Cicero.—“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 It is not allowable to alter this law, nor to derogate from it, nor can it be repealed.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 to-day 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.”[[47]]
Philo Judaeus.—“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.”[[48]]
Gaius.—“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.”[[49]]
Justinian.—“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.”[[50]]
Hooker.—“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.”[[51]]
Christian Thomasius.—“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.”[[52]]
The Jus Gentium of the Roman Lawyers.
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 (peregrini), as opposed to the system which was the exclusive birthright and privilege of Roman citizens (jus civile or jus quiritium); 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 Roman equivalent of the κοινος νόμος of Aristotle and the Greeks; and that 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 peregrini. 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.[[53]]