On the Appeal to Naturalness in Metaphilosophy

This dissertation explores and defends the appeal to metaphysical naturalness in metaphilosophy. Naturalness is the gradable distinction between properties such as being green and being grue (i.e. green-and-discovered-before-3000-AD-or-blue-and-not-so-discovered), whereby one property seems like a “gerrymandered construction” relative to the other. This phenomenon is connected to other philosophically interesting phenomena such as fundamentality, similarity, simplicity, reference, and rationality, and these connections give naturalness a role to play in metaphilosophy, the philosophical subfield that investigates philosophy itself (methodological issues, the status of its disputes, etc.). In this dissertation, I defend first an account of naturalness, then some connections between naturalness and metaphilosophical issues, and finally some applications of these connections. I’ve organized the dissertation into three parts. Part I consists of two introductory chapters that introduce the reader to the two central topics of this dissertation, metaphilosophy and naturalness. In Chapter 1, I give a brief introduction to the field of metaphilosophy as I understand it, including some of its branches and the sorts of issues that arise in them. In Chapter 2, I give a thorough introduction to and defense of the notion of metaphysical naturalness, including its connection to fundamentality, similarity, simplicity, reference, and rationality. Part II consists of four chapters that lay out and defend the connections between naturalness and metaphilosophical issues. In Chapter 3, I connect naturalness to issues in the metaphysics of philosophy, including questions about the existence, reducibility, and objectivity of philosophical facts and properties. In Chapter 4, I connect naturalness to issues in the semantics of philosophy, including the questions of when philosophical terms are semantically indeterminate and when philosophical disputes are merely verbal. In Chapter 5, I connect naturalness to issues in the epistemology of philosophy, including the appropriate epistemic weight of certain theoretical virtues (simplicity, non-arbitrariness, and unification), the strength of analogical and arbitrariness arguments, and the threat of certain forms of skepticism about philosophy. In Chapter 6, I connect naturalness to issues in the conceptual ethics of philosophy (which consists of normative and evaluative questions about linguistic and conceptual choices), including the questions of when we should take a philosophical term as primitive, when philosophical disputes are substantive (in a distinctively normative sense), and when we should change the meaning of a philosophical term. Part III consists of three chapters that defend some applications of the above connections. In Chapter 7, I defend two theses about naturalness and semantic vagueness and discuss some implications for philosophical theories whose central theoretical terms are semantically vague. In Chapter 8, I defend two theses about naturalness and first-order pluralistic theories—that is, theories give an account of some phenomenon in terms of a complex, irreducible plurality of factors—and discuss some implications for such theories in philosophy. Finally, in Chapter 9, I defend myself against concerns of incoherence or self-defeat. The primary aim of this dissertation is to show how the appeal to naturalness can make a difference when addressing methodological and other foundational issues about philosophy. A secondary aim is to show how such an appeal tends to cause trouble for semantically vague and first-order pluralistic philosophical theories—ones that are often otherwise very plausible and worthy of the label ‘common sense’