The most hated sort of such exchange is . . . usury, which makes a gain out of money itself, and not from its natural use. For money was intended as an instrument of exchange, and not as the mother of interest. This usury (tokos), which means the birth of money from money, . . . is of all modes of gain the most unnatural.”75 Money should not breed. Hence “the discussion of the theory of finance is not unworthy of philosophy; but to be engaged in finance, or in money-making, is unworthy of a free man.”