55) If you make a mutuum loan to a friend in need, shouldn’t that friend try to keep you from losing any economic buying power in the process?
A lender of money can expect a recompense from a borrower in a second way as if the recompense is gratuitous and offered without obligation, not as if a debt
Suppose your best friend needs wheat and can’t afford to buy any. He doesn’t need paper: he needs wheat. You’ve got some excess wheat you could lend him, but you like the way paper futures (Question 46) look better, and you want a guarantee that you won’t lose any buying power (Question 54) when you are doing your best friend a favor.
So you lend him paper (even though he needs wheat, and is just going to exchange the paper for wheat) just so that, as a formality, the kind of thing he owes you back (Question 35) is paper. Or you tell him that you know he needs wheat and you have plenty to lend, but you like paper futures better so even though you’ll give him wheat you want him to repay the wheat you gave him by doing imaginary wheat-to-paper exchanges (they will be imaginary to avoid transaction fees and taxes) at the point of borrowing and repayment.
It seems to me that your friendship is as imaginary as the wheat-to-paper exchanges. That is no way to treat a friend in need. The former contract might not be technically usury, while the latter definitely is usury. But this fails to undermine the moral doctrine prohibiting usury, much as the fact that flirting heavily with your secretary is not technically adultery fails to undermine the moral doctrine prohibiting adultery.
And mutuum lending is only morally licit as an act of friendship or charity. It is not morally licit in pursuit of gain. Preservation of market buying power as something guaranteed by someone else is a kind of gain (Question 54).
Because of the excursion into the land of imaginary paper he ends up owing you back more wheat than you lent him on this mutuum loan – usury
If your best friend decides to pay you back more wheat than you loaned him out of gratitude, that is a gift from him to you. There isn’t anything wrong with that. It is even true that he owes you gratitude in a sense. But gratitude between friends is not convertible into a specific dollar amount which he can be said to owe you as a financial matter. No true friend is going to quibble, in dollar terms, as to whether his best friend has been grateful enough in the natural exchange of favors which occurs among friends.
It is possible for friends to do each other injustice in mutuum lending (Question 49); even to have a falling out and to no longer be friends. Suppose you lent your best friend the wheat, he now has enough to repay you the amount that he borrowed, but he refuses to do so. In that case this post he is not being a good friend; and he really does owe you back the amount of wheat that he borrowed, as a matter of justice. His refusal to pay it back now that he can is a kind of theft or fraud. You truly are entitled to return of the principal amount, and the falling out of your friendship does not remove that entitlement in justice.
A lender of money by reason of making a loan can in two ways expect a recompense from a borrower, whether in money or praise or service. A lender of money can expect a recompense from a borrower in one way as if the recompense is a debt by reason of a tacit or express obligation. And then the lender can licitly expect a recompense from the borrower, as one who does a service for another trusts that the other will in the spirit of friendship return the favor.
A lender can in two ways incur the loss of something already possessed. The lender incurs loss in one way because the borrower does not return the [amount of] money lent at the specified date, and then the borrower is obliged to pay compensation. The lender incurs loss in a second way when the borrower returns the [amount of] money lent within the specified time, and then the borrower is not obliged to pay compensation, since the lender ought to have taken precautions against loss to self, and the borrower ought not incur loss regarding the lender’s stupidity.