It is finally here. . . there is no doubt that On What Matters is an epochal work . . . a remarkable achievement, giving us a truly comprehensive picture of the moral outlook . . . of one of the greatest moral thinkers of our time. . . . Parfit's intellectual personality radiates throughout On What Matters, which as a whole presents a gripping and illuminating picture of a single, comprehensive view of the projects of both normative and metaethical inquiry.
Mark Schroeder, Notre Dame Philosophical Reviews
[On What Matters] stands as a grand and dedicated attempt to elaborate a fundamentally misguided perspective. Its diligence and its honesty command respect. Perhaps these real virtues will set standards for a very different ventures in academic ethics. Naturalist or otherwise--for a return to the tradition of attempts to understand and improve everyday judgment, and to provide resources for people and policymakers everywhere. In the end, that is what matters.
Philip Kitcher, The New Republic
the most significant work in ethics since Sidgwick's masterpiece was published in 1873 ... a work of epic proportions and ambitions
Peter Singer, Times Literary Supplement
the most eagerly awaited book in philosophy since Ludwig Wittgenstein's Philosophical Investigations... Should the book become as influential as the stars guiding its arrival suggest, it could seriously alter the way that ethics is thought about and taught.
Constantine Sandis, Times Higher Education
represents many years of work by one of the most influential philosophers of our time
Simon Blackburn, Financial Times
an epochal work... a remarkable achievement, giving us a truly comprehensive picture of the moral outlook - both normative and metaethical - of one of the greatest moral thinkers of our time
Mark Schroeder, Notre Dame Philosophical Reviews
Parfits arguments are of extraordinary brilliance and clarity, and by any standards On What Matters is an immensely powerful achievement. . . Parfits intricate and beautifully lucid book is undoubtedly the work of a philosophical genius.
John Cottingham, The Tablet