Philosopher Robert Nozick’s Anarchy, State, and Utopia, published in 1974, cemented libertarianism’s place among the political philosophies taken seriously in academia. In it, Nozick defended the “minimal state”—what latter came to be called minarchism—and showed how it could become a “framework for utopias.”

But Nozick’s interests weren’t limited to political theory. He turned his remarkable mind to nearly every branch of philosophy in such wide-ranging works as Philosophical Explanations, The Examined Life, and Invariances: The Structure of the Objective World.