The article discusses the contribution of the Brazilian anthropologist E. Castro to the formation of the post-structuralist method in anthropology. The analysis of the key notions of E. Castro’s concept (perspectivism, multinaturalism, equivocation) is proposed, according to which the subjectivity of a human is not unique and is one of the positions within the framework of the universal perspectivist structure of the world. The analysis of the sources and ethnographic data with which E. Castro worked is carried out, and the reaction of the academic community to his research, methods and intellectual moves for the transformation of the anthropological discipline itself is considered. By means of a critical approach to E. Castro's program and the analysis of its reception by his anthropological colleagues, it is revealed that the ontological turn in anthropology in E. Castro’s understanding is an attempt at a theoretical inversion, in which the premise of the unity of nature, which is technically a conceptually indefinite remainder of the ethnological classification, is replaced by the postulation of a fundamental plurality of conditionally independent agents (in the manner of G. Leibniz’s monadology). Ontology is understood here as a kind of hierarchical predicate through which the Amerindian societies are denied the subjectivity of their ways of creating a picture of the world and at the same time the epistemological basis of the dominance of Western modernity is laid. As a result of generalizing the data, the author gives a critical position in relation to the key notions and methods of E. Castro. The author comes to the conclusion that projects for expanding the non-trivial use of E. Castro’s tools also inherit its conceptual features, the ambiguous nature of which is revealed in the text of the article: the costs of “ontologizing” of anthropology, the utopian nature of ideas about access to pre-colonial thought and an even more universalist regime of dominance of modern epistemology.