Timothy Williamson is Senior Research and Teaching Fellow in Philosophy at the University of Oxford and Whitney Griswold Visiting Professor at Yale University. He was formerly the Wykeham Professor of Logic at the University and before that Professor of Logic and Metaphysics at the University of Edinburgh. He has also taught at Trinity College Dublin, and as a visitor at MIT, Princeton, the Australian National University, the Chinese University of Hong Kong, and elsewhere. He has published Identity and Discrimination (Wiley-Blackwell, 1990), Vagueness (Routledge, 1994), Knowledge and its Limits (Clarendon Press, 2000), The Philosophy of Philosophy (Wiley-Blackwell, 2007), Modal Logic as Metaphysics (OUP, 2013), Tetralogue: I'm Right, You're Wrong (OUP, 2015), Suppose and Tell (OUP, 2020), Debating the A Priori (with Paul Boghossian, OUP, 2020), and many articles on logic and philosophy.