Pareto-superior See PARETO EFFICIENCY. Parfit, Derek (b.1942), British philosopher internationally known for his major contributions to the metaphysics of persons, moral theory, and practical reasoning. Parfit first rose to prominence by challenging the prevalent view that personal identity is a ‘deep fact’ that must be all or nothing and that matters greatly in rational and moral deliberations. Exploring puzzle cases involving fission and fusion, Parfit propounded a reductionist account of personal identity, arguing that what matters in survival are physical and psychological continuities. These are a matter of degree, and sometimes there may be no answer as to whether some future person would be me.
Parfit’s magnum opus, Reasons and Persons (1984), is a strikingly original book brimming with startling conclusions that have significantly reshaped the philosophical agenda. Part One treats different theories of morality, rationality, and the good; blameless wrongdoing; moral immorality; rational irrationality; imperceptible harms and benefits; harmless torturers; and the self-defeatingness of certain theories. Part Two introduces a critical present-aim theory of individual rationality, and attacks the standard selfinterest theory. It also discusses the rationality of different attitudes to time, such as caring more about the future than the past, and more about the near than the remote. Addressing the age-old conflict between self-interest and morality, Parfit illustrates that contrary to what the self-interest theory demands, it can be rational to care about certain other aims as much as, or more than, about our own future well-being. In addition, Parfit notes that the self-interest theory is a hybrid position, neutral with respect to time but partial with respect to persons. Thus, it can be challenged from one direction by morality, which is neutral with respect to both persons and time, and from the other by a present-aim theory, which is partial with respect to both persons and time. Part Three refines Parfit’s views regarding personal identity and further criticizes the self-interest theory: personal identity is not what matters, hence reasons to be specially concerned about our future are not provided by the fact that it will be our future. Part Four presents puzzles regarding future generations and argues that the moral principles we need when considering future people must take an impersonal form. Parfit’s arguments deeply challenge our understanding of moral ideals and, some believe, the possibility of comparing outcomes.
Parfit has three forthcoming manuscripts, tentatively titled Rediscovering Reasons, The Metaphysics of the Self, and On What Matters. His current focus is the normativity of reasons. A reductionist about persons, he is a non-reductionist about reasons. He believes in irreducibily normative beliefs that are in a strong sense true. A realist about reasons for acting and caring, he challenges the views of naturalists, noncognitivists, and constructivists. Parfit contends that internalists conflate normativity with motivating force, that contrary to the prevalent view that all reasons are provided by desires, no reasons are, and that Kant poses a greater threat to rationalism than Hume. Parfit is Senior Research Fellow of All Souls College, Oxford, and a regular visiting professor at both Harvard and New York University. Legendary for monograph-length criticisms of book manuscripts, he is editor of the Oxford Ethics Series, whose goal is to make definite moral progress, a goal Parfit himself is widely believed to have attained. See also ETHICS, EXTERNALISM , MORAL REALISM , MOTIVATIONAL INTERNALISM , PER – SONAL IDENTITY, PRACTICAL REASO. L.S.T.