1, 2,. .., n}: ◇ pi While epistemic FC-inferences, i.e., FC-inferences associated with epistemic modals, mostly seem to be well-behaved pragmatic inferences outside of compositional semantics, deontic FC-inferences seem able to penetrate into the computation of semantic values much more freely. It is this Modal Variability Hypothesis, as we will call it, that is the main object of scrutiny in this chapter.