In her book Positivismo jurídico "interno" Cristina Redondo claims that legal theory can be neutral from a moral point of view. An essential part of her argumentation is based on the criticism of an anti-positivist conception of law developed by Fernando Atria, according to which, since law is a functional concept, no descriptive or morally neutral theory of law can be provided. The essay claims that while Atria's conception of law encounters some difficulties, Redondo's criticism is not conclusive. More importantly, there are two types of natural law theories which also claim that law is a functional concept but which do not face Atria's difficulties. One holds that law is a functional kind and the other claims that the concept of law is a normative-functional concept. The latter type of theory seems particularly suitable for avoiding not only Redondo's criticism but also standard objections from the positivist camp. If this type of theory is correct, a theory cannot be morally neutral.