Semantics Research Group Meeting, June 30, 2017

(1) Dark matter exists.
(2) Dark matter may exist.

When we hear (1), we typically assume that, for whatever reason, Speaker believes he knows that dark matter exists. On the other hand, when we hear (2), we assume that Speaker has made an inference; he has some kind of evidence which, in some principled manner, suggests the existence of dark matter. Since Kratzer's model of modality (1981, 1991, 2012) quantifies over factually accessible worlds (based on a modal base) which have been filtered for optimal compliance with an ideal (based on an ordering source), it may seem that it already incorporates inference. However, it turns out that this is not the case.

Based on this observation, I argue for a formal representation of inference in modal expressions in the form of a presupposition on the relationship among the modal base, the ordering source and the prejacent. I then explore how this allows a more accurate portrayal of Hearer interpretation of subjective modal utterances and how it can provide a semantic basis for the speech acts we associate with modal auxiliaries in English.