It is appropriate now to turn to a crucial concept in understanding Hart's legal philosophy and its moral dimension. Hart holds that one can look at a legal order from two different perspectives. First, there is the external point of view. When one looks at a legal order from an external point of view, one observes how members of a different society act with respect to its legal system. The' observer is outside the legal system. So, when he or she observes that people in the system regularly obey the law, observable regularities of behavior can be noted and recorded. The observer is in the role of the social scientist, dutifully recording the behavioral patterns of the individuals in society. It is important to recognize that the observer can explain what people are doing within the system, but he or she cannot explain why they are doing it. The observer can note that the citizen has obeyed the law, but can never ascertain whether the citizen believes that he or she has a moral obligation to obey that law. It is as if the observer is looking at the legal system through a one-way mirror.