Robert Nozick (; November 16, 1938 – January 23, 2002) was an American philosopher. He held the Joseph Pellegrino University Professorship at Harvard University, and was president of the American Philosophical Association. He is best known for his books Anarchy, State, and Utopia (1974), a libertarian answer to John Rawls' A Theory of Justice (1971), in which Nozick also presented his own theory of utopia as one in which people can freely choose the rules of the society they enter into, and Philosophical Explanations (1981), which included his counterfactual theory of knowledge. His other work involved ethics, decision theory, philosophy of mind, metaphysics and epistemology. His final work before his death, Invariances (2001), introduced his theory of evolutionary cosmology, by which he argues invariances, and hence objectivity itself, emerged through evolution across possible worlds. Personal life Nozick was born in Brooklyn to a family of Jewish descent. His mother was born Sophie Cohen, and his father was a Jew from a Russian shtetl who had been born with the name Cohen and who ran a small business. Nozick attended the public schools in Brooklyn. He was then educated at Columbia University (A.B. 1959, summa cum laude), where he studied with Sidney Morgenbesser; Princeton University (PhD 1963) under Carl Hempel; and at Oxford University as a Fulbright Scholar (1963–1964). At one point, he joined the YPSL. In addition, at Columbia he founded the local chapter of the Student League for Industrial Democracy which in 1960 changed its name to Students for a Democratic Society. After receiving his undergraduate degree in 1959, he married Barbara Fierer. They had two children, Emily and David. The Nozicks eventually divorced; Nozick later married the poet Gjertrud Schnackenberg. Nozick died in 2002 after a prolonged struggle with stomach cancer. He was interred at Mount Auburn Cemetery in Cambridge, Massachusetts. Career and works Political philosophy For Anarchy, State, and Utopia (1974) Nozick received a National Book Award in the category Philosophy and Religion. There, Nozick argues that only a minimal state limited to the narrow functions of protection against "force, fraud, theft, and administering courts of law" could be justified, as any more extensive state would violate people's rights. For Nozick, a distribution of goods is just if brought about by free exchange among consenting adults from a just starting position, even if large inequalities subsequently emerge from the process. Nozick challenged the partial conclusion of John