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William Petty, the late seventeenth-century Englishman on whom Diderot draws in this article, was himself working expressly within the empirical and inductive tradition of Francis Bacon, one of the patron saints of the Encyclopédie as a whole.1 For other quantitative political analysis in this volume, see CEREALS, POPULATION, and FIVE PERCENT TAX. A later article very similar to this and more directly derivative of Chambers’s Cyclopedia appeared unsigned under the title POLITIQUE ARITHMETIQUE [Arithmetical Politics], 12:919–20.
*POLITICAL ARITHMETIC is the kind whose purpose is research that would be useful for the art of governing peoples, such as research on the number of men who inhabit a country, the quantity of food they must consume, the work they may have, their life-expectancy, the fertility of the land, the incidence of shipwreck, etc. It is easy to imagine that from these discoveries and many others of the same nature, acquired by calculations based on well-confirmed tests, a skillful minister would derive countless results useful in the perfection of agriculture, commerce (internal as well as external), colonies, the circulation and employment of money, etc. But often ministers (I don’t mean to speak without exception) think they do not need to go through arithmetical combinations and sequences. Many imagine themselves to be endowed with great natural genius, which exempts them
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from such a slow and laborious process—besides which, the nature of affairs hardly ever permits or demands geometric precision. Nonetheless, if the nature of affairs demanded and allowed it, I have no doubt we would manage to convince ourselves that the political world, as well as the natural world, can in many ways be ordered by weight, number, and measure.
Lord Petty, an Englishman, is the first who published essays under this title. The first is on the multiplication of the human race and on the growth of the city of London—its extent, its phases, its causes and consequences. The second is on the houses, the inhabitants, deaths, and births in the city of Dublin. The third is a comparison of the city of London and the city of Paris. Lord Petty tries to prove that England’s capital is overtaking that of France in all these ways. M. Auzout has attacked this essay with many objections, to which Lord Petty has offered responses.2 The fourth aims to show that about three thousand sick people per year die in the Hotel-Dieu in Paris because of mismanagement. The fifth is divided into five parts: the first is in response to M. Auzout; the second contains the comparison of London and Paris on many points; the third estimates the number of parishioners in London’s 134 parishes at 696,000. The fourth is an inquiry into the inhabitants of London, Paris, Amsterdam, Venice, Rome, Dublin, Bristol, and Rouen. The fifth has the same purpose, but with regard to Holland and the rest of the United Provinces. The sixth covers the extent and value of land, the people, houses, industry, economy, manufactures, commerce, fishing, artisans, sailors or seamen, land troops, public revenue, interest rates, taxes, profits, banks, companies, the value of men, the growth in the navy and in the armed forces; residences, locales, the construction of vessels, naval forces, etc., relative to all countries in general, but especially to England, Holland, Zeeland, and France.
This latter essay is addressed to the king, which is as much as to say that its conclusions are favorable to the English nation. It is the most important of all Lord Petty’s essays. Nonetheless, it is very short if compared with the multitude and complexity of the topics. Lord Petty claims to have demonstrated,
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in about a hundred small pages in duodecimo, big letters: (1) that by its situation, its commerce, and its administration, a small country with a small number of inhabitants can equal a large and populous country—whether compared by strength or by wealth—and that there is nothing that tends more effectively to establish this equality than the navy and maritime commerce; (2) that all kinds of taxes and public charges tend to enhance rather than to weaken society and the public good; (3) that there are some natural and permanent obstacles to France becoming more powerful at sea than England or Holland (our Frenchmen will not bring favorable judgment upon Lord Petty’s calculations on this proposition, and I believe they will be right); (4) that by its soil and its natural produce, the people and territory of England are virtually equal in wealth and capacity to the people and territory of France; (5) that the obstacles to the greatness of England are only contingent and removable; (6) that for forty years, the power and wealth of England have greatly increased; (7) that a tenth of all the expenditures of the king’s subjects would suffice to maintain a hundred thousand infantrymen, thirty thousand cavalrymen, forty thousand seamen, and to pay for all the other state expenses, both ordinary and extraordinary—on the sole supposition that this tenth be well-taxed, well-collected, and well-employed; (8) that the number of unemployed subjects is greater than the number needed to procure two million per year for the nation, were they appropriately employed; and these employments are all ready, awaiting only the workers to fill them; (9) that the nation has enough currency to sustain its commerce; (10) finally, that the nation has all the means at its disposal to embark upon the whole world’s commerce, of whatever sort.
There you have some rather excessive claims; be that as it may, the reader will do well to examine the experience and reasoning on which Lord Petty bases his work. In making this examination, one must not forget that revolutions occur—whether for good or ill—that change the face of states in an instant, and that modify and even destroy presuppositions; and that calculations and their results are not less variable than events. Lord Petty’s work was composed before 1699. According to that author, although Holland and Zeeland contain no more than a million acres of land and France contains at least 8 million, nonetheless the former country has almost a third of the wealth and power of the latter. Landed income in Holland is about
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seven or eight times what it is in France. (Observe that it is here a question of the state of Europe in 1699, and that all of Lord Petty’s calculations, good or bad, refer to that year.) The inhabitants of Amsterdam number two-thirds those of Paris or London, and according to the same author, the difference between these two latter cities is only about one-twentieth. The carrying capacity of all the vessels belonging to Europe amounts to about 2 million tons, of which the English have 500,000, the Dutch 900,000, the French 100,000, the Hamburgers, Danes, Swedes, and inhabitants of Danzig 250,000; Spain, Portugal, Italy, etc. about the same. The value of the merchandise that leaves France annually for the use of other countries amounts in all to about 5 million pounds sterling; that is, four times as much as enters England alone. The merchandise exported from Holland to England is worth 300,000 pounds sterling, and what leaves there to be spread throughout the rest of the world is worth 18 million pounds sterling. The money that the king of France levies annually in time of peace is about 6.5 million sterling. The sums levied in Holland and Zeeland are about 2.1 million pounds sterling, and those coming from