Photograph of a Comtesse

Derek Parfit has been described as “the most famous philosopher most people have never heard of.” He was the author of two monumental books in moral philosophy, the first extracted under threat of expulsion from the Eden of All Souls College, Oxford, the second circulated in manuscript so thoroughly that its appearance was an anti-climax. It was published two years after the first collection of essays devoted to its contents.

The books are radically divergent. Reasons and Persons (1984) is a revolutionary work. It argues that our identity with ourselves, and our separateness from others, are more superficial than we take them to be; the upshot is a challenge to our reflexive egoism and a case for greater ethical selflessness. Parfit’s second book, On What Matters (2011), defends the objectivity of ethics, aiming to reconcile the disagreements that tempt us towards relativism by finding a conciliatory common ground.

Both books have been intellectually influential. But it’s fair to say th…