Philosophers today are typically unknown outside their discipline, but within it, Derek Parfit, who died in 2017, was considered one of the most important figures of the past fifty years. He had an extraordinary knack for revealing the hidden weaknesses of common moral theories. We may believe, for example, that an action is wrong only if it causes harm to particular individuals. But consider our relation to future generations. We might act well today to preserve the planet’s ecology or we might act very badly in this regard. In the latter case, those who are alive a couple of centuries from now will have livable but much more difficult lives. It seems we will have failed in our moral duty to them. But Parfit argues that what makes a particular self is the joining of a particular egg and sperm at a particular time. Think of all the contingencies that might have made your parents meet later and have a different child instead of you. Then consider the future individuals who live centuries from now in a world created by our resource-depleting behavior. Without that very behavior and its ramifying consequences, these particular individuals would not have been around. Much more responsible behavior on our part would have changed history enough to generate a very different cohort of individuals. The ones in our thought experiment are surely better off than if they had never existed at all, so they cannot claim that we have harmed them. In short, one common theory about what makes our current behavior wrong, though intuitively appealing, is unconvincing.

That argument is quintessential Parfit. Reactions to his work often depend on whether one finds such arguments to be disturbing threats to our moral frameworks or merely the type of puzzle that sets certain kinds of minds in pleasurable motion. To take another example, consider a utilitarian ethical theory, one aimed at producing the best ratio of pleasurable states to painful ones. It seems we could get a superior utilitarian score if we kept increasing the earth’s population to 20 or 30 billion individuals, so long as each new life added at least slightly more pleasurable states than painful ones. Such an outcome, Parfit says, is repugnant. He was interested in the kinds of actions, regarding environmental damage for example, that bring substantial benefit to an individual agent but at the same time harm millions of other people in ways that are too small to be either felt or measured. It is only when each action of this kind is combined with those of many other individual agents that the harm becomes measurable. Traditional ethical theories do not seem well designed for such cases.

Parfit did not wish to encourage moral skepticism; rather, he wanted to point the way toward a more adequate moral theory. He felt that we were just at the first stage of developing such a secular theory, now that religious and other implausible metaphysical frameworks had finally been abandoned. He was what philosophers call a non-naturalist cognitivist. That is, he believed there are ethical truths to be discovered in the way that there are mathematical truths to be discovered, but that these are not reducible to what we can learn from scientific evidence and experimentation. He felt strongly that his own life, and human life in general, would be completely meaningless if there were not such a valid ethical theory. And he believed that moral values cannot depend simply on what we happen to find ourselves valuing.

Parfit liked to use rather contrived thought experiments (cloning, teleportation, split-brain surgeries, and the like) to test our intuitions about personal identity. He concluded that personal identity has no deep basis, may depend on arbitrary choices that cultures make in the future, and in the end is not of paramount importance. We may have reason to desire the continuation of mental states that we value, but whether one’s self continues should not be a matter of overriding concern. For Parfit, the boundaries between selves were less important and less rigid than we commonly suppose, so that our concern for others is not that different in kind from our concern for ourselves. In fact, one person may identify more with another than with an earlier stage of herself, so why insist on the importance of personal identity or its continuity over time?

Derek Parfit was born in Chengdu, China, to British missionary doctors. Back in England his parents used their spare resources to provide young Derek with a privileged British education: the Dragon School, Eton, and Balliol College, Oxford. He then won competitive fellowships that allowed him to stay at All Souls College, Oxford, for more than forty years, with his daily needs taken care of, with no classes to teach, and with other superior minds to challenge his philosophical positions in discussion groups. Parfit lost his religious belief when very young because he could not accept a God who punished sinners in hell. To believe in a determinist universe, he held, is to acknowledge that our moral-reactive attitudes (praise, blame, shaming, punishment, reward, gratitude, resentment, ostracism) are misplaced.

It is hard to imagine a more sympathetic, fair-minded, and appropriately skilled biographer for Parfit than David Edmonds. Parfit was co-advisor for Edmonds’s BPhil, and Parfit’s longtime partner, Janet Radcliffe Richards, was Edmonds’s DPhil dissertation supervisor. Edmonds is now a Research Fellow at the Uehiro Centre for Practical Ethics at Oxford, produces the podcast Philosophy Bites, and is coauthor of Wittgenstein’s Poker. As one would expect, Edmonds provides lots of details about Parfit’s writings, prizes, and competitive entrance and fellowship exams at Eton and Balliol. But he has also collected many revealing anecdotes from those who knew Parfit well.

Edmonds nicely balances the narrative of Parfit’s life with lucid accounts of his ideas, and that balance is important because the life was, in some respects, a peculiar one. Parfit felt that discovering the true ethical theory was so urgently important that he often kept to his room and did not engage in the kind of socializing expected of All Souls Fellows. A female colleague he had known for two decades was dying of cancer and asked him to dinner; he declined the invitation, saying he was too busy with his work. His partner, Radcliffe Richards, said she was always “a side show in his life.” His only real interest outside of philosophy was an annual trip to either Venice or St. Petersburg, where he would take panoramic long-exposure photographs of famous buildings. Yet he could be remarkably generous when it came to engaging philosophically with others. An unknown student might send him a thirty-page paper and be shocked to receive, in short order, a forty-page single-spaced reply. Near the end of his book, Edmonds proposes the possibility that Parfit was on the autism spectrum; he certainly seems to have been unusually poor at recognizing social cues.

One might object to Parfit’s intellectual project that ethics is not the sort of thing that can yield a systematic theory. There are many goods that a human community might value: liberty, equality, well-being, notable excellence, aesthetic and intellectual achievement, wealth, and so forth. Deciding among these is more like negotiating among factions of a complex political coalition than like discovering a scientific theory. A valid scientific theory replaces its precursors; they become obsolete. By contrast, we should wish to keep alive a range of diverse ethical resources from different eras, both philosophical and literary, that will aid us in thinking about how we ought to act and what a good life consists of. The thought experiments of Parfit are modeled on the laboratory experiments that physicists arrange. But the analogy fails: the artificial, contrived nature of the moral thought experiments means that we are not dealing with the kind of ethical decision-making that real individuals actually engage in. Finally, ethics is also about how to live a life that possesses integrity, character, and a distinctive style; a life is not just the site for the performance of moral or immoral acts.

Parfit may have been right that moral truths are not simply projections upon the world of whatever we happen to value. As we evolve culturally and come to know the world better and to reflect on our place in it, we discover certain things about what is worth valuing. But it is a long way from that claim to the kind of strong objectivity that Parfit desires. Our biological and cultural heritage will remain relevant to the values that we filter out from our experience as most important. Parfit’s heroes were Henry Sidgwick and Kant. He might have challenged himself by becoming more familiar with Aristotle and Nietzsche. The former thought deeply about the ethical importance of habit and social context; the latter showed how one’s highest intellectual achievements may have roots in unconscious features of one’s character. Parfit does not seem to have reflected adequately on how his own personality and upbringing, as Edmonds describes them in this excellent biography, might have made him prefer one kind of “objective” morality over others.

Parfit
A Philosopher and His Mission to Save Morality
David Edmonds
Princeton University Press
$32 | 408 pp.