When INED and Population were first founded, soon after the Second World War, French public research was still very young, and its objectives were dictated by the priorities of public policy. Demography had not yet become the science of populations. Among the team of researchers brought together by Alfred Sauvy at INED, half of whom came from the Fondation Carrel, Jean Stoetzel occupied a central and yet paradoxical position. A French pioneer of quantitative sociology and public opinion research, he formed a bridge with social psychology, decisive for the demography of that period. While combating the Durkheimian tradition, he drew inspiration from his master, Maurice Halbwachs, to view population not as a natural entity but as a product and a factor of social organization.