Robert Nozick was born on 16 November 1938 in Brooklyn, New York. The son of Russian immigrants, he was educated in the Brooklyn public schools. His interest in philosophy was sparked by an early encounter with Plato, as he reports: “When I was 15 years old, or 16, I carried around on the streets of Brooklyn a paperback copy of Plato’s Republic, front cover facing outward. I had read only some of it and understood less, but I was excited by it and knew it was something wonderful.” Nozick went to Columbia University in 1955 where he majored in philosophy, working closely with Sidney Morgenbesser . After receiving his BA at Columbia in 1959, he went to Princeton University where he earned his PhD in philosophy in 1963, under the supervision of Carl G. Hempel . He was assistant professor of philosophy at Princeton from 1963 to 1965; assistant professor at Harvard University from 1965 to 1967; and associate professor at Rockefeller University from 1967 to 1969. In 1969, at the age of thirty, he was appointed full professor of philosophy at Harvard, where he remained for the rest of his career. He served as department chair from 1981 to 1984. In 1985 Harvard University appointed him Arthur Kingsley Porter Professor of Philosophy. In 1998 he was named Joseph Pellegrino University Professor, and held that position until his death on 23 January 2002 in Cambridge, Massachusetts.
Nozick held numerous honors and awards. He was a fellow of the American Academy of Arts and Sciences, a corresponding fellow of the British Academy, a member of the Council of Scholars of the Library of Congress, and a senior fellow at the Harvard Society of Fellows. He held fellowships from the Center for Advanced Study in the Behavioral Sciences in 1971–2; the Rockefeller Foundation in 1979–80; the National Endowment for the Humanities in 1987–8; and the Guggenheim Foundation. He was John Locke Lecturer at Oxford University in 1997, and President of the American Philosophical Association Eastern Division in 1997–8. In 1998, he was awarded the American Psychological Association’s Presidential Citation, which honored him as “one of the most brilliant and original living philosophers.”
Nozick published five books during his career. Anarchy, State and Utopia (1974) offered a vigorous critique of the fundamental principles of distributive justice. Philosophical Explanations (1981) addressed such fundamental matters as the nature of the self, the character of knowledge, the source and status of free will, and the basic structure of ethical norms. The Examined Life (1989) included reflections on themes such as love, death, sex, happiness, creativity, evil, and wisdom. The Nature of Rationality (1993) provided novel accounts of rational action and rational belief. Invariances (2001) addressed such wide-ranging subjects as quantum mechanics, consciousness, and the nature of necessity. In addition, Nozick published a volume of his collected papers, Socratic Puzzles (1997), which included essays on ethics and political philosophy, choice and utility, philosophical methodology, as well as works of short fiction. In addition to these six books, his 1963 dissertation, The Normative Theory of Individual Choice, was published in 1990 and addressed a number of problems in decision theory and game theory.
Although it is Nozick’s political philosophy in Anarchy, State and Utopia that made a name for him among the wider public, his greatest influence among academic philosophers can also be traced to his discussion of Newcomb’s Problem (1969) and his “tracking” theory of knowledge in Philosophical Explanations. Indeed, entire volumes of critical essays have been devoted to discussions of each of these views. Numerous additional article-length discussions of Nozick’s work have been published in a wide range of journals. Despite this large secondary literature, Nozick resolutely refused to attend or respond to critics, saying that “what pleases me and excites me is to think new thoughts about new topics.”
Throughout his career, Nozick’s thinking and writing were characterized by technical prowess, a lively and accessible style, highly engaging examples, and an interdisciplinary focus. From his earliest work to his latest, he drew on work from fields such as decision theory, evolutionary biology, economics, and physics, making original use of conceptual resources from these fields, identifying novel puzzles on their bases, and bringing empirical results to bear on longstanding philosophical questions. His interdisciplinary interests were nurtured by his Harvard and MIT colleagues. He was an active member of the Society of Fellows, where he had dinner weekly with leading scholars from various disciplines. And he co-taught courses with, among others, renowned lawyer Alan Dershowitz, biologist and essayist Stephen Jay Gould, and Nobel Prize-winning economist Amartya Sen . Notorious for asking probing and difficult questions, Nozick was widely known as an excellent philosophical conversationalist.
Nozick first gained visibility in the philosophical community through his 1969 discussion of Newcomb’s Problem. A being with heretofore infallible predictive powers confronts you with a choice between (1) taking an opaque box that contains either no money, or some sizable sum; and (2) taking that opaque box as well as a transparent box that contains an additional sum of money. This being has already decided whether to fill the opaque box based on its prediction on what you will decide. Rationality seemingly requires you to choose both boxes. However, it is also known that in all previous cases, those who have chosen both boxes have discovered the opaque box to be empty, whereas those who have chosen only the opaque box have discovered it to contain the sizable sum. Which choice should you now make? Nozick’s detailed and insightful discussion of this case and its analogues served as a basis for many important distinctions in decision theory, including the distinction between causal utility, the utility associated with outcomes that are caused by the act in question, and evidential utility, which is the utility associated with the outcomes for which the act in question offers evidence.
It was Nozick’s Anarchy, State and Utopia that propelled him to the attention of the wider public. Winner of a National Book Award, the book was listed by The Times Literary Supplement as one of “The Hundred Most Influential Books Since the War.” Along with John Rawls ’s Theory of Justice, it was standard reading in political philosophy courses in American and European universities for the rest of the twentieth century. It has been credited with serving as one of the major intellectual underpinnings of the Reagan–Thatcher era. Nozick argued that the strongest sort of state that can be legitimately defended is a minimal state, a state strong enough to protect citizens against violence and theft, and to ensure the enforcement of contracts, but containing no provisions for redistribution of wealth or resources. Such a state, he suggested, might arise naturally, as the result of “invisible hand” forces.
The task of distributive justice, Nozick contended, can be captured by the slogan “From each as they choose, to each as they are chosen.” Whether a particular distribution of goods is just depends on the process by which the distribution came about, not on the pattern that the distribution exhibits. Just as we would consider it legitimate for basketball player Wilt Chamberlain to acquire wealth as the result of each citizen voluntarily giving a quarter to watch him play, so too might it be legitimate for the resources of society to be distributed in radically inequitable ways: “no … distributional patterned principle of justice can be continuously realized without … stop[ping] people from transferring resources as they wish to … or continually (or periodically) interfer[ing] to take from some persons resources that others … chose to transfer to them.” Such coercive interference, he maintained, is unjustified: it involves a violation of “persons’ rights not to be forced to do certain things.” In addition, he maintained that there is much that is appealing about the minimal state itself: “the minimal state … [which is] the only morally legitimate state … is the one that best realizes … utopian aspirations … treating us with respect by respecting our rights” and allowing us to pursue our own chosen ends with dignity and respect.
Nozick’s Philosophical Explanations won the Ralph Waldo Emerson Award of Phi Beta Kappa. He addressed a number of traditional philosophical problems, including the nature of personal identity, the question of why there is something rather than nothing, the nature of knowledge and the status of skepticism, the relation between free will and determinism, the legitimacy of punishment, the status and structure of ethical claims, and the meaning of life. Methodologically self-conscious, the book represented itself as offering “explanations” rather than “proofs” – responses to our “puzzlement, curiosity, [and] desire to understand” that render our conceptual commitments more “coherent and better understood.” Of the many proposals in Philosophical Explanations, the discussions of knowledge, personal identity, and free will provoked the greatest interest among professional philosophers. Nozick proposed that in order to know something, we must “track” the truth: S knows that p if and only if (1) p is true, (2) S believes that p, (3) if p weren’t true, S wouldn’t believe p (by the method that she does), and (4) if p were true, S would believe that p (by the method that she does). Because the view denies “closure” – according to which if S knows that p and S knows that p implies q, then S knows that q – it provides a novel answer to the skeptic. One can allow that we know all sorts of ordinary propositions about the external world, while conceding that we do not know that we are not subject to massive delusion by an evil demon. While few philosophers – not even Nozick himself – accepted this account as a definitive characterization of the nature of knowledge, and while many found its starting point implausible, the view played an important role as a foil in discussions of knowledge over the next decades. Nozick’s views on identity over time – that “to be something later is to be its closest continuer” – were similarly innovative and similarly controversial. By suggesting that identity over time might be determined in radically extrinsic ways, Nozick opened up important new avenues for discussion.
Nozick’s The Examined Life offered a wide-ranging collection of speculative essays and “meditations” on topics of perennial human concern, such as love, happiness, sex, and evil. A number of the essays offered important insights into the problems they addressed – the discussion of love, for example, includes an influential discussion of the non-interchangeability of the beloved, and the discussion of parents and children includes a widely cited criticism of the legitimacy of unrestricted inheritance laws. As a whole, however, the book did not have major influence among academic philosophers.
In The Nature of Rationality, Nozick suggested that previous discussions of rational belief and rational decision-making had given insufficient weight to what he called “symbolic utility” – the utility associated with the outcomes and actions that are symbolized by the act in question. Throughout the course of the volume, Nozick applied the idea to a number of extant puzzles in rational choice theory and decision theory, including Newcomb’s problem, Prisoner’s dilemmas, issues in the ethics of belief, and the lottery paradox. While the proposals put forth in The Nature of Rationality did not provoke the sort of widespread discussion associated with his first two books, certain of its insights – particularly its discussion of the role of principles in overcoming weakness of the will – generated considerable interest.
Nozick’s final work, Invariances: The Structure of the Objective World, published shortly before his death, was even more wide-ranging than his earlier writings. Drawing on resources from analytic philosophy, evolutionary psychology, quantum mechanics and cosmology, Nozick addressed topics as diverse as the relativity of truth, the nature of objectivity and necessity, the function and origins of consciousness, and the genealogy of ethics. The central insight of the work is that objectivity is “invariance under all admissible transformations.” This allows us to answer the question of why there is an objective world. If we assume that there is a process of evolutionary cosmology, akin to that of evolutionary biology, then we can see why objective laws would be most “heritable,” and hence why they would be present in most universes – “the greater the number of transformations that a law is invariant under, and the wider their number, the greater is that law’s heritability.” This appeal to invisible-hand explanations, echoing the opening pages of Anarchy, State and Utopia, typifies Nozick’s ability to approach problems from a novel direction. Similarly provocative is his account of necessity. Something is necessary only if we cannot imagine how it might be otherwise. But our inability to imagine things, Nozick suggests, may result from constraints on our cognitive capacities, not from the nature of things themselves. As a result, he proposes, it may be that “lack of invention is the mother of necessity.”