Derek Parfit's On What Matters has been the most eagerly awaited work in philosophy since Ludwig Wittgenstein's Philosophical Investigations. Drafts of its chapters – and those of its prototype, Climbing the Mountain – have been in circulation for more than a decade. Indeed, the book – if that is the correct term for two large volumes containing three distinct treatises and much additional matter – has already featured as the focus of numerous academic articles, conferences, blogs, an edited volume and a Facebook reading group. Scholars including Brad Hooker and Peter Singer have hailed it as the most important publication in moral philosophy since Henry Sidgwick's 1874 work The Methods of Ethics, which is no small praise given that the competition includes key works by figures as diverse as Friedrich Nietzsche, Oscar Wilde, G.E. Moore, W.D. Ross, Iris Murdoch, John Rawls, G.H. von Wright, Alasdair MacIntyre, Bernard Williams, Philippa Foot and T.M. Scanlon.
Parfit has not published much since his groundbreaking 1984 book Reasons and Persons, which The Sunday Times described as “something close to a work of genius”. That work almost singlehandedly revived a relatively dormant area of philosophical investigation (the theory of normative reasons) while largely destroying the hopes of another (theories of personal identity, with Parfit arguing that what mattered was not identity but survival).
On What Matters returns to the first of these two themes, opening with a rigorous defence of the view that there exist objective facts that count in favour of certain courses of action regardless of our desires, and closing with an all-out attack on various sceptical moralities that have plagued philosophy ever since Thrasymachus told Socrates that justice is might. However, it is the material that lies between these two undertakings that has caused the most excitement.