Today is the 22nd anniversary of Murray Rothbard’s death. His influence continues to grow, as new generations of students, at the Mises Institute and elsewhere, discover his thought. Many besides Rothbard’s acknowledged followers have been influenced by him, but one striking example must here suffice. One of the most important books of twentieth-century American philosophy has been Robert Nozick’s Anarchy, State, and Utopia. Nozick remarks that it “was a long conversation about six years ago (i.e., in 1968) with Murray Rothbard that stimulated my interest in individualist anarchist theory.” The entire first part of Nozick’s book is an attempt to come to terms with Rothbard’s argument and might have been entitled “Why I Am Not a Rothbardian.”
One anecdote about these two thinkers may be surprising. It is well known that they differed on many controversial issues, e.g., anarchism versus minarchism, Libertarian Party strategy, and American policy in the Middle East. Their first difference of opinion, though, concerned none of these topics. In their initial conversation, they differed sharply over measurement of intensive magnitudes. Rothbard, for the reasons given in his great essay, “Toward a Reconstruction of Utility and Welfare Economics,” argued that intensive magnitudes such as utility cannot be measured, but Nozick disagreed. I understand the discussion became quite heated. As usual, Murray was right.