Robert Nozick

Nozick was born in Brooklyn to Russian-Jewish immigrants; his father ran a small business. He studied philosophy at Columbia, was a socialist in youth, and as a graduate student at Princeton read Hayek and Mises and was argued into libertarianism by a fellow student's case for the market. His 1963 doctorate under Hempel was on decision theory, and after Princeton, Harvard and Rockefeller University he became a full professor at Harvard at thirty in 1969.

Anarchy, State, and Utopia (1974) won the National Book Award. Starting from a Lockean state of nature it argued that a minimal state, limited to protecting people from force, theft and fraud and enforcing contracts, could arise from the state of nature without violating anyone's rights, while any more extensive state, above all a redistributive one, must violate them. Individual rights are 'side constraints' that may not be sacrificed to any social goal. Justice lies in the history of holdings: if the original acquisition was just and later transfers voluntary, then however unequal the result, it is just.

The most famous argument is the Wilt Chamberlain example: suppose a perfectly equal distribution, then a million fans each voluntarily pay the basketball star twenty-five cents to watch him play, and he ends up far richer than anyone; the result arises from voluntary exchange, and any patterned theory of distribution must continually interfere with people's free choices to maintain itself. He also proposed the 'experience machine': if a machine could give you any experience you wanted, would you plug in? Most would not, which shows we want not just experiences but real lives.

He never defended libertarianism again, saying he did not want to spend his life writing 'Son of Anarchy'. Philosophical Explanations (1981) treated personal identity, knowledge, free will and the meaning of life, proposing the 'tracking' theory of knowledge: to know p is such that if p were false you would not believe it. The Examined Life (1989) meditated on living, The Nature of Rationality (1993) on decision and reason, Invariances (2001) on the structure of objectivity. He later called the position of Anarchy 'seriously inadequate' and softened considerably on social provision. He died of stomach cancer at sixty-three.