In this blog post, I will examine Montesquieu’s life, philosophical thought, unique concept of law, and his perspective on the relationship between human freedom and society through a reading of ‘The Spirit of the Laws’.

Montesquieu: A Thinker with Diverse Interests

Montesquieu was born on January 18, 1689, into a family of the “law nobility.” The law nobility was a class of nobility centered on judicial officials, distinct from the ancient, military, and prestigious military nobility. As a child, Montesquieu lived in his hometown of La Brède, where he mingled with other rural children his age; even after his parents settled in Bordeaux, he continued to gain diverse experiences as he grew up.
In 1700, he entered the Oratory Monastery School, which provided a modern education. He later studied law in Bordeaux and worked as a lawyer; in 1714, he was appointed as a counselor to the Bordeaux High Court. Under the French Ancien Régime, the High Court served as the supreme court, hearing appeals and sometimes rendering judgments directly on certain cases. Members of the High Court enjoyed numerous privileges; the sale of judicial offices was rampant, and only a very small number of families could gain entry into these positions. In short, they constituted an exclusive, privileged class. Although they were not an elected political body, after the death of Louis XIV, they frequently opposed the king’s ministers and provincial governors, asserting their intention to play a political role.
In 1715, at the age of twenty-six, Montesquieu married Jeanne de Lartigue, a wealthy Protestant woman. There was already a precedent in his family of several members having married Protestants. The couple had three children. When his great-uncle passed away the following year, Montesquieu inherited his great-uncle’s name, a vast fortune, and the high judicial office he held at the High Court of Bordeaux. At the age of twenty-seven, he thus came to hold a high office and possess the wealth befitting it.
He managed his vineyards well and arranged marriages for his children that would place them in a favorable position to manage the estate. After becoming a member of the Bordeaux Academy of Sciences in 1716, he wrote his memoirs while also authoring treatises on a wide variety of subjects, including law, history, politics, physics, and the natural sciences. He wrote incessantly until his death, leaving behind a diverse body of work ranging from essays on the causes of gravity, the behavior of magnetized needles, the causes of lightning and thunder, moss on oak trees, and the renal meridian, to works such as ‘The Eternal Punishment of the Pagans’ and ‘On Cicero’. The breadth of his intellectual world is evident in his refusal to limit himself to a single field and his interest in the various phenomena that make up the world.
Montesquieu spent a long time in Paris, moving freely between scientific and literary circles. He frequented salons, had several romantic relationships, and in 1724 even wrote a romance novel titled ‘The Temple of Gnidus’. He also harbored some political ambition, hoping to become an ambassador, and showed an interest in political economy. After publishing ‘Letters Persanes’ in 1721, he became a famous writer. In this short novel written in epistolary form, two Persians observe the Kingdom of France through the eyes of foreigners. While skillfully unfolding a fictional story set in a harem, Montesquieu delivered a scathing critique of Parisian customs and the political and religious institutions that had long prevailed under Louis XIV. The term “absolutism” also appears in this work.
However, he did not stop there but continued to explore various topics and began writing ‘De la Duty’. In 1726, he sold his position at the High Court of Bordeaux. When he was away from Bordeaux, his wife handled the duties in his stead.
In 1728, at the age of thirty-nine, Montesquieu embarked on a tour of Europe. He visited Austria, Hungary, Rome and Naples in Italy, Germany, and the Netherlands in succession; he then spent a year in London, where he attended sessions of the British House of Commons. Wherever he went, he took an interest not only in customs and institutions but also in natural phenomena. He even inspected sites firsthand, such as climbing Mount Vesuvius and visiting the Harz mines.
Returning to his hometown of La Bred in 1731, he published ‘Reflections on the Causes of the Greatness and Decline of the Romans’ in Paris in 1734. The title of this book alone reveals that his interests were not limited to political institutions. His examination of Roman history and the rise and fall of the Roman Empire was deeply connected to the line of thought he would later develop in ‘The Spirit of the Laws’.
In 1745, he published ‘The Dialogue Between Silla and Ecrat’, and in 1749, he released his magnum opus, ‘The Spirit of the Laws’, which he had spent many years writing with great dedication. At the time, he was sixty years old and had nearly lost his eyesight. The book’s publication was immediately met with both success and controversy. It was banned in France, and although he published a defense of ‘The Spirit of the Laws’ two years later with the help of his friends, it was also banned in Rome.
Nevertheless, Montesquieu did not cease his activities. He published new editions of ‘Reflections on the Greatness of the Romans and the Causes of Their Decline’ and ‘Letters Persanes’, contributed to the ‘Encyclopédie’ compiled by Diderot and d’Alembert, and began writing ‘The Theory of Taste’. He passed away in Paris on January 20, 1755.
He was appointed a member of the French Academy in 1727 and was also a member of the Royal Society of London. Later, he served as a member of Frederick II’s Berlin Academy and King Stanislas’s Nancy Academy. Voltaire was five years his junior, while Diderot and Rousseau were twenty-four and twenty-three years his juniors, respectively. When we consider the influence Montesquieu had on later Enlightenment thinkers, it becomes clear that he occupied a rather unique position in his own time.

In what sense was Montesquieu a philosopher?

The first question that comes to mind when trying to understand Montesquieu is: in what sense can he truly be called a philosopher? Although the term “philosopher” has various meanings and is sometimes used arbitrarily, I believe it applies to Montesquieu in at least three respects.
First, if the wisdom of a philosopher implies a life that pursues truth while maintaining moderation and equanimity, then Montesquieu’s life closely resembled that of a philosopher. He was neither a hero, nor a saint, nor an ascetic. He was well aware that substantial wealth is beneficial in many ways. Yet he was content that his wealth was commensurate with his birth and status—neither excessive nor insufficient. Nor did he reject the pleasures and satisfactions of social life. However, as he began to suffer from illness—and especially as he lost his sight in his later years—this moderate hedonism appears to have gradually shifted toward a form closer to asceticism.
Second, even when considered in the context of 18th-century writers, Montesquieu was clearly a philosopher. As a rationalist, he believed that truth, virtue, and happiness were inextricably linked. A free-thinking and well-informed man, he attacked moral, political, and religious prejudices from the very moment he published ‘Letters Persanes’. He clearly belonged to the so-called “philosophical camp” and contributed to the writing of the ‘Encyclopédie’.
His mindset was hardly religious, nor did it have a mystical character. From a very early age, he harbored doubts that religion could become a political tool, and he remained a deist until his death. Of course, it is also evident from his writings defending ‘The Spirit of the Laws’ that he seriously regarded Christianity as the perfect form of a natural religion.
For this reason, Montesquieu was sometimes accused of being a conservative obsessed with preserving his own status and privileges. However, he believed that true political freedom could be found in a moderate government characterized by an unstable and complex balance. He always sought to work for the peace and happiness of all humanity.
Among the ideas he left behind, particularly striking was his perspective on the relationships between the individual, the family, the homeland, Europe, and humanity. He believed that if one realized something was beneficial to oneself but harmful to one’s family, one should banish it from one’s heart; if it was beneficial to one’s family but harmful to one’s homeland, one should strive to forget it; and if it was beneficial to one’s homeland but harmful to Europe, or beneficial to Europe but harmful to humanity, it should be regarded as a crime. The fact that he considered relationships extending from the interests of the individual through the family, the nation, and Europe to all of humanity shows that his political thought did not stop at mere individual freedom.
Third, even when understood in the strictest and most classical sense of the term, Montesquieu can be regarded as an important thinker. Today, while figures such as Jean-Jacques Rousseau or Diderot are naturally considered philosophers, some believe that this title does not fit Montesquieu, the author of ‘The Spirit of the Laws’. In a sense, ‘The Spirit of the Laws’—a monumental work of 18th-century literature and political thought—has actually obscured the surprisingly diverse literary, historical, and scientific interests that Montesquieu possessed.
However, I believe it is difficult to fully understand his thought if we evaluate Montesquieu solely as a pioneer of modern social sciences and political science. Interpretations of his works have often been retroactively shaped by modern perspectives, and their strictly philosophical aspects have sometimes been treated as unimportant. There was also a view that his thinking was merely a simple application of an empirical methodology that had not yet fully developed at the time.
Nevertheless, Montesquieu was deeply connected to Descartes’ rationalism, particularly that of Malebranche. Malebranche’s influence permeated the entire 18th century, and traces of it can even be found in thinkers who rejected Malebranche’s “system.” Montesquieu, too, while believing he could refute Malebranche’s system, expressed deep respect for his ideas. He accepted Malebranche’s concept of material mechanism and even argued that Malebranche’s thought originated with Descartes.
Montesquieu respected Newton, as did others of his time, but this respect was for Newton the scientist, not Newton the philosopher. He believed that while Newton’s geometric calculations might be correct, his hypotheses were likely incorrect. Nevertheless, Montesquieu was one of the thinkers who combined Newton’s theories with the Cartesian principles developed by Malebranche to create a more comprehensive system.

What is law, and where does it originate?

‘The Spirit of the Laws’ begins with a definition that is both very famous and difficult to grasp upon first reading. Montesquieu states that, in the broadest sense, law is a necessary relationship arising from the nature of things. This definition differed significantly from those offered by the leading legal theorists of the time.
Grotius defined law as a rule of moral conduct that compels us to act justly and rationally, while Pufendorf defined it as the will of a superior who compels those subject to him to act according to the methods he has established. In contrast, Montesquieu’s definition incorporated the concept of a relationship. Consequently, some people countered that law is not a relationship.
However, what Montesquieu considered important was not limiting the concept of law to merely political and judicial meanings. He was the first to propose a concept of law that encompassed not only moral, political, and social laws but also metaphysical and physical laws. Therefore, likening political law to a complex machine is not merely a simple analogy; rather, it can be seen as an extension of Descartes’ mechanism—further refined by Newton’s discoveries—into the political sphere.
This concept of universal law is also linked to Malebranche’s conception of law. Malebranche expanded the concept of law to encompass not only material and moral nature but also the supernatural realm, such as the law of divine grace. He argued that even though God is the cause of all things, He acts in accordance with a universal will while exercising His wisdom in the simplest manner. Therefore, a distinction must be made between the universal will or law and the individual will of God, which may appear miraculous to us.
It was this determinism that Montesquieu had already referenced in his “Reflections on the Causes of the Greatness and Decline of the Romans.” Even if a chance event in a battle appears to have brought about the downfall of a nation, he believed there was a more universal cause that ultimately made it inevitable for that nation to be defeated in that battle. Through this, Montesquieu believed it was possible to rationally understand the events that occur in history without denying divine grace.
Therefore, theology is not entirely excluded from his thought. Rather, Montesquieu was able to reject an atheistic interpretation of this determinism without causing people to doubt his intentions. Malebranche also explained law as a concept of relations, viewing truth as a relation—one that is real and intelligible. This idea bears a striking resemblance to the definition in the opening paragraph of ‘The Spirit of the Laws’.
What is particularly striking here is the idea that even angels—beings with an intellect superior to that of humans—cannot escape universal law. The law discussed in ‘The Spirit of the Laws’ was not merely a narrow set of rules applicable only to human society, but also encompassed the order of relationships established among all beings.
While the material world is subject to law and necessary relationships and consistently follows them, rational beings do not necessarily follow the law, even if the law itself is immutable. This is because rational beings, while acting of their own accord and being free, are at the same time limited beings and can therefore commit errors at any time.
In the case of rational beings, a distinction must be made between the laws that are inherent to them but not of their own making, and the laws they have created. The fundamental laws, which are based on reason and inherent to rational beings, must not be confused with the laws of nature pertaining to the nature of living beings.
Humans are particularly complex rational beings. They are living beings who, through their physical bodies, follow material natural laws, as well as the natural laws shared with other living beings. Montesquieu begins with the hypothesis of the “state of nature” to identify the natural law specific to humans. This was a very common approach in the 18th century. However, what he considered important was abstraction—a method that did not require direct reference to history or anthropology.
Here, “nature” relates to human nature viewed on a universal level, without taking into account the diversity of societies. This includes peace among beings aware of their own weakness, the desire to secure food, the allure of sex, and the desire to live in society. It is also important to note that these laws are common to both humans and animals. Therefore, the term “natural law” as used here has a very limited meaning, distinct from classical natural law theory.
Montesquieu also differed from theorists who sought to establish natural law based on impartial reason. Unlike Pufendorf, who viewed human behavior as stemming from the principle of duty, Montesquieu believed that human reason intervenes only in the creation of positive law. Although humans are religious beings who possess a certain degree of intuition regarding God, what was particularly important to him was the capacity for speculative cognition rather than knowledge itself.
Furthermore, although Montesquieu briefly mentions the state of nature, he paid little attention to the origins of society and showed no interest in social contract theory. In this respect, he differs significantly from Grotius, Pufendorf, Hobbes, and Rousseau. Therefore, one must be cautious about understanding Montesquieu as being directly linked to natural law.
This does not mean, however, that law did not exist prior to legislation. According to Montesquieu, law already existed prior to any legislation as the law of nature—specifically, as the original state of equity. Law is not something to be newly created but rather something to be restored to its original state. Its ultimate foundation lies not in the social contract—an agreement among humans—but in the wisdom of God.
Political freedom, too, exists after the law and is determined by it. For this reason, the opening sentence of ‘The Spirit of the Laws’ felt to me not merely a statement defining law, but a starting point for understanding the entirety of Montesquieu’s subsequent line of thought. In this regard, the difference between Rousseau—who viewed human freedom as the principle that creates law—and Montesquieu is clearly revealed.

What is the “spirit” referred to in ‘The Spirit of the Laws’?

It is also important to consider the word “spirit” in the title ‘The Spirit of the Laws’. Following the tradition of Descartes, Montesquieu explains “spirit” as a mode of thought combined with knowledge. This mode involves accurately comparing things and distinguishing between the actual and relative states of the same things.
At the same time, “mind” also refers to the disposition that characterizes an individual, a nation, or an era. In this case, “mind” carries a meaning similar to that of a principle or characteristic. For Montesquieu, these two meanings are interconnected.
He explains that the general mind of a nation is formed as various factors—such as climate, religion, laws, the rules of government, past precedents, customs, and way of life—govern human behavior. Therefore, the general spirit is a unique product of a particular nation or ethnic group.
In this sense, the Spirit of the Laws can be described as a system of relationships that includes the general spirit of a nation as one element, while also revealing the law and the various relationships it forms. The law does not exist in isolation but is related to other laws and, at the same time, to everything else—such as climate, religion, customs, and way of life.
How, then, can such a multitude of relationships be analyzed and organized? Montesquieu’s method has sometimes been assessed as an imperfect and inadequate empiricist approach. It was for this reason that he was criticized for using a deductive method. However, if we understand him solely in this way, we miss what Montesquieu considered most important.
What he sought to discover was the general law within the diverse body of positive law. In other words, it was a matter of discovering the reason of intellectual beings who had emerged from the state of nature. The principles of equity, which precede all positive laws, cannot be discovered through simple empirical methods alone. It is difficult to properly understand Montesquieu’s mode of thought if one fails to give sufficient consideration to the early sections of ‘The Spirit of the Laws’ and instead selectively emphasizes only those parts that attracted the attention of late-19th-century sociologists such as Durkheim.
For Montesquieu, what was new did not lie simply in perfecting the old comparative methodology. Rather, it lay in discovering the mediating principle that connects general law to positive law, its application. He stated that once he had established a principle, individual cases seemed to follow that principle of their own accord. He also said that he began with the system and then sought evidence.
Given these ideas, Montesquieu was not merely someone who collected empirical facts. He sought to uncover the rationality that already existed but was obscured by countless variable facts. In this respect, rather than viewing him merely as a pioneer of sociology, he might be seen as a forerunner of the line of thought that leads to Hegel’s ‘Principles of the Philosophy of Right’. Hegel, too, emphasized the relationship between the real and the rational, arguing that it was important not to unconditionally justify accidental facts or customs, but rather to connect them to rational meaning.
Therefore, understanding the spirit of the law means understanding the gap between reason and positive law. Because the relationships among entities are diverse, this gap itself has a rationale. Even the irrationality of a despotic regime can be explained within the context of the relationships that gave rise to it. Positive law can be explained through a chain of relationships, or it can be linked to reason through principles. This is because positive law is the application of reason. These two perspectives are not contradictory but are connected within a single line of thought.
I believe the clearest example is slavery. Slavery is fundamentally opposed to rational equitable relations or natural law. In ‘The Spirit of the Laws’, Montesquieu sharply criticized slavery and viewed it as natural for slaves to gain their freedom through resistance.
However, slavery has been established by positive law in many societies. This does not mean, however, that simply rejecting it is enough to change everything at will. Montesquieu believed that since all humans are born equal, slavery is, in principle, contrary to nature—even if it is based on natural reasons in some countries.
Here, the term “nature” should be understood as referring to the nature of rational beings, while “natural” refers to physical nature, such as the local environment. Even if there are elements that appear to contradict one another, that contradiction does not lie within Montesquieu’s reasoning. Rather, it exists within the nature of things themselves.
Does this mean, then, that we must resign ourselves to and accept slavery? No. This is because the reasoning put forward by a society claiming that slavery is necessary may itself be flawed. For example, while it might be argued that forced labor is necessary in extremely hot countries, such an argument is not necessarily correct. It is all too easy to reduce matters pertaining to law to mere aspects of the physical natural world, and this is precisely why Montesquieu took issue with the theory of climate itself.