Derek Parfit’s Reasons and Persons began, “Many of us want to know what we have most reason to do.” He aimed to establish a foundation for ethics, a project which required addressing the conflicts between morality and self-interest. In asking what the claims of self-interest really are, Parfit came to grips with the question of whether or not there is a rational basis for the special concern that persons feel for themselves. Although Reasons and Persons did not answer that question, Parfit tried to show that the Self-Interest Theory—which claims that each person has the “supremely rational ultimate aim: that his life go, for him, as well as possible”—is false.
Parfit went on to write On What Matters, following an honoured tradition of searching for a kind of Unified Field Theory of ethics—one law, from the correct application of which all moral precepts can be derived. Reasons and Persons famously argued that personal identity is not what matters in survival; and it is surely not coincidental that the phrase “what matters” recurred in the title of Parfit’s new book. Normative ethics consists of giving reasons for action; and reasons for action matter. Because the survival of persons is very important, what matters in survival can be presumed to be a significant part of what matters.
On What Matters says little about personal identity. Parfit’s primary interest is in discovering reasons for action—a rational basis for decision-making. My primary interest is in gaining a better understanding of human nature—of what we are. Parfit’s work is driven by prescriptive aims, mine by descriptive ones. Parfit and I would probably agree that reasons for action are rooted in values. But where he asks what has value, I ask what people actually value, and—a more interesting question—why they value what they do. (more…)