Otto Neurath’s place in the history of economic thought remains somewhat elusive. He has served largely as a foil for his advocacy of in-kind calculation and economic planning. In 1920 Ludwig von Mises cited Neurath’s ideas about the virtues of in-kind or natural calculation superseding monetary calculation in effectuating a planned economy as one of the bases against which he made his case that socialist calculation, and hence a planned economy, was not possible (L. Mises 1920: 102, 119). In 1935 Friedrich von Hayek followed suit, identifying Neurath and Otto Bauer, a well-regarded Marxist economist and leading figure among the Austrian Socialists, as the “most interesting” or “most representative” exponents of socialization (see, for example, Bauer 1919), a form of collectivist economic activity to which Hayek was unalterably opposed (Hayek 1935: 30–31). Neurath served as an intellectual foil for Hayek on a second count: late in life Hayek recounted that it had been the stridency of Neurath’s position on the unity of all sciences that had propelled Hayek to comprehend an insuperable methodological divide between economics and the physical sciences (Hayek 1994: 50).