As Redondo explains, Eugenio Bulygin’s legal positivism embraces the separation thesis, a version of the social thesis (which he calls the ‘social sources thesis’), and an indeterminacy thesis, according to which law is sometimes indeterminate, giving judges discretion to decide cases. Bulygin holds that law can be necessarily normative only in a weak, relative sense. Redondo explains that Bulygin espouses two methodological theses that are positivist – that the task of legal philosophers is to explicate legal concepts and that we need to maintain in our legal thinking a distinction between norms and normative propositions – and that he espouses three substantive theses that are also positivist – that legal positivists must adopt a concept of relative normative validity to account for the existence of legal rights and duties, that legal interpretation must proceed on the assumption of linguistic conventionalism and that there is a fundamental and unbridgeable distinction between prescriptive and power-conferring norms. These theses can be said to be positivist because they all, one way or another, enable a value-neutral study of law, i.e. so-called methodological legal positivism.