There can be no doubt, certainly, that the historical emergence of each one of the human sciences was occasioned by a problem, a requirement, an obstacle of a theoretical or practical order: the new norms imposed by industrial society upon individuals were certainly necessary before psychology, slowly, in the course of the nineteenth century, could constitute itself as a science; and the threats that, since the French Revolution, have weighed so heavily on the social balances, and even on the equilibrium established by the bourgeoisie, were no doubt also necessary before a reﬂection of the sociological type could appear.