- Emeritus Fellow, All Souls College (from 2006 to 2019)
- Senior Research Fellow in Philosophy, All Souls College (from 1996 to 2006)
- Fellow in Philosophy, Robinson College, and University Lecturer in Classics (1978-84) and then Laurence Professor of Ancient Philosophy (1984-96), Cambridge University (from 1978 to 1996)
- Assistant Lecturer, then Lecturer, in Philosophy, University College London (from 1964 to 1978)
- Graduate studies in Philosophy, University College London (from 1963 to 1964)
- Undergraduate, King’s College, Cambridge, studying Classics for Part I of the Tripos, Philosophy for Part II (from 1959 to 1963)
- During National Service in the Royal Navy, qualified as Russian Interpreter (Civil Service Commission, 2nd Class), finishing as Sub-Lieutenant, Royal Naval Reserve (from 1957 to 1959)
- History of ancient and modern philosophy
- Explorations in Ancient and Modern Philosophy, 1976-1996, 2 vols. (Cambridge: Cambridge University Press, 2012).
- Aristotle’s Divine Intellect (Milwaukee: Marquette University Press, 2008).
- A Map of Metaphysics Zeta (Pittsburgh: Mathesis Publications, 2001).
- (co-author with Michael Frede), The Original Sceptics: A Controversy (Indianapolis: Hackett, 1997).
- The Theaetetus of Plato (Indianapolis: Hackett, 1990).
- (ed) The Skeptical Tradition (Berkeley: University of California Press, 1983).
- (co-editor), Philosophy As It Is (London: Allen Lane, 1979).
- Honorary Degree in Philosophy, St Andrews University (2012)
- Continuing to serve in the Royal Naval Reserve as Lieutenant (Sp) 1962, Lieutenant-Commander 1970; Retired 1974 (from 1959 to 1974)
