The aim of the present article is to reflect upon the ontological presuppositions of critical jurisprudence (critical legal science), understood as a set of assumptions in the domain of social ontology, which determine the identity of this form of general reflection upon law. The article proposes to identify four such assumptions: the assumption concerning the political character of the social world; the assumption on the social construction of the social world; the assumption of paninterpretationism; the assumption of the existence of epistemic communities.