My proposal focuses on the uses of Spinoza’s thought in French and German sociological literature from the last three decades of the 19th century up to the end of the First World War. It was in these countries and this period that sociology was progressively institutionalized as an academic discipline. Sociology’s claim for institutional and epistemological autonomy provoked an inevitably tension with political philosophy. The quest for a different conception of normativity was at the core of this querelle. In opposition to the classical conception of political normativity, sociologists posited that moral and legal norms were not imposed by legislators or established by philosophers, but should be analysed as the historical effects of the society’s power to self create.Spinoza was a crucial reference for the early sociologists Tönnies and Worms, Simmel and Tarde and their endeavor to provide a theoretical foundation for the new discipline. Interestingly, however, this reference progressively disappears from the sociological debate from the 1890s onwards, and Spinozism was replaced by normative and Neo-Kantian approaches, as, partially, in Durkheim or definitely in Weber.In this project I intend to provide the first rigorous historical investigation of Spinoza’s uses in classical sociology, thus offering a new paradigm for the philosophy of social sciences. My project aims to answering two sets of questions: 1. Why were classical sociologists drawing on Spinoza? What theoretical devices did Spinozism provide and how did these conceptual tools match the theoretical and epistemological expectations of classical sociology? 2. How are we to interpret the fact that Spinozism was defeated by Kantianism? How can Spinoza and Kant be considered as supporting alternative conceptions of social normativity shaping the realm of classical sociology and how does this alternative still operate in contemporary debates on the philosophy of social sciences?