A Critique Of Natural Law Theory – OpEd


By Idries de Vries

The ideology of the west (capitalism) is founded on the idea that man is capable of determining the good and the bad, and that he is capable of determining the laws and systems that enable humankind to live according to the good, avoiding and suppressing the bad.

This view regarding man and life owes its existence to what in philosophy is known as natural law theory.

Of all the ideas that make up the core of western civilization, natural law theory is probably the least known. Yet, it may be argued that all of its famous ideas, such as secularism, democracy, freedom, individualism, and utilitarianism, owe their existence to natural law theory, at least indirectly. Natural law theory, namely, justified the search of the philosophers of Europe’s Middle Ages for a new way of life, a way of life not based on the teachings of the Bible (as understood at that time). It was only after the development of natural law theory, in other words, that the ideas which rule the world today could be developed.

This makes clear that no critical evaluation of capitalism can be considered complete and comprehensive without a deep understanding of natural law theory. And because the state of today’s world leaves no doubt that a complete and comprehensive critical evaluation of capitalism is urgently needed, the following article attempts to explain natural law theory through an analysis of its history and final conclusions.

Natural law theory in ancient Greek philosophy

In ancient Greece of the 3rd century before the start of the Christian-era, there was a philosophical movement called stoicism. While most other Greek philosophers held the belief that their Gods did not actively engage in running and governing the universe, as they were considered too busy enjoying themselves, the stoics held “God” to be an active part of the universe, ever busy with directing and organizing the progress of nature.

According to the stoics, therefore, existence—or as they called “Nature”—knows both a purpose and an organization. As the human being is part of this Nature, they argued, the correct way of life for the human being is the life which progresses in harmony with the purpose and organization of Nature. The great stoic Zeno of Citium (334 – 262 BCE) expressed, “All things are parts of one single system, which is called Nature; the individual life is good when it is in harmony with Nature.

The stoics believed the human being is capable of living in accordance with Nature. Because God, they said, is Reason, the purpose and organization He has given Nature must follow reason. And since, they  observed, the human being possesses a mind which gives him the ability to reason, they considered the human being as capable of identifying the purpose and organization given to Nature by God.  So, to the stoics, whatever the mind determines to be in accordance with the purpose and organization given to Nature by God is good and will lead the human being to happiness, while the bad is that which goes against the purpose and organization given to Nature by God and leads to chaos.[1] Because of the stoics’ definition of the good and the bad, respectively, as being in accordance with and going against Nature, they are considered to be the first to uphold a natural law theory.[2]

Natural law theory in medieval Christian philosophy

When the Christian philosophers of the Middle Ages learned of Greek philosophy through the writing of the Muslim philosophers, they were intrigued by the idea of natural law. The most prominent amongst these Christian “scholastics”, Thomas Aquinas (1225 – 1274 CE), built a complete philosophy around natural law theory. The essence of this philosophy is as follows.  Being a Christian monk, Aquinas held the belief that God has created the universe, giving it and everything in it a purpose and organization. This organization Aquinas called the “Eternal Law”. In everything created, God also established a “nature”, Aquinas said, by which he meant natural inclinations. All the inclinations have a clear goal, said Aquinas further, and he then defined “living in accordance with nature” as performing the actions that achieve these goals.

Since lifeless matter and animals do not possess a mind, they can do nothing but follow their natural inclinations. And this to Aquinas meant that lifeless matter and animals necessarily live in accordance with the purpose and organization of creation. The human being, on the other hand, has been created with a mind. This mind enables the human being to choose between performing actions that achieve the goals of his natural inclinations and other actions that do not achieve the goals of his natural inclinations. The laws of Eternal Law that address the actions of the human being are, therefore, unique and different because only they need not necessarily be followed. Aquinas, therefore, called these laws—this subset of Eternal Law—natural law.

Regarding this natural law, the dominant Christian view in Aquinas’ time was that since God is the source of all knowledge, it is revelation that sets out the actions that will achieve the goals of man’s inclinations. This implies that natural law must be revealed to man. According to Aquinas, however, the human mind too can find natural law. Aquinas pointed to the ability of the human mind to prove the existence of God without any need for revelation. Equally, he said, the human mind can find the life which is in accordance with human nature.[3] Aquinas then provided a number of examples of natural laws to explain his theory further.

The first natural inclination of man, Aquinas said, is to love the good and hate the evil. If the human mind were to ponder over this inclination deeply, he said, it will understand that “do good” and “abstain from evil” are natural laws.

A second inclination of man, according to Aquinas, is to love life. And if the human mind were to ponder over this inclination deeply, it would realize that protecting life is good and harming it is bad. “Protect life” and “do not harm life” are therefore also natural laws in Aquinas’ view. Consequently, in the view of Aquinas, the human mind can prove that murder goes against natural law, as does suicide, while saving lives agrees with natural law.

The third main inclination of man, according to Aquinas, is to protect and continue humanity. So, he said, the mind can understand that contraception and homosexuality are against natural law, hence, bad, while marriage, on the other hand, is good because it both enables offspring and ensures proper upbringing of the offspring. In his natural law theory, extra-marital affairs and divorce are both bad because they hurt the upbringing of the children.

The fourth natural inclination of man, according to Aquinas, is to love the truth. Lying is, therefore, against natural law, as is ignorance, because it leaves a person without knowing the truth.

The fifth natural inclination of man Aquinas discussed is the inclination to live in groups. According to Aquinas, this helps the mind realize that injustice and provocation are both bad because they hurt the relationships between people.

According to Aquinas, the main reason that man should follow the natural law, whether he learns about it through revelation or through reason, is that it is part of the Eternal Law from God. Not following natural law would, thus, be an act of rebellion against God. Though the human mind plays a prominent role in the natural law theory of Aquinas, this theory is still closely connected to God.[4]

Natural law theory in modern philosophy

The first to separate natural law from God entirely was the Dutch philosopher Grotius (in Dutch Hugo de Groot, 1583 – 1645 CE). He is, therefore, considered the father of the natural law theory on which western civilization was built.

In a lot of what Grotius says, the voice of Aquinas can be heard. In his departure point, namely, Grotius agrees with Aquinas that the human being has been created by God with natural inclinations. According to Grotius the emotions of man are many, but all come forth from just two essential inclinations—survival and society; that man wants to remain alive and wants to live his life together with others, and is, therefore, the core of human nature. The third core element of human nature according to Grotius is the mind.

As the core of human nature consists of three, Grotius said, the human being can follow one of three motivators in his life; he can follow the emotions which are linked to his desire to stay alive, or the emotions which are linked to his desire to live together with others, or he can follow his mind. Of these three, the mind can identify the actions that achieve at least one of the two essential inclinations without hurting the other, Grotius said. And, he continued, these actions would perfectly agree with human nature: they would come forth from the mind and be aligned with the human essential inclinations. So, these actions make up the natural law, he concluded.

Although Grotius himself was deeply religious, this reasoning of his detached natural law theory from God. Unlike in the theory of Aquinas, in Grotius’ natural law theory, the human nature is not used to identify the law determined by God. Rather, in it, man searches for the correct law in his own nature. Grotius says, “The mother of right – that is, of natural law – is human nature”. While Aquinas held the view that man must follow the natural law because it emanates from God, Grotius’ main argument for following natural law is that this law fits human nature. Whoever does not follow natural law, Grotius said, effectively behaves inhumanely; hence, Grotius said, “What we have been saying would have a degree of validity even if we should concede that which cannot be conceded without the utmost wickedness, that there is no God, or that the affairs of men are of no concern to him.”[5]

Examples of the influence of natural law theory on modern life

Shortly after Grotius, the British philosopher John Locke (1632 – 1704 CE) used natural law theory to define universal human rights by arguing that if, for instance, natural law states stealing is a crime, then the right to not be stolen from would also be a natural law. Locke said, “The state of nature has a law of nature to govern it, which obliges everyone, and reason which is that law, teaches all mankind who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty or possessions.” Through Locke, natural law theory then became the foundation of the United States Declaration of Independence of 1776, stating the following:

When in the course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation. We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness….

Locke’s views regarding natural law theory would eventually go on to become the justification for the United Nations’ Universal Declaration of Human Rights “whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world”.

The father of capitalist economics, Adam Smith (1723 – 1790 CE), was also greatly influenced by natural law theory. This is shown by the fact that the arguments in his famous book on economics, An Inquiry into the Nature and Causes of the Wealth of Nations, are based on an analysis of human nature as follows:

…every individual necessarily labours to render the annual revenue of the society as great as he can. He generally, indeed, neither intends to promote the public interest, nor knows how much he is promoting it. By preferring the support of domestic to that of foreign industry, he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. Nor is it always the worse for the society that it was no part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it. I have never known much good done by those who affected to trade for the public good.

It is on this basis—Smith’s understanding of the nature of man and life—that he then argued for individual freedom for man in the realm of the market place.

Lastly, utilitarianism, the philosophy which dominates contemporary thinking about happiness, and which believes that happiness is in maximizing pleasure, has also been greatly influenced by natural law theory. Jeremy Bentham (1748 – 1832 CE) claimed, “Nature has placed mankind under the governance of two sovereign masters, pain and pleasure. It is for them alone to point out what we ought to do, as well as to determine what we shall do.”  On this basis, Bentham argued that whatever brings pleasure to the human being is good.[6]

In summary, it can be said that Grotius’ natural law theory caused philosophers after him to take observations of reality as the starting point for thinking, and alignment with reality—as understood by the philosophers being the measure for differentiating correct and incorrect thought.

A critique of natural law theory – The conflict between the theory and its adherents

At the heart of natural law theory is the idea that everything in existence has a “nature” which gives everything in existence a purpose and goal in life, and that all these natures are related such that everything in existence is in one way or another connected to other things in existence.[7] This idea makes natural law theory conflict with both atheism and agnosticism.

Atheism denies the existence of a Creator for the universe. This idea conflicts with natural law theory which holds that the Creator’s existence has a purpose; the purpose is considered obvious—something that is not under the control of the things in existence[8]. Natural law theory, therefore, holds that life must be aligned with this purpose rather than secondarily adjusting purpose to life. The idea of a purpose for life—with the attribute that purpose dominates existence rather than existence dominating purpose—cannot be rationally accepted without first accepting the existence of a Creator. Nothing else can subject existence to a pre-defined purpose. It is the case, therefore, that he who denies God must also deny that existence has a purpose; so, he must deny natural law theory in its entirety.

Furthermore, if relations do indeed exist between the things in existence, as natural law theory effectively states, then all things in existence must have come into existence at the same time. And how could all things have come to existence at the same time? For, in the case of the relations between the things in existence, nothing could exist without the preexistence of its survival needs in order to sustain it upon arrival. The atheist would argue that all things in existence evolved from one original thing. This position seems to ignore, however, the observable fact that existence consists not only of living things but also of non-living things. Obviously, there exist relationships between the living and the non-living, such as the dependence on water and sunlight. Equally obvious is the fact that the non-living things in existence cannot evolve. What the atheist must say, therefore, is that both the living and the non-living came into existence at the exact same time with perfect relations between one another, after which the living things evolved in perfect co-ordination between themselves without there ever developing a conflict in the relations, and all this by sheer coincidence! This is so utterly unimaginable that one must say he who denies God must also deny the existence of relations between things; so, he must deny natural law theory in its entirety.[9]

While agnosticism accepts the existence of a Creator, it refuses to research His reality deeply—who He is, why He created creation, et cetera. This position can only be justified if one assumes that He did not intend anything with His creation and has, since creation, completely disconnected Himself from His creation, as if He does not care about how His creation proceeds in the existence He has given. Natural law theory stands diametrically opposed to this view, as it claims existence has a purpose.  As explained, a purpose can only be given to existence by a Creator. The presence of a purpose for creation therefore implies that the Creator did not disconnect from his Creation after creating, as He set for it a course.  Therefore, neither the atheist nor the agnostic can accept natural law theory—which, by the way, proves Grotius was wrong when he said, “What we have been saying would have a degree of validity even if we should concede that which cannot be conceded without the utmost wickedness, that there is no God, or that the affairs of men are of no concern to him”. How strange it is, therefore, that western civilization—which refuses God to play an active role in determining the life of man,[10] and today is the ideology of the atheists and the agnostics—utilizes natural law theory.

A critique of natural law theory – Its internal flaw

As aforementioned, at the heart of natural law theory is the idea that everything in existence has a “nature” which gives everything in existence a purpose and goal in life, and all these natures are related in one way or another, such that everything in existence is somehow connected to other things in existence. Specifically for the human being, natural law theory adds to this the idea that the human mind is able to identify the way of life that makes man live in accordance with his nature. Essentially, it says that if man applies his mind, he will find the natural way of life, and if he then lives his life in accordance with his nature, then he will fulfill the purpose and goal of his life; hence, he will experience happiness in life.

Also explained earlier is why this is an implicit acknowledgement of the existence of a Creator—purpose and relations prove his existence obligatory.

What natural law theory is effectively saying, therefore, is that the human mind can find the purpose given to life by the Creator of life simply by looking at the natural inclinations of creation. Clearly, this idea assumes that satisfaction of the natural inclinations of creation is the purpose with which the Creator created existence. What is the proof for this?  In the absence of revelation, there is none. The assumption “Because man has natural inclinations, it must be his purpose in life to satisfy these inclinations” is purely speculative.   It can also be imagined that the Creator intended (some of) the natural inclinations of creation to be a test for creation—that the Creator really wants man to abstain from (some of) what he inclines to.[11] This in turn means the natural law theory does not have the ability to convince the mind because—based on these assumptions—it lacks a rational argument. Natural law theory can only be believed, then, as one would believe in Christianity or Judaism or Hinduism.

So, the truth of the matter is, if one accepts as fact the existence of a Creator, then one must accept as fact that only the Creator knows with certainty what He intended with His creation. That only He knows with certainty how He wants His creation to proceed in its life. In the absence of a revelation—as in, information flowing from the Creator to creation—creation can only speculate about all this. Natural law theory is not internally consistent, as its conclusion (“the mind can determine natural law”) is not lined with its implied assumptions (“there is a Creator who cares about creation”).

A critique of natural law theory – Its natural yet undesirable consequences

If, for just a second, one were to ignore the fact that the human mind cannot determine the purpose of life in the absence of revelation from the Creator, and just assume the human mind can determine the purpose of life as the natural law theory claims, then it will be shown that the natural law theory has very undesirable natural consequences.

The human mind is limited, namely. The human mind can only think about what has been experienced by man, either directly or by means of reliable narration, for instance. This means that at any moment in time other than at the end of it, the human mind will not be able to identify the complete natural law. For, the complete natural law requires man to have experienced all that can be experienced, and new experiences do not end until time ends. Until the end of time, therefore, under the natural law theory, the law must follow the experiences of man. So what natural law theory is really saying to humankind is, “Get in trouble first, and then I will come to rescue you.”  The guidance of natural law theory will leave man struggling with problems until the end of time.[12]

The minds of human beings are furthermore prone to disagreement because experiences differ between humans, as well as their abilities to think. This means that never will there develop a consensus about what the natural laws are. The guidance of natural law theory will, therefore, leave man in perpetual conflict about what is correct.


Idries de Vries is an economist who writes on economics and geopolitics for various publications. As a management professional he has lived and worked in Europe, America and Asia.


[1] The stoics were rationalist to the core. For instance, according to them happiness results from living in accordance with Nature, because they saw living in accordance with Nature as the purpose of life. In their view only the person who applies his mind correctly will find the purpose and organization given to Nature by God, so only he will be able to live in accordance with Nature. The person who does not apply his mind correctly, on the other hand, will not be able to do this. In addition, since he will not understand Nature, he will not understand what happens to him or why it happens to him. Unlike the person who applies his mind correctly, therefore, he will not be able to control the emotions that the events of life trigger in the human being. He will be a slave to his emotions, while the emotions will be a slave to the person who applies his mind correctly. This is the practical expression of happiness, according to the stoics. The stoic Epictetus (55 – 135 according to the Christian calendar) said of the person who applies his mind correctly that he would be “sick and yet happy, in peril and yet happy, dying and yet happy, in exile and happy, in disgrace and happy”, because he controls his emotions. The stoics’ love affair with rationalism did not end there. According to them a unique lifestyle was necessary to achieve the correct understanding of Nature. Man would have to contemplate deeply over everything he experiences, both his sensory experiences and his emotional experiences. Man had to live in a continuous state of contemplation, in other words, and this required man to break with following his desires.

[2] See, for instance, “Stoicism” at the Stanford Encyclopedia of Philosophy, www.plato.stanford.edu/entries/stoicism/ & “Stoicism” at the Internet Encyclopedia of Philosophy, www.iep.utm.edu/stoicism/

[3] The apparent conflict between his view and the Christian teaching that God is the source of all knowledge Aquinas resolved by saying that the human mind can only find knowledge after it has been motivated to search for knowledge by God. In this way God remains the source of all knowledge.

[4] See here www.newadvent.org/summa/ for Aquinas’ main work, the Summa Theologica.

[5] See an introduction to Grotius in the Stanford Encyclopedia of Philosophy, www.plato.stanford.edu/entries/grotius/. Here http://constitution.org/gro/djbp.htm Grotius’ main work “On the Law of War and Peace (De Jure Belli ac Pacis)”, in which many of his thoughts on natural law are developed, can be found.

[6] Strangely enough, at the same time Bentham was a great critique of the idea of natural right: “Natural rights is simple nonsense: natural and imprescriptible rights, rhetorical nonsense, nonsense upon stilts”. See Bentham’s “Critique of the Doctrine of Inalienable, Natural Rights” here: http://www.ditext.com/bentham/bentham.html

[7] Remember, natural law theory talks of the inclinations of the human being, that is what he is driven toward by his nature, or in other words his “needs”. Obviously, if the human being has a tendency towards something outside of him, if he “needs” something outside of him, then there exists a relationship between his nature and the nature of that which he tends towards / needs.

[8] And this is the only rational position, for a “flexible” purpose to life, as in a purpose that can be determined and changed by the thing living, is not really a purpose.

[9] So he must deny that life has a goal, which leaves his mind unable to determine a law to organize life. And he must deny that there exist relations between the things in existence, which leaves him compelled to deny that man needs food and drink to survive. What an awful position philosophical position this is!

[10] A position no believer – be he Muslim, Christian, Jew or any other – can accept, unless there is something in his holy book that explicitly says God does not wish to interfere in the lives of man. But this goes against the very concept of revelation, because revelation intends to let man know how his Creator wants him to live his life!

[11] Especially the Christian believer should have little difficulty accepting this speculative position.

[12] And this is exactly what can be witnessed in the world today. Libraries could be filled with the new laws that are written globally every year.

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