Following the end of World War I, the Ontario Department of Education initiated a series of reforms aimed at both elementary and secondary schooling. This article examines the reforms that were made to elementary school curriculum and pedagogy. These were initiated within the context of a call for a general reconstruction of education and society as a response to the tragic consequences of World War I. They were also based on a series of denunciations that identified scientific materialism, the unity of science and psychology, as the principal causes of war. In numerous public declarations, the religious, political, and education elite of the province expressed their belief that scientific materialism and the unity of science posed an obstacle to the development of education in the province. Although these reforms were the result of a political assessment that fervently rejected scientism, they were, in fact, underpinned by a positivist science that entailed processes of counting, measuring, and sorting to build a system of state-directed human capital formation. This article considers the nature of the scientific knowledge that underscored elementary school reform and assesses whether it represented a significant departure or simply a reconfiguration of knowledge and techniques that ensured the state's ability to govern and administrate. (Contains 104 footnotes.)