The aim of the present paper is defending the idea that epistemic modals like “may”, “might”, “must”, etc. are indexical expressions and providing an outline of their semantics in terms of Kaplanian semantics for indexicals. It is argued that, though closely similar to ordinary indexicals in having both deictic and anaphoric use, epistemic modals are special in having more complicated meaning. This is because their (Kaplanian) content (as well as their character and extension) is twofold – apart from expressing an ordinary intension, like typical indexicals do, they also express a relation between a proposition and a collection of propositions. In particular, assume that SE is a sentence that contains an epistemic modal E, S is a sentence obtained from SE by deleting E (and making all grammatical amendments that are required in order for S to be grammatical), A is an agent and PA is an epistemic perspective of A (i.e. a (sub)set of A’s beliefs); it holds that a speaker’s utterance of SE (where the speaker may, but need not, be identical with A) expresses as its content (relative to a context of utterance) the proposition according to which the proposition expressed by S (relative to the context of utterance) is in a certain relation (like the compatibility relation or the entailment relation, etc.) with PA. The semantic role of E consists in introducing both the epistemic perspective and the relation into the content of utterances of SE.
Character of epistemic modals, Content of epistemic modals, David Kaplan, Epistemic modals, Epistemic perspective, Indexicals