The key aim of a compositional account of the Incarnation is to give an account that allows the relevant sort of reduplication. Eleonore Stump attempts to provide this by using a notion borrowed from Lynne Rudder Baker, that of property-borrowing. Baker understands property-borrowing in the following way: if x borrows property H from y, x has H, really but by 'piggyback'. One of Baker's examples is bleeding: I, as a whole, borrow the property of bleeding from my cut hand. My hand is bleeding, but by 'piggyback', this is as much to say, "I am bleeding (by virtue of my cut hand)." And I am really bleeding, because property-borrowing is a real feature of the world.
Stump adapts this to the case of the Incarnation, arguing that just as a molecule that has a coiled part is properly allowed to be coiled (in part), so the Word can have (e.g.) a limited part and be said to be limited (at least with regard to its part). Stump sees this as an example of property borrowing. Senor objects to this, saying:
Yet on Baker’s account of borrowing, the whole neither borrows every property from every part nor borrows any property only in "some respect" or "to some degree." Properties that are borrowed are "really" had by the whole.
But this is an odd sort of objection to make, for Stump is not claiming that the property-borrower doesn't really have the borrowed property; rather, she is saying that it really has the property but not genuinely simpliciter. Nor is this obviously different from Baker. Contrary to what Senor implies, Baker does say something that suggests that the borrowed property is had in a qualified way; she says it has it "piggyback, so to speak." And it isn't clear why Senor doesn't think that Stump's 'having a property in some respect' or 'having a property to a degree' indicate ways of having properties piggyback. He certainly has not justified his claim that Stump "misuses" Baker's notion.
But Senor goes farther and argues that Baker's notion can't do the work Stump wants it to do:
For on Baker’s account of borrowing, if x were to borrow H from y, and at the same time x were to borrow ~H from z, then x would really be H and ~H. So if JC borrows omnipotence from his divine part and non-omnipotence from his human part, then JC would really be omnipotent and non-omnipotent, and, like the poor, the logical problems would always be with us.
But this is certainly hasty. For the logical problem only arises if x is really H and ~H in the same respect. But since by supposition x is borrowing the properties from different parts (y and z), x really is H, and really is ~H, but is not H and ~H in the same respect. Thus using Baker's notion in the case of the Incarnation, we could say that Jesus is omnipotent (a property piggybacking on his divine nature) and non-omnipotent (a property piggybacking on his human nature); or, in other words, Jesus would be omnipotent with regard to his divine nature and not omnipotent with regard to his human nature. There are two distinct borrowings or 'piggybackings' occurring here; and Senor has not shown that this is irrelevant to the logical question. To put it another way: Senor is only right if the possession of a property 'piggyback' is not significantly different from possessing a property in a non-piggyback way, which seems highly implausible. That Senor is making this mistake is suggested by what he goes on to say:
I get a gash on my leg and blood is pouring out. My leg is bleeding. I’m bleeding. I am bleeding because I have a part that is bleeding. As explained above, Baker’s account of "borrowing" has it that I have this property in an unqualified way. That is, it isn’t that since I am bleeding only because my leg is bleeding (and my leg is a part of me), I am only bleeding "in a respect." No, I am just plain bleeding.
As I noted above, Baker's account of borrowing does not have it that I have this property 'in an unqualified way', but that I have it piggyback, in virtue of my bleeding leg. I genuinely have it, because my leg is genuinely my leg; but 'bleeding' is not the sort of property that can attach to me simpliciter -- I can only bleed in virtue of one of my parts. There is, properly speaking, no such thing as 'just plain bleeding'; bleeding is always the bleeding of a part, genuinely attributable to me because it is my part.