Professor Robert Nozick

Robert Nozick, philosopher: born New York 16 November 1938; Instructor, Princeton University 1962-63, Assistant Professor 1963-65; Assistant Professor, Harvard University 1965-67, Professor of Philosophy 1969-2002, Chair of Department 1981-84, Arthur Kingsley Porter Professor of Philosophy 1985-98, Joseph Pellegrino University Professor 1998-2002; Associate Professor, Rockefeller University 1967-69; married 1959 Barbara Fierer (one son, one daughter; marriage dissolved 1981), 1987 Gjertrud Schnackenberg; died Cambridge, Massachusetts 23 January 2002.

When Robert Nozick was diagnosed with stomach cancer almost a decade ago, it was supposed to kill him within six months. He bore his illness not only with grace but with something very like insouciance. This was wholly in character; he was an original thinker who worked towards his own conclusions in his own way, and his work was stylish, radical, and endowed with an intellectual gaiety that was not common in 20th-century Anglo-American philosophy.

Nozick is best known for his first book, Anarchy, State and Utopia (1974), but this excursion into political theory was not as important to Nozick himself as it was to his reputation. He wrote little about politics after it, and was emphatic that he did not wish to spend his life writing "son of Anarchy, State and Utopia". In this, he was very different from John Rawls, the colleague and mentor whose A Theory of Justice (1971) provoked the writing of Anarchy, State and Utopia. Rawls spent the past 30 years exploring the implications of his carefully crafted moral and political theory in a way that Nozick neither wanted to, nor, perhaps, could have done.

That Nozick wrote a book that the neo-conservative, free-market American right of the 1970s and 1980s fell in love with is slightly surprising. He was born in 1938 in Brooklyn, the son of a Russian immigrant. As a student at Columbia University he joined the Socialist Party led by Norman Thomas, and founded the Columbia branch of the Student League for Industrial Democracy. Although the latter transformed itself in the 1960s into the Students for a Democratic Society, and was at the heart of the rebellion of 1968, the inspiration of both organisations in the 1950s owed more to John Dewey than Karl Marx.

He went on to graduate work in the Princeton philosophy department, working on problems in the rationality of decision-making that resurfaced 30 years later in The Nature of Rationality (1993). He became an assistant professor at Princeton, then at Harvard, worked briefly at Rockefeller University, and in 1969 returned to Harvard as a full professor at the astonishingly early age of 30. He remained there for the rest of his life, serving as Chair of the Department of Philosophy from 1981 to 1984, and in 1998 was named University Professor.

Anarchy, State and Utopia is a book that is more misunderstood by its admirers than its critics. It is often thought to have provided philosophical support for the policies of Ronald Reagan and Margaret Thatcher, but its criticism of social conservatism is at least as devastating as its criticism of the redistributive welfare state. As Nozick more than once observed, the people who liked the book, when he was arguing that everyone should be allowed to do what he liked with his own property, flinched when he drew the conclusion that this entailed the legalisation of hard drugs and prostitution. But he insisted that the two things hung together inseparably.

Nozick was right. He took as his starting point the thought that each of us comes into the world as the owner of herself or himself, body, mind, and abilities. It was the ownership of our own selves that drove the argument rather than the capitalist's ownership of the means of production. It was this that led him to mock the welfare state as doomed to forbid "consenting capitalist acts in private", and this that inspired the wonderful parody of Marx's "From each according to his ability, to each according to his needs": "From each as he chooses, to each as he is chosen".

A prostitute may choose to offer his or her sexual services to anyone who chooses to purchase them; it is her (or his) body, and it is up to her (or him) to decide who may use it, in what ways, and at what price. By the same token, the lungs into which we inhale cannabis fumes are our lungs.

Although he was, rightly, seen as a critic of Rawls, whose A Theory of Justice was quite self-consciously intended to elucidate the moral basis of the modern, liberal welfare state, Nozick was in crucial ways on the same side. Both were opposed to the utilitarianism that underpins most defences of the welfare state. Both thought that the limits of state action were set by individual rights. Utilitarians have extreme difficulty explaining how anyone can possess inviolable rights that override the needs of the rest of society; Nozick insisted that the rights of individuals are what dictate the ways in which society – that is, everyone else – can pursue its goals.

He memorably observed that he was not quite sure whether taxation was like forced labour or was forced labour. The argument was agreeably simple; my time is my time. If I have to spend it to create resources that the state uses for purposes I haven't subscribed to, I am doing forced labour. The fact that the majority votes for policies that require forced labour is no argument; we are simply slaves of the majority rather than of one or two individuals.

The crucial difference between Rawls and Nozick was that Rawls thought the rights to life and liberty were different from, and prior to, rights to property, Nozick thought they were property rights. And what made his social libertarianism more alarming to his neo-conservative admirers was his conviction that if we did not start from a view of self- ownership that licenses prostitution and the like, we could not defend private property in factories, shares, land or anything else.

He enjoyed the fame the book brought him; among other prizes, it won the 1975 National Book Award, and was later listed by the Times Literary Supplement among the 100 most influential books of the 20th century. But he then took up quite other subjects. He had always hoped that the political theory of Anarchy, State and Utopia, which in the book rests mostly on some wonderful negative arguments about the horrors implied by all alternatives, might be linked to a deep theory of human nature and morality. It never happened; he could not find what he wanted.

He did not exactly return to the topics in logic, decision-making, and the theory of knowledge that he had started on as a graduate student; he roamed all over the landscape, cheerfully offering to explore philosophical theories of pleasure with reference to ice cream among other human goods. Still, Philosophical Explanations (1981) was especially admired for his account of issues in epistemology. Its successor, The Examined Life (1989), not only borrowed its title from Plato, but tackled Socrates's favourite question: how shall we live?

Nozick lacked the moralist's touch, and his forays into listing the human goods sometimes sounded more like rabbinical homilies than like the work of the author of Anarchy, State and Utopia. Nobody could have said that about his penultimate book, The Nature of Rationality, which returned to vexed questions about the rationality of decision- making, and was clever, wry, and full of insight. His last book, Invariances: the structure of the objective world, appeared last October.

Alan Ryan