Date of Award
Doctor of Philosophy (PhD)
Graeme R. Forbes
This dissertation investigates the propositional content of vague sentences. It is a study in analytic metaphysics and analytic philosophy of language. A standard view in those sub-fields is that the content of a sentence is the proposition it expresses. For example, the English sentence ‘Snow is white’ and the German sentence ‘Schnee ist weiss’ have the same content because each expresses the proposition that snow is white. It is also standard to assume that propositions are bivalent, which is to say that any proposition P is either true or false in every possible case. However, these assumptions are called into question when we consider the phenomenon of vagueness. Sentences such as, ‘John is an adult’, ‘Johanna is tall’, and ‘This avocado is ripe’, admit of borderline cases in which they are neither clearly true nor clearly false.
The question of the content of vague sentences has not received sufficient attention. The literature on vagueness has largely preferred to work with the sentences of vague languages, setting aside the question of their contents, while the literature on propositional content has largely preferred to bracket off questions of vagueness for later stages of theorizing. I draw upon both bodies of work to construct and evaluate several accounts of the content of vague sentences.
Ch. 1 lays groundwork in the metaphysics of vagueness. I clarify and refine the taxonomy of views on the nature of vagueness, which are the epistemic, linguistic, and ontological views of the phenomenon. Ch. 2 considers prospects for a supervaluationist account of the content of vague sentences, which would accommodate borderline cases with standard bivalent propositions. I conclude that these prospects are dim. Ch. 3 argues for an account of the content of vague sentences as Fregean propositions that are not bivalent. These propositions are highly non-standard, but I argue that the account has significant theoretical advantages over epistemicist and supervaluational alternatives. Ch. 4 compares my preferred account to Russellian alternates constructed from three recent Russellian theories of propositions. I argue that my account is preferable.
Rohrs, Benjamin Wayne, "Vagueness and Propositional Content" (2016). Philosophy Graduate Theses & Dissertations. 54.