In the last decades of the twentieth century anthropology appeared to develop a new sense of purpose around issues such as impurity, mixture, and fragmentation that self-consciously brought under critique a variety of conceptions that had guided ethnography and anthropological analysis for much of the preceding century. Yet no matter how much some of us like to think of hybridity as a conceptual tool that can absolve us from earlier sins of holism and totalization, such hopes are ironically premised on an ontology that presupposes the existence of “real”, non-negotiable discontinuities beyond human classificatory maneuver “out there in the world”. As I will argue by drawing on a wide range of examples of classificatory infrastructures underwriting variously naturalized distinctions (from animal breeding to race, sexual dimorphism, language, and the history of anthropological notions of cultural objects of analysis), such unwitting recurrence to a “metaphysics of substance” betrays our own discipline’s lasting rootedness in ultimately Platonic notions of pluralism that may well be worth opening up to sustained metatheoretical reflection.