If we ask in what precisely consists the greatest good of all, which should be the end of every system of legislation, we shall find it reduce itself to two main objects, liberty and equality—liberty, because all particular dependence means so much force taken from the body of the State, and equality, because liberty cannot exist without it.
I have already defined civil liberty; by equality, we should understand, not that the degrees of power and riches are to be absolutely identical for everybody; but that power shall never be great enough for violence, and shall always be exercised by virtue of rank and law; and that, in respect of riches, no citizen shall ever be wealthy enough to buy another, and none poor enough to be forced to sell himself:  which implies, on the part of the great, moderation in goods and position, and, on the side of the common sort, moderation in avarice and covetousness.
Such equality, we are told, is an unpractical ideal that cannot actually exist. But if its abuse is inevitable, does it follow that we should not at least make regulations concerning it? It is precisely because the force of circumstances tends continually to destroy equality that the force of legislation should always tend to its maintenance.
But these general objects of every good legislative system need modifying in every country in accordance with the local situation and the temper of the inhabitants; and these circumstances should determine, in each case, the particular system of institutions which is best, not perhaps in itself, but for the State for which it is destined. If, for instance, the soil is barren and unproductive, or the land too crowded for its inhabitants, the people should turn to industry and the crafts, and exchange what they produce for the commodities they lack. If, on the other hand, a people dwells in rich plains and fertile slopes, or, in a good land, lacks inhabitants, it should give all its attention to agriculture, which causes men to multiply, and should drive out the crafts, which would only result in depopulation, by grouping in a few localities the few inhabitants there are.  If a nation dwells on an extensive and convenient coast-line, let it cover the sea with ships and foster commerce and navigation. It will have a life that will be short and glorious. If, on its coasts, the sea washes nothing but almost inaccessible rocks, let it remain barbarous and ichthyophagous: it will have a quieter, perhaps a better, and certainly a happier life. In a word, besides the principles that are common to all, every nation has in itself something that gives them a particular application, and makes its legislation peculiarly its own. Thus, among the Jews long ago and more recently among the Arabs, the chief object was religion, among the Athenians letters, at Carthage and Tyre commerce, at Rhodes shipping, at Sparta war, at Rome virtue. The author of The Spirit of the Laws has shown with many examples by what art the legislator directs the constitution towards each of these objects.
What makes the constitution of a State really solid and lasting is the due observance of what is proper, so that the natural relations are always in agreement with the laws on every point, and law only serves, so to speak, to assure, accompany and rectify them. But if the legislator mistakes his object and adopts a principle other than circumstances naturally direct; if his principle makes for servitude while they make for liberty, or if it makes for riches, while they make for populousness, or if it makes for peace, while they make for conquest—the laws will insensibly lose their influence, the constitution will alter, and the State will have no rest from trouble till it is either destroyed or changed, and nature has resumed her invincible sway.
 If the object is to give the State consistency, bring the two extremes as near to each other as possible; allow neither rich men nor beggars. These two estates, which are naturally inseparable, are equally fatal to the common good; from the one come the friends of tyranny, and from the other tyrants. It is always between them that public liberty is put up to auction; the one buys, and the other sells.
 "Any branch of foreign commerce," says M. d'Argenson, "creates on the whole only apparent advantage for the kingdom in general; it may enrich some individuals, or even some towns; but the nation as a whole gains nothing by it, and the people is no better off."