Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Linguistics and Philosophy, 2008.Includes bibliographical references (p. 117-125).The possibilities we consider or eliminate in inquiry are epistemic possibilities. This dissertation is mainly about what it is to say or believe that something is possible in this sense. Chapter 1 ('Epistemic Contradictions') describes a new puzzle about epistemic modals and uses it to explore their logic and semantics. Chapter 2 ('Nonfactualism about Epistemic Modality') situates the work of chapter 1 into a larger picture of content and communication, developing a broadly expressivist account of the language of epistemic modality. Chapter 3 ('Content and Modal Resolution') argues that states o...