Sir Henry Sumner Maine mainly disagrees with those writers on the origin of international law who believe that mankind started from a condition of innocent peace which was, they assert, transformed by man's wickedness into virtually universal and unceasing war. "It is not peace," he says, "which was natural and primeval and old, but rather war. War appears to be as old as mankind, but peace is a contemporary invention. Our intelligence is just beginning to enable us to infiltrate the clouds which rest on the farther verge of history, but what does seem clear to trained observation is the universal belligerency of primitive mankind.
Not only is war to be seen everywhere, but it is war more appalling than we, with our ideas, can simply conceive. " (Maine, 1888, p. 8). But let us return to Grotius and see what was his theory of the law of nature in the law of nations. While he made profuse use of the Scriptures and of the poets, he did not take on to premise the law of nature upon the delightful state of man in Paradise or in the mythical Golden Age.
As, his treatise, universally recognized to be the first systematic general exposition of international law, dealt mainly with the law of war, and that law is regarded in some quarters as having been the raison d'etre of his work ( J. B. Scott 1925), p. xxvi). Grotius, besides being a philosopher, a theologian, and a poet, was a man of experience in realistic affairs, and he did not effort the impractical task of reviving any supposed lost Code of the Law of Nature.
What he undertook to do was to set forth a system of law based upon the history and experience of mankind as they were recognized to him. Regardless of the view one can take of the present relation of natural to positive law, the history of the development of the science of international law contains support for the following propositions: First, at its birth and throughout the infancy of international law, the law of nature was a significant source and a crucial guide.
In its earliest years, when the law of nations was so mostly confined to the law of war, natural law exerted its greatest influence in ameliorating the ruthless practices of primitive war. In referring to this period, Sir Henry Sumner Maine, in his Cambridge lectures, says that "the greatest function of the law of nature was discharged in giving birth to contemporary international law and the modern law of war" (Maine, 1888, p. 8). And Oppenheim pays this tribute to the influence of the law of nature upon the growth of international law:
Whatever we can nowadays think of this Law of Nature, the fact remains unshaken that for more than two hundred years after Grotius, jurists, philosophers, and theologians decisively believed in it. And there is no doubt that, but for the system of the Law of Nature and the principles of its prophets, the modern Constitutional Law and the modern Law of Nations would not be what they actually are. The Law of Nature supplied the crutches with whose help history has taught mankind to walk out of the institutions of the Middle Ages into those of contemporary times (Oppenheim, 1905-6, p. 87).
Secondly, in international law as a customary system governing the relations of modern sovereign states, conflicts take place between concepts based upon the law of nature and principles flowing from the theory of the consent of nations. In such conflicts natural law theories typically are subordinated to the more pressing demands of material deliberations.
• Oppenheim Lassa. International Law; A Treatise. London, 1905-6. • Guggenheim, Paul Traite De Droit International Public, Geneva: Librairie De L'universite, 1953. • Cheng, Bin General Principles Of Law As Applied By International Courts And Tribunals London: Stevens, 1953.