J. P. Moreland presents and defends a tripartite ontology of properties (universals) and two basic kinds of concrete particulars that can be the subject of properties: substances and “property-things.” Paradigm cases of substances are living organisms like humans, dogs, trees, turtles, etc. Paradigm cases of property-things are artifacts like hammers, plates, cars, etc. and natural objects like rocks, mountains, water, etc.
Moreland gets a lot of distance out of this distinction. I’ve reproduced his comparison chart here. Here I want to briefly consider a case that I think generates some problems for his view.
One interesting feature of his view is the following. When a substance loses a part–say, a human loses a hand–then according to Moreland, the hand ceases to be a human hand and becomes a mere property-thing. This is because a substance’s parts get their identity from the whole. As another example, consider a heart transplant. Suppose Tom receives a heart from Jerry. The human heart qua human heart does not get its identity from being some particular human’s heart (e.g., Tom’s heart), but by being the heart of some human or other. So the heart is human while part of Tom, ceases to be human in transition from Jerry to Tom (at this stage it is still a heart, only merely a heart) and becomes human again once successfully planted in Jerry.
But a more interesting case would be successful cross-species organ transplant (which have, in fact, been attempted, though not with much success). Suppose Jerry receives a successful heart transplant from a chimpanzee named Lucy. This seems to create real problems.
Moreland says a substance’s essence or nature grounds its natural kind membership. So Jerry has a human nature, whereas Lucy has a chimpanzee nature. So if a human heart is a human heart in virtue of being part of a human (Tom’s human nature is what makes his heart a human heart), the same holds for a chimp’s heart. So what happens upon the successful transplant? Here are the options:
1. Tom’s heart is neither human nor chimp
2. Tom has a chimpanzee heart
3. Tom’s heart is formerly chimp but now human
But no option looks plausible on Moreland’s view: Options 1 and 2 are non-starters. Option 1: If neither human nor chimp, the part’s identity (as human or chimp) does not depend on the whole. Option 2: If a heart is not part of a chimp, it is not a chimp heart. This leaves option 3. Moreland says the whole “creates inseparable parts according to its essence.” So would Jerry’s essence therefore “create” a human heart out of the formerly chimp heart? Seems so…
Because the heart’s identity as a chimp heart is lost once removed from Lucy, the heart in transit is a property-thing. The heart must therefore perdure through going from being chimp to being human. But this creates the following odd situation: upon exiting Lucy, a property-thing has ceased to exist (a chimp heart), a new property-thing comes into existence for a brief time (a mere heart, neither chimp nor human), and, once in Tom, that property-thing ceases to exist and a new one comes into existence (a human heart).
If the coming-into-and-out-of-existence consequence isn’t odd enough, note that it is possible for all of this to take place with no loss or gain of parts between the chimp heart, the mere heart, and the human heart (note: Moreland distinguishes properties from parts, the former being abstract universals, the latter being concrete particular constituents). On the comparison chart (and as he explains elsewhere), the salient difference in the persistence conditions of a property-thing and substance is that the former loses its identity through loss, gain or replacement of parts, whereas the latter retains its identity through accidental change.
So either the persistence conditions that Moreland lists for property-things are sufficient conditions only, or Moreland’s view is incoherent (it would entail that a property-thing is a substance, which are supposed to be mutually-exclusive categories). But if they are sufficient conditions only, then Moreland has not proposed the salient difference between the persistence conditions of property-things and substances.
So there must be more to the persistence conditions for property-things than gain, loss, or replacement of parts. So what about gain, loss, or replacement of essential properties? As the chart has it, property-things “have no new properties not in parts except new utility for human purpose and new shape, dimension, and spatial order.” Moreland elsewhere says that what kind or class a property-thing belongs to is determined by its role or function (Body & Soul, p. 84). This suggests that the essential properties of property-things are their roles or functions. So maybe he could amend the persistence conditions of property-things to “gain, loss, or replacement of parts or role or function.”
But is it any more plausible to say entities can come into or out of existence just by virtue of a role switch? Suppose scientists engineer a multi-organ transformer device (a prosthetic organ that can assume the role or function of multiple different organs) out of rubber, plastic, and metal. Once successfully planted in Jerry, does a human heart come into existence, and a prosthetic organ cease to exist? By Moreland’s lights, it must be so. Further, suppose this is a very high-tech organ can also be implanted in other species. The scientists take the heart from Jerry and put it into Lucy as a liver. Have we again witnessed the annihilation, coming-to-be, annihilation, and coming-to-be of three separate entities? Seems a bit steep to me.
Here’s the best sense I can make of the situation. Take the distinction between a kind-essence and an individual essence. A kind-essence is whatever properties a thing must have to belong to a certain kind. For example, all closed plane figures whose interior angles add up to 180deg belongs to the kind-essence ‘triangle’. An individual essence is whatever properties a thing has that makes it that very thing and not some other thing. So we could compare a scalene and a right triangle, each of which have different individual-essences but the same kind-essence.
Now consider a heart. The individual essence of a heart will be made up of its functional or organic properties like “pumps blood” or “has valves” etc. But to belong to the kind-essence ‘human heart,’ the heart must possess the property of belonging to some human. So maybe the idea is that a heart can lose its kind-essence upon being removed from a human, but retain its individual essence. What exists apart from the whole is a property-thing with the individual essence ‘heart’. Once it gets put back into a human, it reacquires a human’s kind-essence. So when Moreland says a part of a substance “gets its identity from the whole,” maybe he means something like “acquires the natural-kind essence from the whole.”
But it doesn’t seem like Moreland can help himself to this distinction. The way he describes them, property-things don’t seem to have enough integrity to have individual essences. He says property-things have an “artificial unity that resides in surface features of the whole or in functional intentions of designer totally outside the whole.” And, more decisively, he denies of property-things “absolute sameness and strict identity through part replacement, loss, gain [and, as we saw earlier, essential properties].” So presumably the individual essence of a heart cannot retain the identity of a heart qua heart through change.
Note also that for Moreland, a prosthetic or artificial heart is just as genuine of a heart as the organic one you were born with. “Prosthetic” and “artificial” here cannot be treated as alienans adjectives, much like it can’t in “artificial insemination.”