Robert Nozick (November 16, 1938 ? January 23, 2002) was an American political philosopher . His best known work is Anarchy, State, and Utopia (1974). It responds to A Theory of Justice , a book by John Rawls .

Politically, Nozick was a libertarian . He believed that the government should protect property and resolve contractual disputes but not much else. Nozick also created the thought experiment of the experience machine .