The origin, development, nature and evolution of the international law are usually confounded – whereas its origin and development fall in the domain of historiography, its nature and evolution belong to the discipline of jurisprudence, which is a specialized branch of legal studies. Instant write-up will briefly adumbrate different theories dealing with the nature of international law followed by modern views on the subject.

Background to the Theories

The nature of international law has, historically, been a subject of discussion. And, this discussion has resulted in a variety of views which can broadly be categorized into two schools of thought: the Natural Law and the Positive Law. The two schools of thought differ on the basis of method employed by them to study an international legal concept. The Natural Law is pegged into the belief that there is a moralistic universal system that is derived from the rules of nature; the Positivist Law, on the other hand, stresses the importance of empirical method of study that accords primacy to validity of processes. The methodological difference gives rise to different outcomes. The Natural Law, therefore, emphasizes upon the content, the Positive Law, contrarily, lays stress on the process. Malcolm Shaw, Sir Robert Jennings Professor of International Law at the University of Leicester, in his book, International Law (Sixth Edition) has traced the idea of ‘Natural Law’ to Greek Stoic philosophers, who, in turn, influenced the Romans. The Stoic philosophers opined that the Natural Law was based on rational and logical rules that were rooted in human intelligence and could not be restricted to any nation. This element of universality, according to Malcolm Shaw, was the basis of modern doctrines of international law.

Natural Law

Having outlined the background of the theories, the idea of Natural Law is now elucidated, which is by no means, modern. Besides Greeks and Romans, the Islamic jurists, due to their belief in God, and the universality principle of Islam, find themselves in the league of adherents of the Natural Law. Professor Anver. M. Emon, in his book, Islamic Natural Law Theories, has documented this aspect of Islamic Law elaborately. Therefore, within the Natural Law paradigm, there are multiple versions. In order to present a conceptual narrative, some versions within Natural Law are stated hereunder:

1. St. Thomas Aquinas, according to Malcolm Shaw, ‘maintained that Natural Law formed part of the law of God’. ‘Reason, declared Aquinas, was the essence of man and thus it must be involved in the ordering of life according to the divine will’. So Aquinas is considered the first one to open the door of reason in theological orientation towards the Natural Law.

2. Maine, a British historical lawyer, stated that ‘the birth of modern international law was the grandest function of the law of nature’. Shaw, however, states that the claim is ‘arguable’. But, this statement of Maine is regarded as the basis of relationship between modern international law and Natural Law.

3. Francisco Vitoria, a Spanish Professor of Theology, of the fifteenth century, stated that conquered South American Indians be regarded as ‘nations’, which was much contrary to the views held by then on the European continent. Hence, the widening of the concept of nations based on the universality aspect of Natural Law is one of the reasons that modern international law and Natural Law proximate each other as far as their philosophical basis are concerned.

4. The theological influence on the Natural Law school, it is said, was minimized by Alberico Gentilli, who was a professor at Oxford, in early seventeenth century, in his book ‘De Jure Belli’, wherein he originated the secular linkages of Natural Law.

5. Hugo Grotious, a Dutch lawyer, who, according to Shaw, is ‘exaggeratedly’ celebrated as father of modern international law, remarked ‘that the law of nature would be valid even if there were no God’. However, he retained the theological distinction of ‘just war and unjust war’ in his writings. His ‘enduring’ opinion is considered his view about ‘open seas’ as against ‘closed seas’, which by then, was the mainstream view in Europe insofar as the law of seas is concerned. It may be noted that Grotious titled his book as De Jure Belli ac Pacis (the Law of War and Peace), which he authored in 1625.

6. Thereafter, the Natural Law, started getting challenged more seriously. On the one hand, there were authors like Samuel Pufendorf who equated international law with law of nature, while on the other, there were others who completely ignored the thinking behind Natural Law. The latter group of authors included Richard Zouche and Bynkershoek. Then there were people who tried to reconcile between the Natural Law and the new emerging view, which by then had not been styled as Positive Law. This last category included people like Vattel, who stated that there were two types of laws: laws of conscience, which were based on Natural Law, and laws of action, which were based on ‘practical’ law: the practicality component, later, became the empirical basis of processes that laid the foundations for the Positive Law.

7. Besides, the Continental lawyers, there were approaches of the people of the USSR and the Chinese towards the international law, which were not Eurocentric, and looked at law, in general, and international law, in particular, differently. Their basis for society was evolutionary, and therefore, the law, in their understanding was also evolutionary. The outcome of effect of the evolutionary thought on the nature of international law was significant as it shaped the views of Chinese and Russians on the sources of law, which were looked in the light of historical evolution of the society.


As noted above, the Positive Law emanated out of the pragmatism and practicality. It witnessed its climax in the nineteenth and twentieth centuries. Its chief proponents are:

1. German jurist, Hans Kelsen (same Kelsen whose thought was applied in the constitutional case of Dosso in 1958 by the Supreme Court of Pakistan) is considered the main architect of this school of thought. His Pure Theory of Law influenced Positive Law aggressively. In this Theory, he advocated that law needs to be solely looked in terms of itself. He eschewed the notion of justice from his theory and stated that the notion belongs to political science. He based his Theory on legality in a rigid manner. He, therefore, envisioned a logical unified structure. According to Shaw, for Kelsen, the international law was a primitive legal order because it lacked legislative, judicial and enforcement organs. The theory, it may be noted, is far from perfect. Its superstructure of legality builds layer upon layer of rules, but the basic rule or norm is without any foundation, and absence of basic norm or rule demolishes the theory. His stance is considered monist and inflexible and bereft of the sociological considerations.

2. H. L. A Hart followed the Positive Law paradigm vigorously. He was a professor at Oxford. In his book, the Concept of Law, he tried to refine the approach propounded by Kelsen by offering his theory in more sociological sense. For him, the legal system was composed of primary and secondary rules: while the former controlled the behavioural standards, the latter helped in identifying the primary rules through processes. He stated the primitive societies had only primary rules and had not yet developed secondary rules. Based on his concept of law, he opined that international law was primitive in nature as it lacked secondary rules.

3. The rigid views of Kelsen and Hart did not hold ground for long. Other areas of knowledge started affecting their thought. In America, Late Professor Roscoe Pound offered a sociological perspective of law. He viewed law as a form of social engineering, and started questioning the sociological side of the arguments of Kelsen and Hart.

4. Rudolf Stammler, a German jurist, tried to reconcile the Positive and Natural Laws by adopting realist stance. Shaw states that he offered ‘Natural Law with changing content’ approach by offering to distinguish between the idea and the concept of law-while the idea of concept of law dealt with ‘abstract, formal definition universally applicable’, the idea of law dealt with purpose and direction of legal system.


With the advantage of having seen varied views in the two schools of thought, it would be apt to examine modern views on the nature of international law. Late Professor Myres McDougal of the University of Yale, had utilized the behavioural approach towards international relations to explain the nature of modern international law. It may be noted that the behavioural approach towards international relations divides it into two studies: first study presents international relations and as consideration of foreign policy techniques, and reasons and why one technique is preferred over others; second study, in contrast, analyzes international relations as a system. McDougal approached international law from the point of view of the second study and looked at the international law from a systemic perspective. Shaw says that he presented international law as ‘the whole process of authoritative decision making’ at the international level. McDougal employed his contextual-policy-oriented jurisprudence approach to analyze world public order. Besides the behavioural approach, another modern view is informed by the critical legal studies approach (that is also termed as New Approaches International Law or NAIL). The view holds, according to Shaw, ‘that the nexus between state power and international legal concepts’ needs to be considered in this approach. Its advocates include former diplomat and Professor of International Law at the University of Cambridge, Martti Koskenniemi. The two modern views coupled with the evidence of insistence of international legal order on human rights and globalized trends evince that the propensity of the modern international law is towards Natural Law; this tendency, however, can recede in the light of the latest political developments in the US and the UK.

The author is an independent researcher and has done his BCL from the University of Oxford.  

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