Friedman’s economics worked because he had worked. Friedman explained to fellow economists in the 1950s that “theory is to be judged by its predictive power for the class of phenomena which it is intended to ‘explain.’” He rejected ideas that worked in smart men’s heads but failed in working men’s lives. Former Obama cabinet member Austan Goolsbee (Skull & Bones ’91) can afford his bad ideas; his most famous forebear on the University of Chicago faculty couldn’t. The future Nobel Prize winner scooped ice cream in his parents’ in-home parlor, sold fireworks by the roadside, waited tables in exchange for lunch, and peddled clothing and books to his fellow Rutgers undergraduates. Friedman came from the real world. So did his economics.

Friedman sought to persuade adversaries, not demonize them. Friedman shifted from New Dealer to libertarian. If he could be won over, then others could, too. He converted without condemning, and he debated adversaries with unfailing patience and graciousness. When conversing with progressives, the modern-liberal-turned-classical-liberal found it easier to offer counterproposals (e.g., a negative income tax to replace welfare) than to use a word—“no”—that progressives don’t appreciate. “If someone wants to achieve something, it’s easier to say ‘here is a better way of achieving your objectives’ than to say ‘you’re wrong,’” Friedman’s son David, also an economist, told me. “He made arguments that people found hard to answer. He made them politely, and without implying that the people who disagreed with him were stupid or wicked.”