The blanks in the following passage indicate deletions from the text. Select the completion that is most appropriate to the context. Contemporary legal positivism depends upon the methodological assumption that a theory of law may be conceptual without, at the same time, being normative. In point of fact this assumption is a composite principle. It makes the fairly obvious claim that a conceptual theory, which strives to be descriptive rather than normative, says what the law is not what it ought to be. A conceptual theory must be supplemented by a normative theory, and the arguments in favor of a particular content for law are couched in terms of the results which are expected to flow from proposed legal acts. It is never a part of an argument for what the law ought to be, in the positivist's view, that to be a law it must have a certain content. While the normative argument refers ultimately to agreed-upon ends, it does not assert that these ends_(6)_ Rather, that they are accepted and acted upon is merely a contingent matter. The second part of the methodological premise is more subtle: A conceptual theory such as legal positivism does not claim that the particular description it offers is uniquely correct. Proponents of legal positivism regard their study of law as 'analogous to the physicists' study of the universe: They have one theory of legal institutions _(7)_.