Transvaluationism about Vagueness: a Progress Report

The philosophical account of vagueness I call “transvaluationism” makes three fundamental claims. First, vagueness is logically incoherent in a certain way: it essentially involves mutually unsatisfiable requirements that govern vague language, vague thought-content, and putative vague objects and properties. Second, vagueness in language and thought (i.e., semantic vagueness) is a genuine phenomenon despite possessing this form of incoherence—and is viable, legitimate, and indeed indispensable. Third, vagueness as a feature of objects, properties, or relations (i.e., ontological vagueness) is impossible, because of the mutually unsatisfiable conditions that such putative items would have to meet. In this paper I set forth the core claims of transvaluationism in a way that acknowledges and explicitly addresses a challenging critique by Timothy Williamson of my prior attempts to articulate and defend this approach to vagueness. I sketch my favored approach to truth and ontological commitment, and I explain how it accommodates the impossibility of ontological vagueness. I argue that any approach to the logic and semantics of vagueness that both (i) eschews epistemicism and (ii) thoroughly avoids positing any arbitrary sharp boundaries (either first-order or higher-order) will have to be not an alternative to transvaluationism but an implementation of it. I sketch my reasons for repudiating epistemicism. I briefly describe my current thinking about how to accommodate intentional mental properties with vague content within an ontology that eschews ontological vagueness. And I revisit the idea, which played a key role in my earlier articulations of transvaluationism, that moral conflicts provide an illuminating model for understanding vagueness. Terry Horgan is Professor of Philosophy at the University of Arizona and was a member of the University of Memphis Philosophy Department for twenty-one years. He is author (with John Tienson) of Connectionism and the Philosophy of Psychology (MIT, 1996) and (with Matjaž Potrč) of Austere Realism: Contextual Semantics Meets Minimal Ontology (MIT, 2008). He has published (often collaboratively) many papers on various aspects of philosophy—including philosophy of mind, metaphysics, philosophy of language, epistemology, and metaethics. He edited or coedited several Spindel Conference Supplements to The Southern Journal of Philosophy, and contributed the following papers to SJP Supplements: “Supervenience and Cosmic Hermeneutics” (1984), “Settling into a New Paradigm” (with John Tienson, 1988), “Transvaluationism: A Dionysian Approach to Vagueness” (1995), and “What is A Priori and What Is It Good For?” (with David Henderson, 2000). The Southern Journal of Philosophy Volume 48, Issue 1 March 2010 The Southern Journal of Philosophy, Volume 48, Issue 1 (2010), 67–94. ISSN 0038-4283, online ISSN 2041-6962. DOI: 10.1111/j.2041-6962.2010.01006.x