Usury, or in other words the price of use, is the emolument, of whatever nature, which the proprietor derives from the loan of his property. Quidquid sorti accrescit usura est, say the theologians. Usury, the foundation of credit, was one of the first of the means which social spontaneity employed in its work of organization, and whose analysis discloses the profound laws of civilization. The ancient philosophers and the Fathers of the Church, who must be regarded here as the representatives of socialism in the early centuries of the Christian era, by a singular fallacy,--which arose however from the paucity of economic knowledge in their day,--allowed farm-rent and condemned interest on money, because, as they believed, money was unproductive. They distinguished consequently between the loan of things which are consumed by use--among which they included money--and the loan of things which, without being consumed, yield a product to the user. The economists had no difficulty in showing, by generalizing the idea of rent, that in the economy of society the action of capital, or its productivity, was the same whether it was consumed in wages or retained the character of an instrument; that, consequently, it was necessary either to prohibit the rent of land or to allow interest on money, since both were by the same title payment for privilege, indemnity for loan. It required more than fifteen centuries to get this idea accepted, and to reassure the consciences that had been terrified by the anathemas pronounced by Catholicism against usury. But finally the weight of evidence and the general desire favored the usurers: they won the battle against socialism; and from this legitimation of usury society gained some immense and unquestionable advantages. Under these circumstances socialism, which had tried to generalize the law enacted by Moses for the Israelites alone, Non foeneraberis proximo tuo, sed alieno, was beaten by an idea which it had accepted from the economic routine,-- namely, farm-rent,--elevated into the theory of the productivity of capital. But the economists in their turn were less fortunate, when they were afterwards called upon to justify farm-rent in itself, and to establish this theory of the product of capital. It may be said that, on this point, they have lost all the advantage they had at first gained against socialism.