From the outset of his career, Montesquieu found himself obsessed with the uneasy relationship between wealth, virtue, and justice. In the Lettres persanes, published anonymously in 1721 when their author was only thirty-two, Montesquieu's porte-parole Usbek emphatically asserts the objective reality of justice and attacks the pretensions of the positivists. “Justice,” he announces, “is a relation of suitability, which actually exists between two things. This relationship is always the same, by whatever being it is perceived, whether by God, or by an angel, or finally by man.” Indeed, “justice is eternal, and does not depend on human conventions;” like Leibniz before him, Montesquieu makes clear that it even exists independently of the will of God himself. Usbek continues that “it is true that men do not see these relationships all the time. Often, indeed, when they do not see them, they turn away from them, and what they see best is always their self-interest. Justice raises its voice, but has difficulty in making itself heard amongst the tumult of the passions.” Justice is, then, a fixed, eternal rapport de convenance (Montesquieu took the phrase from Leibniz's Théodicée) which towers above the abundant variety of human laws, but finds itself obscured by human passions. The chief agent responsible for promoting the passions at the expense of justice turns out to be wealth.

Montesquieu explores this theme in Letters 11 through 14 of the Lettres persanes, in which he describes the fanciful republic of the Troglodytes.