Many important distinctions, which are not immediately obvious, between types of social situation or relationships may best be brought to light by an examination of the standard uses of the relevant expressions and of the way in which these depend on a social context, itself often left unstated. In this field of study it is particularly true that we may use, as Professor J. L. Austin said, ‘a sharpened awareness of words to sharpen our perception of the phenomena’.

For many years Hart had it in mind to add a chapter to The Concept of Law. He did not wish to tinker with the text whose influence has been so great, and in accordance with his wishes it is here published unchanged, except for minor corrections.

A customary practice of those whose role it is to apply primary rules, a rule of recognition provides criteria of legal validity by determining which acts create law. So the fundamental constitution of a legal system does not rest on moral justifications or logical presuppositions, but on this customary social rule created by ‘a complex … practice of the courts, officials, and private persons’ (107).

The gunman orders his victim to hand over his purse and threatens to shoot if he refuses; if the victim complies we refer to the way in which he was forced to do so by saying that he was obliged to do so.

Legal rules defining the ways in which valid contracts or wills or marriages are made do not require persons to act in certain ways whether they wish to or not. Such laws do not impose duties or obligations. Instead, they provide individuals with facilities for realizing their wishes, by conferring legal powers upon them to create, by certain specified procedures and subject to certain conditions, structures of rights and duties within the coercive framework of the law.

A social rule has an ‘internal’ aspect, in addition to the external aspect which it shares with a social habit and which consists in the regular uniform behaviour which an observer could record.

A constitution which effectively restricts the legislative powers of the supreme legislature in the system does not do so by imposing (or at any rate need not impose) duties on the legislature not to attempt to legislate in certain ways; instead it provides that any such purported legislation shall be void. It imposes not legal duties but legal disabilities. ‘Limits’ here implies not the presence of duty but the absence of legal power.

Under rules of the one type, which may well be considered the basic or primary type, human beings are required to do or abstain from certain actions, whether they wish to or not. Rules of the other type are in a sense parasitic upon or secondary to the first; for they provide that human beings may by doing or saying certain things introduce new rules of the primary type, extinguish or modify old ones, or in various ways determine their incidence or control their operations. Rules of the first type impose duties; rules of the second type confer powers, public or private.

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.

The use of unstated rules of recognition, by courts and others, in identifying particular rules of the system is characteristic of the internal point of view. Those who use them in this way thereby manifest their own acceptance of them as guiding rules and with this attitude there goes a characteristic vocabulary different from the natural expressions of the external point of view.

The case for calling the rule of recognition ‘law’ is that the rule providing criteria for the identification of other rules of the system may well be thought a defining feature of a legal system, and so itself worth calling ‘law’; the case for calling it ‘fact’ is that to assert that such a rule exists is indeed to make an external statement of an actual fact concerning the manner in which the rules of an ‘efficacious’ system are identified.

The first condition is the only one which private citizens need satisfy: they may obey each ‘for his part only’ and from any motive whatever; though in a healthy society they will in fact often accept these rules as common standards of behaviour and acknowledge an obligation to obey them, or even trace this obligation to a more general obligation to respect the constitution.

In an extreme case the internal point of view with its characteristic normative use of legal language (‘This is a valid rule’) might be confined to the official world. In this more complex system, only officials might accept and use the system’s criteria of legal validity.

It is a feature of the human predicament (and so of the legislative one) that we labour under two connected handicaps whenever we seek to regulate, unambiguously and in advance, some sphere of conduct by means of general standards to be used without further official direction on particular occasions. The first handicap is our relative ignorance of fact: the second is our relative indeterminacy of aim.

The vice known to legal theory as formalism or conceptualism consists in an attitude to verbally formulated rules which both seeks to disguise and to minimize the need for such choice, once the general rule has been laid down. One way of doing this is to freeze the meaning of the rule so that its general terms must have the same meaning in every case where its application is in question.

The general principle latent in these diverse applications of the idea of justice is that individuals are entitled in respect of each other to a certain relative position of equality or inequality. This is something to be respected in the vicissitudes of social life when burdens or benefits fall to be distributed; it is also something to be restored when it is disturbed. Hence justice is traditionally thought of as maintaining or restoring a balance or proportion, and its leading precept is often formulated as ‘Treat like cases alike’; though we need to add to the latter ‘and treat different cases differently’.

By contrast moral rules or principles cannot be brought into being or changed or eliminated in this way. To assert that this ‘cannot’ be is not, however, to deny that some conceivable state of affairs is actually the case, as the assertion that human beings ‘cannot’ alter the climate would be. Instead this assertion points to the following facts. It is perfectly good sense to say such things as ‘As from 1 January 1960 it will be a criminal offence to do so-and-so’ or ‘As from 1 January 1960 it will be no longer illegal to do so-and-so’ and to support such statements by reference to laws which have been enacted or repealed. By contrast such statements as ‘As from tomorrow it will no longer be immoral to do so-and-so’ or ‘On 1 January last it became immoral to do so-and-so’ and attempts to support these by reference to deliberate enactment would be astonishing paradoxes, if not senseless.

What surely is most needed in order to make men clear-sighted in confronting the official abuse of power, is that they should preserve the sense that the certification of something as legally valid is not conclusive of the question of obedience, and that, however great the aura of majesty or authority which the official system may have, its demands must in the end be submitted to a moral scrutiny.

Yet, because of the same fact of approximate equality and the patent advantages of submission to a system of restraints, no combination of malefactors is likely to exceed in strength those who would voluntarily co-operate in its maintenance. In these circumstances, which constitute the background of municipal law, sanctions may successfully be used against malefactors with relatively small risks, and the threat of them will add much to whatever natural deterrents there may be.

For if in fact we find that there exists among states a given form of international authority, the sovereignty of states is to that extent limited, and it has just that extent which the rules allow. Hence we can only know which states are sovereign, and what the extent of their sovereignty is, when we know what the rules are; just as we can only know whether an Englishman or an American is free and the extent of his freedom when we know what English or American law is.

It has never been doubted that when a new, independent state emerges into existence, as did Iraq in 1932, and Israel in 1948, it is bound by the general obligations of international law including, among others, the rules that give binding force to treaties. Here the attempt to rest the new state’s international obligations on a ‘tacit’ or ‘inferred’ consent seems wholly threadbare.

Law, however, though it also contains much that is of moral importance, can and does contain just such rules, and the arbitrary distinctions, formalities, and highly specific detail which would be most difficult to understand as part of morality, are consequently natural and easily comprehensible features of law. For one of the typical functions of law, unlike morality, is to introduce just these elements in order to maximize certainty and predictability and to facilitate the proof or assessments of claims.

To reduce the two types of rule in this way to a single type would, however, obscure their character and subordinate what is of central importance in the game to what is merely ancillary. It is worth considering how far the reductionist legal theories, criticized in this chapter, similarly obscure the diverse functions which different types of legal rules have in the system of social activity of which they form part.

For there is plainly a distinction between the case in which the members of a society each as a matter of fact habitually obey whoever for the time being answers to a certain description, and one in which a rule is accepted that whoever answers this description has a right or title to be obeyed.

It is important to distinguish the external statement of fact asserting that members of society accept a given rule from the internal statement of the rule made by one who himself accepts it.

The question whether a rule of recognition exists and what its content is, i.e. what the criteria of validity in any given legal system are, is regarded throughout this book as an empirical, though complex, question of fact.

Hart uses this distinction inconsistently to mark a difference of (a) normative type (81: primary rules as duty-imposing, secondary rules as power-conferring); (b) object (94, 97: primary rules govern conduct, secondary rules govern rules); (c) social function (40–1: primary rules direct behaviour, secondary rules provide facilities); (d) importance (91, 235: primary rules are essential to human society, secondary rules are valuable but optional); and (e) genesis (91, 95: primary rules emerge first, secondary rules later).