A personally guaranteed note looks, superficially, like the same sort of contract; but it isn’t. It – specifically the personal guarantee – isn’t a property interest in a thing. It attempts to assert a property interest in no thing: nothing. The fact that you cannot foreclose and collect your property demonstrates Aquinas’ point: the thing in which the contract asserts an ownership interest or other claim is no thing at all: nothing.
The apples have been eaten, the wine has been drunk, and the borrower has to take action to acquire new, different apples or wine precisely because the thing to which the mutuum lender lays claim does not exist
A mutuum for interest looks superficially like a census contract against a farmer’s field, as described by John de Lugo and affirmed as morally licit by Pius V. The difference is that there is no field: instead of representing a de-facto buy-leaseback of a claim against a field or other actual property, the personally guaranteed note represents a buy-leaseback of nothing at all.
32) In question 16 you say that the value of future labor is not a real asset which can be used as collateral on a for-profit loan. But wasn’t it relatively common before the modern era for people to be sold into slavery to pay off a debt?
Yes. Both are true. It is possible that moral waffling on chattel slavery kept the door open for usury in many peoples’ minds. Other people might see prison jobs as a kind of ‘slave labor’ and propose that it is immoral to throw people into prison just to get work out of them, even if they are willing to agree to it. But that kind of speculation and casuistry aside, clearly a slave’s future labor cannot, as a matter of objective fact, be alienated from the slave himself.
Yes, though that probably doesn’t have the implications that modern people presume it to have. The language may not mean what they think it means, the relation between master and slave is (like the relation between usurer and borrower) morally asymmetrical, moral doctrine actually does develop as we gain a deeper understanding of eternal truths and encounter new situations, modern people generally have a distorted concept of property, and we also tend to view any sort of subjection to authority as dehumanizing.
It is true though that, at least in my understanding of the moral theology, rejection of chattel slavery and of usury are closely connected.
Even with the safeguard of personal bankruptcy, a usurious contract is – by its full recourse nature – a purchase of the potentialities of a person. The potentialities of a person are not something which actually exist at the time of purchase. Recall that, in order to “own an economic share” in (or have economic access to) the potentialities of a thing, you must own a share in (or have some sort of property claim against) the actual thing; and it is not morally licit to buy and sell economic shares in persons as if they were property.
Continuing the comparison to slavery (since usury and slavery are in the same moral genus), that a slave might have certain legal remedies in the case of an abusive master, or might under certain conditions have an opportunity to escape his condition, doesn’t make him any less a slave. He might be in better shape than other slaves who lack those remedies and opportunities; but he is still a slave.
Furthermore, that personal bankruptcy protection is available in cases of extreme financial duress does not change the fact that mutuum contracts require return of what is lent in kind as opposed to in particular (see Question 35): that what is loaned is, in Aquinas’ terms, consumed in its use by the borrower. Personal bankruptcy protection therefore does not change the basic nature of a usurious contract.