[image=http://carstenknoch.com/wp-content/uploads/2011/09/Derek-Parfit-On-What-Matters.jpg] On What Matters is a major work in moral philosophy. It is the long-awaited follow-up to Derek Parfit's 1984 book Reasons and Persons, one of the landmarks of twentieth-century philosophy. Parfit now presents a powerful new treatment of reasons, rationality, and normativity, and a critical examination of three systematic moral theories - Kant's ethics, contractualism, and consequentialism - leading to his own ground-breaking synthetic conclusion. Along the way he discusses a wide range of moral issues, such as the significance of consent, treating people as a means rather than an end, and free will and responsibility. On What Matters is already the most-discussed work in moral philosophy: its publication is likely to establish it as a modern classic which everyone working on moral philosophy will have to read, and which many others will turn to for stimulation and illumination. Parfit?s big idea is that the rules whose universal acceptance everyone could rationally will, which are also the rules that no one could reasonably reject, are in fact the rules whose universal acceptance would make things have the best consequences, impartially considered. Rule-consequentialism is thus argued to be the upshot of the best forms of Kantian and contractualist ethics. So, Parfit argues that personal opinion is not always just personal. Wanting something is not always selfish - for instance, wanting to do something for charity is for the greater good, and that's something nobody could reasonably object to. But they could! After all, isn't "what nobody could reasonably object to", in the end... restrictive? For one thing, I'm not sure the Voluntary Human Extinction Movement would agree that helping charity is always a good idea. Also, morals change. I could say slavery is bad. Nobody would reasonably object. But they wouldn't always have agreed... Now, theories in this book have been making the rounds in the philosophical community for a decade before finetuning and publication. It should be impossible for an amateur like me to rip them apart in mere days. So... anybody got anything smart?