Five-minute digest
The Spirit of the Laws
Summary
Montesquieu's The Spirit of the Laws (De l'esprit des lois), published anonymously at Geneva in 1748 after many years of reading and travel, asks why the laws of different peoples differ and what makes them fit or unfit for those who live under them. His answer is that laws are relations: they must suit the form of government and also the climate and soil, the religion, commerce, manners and size of a nation. The library text is Thomas Nugent's English translation of 1750 as revised by J. V. Prichard for the 1914 Bell edition, with the preface and all thirty-one books. Book I defines laws in the widest sense as relations arising from the nature of things, so that God, the material world, the beasts and man each have their laws. Books II to VIII set out three kinds of government, each with a nature and a principle that moves it. The republic, democratic or aristocratic, needs virtue, meaning love of country and of equality; monarchy runs on honour and depends on intermediate powers such as nobility, clergy and parlements; despotism, where one man rules by will and caprice, is moved by fear. Montesquieu shows how education, sumptuary and criminal laws, and the place of women follow from each principle, and how each government decays when its principle is corrupted. Books IX to XIII turn to defence, conquest, political liberty and taxation. In Book XI liberty is the right to do what the laws permit, and it is found only in moderate governments where power is a check to power. Chapter 6, on the constitution of England, separates legislative, executive and judicial power and argues that liberty is lost when any two are joined. Book XII applies the idea to the citizen's security, warning against punishing thoughts or indiscreet words. Books XIV to XIX treat climate, soil and the general spirit of a nation. Heat and cold, Montesquieu argues, shape temperament, but good legislators resist the vices a climate encourages instead of yielding to them. Book XV calls slavery bad in its own nature and answers its defenders with sustained irony in chapter 5. Books XX to XXII describe commerce as a gentle force that makes trading nations depend on one another, and examine money and exchange. Book XXIII considers population; Books XXIV and XXV weigh religion by its civil effects, while praising the Christian religion as the friend of good laws; and Books XXVI to XXXI treat the order of laws, the art of composing them, and the history of Roman and Frankish feudal law. The Church placed the book on the Index in 1751 after Montesquieu had published a Defence of it in 1750. It was read across Europe and in America, where Madison, in Federalist 47, called Montesquieu the oracle always consulted on the separation of powers.
Top Lessons
Laws must suit the nation that lives under them
Montesquieu does not write a single code for all mankind. He argues that a good law in one country may be a poor law in another, because laws are tied to a people's government, climate, religion, commerce and customs. Wise legislation begins with knowing the people well.
Every holder of power tends to push it further
Book XI starts from a realistic view of human nature: whoever holds power is tempted to abuse it. Montesquieu's answer is not to trust better rulers but to arrange institutions so that one power checks another, and to keep the power of judging apart from the powers of making and executing law.
Virtue, honour and fear as springs of government
Each form of government is moved by a passion that citizens must share: love of country and equality in a republic, desire for distinction in a monarchy, fear under a despot. A regime declines when its spring weakens, so laws of education and manners matter as much as constitutions.
Climate is a condition, not a destiny
Montesquieu believed heat and cold affect the body and the temper of peoples, but Book XIV insists that good legislators work against the vices a climate encourages. Natural causes set the problem; law, education and religion can answer it.
Trade as a bond between peoples
Book XX presents commerce as a force that softens manners and makes nations depend on one another, so that peace becomes their interest. Montesquieu also notes that a purely commercial spirit can make people calculate every service, so he weighs commerce as a good with limits.
Verified Quotes
“Laws, in their most general signification, are the necessary relations arising from the nature of things.”
“As virtue is necessary in a republic, and in a monarchy honour, so fear is necessary in a despotic government”
“constant experience shows us that every man invested with power is apt to abuse it, and to carry his authority as far as it will go.”
“To prevent this abuse, it is necessary from the very nature of things that power should be a check to power.”
“When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty”
“As it is the business of legislators to watch over the health of the citizens, it would have been a wise part in them to have stopped this communication by laws made on the plan of those of Moses.”
“The state of slavery is in its own nature bad.”
“Peace is the natural effect of trade.”
Medical Lens
Book XIV is a document in the eighteenth-century medicine of climates. Drawing on the iatromechanical physiology of his day, Montesquieu explains that cold air contracts and strengthens the body's fibres while heat relaxes them, and he links these changes to courage, sensibility and indolence; he even reports observing a sheep's tongue under a microscope as the cold contracted its papillae. Readers can place this alongside the Hippocratic Airs, Waters, Places tradition and John Arbuthnot's Essay Concerning the Effects of Air on Human Bodies (1733), without treating it as modern physiology. Chapter 11 is an early argument that legislators have a duty to protect health: it recalls the Mosaic separation of lepers, describes the arrival of the disease from the New World (generally read as syphilis), and praises the cordon of troops used against plague. Chapter 12 contrasts Roman suicide, a matter of education and principle, with an English disposition to suicide that he attributes to a bodily distemper, an example of the eighteenth-century idea of the English malady. Chapter 10 ties sobriety laws to climate. These are period theories; any modern reading of them should be offered as interpretation.
- Book XIV, ch. 2
Cold and warm air act on the external fibres of the body, with the experiment on a sheep's tongue, and Montesquieu's inferences about vigour and sensibility.
- Book XIV, ch. 10
Laws about drinking and sobriety explained by the needs of hot and cold climates.
- Book XIV, ch. 11
Laws in relation to the distempers of the climate: leprosy and the laws of Moses, the disease brought from America, and the military cordon against plague.
- Book XIV, ch. 12
Roman and English suicide compared; the English case attributed to a distemper of the body rather than to education.