This essay explores a form of reflexivity peculiar to the postwar social sciences. The mobilization of science in the United States during World War II released across the social sciences a wave of new research tools: mathematical models and calculation techniques ranging from game theory to cybernetics. As this profusion of analytical technologies gathered pace in the early years of the Cold War, practitioners of economics and cognate disciplines began to register what I term tool shock. Foundational debates about the epistemological properties and scientific legitimacy of the new tools were conducted in various fields. Focusing on economics and sociology, and in particular on economic theory and social theory, I track these debates across the immediate postwar years. I show that the intensity and location of tool shock varied noticeably in these two disciplines. Such differences, I argue, can be explained by the extent to which the postwar techniques were built into the pedagogical and research practices of the two fields in question.