While formulating his theory of law, it was one of Hart’s primary concerns to address the deficiencies in John Austin’s “command theory.” Austin and the positivist school viewed statements of obligation not as psychological statements, but as predictions of chances of incurring punishment or evil. To this Hart put forth two fundamental objections: first, that deviations from obligations are not only grounds for prediction that harm will follow, but also grounds for justification for that harm. And second, that evasion of obligation does not necessarily mean dissolution of the obligation itself, something that would be a necessary (and absurd) corollary of the Austinian definition.
According to Hart, rules are conceived and spoken of as imposing obligations when the general demand for conformity is insistent, and the social pressure brought to bear upon those who deviate, or threaten to deviate, is great.
It is crucial to distinguish rules from mere habits, or convergence of behaviour, and this is the point at which Hart departs from the Austinian viewpoint. Hart argues that the predictive theory looks merely at the external aspect of rules, and makes statements about habit (somewhat similar to the American legal realist concept of the bad man). However, there exists a second aspect of rules, namely, the internal aspect. Rules are viewed as standards governing behaviour, and therefore, deviation is a reason for criticism, and not merely the basis for a prediction. For Hart, therefore, the concept of rules encapsulates not only convergence of behaviour (the external viewpoint), but also the convergence of attitudes.
Using the internal viewpoint, people within the legal system judge, evaluate and criticise their conduct and that of their peers. While the external viewpoint is purely descriptive, made by an observer outside the system (“In England, they recognize as law…”), the internal viewpoint is evaluative (“It is the law that…”).
Hart connects the concept of “efficacy” with external statements about the legal system – for instance, an external observer would obviously talk about the legal system from the point of view of its practical working. Similarly, the concept of “validity” is connected with the internal statement, where rules are viewed as standards, and deviation is a reason for criticism. There is, however, a contextual connection between the internal statement of validity and the external statement of efficacy. This is because if within a legal system, internal statements cease altogether, this will have so great an impact upon efficacy, that for all practical purposes, the legal system may as well be treated as dissolved and extinct.
Having developed this concept of the internal aspect of rules, Hart now ascribes to it its place in a legal system. Law is a union of primary and secondary rules; primary rules confer obligations upon citizens, and secondary rules are directions to officials authorizing them to change, recognize (create) or adjudicate upon the primary rules. Hart argues that it is a sufficient condition that the citizenry, which is subject to the primary rules, need only take an external viewpoint towards primary rules. They may not view the rules as standards; they may not consider themselves obligated to obey them; and they may not even make a moral commitment to follow the law. All that, however, is irrelevant with regard to the existence of a legal system. All that is needed is the existence of the external viewpoint, so that the detached observer can look upon the behaviour of the citizenry, and on that basis alone, find the legal system to be in good, practical working order.
It is at the level of secondary rules that the internal aspect comes in. Hart argues that it is a necessary condition for the existence of the legal system that the officials directed to identify and apply the primary rules through the means of secondary rules, take the internal viewpoint towards those. This is so because it is the only way in which reasons or justifications of enforcing, creating or changing obligations can be given, a concept which is parasitic upon Hart’s idea of the “social rule.”
Two powerful criticisms have been made to Hart’s idea of the internal aspect of rules. The first is by John Finnis. Finnis argues that when Hart uses the idea of primary and secondary rules to distinguish a developed legal system from a primitive legal system, he is using a philosophical tool called “the central case” (an idea bearing close resemblance to the Weberian ideal type). The central case is one which, within a certain paradigm, best fulfills the characteristics of that paradigm. Finnis then argues that Hart should not have stopped at the level of the existence of the internal aspect of rules as a means of differentiating the central case from other, peripheral cases. He should have further differentiated the notion of the internal aspect itself. What this means is that there are many reasons or motivations behind people viewing rules as standards (using the internal point of view), including self-interest, a detached interest in the well-being of others etc. Finnis argues that all these are “watered-down” notions of the internal aspect of rules: the central case is the viewpoint of the moral man, the one who views the law as a moral standard. Finnis does not explain further as to why the moral man standard is to be the central case for legal systems, and this is a weakness that has been pointed out by some scholars.
The second criticism is one made by Joseph Raz. Raz argues that Hart’s dichotomy between internal and external aspects of rules commits him to a position where either one must be a detached observer commenting upon the efficacy of the legal system, or an internal actor who is endorsing the law’s moral authority. According to Raz, however, there is a third category of statements, that of lawyers, or law teachers explaining the law to others. This allows an internal statement to be made without espousing it as a normative standard; for instance, I may be a vehement opponent of capital punishment, but within the framework of my country’s legal system, I may end up writing a legal opinion with the statement, “Given the law on this point, he ought to be hanged.” The use of the word ought in this sentence does not commit me to an endorsement of the moral content of the rule itself.
This supposed contradiction in Hart’s theory of rules has been elegantly explained by Neil MacCormick. MacCormick argues that understanding, and not will, determines the internality of a statement. It is possible to understand a norm, to be able to frame judgments in terms of it, and yet remain hostile or indifferent to it. Therefore, according to MacCormick, the internal point of view should be further classified into two categories: merely an understanding of what the rule requires, and volitional commitment to upholding the rule. MacCormick concludes with the reasonable assumption that no legal system can exist without at least some people who do care about the maintenance of patterns of conduct, who do have volitional commitment towards the rule.
In summation, therefore, Hart views the internal aspect of rules as providing reasons, or justifications for criticism in case of deviation, as opposed to the external aspect, which merely predicts consequences. In a legal system, it is a necessary condition that officials take an internal view towards secondary rules. Such an internal view, however, may be restricted to only an understanding of what the rule requires, or could extend to a volitional commitment towards upholding the rule.