This paper takes into account the processes of social construction in classification frameworks or conceptual schemes that all societies use as a frame of reference, with its interpretive codes, that give meaning and value to what we do, think, utter and perceive. In modern societies there is conflict between a rigid classificatory frame, based upon "purity" and with quasi-naturalized distinctions, and a flexible classificatory frame, based upon ambivalence, with more blurred and permeable distinctions. Authors considered in this reflection are, among others: Durkheim, Mauss, Simmel, Derrida, Foucault, Rorty, Goffman, Bourdieu, Douglas, Zerubavel, Luhmann, Bauman, Haraway, Elias, Zizek, Jokisch and Marquard. [ABSTRACT FROM AUTHOR]