In the second half of the Twentieth Century, Mill’s deductive method was criticized by defenders of more positivistic or modernist views of economic methodology, which I criticize in chapter 11. A number of economists, including Terence Hutchison, Paul Samuelson, Fritz Machlup, Milton Friedman, and Tjallings Koopmans argued that Mill’s deductive method is insufficiently empirical and that economic models should be judged by the agreement of their implications with economic outcomes. Yet they rarely practiced what they preached. This chapter thus highlights the methodological schizophrenia of many economists, in which methodological pronouncements and practice contradict one another.