Naturalism in the social sciences, described in this article as 'constitutive', tends to substantiate a single principle of social and human development by extrapolating the modes of development for the basic forms of life to the modes of development of its superior forms. Several versions of the nature of mankind are thus put forward invoking biological inheritance, originating amorality, pure forms of original humanity or, on the contrary, the evolutionary progress of his nature thanks to adaptive processes that participate in the interdependence of the individual and the social. Along these lines, we show, through the important examples of the works of Freud, Bourdieu, Marx, Lévi-Strauss, Spencer, Baldwin and Piaget, that naturalism has served in the building of unacknowledged interpretative systems that have placed the scientific approach at the service of a political-cultural enterprise.