Indeterminacy is metaphysical (or worldly) if it has its source in the way the world is (rather than how it is represented or known). There are two questions we could ask about indeterminacy. First: does it exist? Second: is indeterminacy derivative? I focus on the second question. Specifically, I argue that (at least some) metaphysical indeterminacy can be derivative, where this roughly means that facts about indeterminacy are metaphysically grounded in facts about what is determinate.

Many classically valid meta-inferences fail in a standard supervaluationist framework. This allegedly prevents supervaluationism from offering an account of good deductive reasoning. We provide a proof system for supervaluationist logic which includes supervaluationistically acceptable versions of the classical meta-inferences. The proof system emerges naturally by thinking of truth as licensing assertion, falsity as licensing negative assertion and lack of truth-value as licensing rejection and weak assertion. Moreover, the proof system respects well-known criteria for the admissibility of inference rules. Thus, supervaluationists (...) can provide an account of good deductive reasoning. Our proof system moreover brings to light how one can revise the standard supervaluationist framework to make room for higher-order vagueness. We prove that the resulting logic is sound and complete with respect to the consequence relation that preserves truth in a model of the non-normal modal logic _NT_. Finally, we extend our approach to a first-order setting and show that supervaluationism can treat vagueness in the same way at every order. The failure of conditional proof and other meta-inferences is a crucial ingredient in this treatment and hence should be embraced, not lamented. (shrink)

Unger’s Problem of the Many seems to show that the familiar macroscopic world is much stranger than it appears. From plausible theses about the boundaries of or- dinary objects, Unger drew the conclusion that wherever there seems to be just one cat, cloud, table, human, or thinker, really there are many millions; and likewise for any other familiar kind of individual. In Lewis’s hands, this puzzle was subtly altered by an appeal to vagueness or indeterminacy about the the boundaries of (...) ordinary objects. This thesis examines the relation between these puzzles, and also to the phenomenon of vagueness. Chapter 1 begins by distinguishing Unger’s puzzle of too many candidates from Lewis’s puzzle of borderline, or vague, candidates. We show that, contra Unger, the question of whether this is a genuine, as opposed to merely apparent, distinction cannot be settled without investigation into the nature of vagueness. Chapter 2 begins this investigation by developing a broadly supervaluationist account of vague- ness that is immune to the standard objections. This account is applied to Unger’s and Lewis’s puzzles in chapters 3 and 4. Chapter 3 shows that, despite its popularity, Lewis’s own approach to the puzzles is unsatisfactory: it does not so much solve the puzzle, as prevent us from expressing them; it cannot be extended to objects that self-refer; it is committed to objectionable theses about temporal and modal metaphysics and semantics. Chapter 4 develops a conception of ordinary objects that emphasises the role of identity conditions and change, and uses it to resolve both Problems of the Many. This allows us to diagnose the source of the puzzles: an overemphasis on mereology in contemporary material ontology. (shrink)