The Spirit of Laws

Part 4 is more thematically unified than Parts 2 or 3 and explores commercial law and its history. It is divided into four books: on the nature of commerce, on its revolutions in world history, and the use of money, before taking a left turn to discuss population size and law.

Book 20, “on the laws in their relation to commerce, considered in its nature and its distinctions,” lays the groundwork for Part 4. Therein, Montesquieu outlines the spirit of commerce and its effects on the mores of commercial peoples. He writes approvingly of commerce that it “cures destructive prejudices, and it is an almost general rule that everywhere there are gentle mores, there is commerce and that everywhere there is commerce, there are gentle mores” (338). The value of commerce in pacifying societal mores is unparalleled in its universality. Commerce engenders a mutual need between two countries reciprocally engaged in commercial enterprise. Commerce also requires and reinforces peace amongst nations and is, in Montesquieu’s view, antithetical to war. Different forms of ideal government are differentially committed to economic activity, with republics typically being more commercial. Montesquieu points to England throughout Part 4 as exemplary of commercial enterprise. According to Montesquieu, “the object of commerce is to export and import commodities in favor of the state” (346). Therefore it is reasonable, and expected, that the government will heavily regulate free commercial enterprise to its own favor and not necessarily that of the private merchant. This may include ensuring competition (in a wise republic) because competition leads to just pricing.

In Book 21, Montesquieu discusses the effects of global commerce and what laws are good for commerce. Since commerce creates wealth, it cannot be silenced by the laws of a particular regime. It may be restricted or banished from a given society, but the spirit of commerce will go where it is accepted and will, so to speak, set up shop. Montesquieu writes, “It reigns today where one used to see only deserted places, seas, and rocks; there where it used to reign are now only deserted places” (356). The wealth created by commerce further affects societal development: Wealth leads to luxury, and luxury leads to the fruitful production of artistic enterprise. Montesquieu thus connects artistic achievement to good law governing commercial enterprise, as in Athens. Montesquieu includes examples from Egypt, Rome, and Greece to relay the good and bad effects of commerce. The Roman situation reveals that luxury is a double-edged sword that can lead to an empire’s decline. He then discusses commerce in the modern era after the Age of Exploration, which led to colonial empires from major European powers. He defends these colonial empires when they are not simply destructive conquests, of which Montesquieu accuses the Spanish. Colonies allow the “primary” country to set up exclusive trading relations with their colonies. This can greatly benefit the wealth of the colonizer.

The nature of money, which develops in tandem with the nature of commercial enterprise, is the subject of Book 22. Money is necessary when commerce becomes extensive and the traded commodities are large in scope. Money is just the sign of value attributed to commodities; its signifying function extends generally to all commodities. Precious metals, like silver and gold, are often used as this sign. Paper money can then be a sign of this sign, i.e., a sign of the precious metal. The price of any given commodity is fixed by the ratio of total commodities to the total amount of available money. Montesquieu also works through the distinction between relative and positive monetary value, especially as it concerns the exchange of various currencies in the international marketplace. The positive value of money can be fixed in law by the legislator. Relative value, though, is out of the hands of a given government, as it is established by the value of a currency relative to the value of another currency in open exchange. Montesquieu discusses several drawbacks of national debt, the successes of Holland and England, and the history of usury (the act of lending at an interest). Montesquieu’s work in this section is a very early attempt at economic theory, preceding the work of Adam Smith, famed articulator of the “invisible hand” of capitalism, by several decades.

Part 4 ends with a discussion of various prudent legal actions relative to the population size of a state. Montesquieu surveys families, marriages, cultivated lands, artisanry, and poorhouses. Each of these institutions is related to population control, in some manner. For instance, Montesquieu is a strong proponent of the marriage institution and links it to the natural “propagation of the species” (428). In condemnation of extramarital sex, he writes, “Illicit unions contribute little to the propagation of the species. In them the father, whose natural obligation is to nourish and raise the children, is not fixed, and the mother, on whom the obligation falls, meets thousands of obstacles” (428). For Montesquieu, then, marriage is practically necessary for the success of the species (and subsequently the society and government) because it forces the father to assist the mother in care of the children. Much of this section concerns domestic law of the family, especially in Roman history. Throughout The Spirit of the Laws, Rome is consistently both an ideal model and a cautionary tale. In Rome, Montesquieu observes, interprets, and creates predictions from the results of various legislation of the course of many centuries.