We are now in a position to return to the question posed in the first chapter of the character and scientific status of the reorientation of social thought that took place at the end of the nineteenth-century. There is little doubt that such a reorientation did in fact take place, and that this reorientation did not simply involve a change in a number of elements of a given system. It involved a fundamental change in the 'structure of the theoretical system" (Parsons, 1949, p. 7). According to Parsons this change was marked by the substantive advance represented by the emergence of a voluntaristic theory of action out of the convergence of the earlier positivistic and idealistic theories of action. However, I hope to have shown in the course of this book that the development of marginalism and of Weberian sociology was not marked by such a substantive scientific revolution. The substantive foundation of marginalism and of Weber's sociology continues to be the naturalistic conception of the social relations of production of capitalist society that characterised nineteenth-century classical political economy, vulgar economy, sociology and historicism. The end of the nineteenth-century saw a reorientation of social thought, not a scientific revolution. In Parsonian terms this reorientation was marked by a reformulation of the relationship between the theory of action and the theory of social structure.