Christopher Gauker (University of Salzburg):
Epistemic versus Objective Possibilities
In recent decades, many philosophers of language have advocated an approach to the semantics of natural language modal operators that evaluates all sentences as acceptable or not relative to a set of possible worlds (Yalcin, Bledin, Ciardelli, etc.). An atomic sentence will be said to be acceptable relative to a set of worlds if and only if it is true in all of the worlds in the set. The modal sentence “Vivian might be in Vienna” will be evaluated as acceptable if and only if there is a world in the set in which Vivian is in Vienna. Most of these authors have assumed that the set of worlds pertinent to a given utterance models the information state of the speaker. An alternative is to say that the pertinent set of worlds is the set of worlds that are, in a sense to be explained here, objectively relevant to the conversation. It will be argued that the objective relevance approach yields better explanations of the fact that modal sentences can be used informatively, the fact that they can be accepted as testimony on the authority of the speaker, and the fact that we can support modal claims on the basis of factual claims.