 That approach is not only simpler; it closes the gap that Hart left in his theory. According to Hart, the meaning of normative language differs in morality and in law. But in fact, Hart had nothing to say about the meaning of normative expressions such as ‘ought’ and ‘must’ or ‘obligation’ or ‘right’ (except that their meaning differs in law and in morality). He only pointed out that people display an attitude when they use such language.