John MacFarlane is Professor of Philosophy at the University of California, Berkeley, and a member of the American Academy of Arts and Sciences. His early work in the philosophy of logic sought to shed light on debates about the demarcation of logic by uncovering their history. Most of his work in the last decade has been devoted to making sense of relativism about truth, and to providing models of meaning that help resolve contentious philosophical debates about taste, knowledge, future contingents, modality, conditionals, and obligation.
Relativism; contextual sensitivity; semantics of modals and conditionals; knowledge attributions; future contingents; normative language; vagueness; philosophy of mathematics (especially logicism and neologicism); inferentialism; philosophy of logic (especially the demarcation of logic and the normativity of logic); history of logic and conceptions of logicality; ancient philosophy
An expressivist account of vagueness
The project seeks to give a more adequate theory of meaning for vague language by incorporating insights from the expressivist tradition of meta-ethics. The first, negative part of the project seeks to give a very general argument against all truth-conditional semantic accounts of vague expressions. It will be argued that none of these accounts can explain the flexibility of vague language: our ability to negotiate partial boundaries on the fly in conversations. The second, positive part seeks to articulate an alternative view, on which vague assertions express joint constraints on factual belief and plans for the use of words or concepts. The goal is to provide a systematic and compositional account of the meanings of vague expressions which explains, rather than merely recording, the distinctive phenomena surrounding vagueness.
Assessment Sensitivity: Relative Truth and Its Applications, Oxford, Oxford University Press, 2014.
“Ifs and Oughts”, with Niko Kolodny, Journal of Philosophy 107, 2010, p. 115-143.
“Making Sense of Relative Truth,” Proceedings of the Aristotelian Society 105, 2005, p. 321-39.
“Frege, Kant, and the Logic in Logicism,” The Philosophical Review 111, 2002, p. 25-65.