A lot of confusion in the discussion of law, and in the philosophy of law, has been occasioned by the failure to distinguish the different modes of discourse in which the term “law” appears and is meaningful, and there are good reasons for it being used. St. Thomas Aquinas, the great medieval philosopher, has in mind what I call “fully critical discourse” when he defines law as the ordinance of reason for the common good, promulgated by the one who has responsibility for the common good or the care of the common good, of the community. Aquinas is there engaging in a mode of discourse that I would call fully critical discourse, conscience-informing discourse, moral discourse. He wants to know how it is that the law binds human beings in conscience. That's a perfectly legitimate question. More than legitimate. A necessary question. That kind of discourse, fully critical discourse, is discourse we need. But there are two other kinds of discourse, or modes of discourse, in which the term law is used and is rightly used. One is in intrasystemic legal argumentation or disputation. So, lawyers in a courtroom, for example, arguing before a judge will use the term law, or will refer to “the law” but they are doing so in a more restricted sense not in the fully critical sense. They're here, these actors in a system, talking about what we call the positive law, the law laid down by the human lawmaker, the law of the polity, the law of the state. The law is the law whether we like it or not, whether the judge or other actor in the system happens to think it’s good law or bad law, expedient or inexpedient, even just or unjust. So the judge needs to know what the law is. Sometimes he needs to decide in view of the arguments made by the advocates before him what the law is. He's got to hear the arguments when there's a dispute about what the law is or how it applies, got to hear the argument between the lawyers in order to make up his mind about what the law really does require in the case at hand. Here, his discourse is restricted somewhat. It's not the fully critical or moral discourse. The judge needs to know what legitimately counts as the law, be it good or bad, right or wrong, just or unjust. Then there's a third mode of discourse. following the great modern legal philosopher H.L.A. Hart, I'll call descriptive sociological discourse. This is the discourse of legal scholars, and especially comparative law scholars, who are trying to figure out what's going on in different legal systems. Often systems that are not the scholars’ own legal system, not the system in the scholar’s own society. So, a British legal comparative law scholar might be looking at the Japanese legal system, for example, or the Ancient Roman legal system, or one of the legal systems in Africa or east Asian civilizations. There, the scholar is really concerned about what counts as law, is treated as law by the key actors in the legal system under review or the society under review. So, Hart, rightly, urges that we have to adopt, even though we're outsiders, or maybe outsiders, what Hart calls the internal point of view. Hart is critical of his predecessors in the tradition of what we call “analytical jurisprudence” - Jeremy Bentham, John Austin, even though in many ways he's drawing on them, because he thinks they fail to see the need to adopt the internal point of view precisely in order to understand what's actually going on in a legal system. They treat the matter entirely externally. They don't look at law or try to understand law from the point of view of the people whose behavior actually constitutes the legal system. They look at it from a purely outsider point of view. Hart thinks, and I completely agree with him, that this means that their accounts will consistently fail to fit the facts. (I’m quoting Professor Hart there.) They will not be really accurate and refined accounts that are social science and social study at its best. To get really accurate and refined accounts of any legal system or any social system, even if our goal is purely the descriptive, sociological one, we need to adopt an internal point of view. We need to see the ways in which people in a system, officials and citizens, make laws for reasons and act on reasons that are provided by the laws. So, people's behavior is shaped in part by the norms that they believe that they have reason to act on because they're the legal requirements.