The concept of law is not a theorist's invention but one that people use every day. Thus one measure of the adequacy of a theory of law is its degree of fidelity to the concept as it is understood by those who use it. That means as far as possible. There are important truisms about the law that have an evaluative cast. The theorist has either to say what would make those evaluative truisms true or to defend her choice to (...) dismiss them as false of law or not of the essence of law. Thus the legal theorist must give an account of the truth grounds of the more central evaluative truisms about law. This account is a theory of legitimacy. It will contain framing judgments that state logical relations between descriptive judgments and directly evaluative judgments. Framing judgments are not directly evaluative, nor do they entail directly evaluative judgments, but they are nonetheless moral judgments. Therefore, an adequate theory of law must make (some) moral judgments. This means that an adequate theory of law has to take a stand on certain (but not all) contested issues in political philosophy. Legal theory is thus a branch of political philosophy. Moreover, one cannot be a moral-aim functionalist about legal institutions without compromising one's positivism about legal norms. (shrink)