Questions in context

According to the traditional picture in semantics, the meaning of a sentence is given by its truth conditions: they state what the world has to be like for the sentence to be true. This dissertation is about two phenomena that require a refinement of this picture: indexicality and questions.
What indexical expressions like 'I', 'you', 'here' or 'now' refer to depends on the context of use. As a consequence, the truth conditions of sentences in which indexical expressions appear may vary between contexts too. Questions pose a different challenge: because they are not true or false, their meaning cannot be given in terms of truth conditions. Moreover, indexicality and questions interact in interesting ways. According to the standard analysis, an expression is context-sensitive if what is said by it depends on the context. Questions can be context-sensitive in a different way too. For instance, what is asked by 'Who am I?' does not vary between contexts, but rather makes the context an object of inquiry. Another phenomenon unique to questions is that they can require indexical answers, while being non-indexical themselves.
This dissertation develops a semantic framework that can account for these observations. It does so by combining insights from two traditions in the semantic literature: two-dimensional semantics and inquisitive semantics. The resulting framework shows how questions about facts like identity, which have been argued to be necessary, can be cognitively significant, and how questions that can be answered a priori can be about contingent facts. The logical properties of this framework are investigated, and a sound and complete axiomatization for the logic is given.