In its widest sense the term law includes any rule of action; that is to say, any standard or pattern to which actions (whether the acts of rational agents or the operations of nature) are or ought to be conformed. In the words of Hooker: “ We term any kind of rule or canon whereby actions are framed a law.” So Blackstone says: “Law in its most general and comprehensive sense signifies a rule of action, and is applied indiscriminately to all kinds of action whether animate or inanimate, rational or irrational. Thus we say, the laws of motion, of gravitation, of optics or mechanics, as well as the laws of nature and of nations.”

Of law in this sense there are many kinds, and the following are sufficiently important and distinct to deserve separate mention and examination:

1. Imperative law,
2. Physical or Scientific law,
3. Natural or Moral law,
4. Conventional law,
5. Customary law,
6. Practical or Technical law,
7. International law or the law of Nations,
8. Civil law or the law of the state.

Before proceeding to analyse and distinguish these, there are the following introductory observations to be made:

1. This list is not based on any logical scheme of division or classification, but is a mere simplex enumeratio of the chief forms of law in the widest sense of that term.
2. There is nothing to prevent the same rule from belonging to more than one of those classes. The same rule may possess more than one aspect or quality, by virtue of which it may belong concurrently to more than one species of law.
3. It may be that some of those classes are merely sub-species of some other class. It is, for example, a widely received opinion that civil law is merely a particular kind of imperative law. So, also, international law is regarded variously by different authorities as a kind of conventional law or as a kind of customary law However this may be, it is convenient to classify those forms of law as co-ordinate with the others, partly on account of their special importance, and partly because of the fact that opinions differ as to the generic form to which they really belong.
4. Any discussion as to the rightful claims of any of those classes of rules to be called laws; any attempt to distinguish laws properly so called from laws improperly so called; would seem to be nothing more than a purposeless dispute about words Our business is to recognise that they are in fact called laws, and to distinguish accurately between the different classes of rules that are thus known by the same name.

We proceed, accordingly, to deal briefly with each class in its order.

Imperative law means a rule of action imposed upon men by some authority which enforces obedience to it. In other words, an imperative law is a command which prescribes some general course of action, and which is imposed and enforced by some superior power. The instrument of such enforcement is not necessarily physical force, but may consist in any other form of constraint or compulsion by which the actions of men may be determined In the words of Pufendorf: Lex est decretum quo superior sibi subjectum obligat, ut ad istius praescriptum actiones suas componat. “ A law,” says Austin, “is a command which obliges a person or persons to a course of conduct.” A law in this sense therefore possesses two essential attributes. The first of these is generality. A command, in order to amount to a law, must assume the form of a general rule; a particular command, requiring obedience in the individual instance merely, does not possess the essential characteristic of a law. The second requisite is enforcement by authority. A rule the observance of which is left to the good pleasure of those for whom it is laid down, is not a law in this sense.

Every organised community or society of men tends to develop imperative laws formulated by the governing authority of that community or society for the control of its members with intent to secure the purposes for which it exists. The state makes laws of this kind for its citizens for the purpose of securing peace, order, and good government within its territories. In the same way other forms of imperative law are developed within a church, an army, a school, a family, a ship’s company, a social club, and any other institution so organised as to possess a governing body capable of imposing its will upon the members. Even in the absence of such a definite organisation, rules of conduct which are approved by the public opinion of the society, and the breach of which is visited by public censure, are regarded and spoken of as imperative laws imposed by the unorganised society upon its members. In this sense and in this aspect the rules of morality recognised by public opinion m any community are imperative laws standing side by side with the civil law of the state and fulfilling the same purposes. Law of this kind—the law of opinion or of reputation, as Locke calls it; is commonly known as positive morality; the epithet positive being used to distinguish morality of this kind, so recognised and enforced by the public opinion of the community, from those ideal or absolute rules of right and wrong which are derived from reason and nature and are independent of recognition and acceptance by any human society. Rules of the latter kind constitute natural morality, as opposed to positive morality. The positive morality of a particular community may approve of polygamy or infanticide, while natural or ideal morality may disapprove of both.

Just as an individual state develops within itself a system of imperative law imposed by it upon its members, so the society of states develops a system of imperative law for the regulation of the conduct of those states towards each other. The law of nations or international law consists, in part at least and in one aspect, of rules imposed upon states by the society of states, and enforced partly by international opinion and partly by the threat of war.

Many writers are content to classify the civil law; the law of the state; as being essentially, and throughout its whole compass, nothing more than a particular form of imperative law. They consider it a sufficient analysis and definition of civil law to say that it consists of the general commands issued by the state to its subjects, and enforced, if necessary, by the physical power of the state. This may be termed the imperative, or, more accurately, the purely imperative, theory of civil law’. “ The civil laws,” says Hobbes, “ are the command of him who is endued with supreme power m the city ” (that is to say, the state, civitas) “ concerning the future actions of his subjects.” Similar opinions are expressed by Bentham, and by Austin, and have been widely, though by no means universally, accepted by English writers. We shall have occasion later to consider fully this view as to the nature of civil law. It is sufficient to indicate here that though it falls short of an adequate analysis, it undoubtedly expresses a very important aspect of the truth. It rightly emphasises the central fact that the civil law is based on the will and physical force of the organised political community Such law exists only as an incident of the administration of justice by the state, and this consists essentially in the imperative and coercive action of the state in imposing its will, by force if need be, upon the members of the body politic. “It is men and arms,” says Hobbes, “ that make the force and power of the laws.” The civil law has its sole source, not in consent, or in custom, or in reason, but in the will and the power of him who in a commonwealth beareth not the sword in vain. In what respects this doctrine represents not the whole truth but merely one part and aspect of it, we shall consider at large and more appropriately at a later stage of this inquiry.

The instrument of coercion by which any system of imperative law is enforced is called a sanction, and any rule so enforced is said to be sanctioned. Thus physical force in the various methods of its application is the sanction applied by the state in the administration of justice Censure, ridicule, and contempt are the sanctions by which society (as distinguished from the state) enforces the rules of positive morality. War is the last and most formidable of the sanctions which in the society of nations maintains the law of nations. Threatening of evils to flow here or hereafter from Divine anger are the sanctions of religion, so far as religion assumes the form of a regulative or coercive system of imperative law.

A sanction is not necessarily a punishment or penalty. To punish law-breakers is an effective way of maintaining the law, but it is not the only way. The state enforces the law not only by imprisoning the thief, but by depriving him of his plunder and restoring it to the true owner, and each of these applications of the physical force of the state is equally a sanction. An examination and classification of the different forms of sanction by which the civil law is maintained will claim our attention later.

Physical laws or the laws of science are expressions of the uniformities of nature; general principles expressing the regularity and harmony observable in the activities and operations of the universe. It is in this sense that we speak of the law of gravitation, the laws of the tides, or the laws of chemical combination. Even the actions of human beings, so far as they are uniform, are the subject of law of this description as, for example, when we speak of the laws of political economy. These are rules expressing not what men ought to do, but what they do.

Physical laws are also, and more commonly, called natural laws, or the laws of nature, but these latter terms are ambiguous, for they signify also the moral law , that is to say, the principles of natural right and wrong.

This use of the term ‘law’ to connote nothing more than uniformity of action is derived from law in the sense of an imperative rule of action, by way of the theological conception of the universe as governed in all its operations (animate and inanimate, rational and irrational) by the will and command of God. The primary source of this conception is to be found in the Hebrew scriptures, and its secondary and immediate source in the scholasticism of the Middle Ages; a system of thought which was formed by a combination of the theology of the Hebrews with the philosophy of the Greeks. The Bible constantly speaks of the Deity as governing the universe, animate and inanimate, just as a ruler governs a society of men; and the order of the world is conceived as due to the obedience of all created things to the will and commands of their Creator “ He gave to the sea his decree, that the waters should not pass his commandment ”. “ He made a decree for the rain, and a way for the lightning of the thunder ”. The Schoolmen made this same conception one of the first principles of their philosophic system. The lex aeterna, according to St Thomas Aquinas, is the ordinance of the Divine wisdom, by which all things in heaven and earth are governed. “ There is a certain eternal law, to wit, reason, existing in the mind of God and governing the whole universe . For law is nothing else than the dictate of the practical reason in the ruler who governs a perfect community. ” “ Just the reason of the Divine wisdom, inasmuch as by it all things were created, has the nature of a type or idea; so also, inasmuch as by this reason all things are directed to their proper ends, it may be said to have the nature of an eternal law … And accordingly the law eternal is nothing else than the reason of the Divine wisdom regarded as regulative and directive of all actions and motions.”

This lex aeterna was divided by the Schoolmen into two parts One of these was that which governed the actions of men : this is the moral law, the law of nature, or of reason. The other is that which governs the actions of all other created things, this is that which we now term physical law, or natural law in the modern and prevalent sense of that ambiguous term. This latter branch of the eternal law is perfectly and uniformly obeyed , for the irrational agents on which it is imposed can do no otherwise than obey the dictates of the Divine will. But the former branch; the moral law of reason; is obeyed only partially and imperfectly, for man by reason of his prerogative of freedom may turn aside from that will to follow’ his own desires Physical law, therefore, is an expression of actions as they actually are, moral law, or the law of reason, is an expression of actions as they ought to be.

This scholastic theory of law finds eloquent expression in the writing of Hooker in the sixteenth century “ His commanding those things to be which are, and to be in such sort as they are, to keep that tenure and course which they do, importeth the establishment of nature’s law. Since the time that God did first proclaim the edicts of his law upon it, heaven and earth have hearkened unto his voice, and their labour hath been to do his will. See we not plainly that the obedience of creatures unto the law of nature is the stay of the whole world ”. “ Of law there can be no less acknowledged, than that her seat is the bosom of God, her voice the harmony of the world, all things in heaven and earth do her homage. ”

The modern use of the term law, in the sense of physical or natural law, to indicate the uniformities of nature, is directly derived from this scholastic theory of the lex aeterna; but the theological conception of Divine legislation on which it was originally based is now eliminated or disregarded. The relation between the physical law of inanimate nature and the moral or civil laws by which men are ruled has been reduced accordingly to one of remote analogy.

By natural or moral law is meant the principles of natural right and wrong; the principles of natural justice, if we use the term justice in its widest sense to include all forms of rightful action. Right or justice is of two kinds, distinguished as natural and positive. Natural justice is justice as it is in deed and in truth; in its perfect idea Positive justice is justice as it is conceived, recognised, and expressed, more or less incompletely and inaccurately, by the civil or some other form of human and positive law. Just as positive law, therefore, is the expression of positive justice, so philosophers have recognised a natural law, which is the expression of natural justice.

This distinction between natural and positive justice, together with the corresponding and derivative distinction between natural and positive law, comes to us from Greek philosophy. This natural law was conceived by the Greeks as a body of imperative rules imposed upon mankind by Nature, the personified universe. The Stoics, more particularly, thought of Nature or the Universe as a living organism, of which the material world was the body, and of which the Deity or the Universal Reason was the pervading, animating, and governing soul; and natural law was the rule of conduct laid down by this Universal Reason for the direction of mankind.

Natural law has received many other names expressive of its divers qualities and aspects. It is Divine Law (jus divinum) the command of God imposed upon men; this aspect of it being recognised in the pantheism of the Stoics, and coming into the forefront of the conception so soon as natural law obtained a place in the philosophical system of Christian writers. Natural law is also the Law of Reason, as being established by that. Reason by which the world is governed, and also as being addressed to and perceived by the rational nature of man. It is also the Unwritten Law (jus non scriptum), as being written not on brazen tablets or on pillars of stone, but solely by the finger of nature in the hearts of men. It is also the Universal or Common Law, as being of universal validity, the same in all places and binding on all peoples, and not one thing at Athens and another at Rome, as are the civil laws of states. It is also the Eternal Law (lex aeterna), as having existed from the commencement of the world, uncreated and immutable. Lastly, in modem times we find it termed the Moral Law, as being the expression of the principles of morality.

The term natural law, in the sense with which we are here concerned, is now fallen almost wholly out of use. We speak of the principles of natural justice, or of the rules of natural morality, but seldom of the law of nature, and for this departure from the established usage of ancient and medieval speech there are at least two reasons. The first is that the term natural law has become equivocal, for it is now used to signify physical law; the expression of the uniformities of nature. The second is that the term law, as applied to the principles of natural justice, brings with it certain misleading associations; suggestions of command, imposition, external authority, legislation; which are not in harmony with the moral philosophy of the present day.

The following quotations illustrate sufficiently the ancient and medieval conceptions of the law of nature.

Law is either universal or special. Special law consists of the written enactments by which men are governed. The universal law consists of those unwritten rules which are recognised among all men. Right and wrong have been defined by reference to two kinds of law . Special law is that which is established by each people for itself. The universal law is that which is conformable merely to Nature.

There is indeed a true law (lex), right reason, agreeing with nature, diffused among all men, unchanging, everlasting… It is not allowable to alter this law, nor to derogate from it, nor can it be repealed. We cannot be released from this law, either by the praetor or by the people, nor is any person required to explain or interpret it. Nor is it one law at Rome and another at Athens, one law today and another hereafter , but the same law, everlasting and unchangeable, will bind all nations at all times; and there will be one common lord and ruler of all, even God the framer and proposer of this law.

The unerring law is right reason , not an ordinance made by this or that mortal, a corruptible and perishable law, a lifeless law written on lifeless parchment, or engraved on lifeless columns; but one imperishable, and impressed by immortal nature on the immortal mind.

All peoples that are ruled by laws and customs observe partly law peculiar to themselves and partly law common to all mankind. That which any people has established for itself is called jus civile, as being law peculiar to that State (jus proprium civitatis). But that law which natural reason establishes among all mankind is observed equally by all peoples, and is for that reason called jus gentium.

Natural law (jura naturalia), which is observed equally in all nations, being established by divine providence, remains for ever settled and immutable; but that law which each State has established for itself is often changed, either by legislation or by the tacit consent of the people.

The law of reason or human nature is that which men by discourse of natural reason have rightly found out themselves to be all for ever bound unto in their actions.

Natural law is a divine law, written in the hearts of all men, obliging them to do those things which are necessarily consonant to the rational nature of mankind, and to refrain from those things which are repugnant to it.

It is a commonly received opinion, that jus gentium, although identified as early as the time of Cicero with the jus naturale of the Greeks, was in its origin and primary signification something quite distinct; a product not of Greek philosophy but of Roman law. It is alleged that jus gentium meant originally that system of civil and positive law which was administered in Rome to aliens, as opposed to the system which was the exclusive birth right and privilege of Roman citizens; that this jus gentium, being later in date than the jus civile, was so much more reasonable and perfect that it came to be identified with the law of reason itself, the jus naturale of the Greeks, and so acquired a double meaning, (1) jus gentium, viz jus naturale, and (2) jus gentium, viz. that part of the positive law of Rome which was applicable to aliens, and not merely to citizens. That the term jus gentium did possess this double meaning cannot be doubted; but it may be gravely doubted whether the true explanation of the fact is that which has just been set forth. It would seem more probable that jus gentium was in its very origin synonymous with jus naturale; a philosophical or ethical, and not a technical legal term; the technical significance of the term is secondary and derivative. Jus gentium came to mean not only the law of nature; the principles of natural justice; but also a particular part of the positive law of Rome, namely, that part which was derived from and in harmony with those principles of natural justice, and which therefore was applicable in Roman law courts to all men equally, whether cives or peregini. In the same way in England, the term equity, although originally purely ethical and the mere equivalent of natural justice or jus naturae, acquired a secondary, derivative, and technical use to signify a particular portion of the civil law of England, namely, that portion which was administered in the Court of Chancery, and which was called equity because derived from equity in the original ethical sense.

This, however, is not the place in which to enter into any detailed examination of this very interesting and difficult problem in the history of human ideas.

By conventional law is meant any rule or system of rules agreed upon by persons for the regulation of their conduct towards each other. Agreement is a law for the parties to it. Examples are the rules and regulations of a club or other voluntary society, and the laws of cricket, golf, or any other game. The laws of chess, for example, are the rules which the players have expressly or tacitly agreed to observe in their conduct of the game. In many cases conventional law is also civil law, for the rules which persons by mutual agreement lay down for themselves are often enforced by the courts of justice of a state But whether or not; these conventional rules thus receive recognition and enforcement as part of the civil law, they constitute law in the generic sense of a rule of human action. That part of civil law which has its source in agreement may itself be termed conventional law, for example the regulations of an incorporated company, but such a use of the term must be distinguished from that which is here under consideration Conventional law in the present sense is not a part of the civil law, but a different kind of law.

The most important branch of conventional law is the law of nations, which, as we shall see later, consists essentially, and in its most important aspect, of the rules which have been expressly or impliedly agreed upon by states as governing their conduct and relations to each other.

By customary law is here meant any rule of action which is actually observed by men; any rule which is the expression of some actual uniformity of voluntary action. Custom is a law for those who observe it; a law or rule which they have set for themselves and to which they voluntarily conform their actions Of this nature are the laws of dress, deportment, and etiquette. It is true that custom is very often obligatory; that is to say, its observance is very often enforced by some form of imperative law, whether the civil law or the law of positive morality, but irrespective of any such enforcement, and by reason solely of its de facto observance, it is itself a law in that generic sense in which law includes any rule of action. The operation of custom as one of the sources of civil law will be considered later. That portion of the civil law which has its source in custom is itself called customary law, but it is not in this sense that the term is here used Customary law in the present sense is not a part of civil law, but a different kind of law in the generic sense.

Yet another kind of law is that which consists of rules for the attainment of some practical end, and which, for want of a better name, we may term practical or technical law. These laws are the rules which guide us to the fulfilment of our purposes, which inform us as to what we ought to do, or must do, in order to attain a certain end. Examples of such are the laws of health, the laws of musical and poetical composition, the laws of style, the laws of architecture, and the rules for the efficient conduct of any art or business. The laws of a game are of two kinds; some are conventional, being the rules agreed upon by the players, others are practical or technical, being the rules for the successful playing of the game.

International law, or the law of nations, consists of those rules which govern sovereign states in their relations and conduct towards each other. All men agree that such a body of law exists, and that states do in fact act in obedience to it; but when we come to inquire what is the essential nature and source of this law, we find in the writings of those who deal with it a very curious absence of definiteness and unanimity. The opinion which we shall here adopt as correct, is that the law of nations is essentially a species of conventional law; that it has its source in international agreement; that it consists of the rules which sovereign states have agreed to observe in their dealings with each other.

This law has been defined by Lord Bussell of Killowen as “ the aggregate of the rules to which nations have agreed to conform in their conduct towards one another”. “The law of nations ” says Lord Chief Justice Coleridge, “ is that collection of usages which civilised states have agreed to observe in their dealings with each other ”. “ The authorities seem to me ” says Lord Esher, “ to make it clear that the consent of nations is requisite to make any proposition part of the law of nations ”. “ To be binding,” says Lord Cockburn “ the law must have received the assent of the nations who are to be bound by it. This assent may be express, as by treaty or the acknowledged concurrence of Governments, or may be implied from established usage.”

The international agreement which thus makes international law is of two kinds, being either express or implied. Express agreement is contained in treaties and international conventions, such as the Declaration of Paris or the Covenant of the League of Nations or United Nations Organisations. Implied agreement is evidenced chiefly by the custom or practice of states. By observing certain rules of conduct in the past, states have impliedly agreed to abide by them in the future. By claiming the observance of such customs from other states, they have impliedly agreed to be bound by them themselves. International law derived from express agreement is called in a narrow sense the conventional law of nations, although in a wider sense the whole of that law is conventional, that part which is based on implied agreement is called the customary law of nations. The tendency of historical development is for the whole body of the law to be reduced to the first of these two forms, to be codified and expressed in the form of an international convention, to which all civilised states have given their express consent. Just as customary civil law tends to be absorbed in enacted law, so customary international law tends to be merged in treaty law.

International law is further divisible into two kinds, which may be distinguished as the common law of nations and the particular law of nations. The common law is that which prevails universally, or at least generally, among all civilised states, being based on their unanimous or general agreement, express or implied. The particular law is that which is in force solely between two or more states, by virtue of an agreement made between them alone, and derogating from the common law.

International law exists only between those states which have expressly or impliedly agreed to observe it. Those states (which now include all civilised communities, and some which are as yet only imperfectly civilised) are said to constitute the family or society of nations; an international society governed by the law of nations, just as each national society is governed by its own civil law. New states are received into this society by mutual agreement, and thereby obtain the rights and become subject to the duties created and imposed by international law.

Finally, we come to the consideration of that kind of law which is the special subject-matter of this work. This is the civil law, the law of the state or of the land, the law of lawyers and the law courts. This is law in the strictest and original sense of the term, all other applications of the term being derived from this by analogical extension. In the absence of any indication in the context of a different intention, the term law, when used simpliciter, means civil law and nothing else, and in this sense the term is used in future throughout these notes.

The question of the true nature of civil law is one of so much difficulty and importance that it must be reserved for detailed consideration in the following notes.

Law in its most general sense; any rule of action. Kinds of law in this sense.

1. Imperative law.
   1. Rules of action imposed on men by authority.
   2. The imperative theory of civil law; partially true but incomplete and one-sided.
   3. The sanctions of imperative law.
2. Physical or scientific law.
   1. Rules formulating the uniformities of nature.
   2. This conception of law derived from scholastic philosophy.
   3. The lex aeterna.
3. Natural or moral law.
   1. Rules formulating the principles of natural justice.
   2. This conception of law derived from Greek philosophy and Roman law.
   3. Two meanings of natural law:
      1. Scientific or physical law,
      2. Moral law.
   4. The jus gentium of the Romans.
4. Conventional law: Rules agreed upon by persons for the regulation of their conduct towards each other.
5. Customary law: Rules of action embodied in custom.
6. Practical or technical law: Rules of action for the attainment of practical ends.
7. International law: The rules which govern sovereign states in their relations towards each other.
8. Civil law: The law of the state as applied in the state's courts of justice.