Tracing the three threads of development in ideas of natural law worldwide: Cicero, the Stoics, and Justinian.

Divergence of Divine and Natural Law
Divergence of Divine and Natural Law


Enter Cicero

After one understands how Rome transformed Homer's horrific tragedy into an adulation of war, it may be of no surprise that Rome also based its laws on Greece too. At ca. 450 BCE, it is said Rome sent ambassadors to Athens in order to gather the12 Tables, with hundreds of specific procedures specified by the 'Father of democracy,' Solon. Nonetheless, however cynical one becomes of Rome's rapist attitudes to social usury and military conquest, its history is also studded with miraculous and genuinely good people, one of whom was Cicero (106-46 BCE). In fact, as an indication of Cicero's significance in history, the rediscovery of this letters in the 13th Century is considered the cause of the end of the Dark Ages.

ThatJefferson was familiar with the work of Cicero, there is no doubt:

Altho' Cicero did not wield the dense logic of Demosthenes, yet he was able, learned, laborious, practiced in the business of the world, and honest. He could not be the dupe of mere style, of which he was himself the first master in the world.
To John Adams, Thomas Jefferson (Monticello, July 5, 1814)

John Adams also admired Cicero deeply:

Cicero had the most Capacity and the most constant as well as the wisest and most persevering Attachment to the Republick. Almost fifty years ago I read Middleton's Life of this Man, with great pleasure and Some Advantage. Since that time I have been more conversant in his Writings as well as in the other Writers and general History of that Period. Within a month past I have read Middleton's Life of him again, and with more pleasure because with more Understanding than before. I Seem to read the History of all ages and Nations in every Page, and especially the History of our own Country for forty years past. Change the Names and every Anecdote will be applicable to Us.
The Adams Papers, "To Benjamin Rush" (Massachusetts, December 4, 1805)

King Henry VIII's Childhood Copy of De Oficiis, on which he Wrote, 'This Book is Mine'
King Henry VIII's Childhood Copy of De Oficiis, on which he Wrote, 'This Book is Mine'

Lex Gentium

At the age of 62, while Cicero was trying to stop revolutionary forces from taking control of the Roman Republic, he wroteDe Oficiis, which discusses the concepts ofJus Gentium (the "universal laws of nature") in comparison and opposition tomos maiorum (laws arising from ancestral custom). In modern terms, we would nameJus Gentium as Natural Law, andMos Maiorum as legislative law.

For, if we are so disposed that each, to gain some personal profit, will defraud or injure his neighbor, then those bonds of human society, which are most in accord with Nature's laws, must of necessity be broken. Suppose, by way of comparison, that each one of our bodily members should conceive this idea and imagine that it could be strong and well if it should draw off to itself the health and strength of its neighboring member, the whole body would necessarily be enfeebled and die; so, if each one of us should seize upon the property of his neighbors and take from each whatever he could appropriate to his own use, the bonds of human society must inevitably be annihilated.For, without any conflict with Nature's laws, it is granted that everybody may prefer to secure for himself rather than for his neighbor what is essential for the conduct of life; but Nature's laws do forbid us to increase our means, wealth, and resources by despoiling others.
De Officiis, 3:5:22, Marcus Tullius Cicero (Rome, 44 BCE)

While Cicero did not state any social contract or natural rights, he defined natural law as understood by reason, and undeniable in both secular and religious senses:

But this principle is established not by Nature's laws alone (that is, by the common rules of equity), but also by the statutes of particular communities, in accordance with which in individual states the public interests are maintained. In all these it is with one accord ordained that no man shall be allowed for the sake of his own advantage to injure his neighbor. For it is to this that the laws have regard; this is their intent, that the bonds of union between citizens should not be impaired; and any attempt to destroy these bonds is repressed by the penalty of death, exile, imprisonment, or fine. Again,this principle follows much more effectually directly from the Reason which is in Nature, which is the law of gods and men.
De Officiis, 3:5:23, Marcus Tullius Cicero (Rome, 44 BCE)

Cicero observes that the greatly virtuous may transcend common interpretations of law, but that Rome nevertheless should honor the local customs and rules of a society (as long as they did not contravene theJus Gentium):

But no rules need to be given about what is done in accordance with the established customs and conventions of a community; for these are in themselves rules; and no one ought to make the mistake of supposing that, because Socrates or Aristippus did or said something contrary to the manners and established customs of their city, he has a right to do the same; it was only by reason of their great and superhuman virtues that those famous men acquired this special privilege. But the Cynics' whole system of philosophy must be rejected, for it is inimical to moral sensibility, and without moral sensibility nothing can be upright, nothing morally good. It is, furthermore, our duty to honour and reverence those whose lives are conspicuous for conduct in keeping with their high moral standards, and who, as true patriots, have rendered or are now rendering efficient service to their country, just as much as if they were invested with some civil or military authority; it is our duty also to show proper respect to old age, to yield precedence to magistrates, to make a distinction between a fellow-citizen and a foreigner, and, in the case of the foreigner himself, to discriminate according to whether he has come in an official or a private capacity. In a word, not to go into details, it is our duty to respect, defend, and maintain the common bonds of union and fellowship subsisting between all the members of the human race.>
De Officiis, 3:5:63, Marcus Tullius Cicero (Rome, 44 BCE)

Later, a jurist known only as Gaius defined the Jus Gentium in very concise terms:

Every people that is governed by statutes and customs observes partly its own peculiar law and partly the common law of all mankind. That law which a people established for itself is peculiar to it and is calledcivil law, as being the special law of states, while the law that natural reason establishes among all mankind is followed by all peoples alike, and is calledJus Gentium, as being the law observed by all mankind. Thus the Roman people observes partly its own peculiar law and partly the common law of all mankind.
-The Commentaries of Gaius and Rules of Ulpian (Rome, 161-185)

Stoicism: Cicero's Value System

Cicero did not consider natural law the consequence of a social contract, but rather, a way of defining that which is necessary for harmonious existence. However, that which a harmonious existence might actually be remained an issue of contention. For Cicero himself, it did not matter whether the source of authority was secular or religious, but rather derived from ethics.

In defining his value system, Cicero wroteDe Finibus Bonorum et Malorum ("On the ends of good and evil"). Here Cicero explains the philosophical views ofHedonism,Epicureanism,Platonism, andStoicism:

  • Hedonism is living only for physical pleasure. Cicero starts with the idea that pleasure, in the form of the absence of pain, is regarded as the only goal.
  • Epicureanism argues that the satiation of pleasure diminishes it, and therefore the ideal life is a simple one, seeking pleasure only rarely. As such, Epicureanism defines values such as humility, absence of greed, and manual for self-reliance. Money has no value. In the modern era,Thoreau is considered one of the best examples of epicurean ideal, in "Walden; or, Life in the Woods" (Boston, 1854). But he argues pleasure alone cannot result in the highest good. Epicureanism, in Cicero's opinion, is simply another form of hedonism.
  • In Cicero's view ofPlatonism, both during and after a person's life, the Gods rewarded or punished human beings according to their conduct in life. The Gods also provide human beings with the gift of reason. Since humans have this in common with the gods, but animals share our love of pleasure, Cicero argued, as Socrates had, that the best, most virtuous, and most divine life was one lived according to reason, not according to the search for pleasure. This did not mean that humans had to shun pleasure, only that it must be enjoyed in the right way. For example, it was fine to enjoy sex, but not with another man's wife. It was fine to enjoy wine, but not to the point of shameful drunkenness.
  • Stoicism, by contrast with Epicureanism, considers how to improve the character by making commitments to individual virtue and social stability, ahead of their desires for fame, wealth, and power. Money does have value only insofar as it serves these ends. Like Platonism, it considers there to be reason for virtuous life, although the virtue itself results in sufficient pleasure that the Gods do not need to enforce it in any way. Human beings are all meant to follow natural law, which arises from reason. The natural law is also the source of all properly made human laws and communities. Because human beings share reason and the natural law, humanity as a whole can be thought of as a kind of community, and because each of us is part of a group of human beings with shared human laws, each of us is also part of a political community. Therefore we haveduties to each of these communities. Cicero considers it a necessary obligation under natural law to take part in politics (so far as is possible) in order to discharge those duties. Thus the Stoic enters politics not for public approval, wealth, or power (which are meaningless) but in order to improve the communities of which they are a part. If politics is painful, as it would often prove to be for Cicero, that's not important. What matters is that the virtuous life requires it.

As to Stoicism being part of natural law, Cicero does not believe any further explanation is necessary:

It is sufficient proof that Nature shrinks from destruction. (Nature abhors a vacuum.)

De Finibus Bonorum et Malorum, 5:31, Marcus Tullius Cicero (Rome, 45 BCE)

Unfortunately, while Platonics are rare, there remain many who follow the hedonistic and Epicurean lifestyles, and there is nothing in the derivation of Stoic idealism that can refute their view without falling back on Aristotelian fate. Stoicism does not seek to invoke fate, but rather that a virtuous life is a reward in itself, and therefore, the values behind Cicero's Stoicism have become increasingly rare.

Justinian's Synthesis

However, in 534 AD, theCorpus Juris Civilis of Emperor Justinian synthesized existing legal documents in a single unified work, including that of Gaius. In the process, he redefined the division between universal law and local custom into seven parts, instead of two:

Those who apply themselves to the study of law should know, in the first place, from whence the science is derived. The law obtains its name from justice; for (as Celsus elegantly says), law is the art of knowing what is good and just. Anyone may properly call us the priests of this art, for we cultivate justice and profess to know what is good and equitable, dividing right from wrong, and distinguishing what is lawful from what is unlawful; desiring to make men good through fear of punishment, but also by the encouragement of reward; aiming (if I am not mistaken) at a true, and not a pretended philosophy.

Of this subject there are two divisions,public and private law. Public law is that which has reference to the administration of the Roman government; private law is that which concerns the interests of individuals; for there are some things which are useful to the public, and others which are of benefit to private persons. Public law has reference to sacred ceremonies, and to the duties of priests and magistrates.Private law is threefold in its nature, for it is derived either from natural precepts, from those of nations, or from those of the Civil Law.

Natural law is that which nature teaches to all animals, for this law is not peculiar to the human race, but affects all creatures which deduce their origin from the sea or the land, and it is also common to birds. From it proceeds the union of male and female which we designate as marriage; hence also arises the procreation of children and the bringing up of the same; for we see that all animals, and even wild beasts, appear to be acquainted with this law. TheLaw of Nations is that used by the human race, and it is easy to understand that it differs from natural law, for the reason that the latter is common to all animals, while the former only concerns men in their relations to one another.
-Corpus Juris Civilis, Justinian Imperator I (Constantinople, 534)

Within Justinian's natural law, people are born free, but have no rights deriving from that:

Those are freedmen, or made free, who have been manumitted from legal slavery. Manumission is the giving of freedom; for while a man is in slavery he is subject to the power once known as 'manus'; and from that power he is set free by manumission. All this originated in the law of nations; forby natural law all men were born free—slavery, and by consequence manumission, being unknown. But afterwards slavery came in by the law of nations; and was followed by the boon of manumission; so that though we are all known by the common name of 'man,' three classes of men came into existence with the law of nations, namely men free born, slaves, and thirdly freedmen who had ceased to be slaves.
-Corpus Juris Civilis, Justinian Imperator I (Constantinople, 534)

With regards to possession, Justinian defined a wide range of public property due to natural law:

Now let us proceed to the law of Things. Of these, some admit of private ownership, while others, it is held, cannot belong to individuals: for some things are by natural law common to all, some are public, some belong to a society or corporation, and some belong to no one. But most things belong to individuals, being acquired by various titles, as will appear from what follows. Thus, the following things are by natural law common to all—the air, running water, the sea, and consequently the seashore. No one therefore is forbidden access to the seashore, provided he abstains from injury to houses, monuments, and buildings generally; for these are not, like the sea itself, subject to the law of nations.
-Corpus Juris Civilis, Justinian Imperator I (Constantinople, 534)

The following list of public property includes: rivers, harbors, fishing, and wildfowl; riverbanks for mooring boats; vacation cottages on the seashore; theaters, racecourses, temples, churches, graveyards, and the walls and gates of a city. But once a fish or wildfowl is caught, it becomes private properly. There follows extensive qualifications (starting with bees, geese, and pigeons, as they are farmed), rules of transactions as transfers or property, inheritance, adoption, as parts of natural law.

The point of the division between natural law and the Law on Nations is best illustrated with the escape of wild bears:

OF PAUPERIES, OR DAMAGE DONE BY QUADRUPEDS. A noxal action was granted by the statute of the Twelve Tables in cases of mischief done through wantonness, passion, or ferocity, by irrational animals; it being by an enactment of that statute provided, that if the owner of such an animal is ready to surrender it as compensation for the damage, he shall thereby be released from all liability. Examples of the application of this enactment may be found in kicking by a horse, or goring by a bull, known to be given that way; but the action does not lie unless in causing the damage the animal is acting contrary to its natural disposition; if its nature be to be savage, this remedy is not available. Thus, if a bear runs away from its owner, and causes damage, the quondam owner cannot be sued, for immediately with its escape his ownership ceased to exist. The term pauperies, or 'mischief,' is used to denote damage done without there being any wrong in the doer of it, for an unreasoning animal cannot be said to have done a wrong. Thus far as to the noxal action. It is, however, to be observed that the Edict of the aedile forbids dogs, boars, bears, or lions to be kept near where there is a public road, and directs that if any injury be caused to a free man through disobedience of this provision, the owner of the beast shall be condemned to pay such sum as to the judge shall seem fair and equitable...
-Corpus Juris Civilis, Justinian Imperator I (Constantinople, 534)

Justinian's collation was the first to set forth completely the multiple levels and interpretations of law as an abstraction from that which constitutes law as specific rules, which also included the concept of natural law. Many of the ideas remain now, for example, the land between the low-tide and high-tide marks remain public property in England. However, with the subsequent decline of intellectual pursuits in the Dark Ages, the divisions were not pursued in any structured or rational manner, and with the collapse of the Roman Empire, much of it was lost for almost 1500 years. Thus Cicero's original idea remained prominent.

In fact, the significance of Cicero's invention cannot be understated. It remained the basis of law in most nations for thousands of years, and persisted until the 16th century. The reason for the persistence is that his method of thought permitted the conquered provinces to maintain their own systems of law within the constraints of Jus Gentium. Whether the local people had established ideas of law or not, Rome did not intervene with local customs for government, unless they did not resolve an issue of pertinent conflict, in which case it was referred to the governors of each province.

As noted in the New Testament, the governors were on the whole reluctant to enforceJus Gentium unless absolutely necessary, and they were extremely sensitive to the boundaries of their rule also; but if necessary to repress rebellion, they would not hesitate to impose widespread death (Herod's massacre of all first-born children, on hearing of that a King of the Jews had been born that would rebel against him; and the handing of Jesus from Pontius Pilate to Herod, as he was born under Herod's jurisdiction).

While the theory ofJus Gentium honored private property, it did not extend to entitlements of slaves, who were regarded as property themselves of various levels. This paradoxical situation caused many variations in interpretation over the next 400 years, and emerged again when Europe started enslaving overseas populations again.

But more importantly,Jus Gentium established aHierarchy of Courts which still exists to this day. In Roman times, the courts of nations were subservient to the higher court of the Holy Roman Empire. The pope, as the highest representative of God on earth, acted as an international arbiter, imposing sanctions (excommunication) even on entire nations if they did not upholdJus Gentium.