Meaning of natural law

what is natural law?

The term ‘natural law’ like ‘positivism’ has been variously applied by different people at different times.  Dias has tabulated them as follows:

  1. i) Ideals which guide legal development and administration.
  2. ii) A basic moral quality in law which prevents a total separation of the ‘is’ from the ‘ought’.

iii) The method of discovering perfect law.

  1. iv) The content of perfect law deducible by reason.
  2. v) The conditions sine quibus non for the existence of law.


Dias had drawn a distinction between two kinds of natural law thought: ‘natural law of method’ and ‘natural law of content’. The former was the older dating from ancient times and was also prevalent in the early middle ages.  It concerned itself with trying to discover the method by which just rules may be devised to meet ever-varying circumstances.  It is a prescription for rule-making not a catalogue of rules.  The ‘natural law of content’ was a feature of the 17th and 18th century and was characterised by attempts to deduce entire bodies of rules from absolute first principles.

Natural law theory has a history reaching back centuries BC.  There is no one theory: many versions have evolved through out this enormous span of time.  Natural law theory should not be dismissed simply on account of its variety.  A brief discussion of natural law theories shall be presented in the historical order to give an idea of the various ideologies that it tried to establish from time to time and its effect on law.  Natural law theories may be divided into four classes for the purpose of our study:

  1. Ancient theories
  2. Medieval theories
  3. Renaissance theories
  4. Modern theories.

Ancient theories

Natural law thinking has occupied a pervasive role in the realms of ethics, politics, and law from the time of Greek civilization.  If we start our survey of the legal theory of the Greeks rather than that of some other nation, it is because the gift of philosophical penetration of natural and social phenomena was possessed to an unusual degree by the intellectual leaders of ancient Greece.  The legal conceptions of the archaic age of the Greeks are known to us through the epic works of Homer.  Law at that time was regarded as issuing from the gods and known to mankind through revelation of the divine will.  Law and religion remained largely undifferentiated in the early period.  The forms of law making and adjudication were permeated with religious ceremonials, and the priests played an important role in the administration of justice.  The King, as the supreme judge, was believed to have been invested with his office and authority by God himself.  A burial of the dead was regarded by the Greeks as a command of the sacred law, whose violation would be avenged by divine curse and punishment.

The Greek thinkers developed the idea of natural law and laid down its essential features. Heraclitus (530 – 470 B.C.) was the first Greek Philosopher who found natural law in the rhythm of events.  He turned to nature to say that in nature, all things – sun, moon, seasons, plants and animals – follow a certain definite order and deducible therefrom that nature must have rules for the orderly conduct of everything and therefore for man too, and it must be ideal law.  This led to a conception of natural law as the higher law which the Greek philosophers declared should be the model for all man made laws.

The Greek concept of natural law may be explained thus: Animals act by instincts.  Man as part of the nature must also have instincts, which set passions in him.  But he is something more than an animal because he is endowed with a will governed by an intellectual faculty which is called reason. Man’s power of reason enables him to suppress his instinct and act against its dictates.  He can act or not, as he pleases.  This faculty of reason is part of nature working in man.  It inspires a sense of good and evil. It induces conduct, which is consistent with good conduct and forbids evil conduct.  The criteria, which distinguish good from evil, right conduct from wrong conduct, are the instinctive laws of nature.

The unstability of political institutions and frequent changes in law and government in a small city states of Greece made some jurists to think that law was for the purpose of serving the interests of the strong and was a matter of expediency.  Against changing governments, arbitrariness and tyranny, philosophers started thinking of some immutable and universal principles.  This gave them the idea of natural law.

Socrates (470-399 BC) was a great inquirer of truth and moral values.  He said ‘virtue is knowledge and whatever is not knowledge is sin’.  A very systematic and logical expression of the idea we find in Socrates. He said that like ‘natural physical law’ there is a ‘natural moral law’. Man possesses ‘insight’ and this ‘insight’ reveals to him the goodness and badness of things and makes him know the absolute and eternal moral rules.  This human insight is the basis to judge the law.  Socrates did not say that if the positive law is not in conformity with moral law it would be disobeyed.  Perhaps that was why he preferred to drink poison in obedience to law than to run away from the prison.

Plato (429 – 348 B.C.) supported the same theory.  In Plato’s philosophy, a clear cut distinction is there between his thinking about justice and his ideas about law.  His approach to justice was metaphysical based on divine inspiration.  This confounded law with religion and morality, and made law as a matter of faith and belief.  Justice meant in Plato’s view that a man should do his work in the station of life to which he was called by his capacities.  Every member of society has his specific functions and should confine his activity to the proper discharge of these functions. Some people have the power of command, the capacity to govern, others are capable of helping those in power to achieve their ends, as subordinate members of the government.  Plato says “to mind one’s own business and not to be meddlesome is justice”.

Plato realised that even in his ideal commonwealth disputes will arise which must be decided by the public authorities.  It is the theory of the Republic that in deciding such controversies, the judges of the state should have a large amount of discretion. Plato does not wish them to be bound by fixed and rigid rules embodied in a code of laws.  The State of the Republic is an executive state, governed by the free intelligence of the best men rather than by the rule of law. According to Plato “Justice is to be administered without law”.  The non-law state was upheld by him as the highest and most perfect type of government.  Its effective operation required men of the highest wisdom and infallibility of judgment.

It is in Aristotle (384-322 BC) that we find a proper and logical elaboration of the theory.  According to him, man is a part of nature in two ways: first, he is the part of the creatures of God; and second, he possesses active reason by which he can shape his will.  By his reason man can discover the eternal principles of justice.  The man’s reason being the part of the nature, the law discovered by reason is called natural law.  Natural law is inherent in the nature of man.  As nature is common to all races and nations, natural law must be the same for all.

Aristotle’s contributions to legal theory was considerable:

1) He conceived man to have a dual character, as part of nature man is apt to act under instinctive emotions, but he possesses a will of his own by which he can master nature and control his emotions according to his notion of right and wrong.

2) He conceived natural law as inherent in human reason and as the ideal to which all other laws should conform.

3) He stressed the need to supplement law with equity.  Whenever a general proposition of law is found to work hardship in particular circumstances of a case, equity must be applied to mitigate and rectify its harshness.

4) He declared law to bind not only the people but the government as well.

5) He drew a distinction between ‘distributive justice’ and ‘remedial justice’.  The former connoted equal treatment of those equal before the law. Distributive justice has to classify persons as equals and non-equals.  Injustice would arise when equals are treated unequally, and when unequals are treated equally.  The practical significance of this proposition would depend on who are treated as equals before the law.  It had long been held that freemen and slaves were not equals, nor blacks and whites, nor men and women, and with such discriminations equality for equals was held to rule. Even under Article 14 of the Constitution of India, courts have upheld classifications of different groups as equals and unequals.

Aristotle says of political justice part is natural, part legal – natural which everywhere has the same force and does not exist by people’s thinking this or that; legal, that which is originally indifferent, but when it has been laid down is not indifferent.’ He made a useful distinction between natural justice which is universal and conventional justice which binds only because it was decreed by a particular authority.  However, the question as to the legal consequences of a collision between a rule of natural justice and a positive enactment of the state is left unanswered by Aristotle.  He clearly admitted the possibility of an ‘unjust law’ but he does not say categorically that positive law which conflicts with natural justice is invalid.

An incisive change in Greek legal thought took place in the fifth century B.C. Philosophy became divorced from religion. Law came to be regarded not as an unchanging command of a divine, but as a purely human invention, born of expediency and alterable at will.  The concept of justice was likewise stripped of its metaphysical attributes and analysed in terms of human psychological traits or social interests.  The thinkers who performed this ‘transformation of values’ were called the Sophists. And they may be regarded as, according to Bodenheimer, the first representatives of philosophical relativism and skepticism.

Thus the philosophers and sophists in Greece developed a general omnibus theory of state, society and law as philosophers rather than as jurists.

In Rome, Stoics built up on the theory of Aristotle but transformed it into an ethical theory. According to them, the entire universe is governed by reason. Man’s reason is a part of the ‘universal reason’.  Therefore, when he lives according to reason, he lives according to nature or lives naturally. Stoics used their famous phrase ‘live according to nature’.  The laws of nature are of universal application and are binding on all men.  Positive law must conform to the ‘natural law’. The Stoic philosophy greatly influenced the Roman theory of natural law.

Although the Greek philosophers and Stoics expounded the doctrine of higher law of nature based on reason in the philosophical sense, it was Romans who explained natural law as lawyers and jurists in a legal manner.  Romans gave practical application to natural law.  Roman jurists contributed for the scientific development of natural law strictly on legal basis which finally resulted in the famous Code of Justinian.  By the time of Justinian the Roman jurists were able to distinguish the jus naturale, the jus gentium and the jus civile.  Julius Stone rightly pointed out that natural law with the Greeks remained a philosopher’s speculation whereas at Rome natural law was given a revolutionary role in legal development.

The creative period of natural law commenced when the Roman Practors began their compilation of jus gentium.  The jus civile of the Romans applied only to the Roman citizens.  It did not apply to the foreign settlers in Rome or to other parts of the Roman Empire.  The Roman Praetors made use of the jus naturale as a universal law, to apply it to all non-Romans.  They adopted the usages and customs which were commonly observed by different people and were consistent with moral reason and were also in consonance with rules of the jus naturale.  Thus they developed a code of laws applicable to foreigners under the name of jus gentium.  In later ages, the jus gentium was used to moderate the rigidity of the jus civile and convert it into a refined legal system, which became subsequently a model law for many legal systems of the world.  Thus, Roman jurists used natural law to modify, to refine and to expand their laws.

Cicero (104-43 B.C.) in his work De Legibus examined the basis of law.  His major contribution to jurisprudence rests upon his concept of ‘nature’ as providing a source of rules by which man ought to live.  To him law is the highest reason implanted in man.  The highest form of reason may be discovered in nature.  Law is the standard by which justice and injustice may be measured.  Cicero stated:

“True law is right reason in agreement with the nature, it is of universal application, unchanging and everlasting…. It is a sin to try to alter this law, nor is it allowable to attempt to repeal any part of it, and it is impossible to abolish it entirely…. God is the author of this law, its promulgator and its enforcing judge”.

According to Cicero, natural law is universal and immutable, it is higher law and is discoverable by reason.

Medieval theories

 Catholic philosophers and theologians of the middle ages gave a new theory of natural law.  When Rome lost its supremacy, the Christian church began to assert its power.  It became the universal religion of Europe and was organized on a hierarchical pattern with the Pope as its head.  The Religious authorities began to claim supremacy over the political authorities and asserted that the Christian teaching was the embodiment of the supreme law.  During the medieval period, natural law was given religious colour.

St.Augustine (354-430 A.D.) asserted that a king made law could be disregarded if it was contrary to the law of God.  The Church as the exponent of divine law could interfere with and override the state.  It implied that the ultimate interpreter of the law was the Pope, and not the Emperor.  This led to a struggle for power between the Church and the state.  As both the State and the church invoked the natural law to support their assertions, it marked a period of authority for natural law.  St.Augustine believed that divine wisdom was revealed in the scriptures.

The moral precepts of Holy Scriptures were the precepts of the natural law. According to him, man is governed by two laws, the law of nature and custom.  The law of nature contained in the scriptures and the gospel.  He said that natural law overrides customs and constitutions.  Customs and constitutions which contradict natural law are void and of no effect.  He asked ‘what are States without justice, robber bands enlarged?

St.Thomas Acquinas (1225-1274) propounded the scholastic theory of law in the middle of the 13th century.  He defined law as “an ordinance of reason for the common good made by him who has the care of the community and promulgated”.  His theory may be summarized thus: the world is ruled by divine providence and therefore the divine law is supreme in the world; a part of the divine law is given by God himself to man in the Scriptures; and they shall not be transgressed by any man made law; and another part of divine law is revealed in the inherent reason of man and is called the natural law.  He asserted the supreme authority of the church as the custodian and interpreter of the divine laws.

Acquina’s four categories of Law:

  1. Lex aeterna (eternal law): It is divine reason known only to God. It is God’s plan for the universe. It is absolutely perfect.
  2. Lex naturalis (Natural law): Participation of the eternal law in rational creatures. It is discoverable by human reason.

3. Lex divina (Divine Law): It is God’s positive law for for mankind.  It is revealed in the Scriptures like Ten Commandments.

4. Lex humana (Human Law): It is humanly posited law. Enacted for the common good. Supported by reason.  It provides the details to solve day to day problems.

According to Acquinas, human law or positive law must remain within the limits of that of which it is a part.  He pleaded for establishing the authority of the church over the law. In the words of Acquinas, ‘The eternal law is the plan of Divine providence and, therefore, is absolutely perfect.  The natural law on the other hand, is only imprint of the eternal law which is finite and cannot be absolutely perfect.   The positive law or the human law is really an implementation of natural law and varies with changing circumstances and conditions of social life.

In the controversy for power, the State, which was organized on a feudal foundation conceded the right of private property to be a natural and inviolable right of the acquirer, but the Catholic church refused to recognize the private property to be natural right.  This gave an impetus to the State over the Church, and consequently positive law came to prevail over religion and compelled divine law or natural law to recede to the background of social life.  The position became stronger for positive law with the revolutions marked by the renaissance and reformation, which brought forth the spiritual emancipation of the individual and the emergence of the modern state.

The individual wanted protection of their life and liberty.  The Protestants denied authority of the church to expound the law of God.  In this new set up the theory of natural law came again to prominence but was set on a new basis.  It was no more a divine law with spiritual authority, it became the law of the reason with intellectual authority.

Renaissance theories

This period marks a general awakening and resurgence of new ideas in all the fields of knowledge.  Rationalism became the creed of the age.  The development in the field of commerce created new classes in the society which wanted more protection from the state. Colonization created a rivalry among the states.  It gave birth to the conception of nationalization.

Hugo Grotius (1583-1645) built his legal theory on social contract. His view is that political society rests on a social contract.  It is the duty of the sovereign to safeguard the citizen because the former was given power only for that purpose.  The sovereign is bound by natural law.  The law of nature is discoverable by man’s reason.  The reason is not the reason of Divine, it is a self supporting reason of the man.  Grotius declared that natural law would exist and be valid even if there were no God.  For him, the natural law is the dictate of right reason.


Grotius asserted that man always desired to live in peaceful society.  This desire for peaceful society compels him to observe certain rules of conduct by intelligent reason.  That reason constitutes rudimentary principles of natural law.  Thus arose the obligation to fulfil promises, the respect for other’s property, the liability to repair the damage caused by one’s fault etc. The human reason and natural law are common to mankind.  The rulers must also have a peaceful society. The society of rulers is the society of nations.  The law of nations is originally no other than the law of nature applied to nations.  In this way, Grotius conceived a system of international law.  The greatest creative work done by the natural law theory was its giving birth to the international law in the 17th century.

Friedmann enumerates four legal principles as common to private law and international law.

i) Pacta sunt servanda (agreements must be fulfilled), rebus sic stantibus (agreements must accord with real affairs)

ii) Principle of Estoppel: which says that a person cannot deny what he has impressed on others by his own conduct. This rule may help to solve controversies on legal aspects of state promises to foreign investors.

iii) The principle of unjust enrichment: which insists that none should enrich himself at other’s expense without lawful cause.

iv) The principle of Abuse of rights: which expresses a social duty in the exercise of private rights. It is an elastic principle which can be stretched even to nullify a right.

These principles which are called by Grotius as ‘natural law’ and modern jurists called ‘general principles of law’ will become the foundations of the international law.