Vagueness

This dissertation is concerned with the problem of giving a correct account of the semantics of vague predicates such as ‘…is tall’, ‘…is bald’ and ‘…is near…’.; In Chapter 1 I present a definition of vagueness that aims to capture, in a useful form, all our fundamental intuitions about the vagueness of predicates such as those mentioned above; such a definition is lacking in the literature. is independent of the particular forms in which the paradox may be presented, and brings to light the essence of the paradox.; In Chapter 2 I examine existing theories of vagueness. In light of the definition of vagueness defended in Chapter 1, I argue that we need a semantics for vague language that countenances degrees of truth. I distinguish two sorts of degree theory. One sort—which includes the degree form of supervaluation semantics—sees vagueness as an essentially semantic matter. The other sort—which includes accounts based on fuzzy set theory—accounts for vagueness in language in terms of vagueness in the world. I argue that we need a degree theory of the latter, worldly sort.; In Chapter 3 I examine the fuzzy theory in detail. I show that many of the objections to the fuzzy view that have been raised in the literature do not carry weight. In particular, I defend the coherence of the idea of degrees of truth. However, I isolate a problem for the fuzzy view—the problem of higher-order vagueness—that is serious enough to render the view unacceptable.; In Chapter 4 I present a new theory of vagueness: one that is intended to share the advantages of the fuzzy view, while avoiding its disadvantages. In particular, this theory accommodates the phenomenon of higher-order vagueness. The theory involves degrees of truth, but they are not the same as the degrees of truth involved in the fuzzy theory. Although the theory involves a non-classical semantics for vague language, this semantics validates classical logic.