The difficulty which moderns find in understanding this teaching, is that it is said to be based on the sterility of money.  A moment’s thought, however, will convince us that money is in fact sterile until labour has been applied to it.  In this sense money differs in its essence from a cow or a tree.  A cow will produce calves, or a tree will produce fruit without the application of any exertion by its owner; but, whatever profit is derived from money, is derived from the use to which it is put by the person who owns it.  This is all that the scholastics meant by the sterility of money.  They never thought of denying that money, when properly used, was capable of bringing its employer a profit; but they emphatically asserted that the profit was due to the labour, and not to the money.

Antoninus of Florence clearly realised this:  ’Money is not profitable of itself alone, nor can it multiply itself, but it may become profitable through its employment by merchants’;[1] and Bernardine of Sienna says:  ’Money has not simply the character of money, but it has beyond this a productive character, which we commonly call capital.’[2] ‘What is money,’ says Brants, ’if it is not a means of exchange, of which the employment and preservation will give a profit, if he who possesses it is prudent, active, and intelligent?  If this money is well employed, it will become a capital, and one may derive a profit from it; but this profit arises from the activity of him who uses it, and consequently this profit belongs to him—­it is the fruit, the remuneration of his labour....  Did they (the scholastics) say that it was impossible to draw a profit from a sum of money?  No; they admitted fully that one might de pecunia lucrari; but this lucrum does not come from the pecunia, but from the application of labour to the sum.’[3]

[Footnote 1:  Quoted in Brants, op. cit., p. 134.]

[Footnote 2:  Ibid.]

[Footnote 3:  Brants, op. cit., pp. 133-5; Nider, De Cont.  Merc. iii. 15.]

Therefore, if the borrower did not derive any profit from the loan, the sum lent had in fact been sterile, and obviously the just price of the loan was the return of the amount lent; if, on the contrary, the borrower had made a profit from it, it was the reward of his labour, and not the fruit of the loan itself.  To repay more than the sum lent would therefore be to make a payment to one person for the labour of another.[1] The exaction of usury was therefore the exploitation of another man’s exertion.[2]

[Footnote 1:  Gerson, De Cont., iv. 15.]

[Footnote 2:  Neumann, when he says that ’it was sinful to recompense the use of capital belonging to another’ (Geschichte des Wuchers in Deutschland, p. 25), seems to miss the whole point of the discussion.  The teaching of the canonists on rents and partnership shows clearly that the owner of capital might draw a profit from another’s labour, and the central point of the usury teaching was that money which has been lent, and employed so as to produce a profit by the borrower, belongs not ‘to another,’ but to the very man who employed it, namely, the borrower.]