If I understand Duns Scotus on the divine simplicity, his view in one sentence is that the divine attributes are really identical in God but formally distinct. (Cf. Richard Cross, Duns Scotus on God, Ashgate 2005, p. 111) I can understand this if I can understand the formal distinction (distinctio formalis) and how it differs from the real distinction (distinctio realis). This will be the cynosure of my interest in this post.
There appear to be two ways of construing 'real distinction.' On the first construal, the real distinction is plainly different from the formal distinction. On a second construal, it is not so clear what the difference is. I have no worked-out view. In this entry I am merely trying to understand the difference between these two sorts of distinction and how they bear upon the divine simplicity, though I will not say anything more about the latter in this installment.
First Construal of 'Real Distinction'
On the first construal, the real distinction is to be understood in terms of separability. But 'separable' has several senses. Here are my definitions of the relevant senses. I am not trying to exposit Thomas or any scholastic. I am merely trying to get to the truth of the matter.
D1. Individuals x, y are mutually separable =df it is broadly logically possible that x exist without y, and y exist without x.
Example. The separability of my eyeglasses and my head is mutual: each can (in a number of different senses of 'can' including the broadly logical sense) exist without the other. This distinction is called real because it has a basis in extramental and extralinguistic reality. It is not a merely verbal distinction like that between 'eyeglasses' and 'spectacles.'
D2. Properties F, G are mutually separable =df it is broadly logically possible that F be instantiated by x without G being instantiated by x, and vice versa.
Example. Socrates is both seated and speaking. But he is possibly such as to be the one without the other, and the other without the one. He can sit without speaking, and speak without sitting. The properties of being seated and speaking, though co-instantiated by Socrates, are mutually separable. Of course, this does not imply that these properties can exist uninstantiated.
D3. Individuals x, y are unilaterally separable =df it is broadly logically possible that one of the pair x, y exist without the other, but not the other without the one.
Example. A (primary) substance S and one of its accidents A. Both are individuals, unrepeatables. But while A cannot exist without S, S can exist without A. Second example. Consider a fetus prior to viability. It is not an accident of the mother, but a substance in its own right. Yet it cannot exist apart from the mother, while the mother can exist apart from it. So what we seem to have here are two individuals that are unilaterally separable.
D4. Properties F, G are unilaterally separable =df it is broadly logically possible that one of the pair F, G be instantiated by x without the other being instantiated, but not the other without the one.
Example. Suppose Socrates is on his feet, running. His being on his feet and his running are unilaterally separable in that he can be on his feet wthout running, but he cannot be running without being on his feet.
D5. Items (whether individuals or properties) I, J are weakly separable =df I, J are either mutually separable or unilaterally separable.
On the first construal of 'real distinction,' it comes to this:
D6. Items (whether individuals or properties), I, J are really distinct =df I, J are weakly separable.
My impression is that when Scotists speak of the real distinction they mean something identical to or very close to my (D6). Real distinctness is weak separability. Two items, whether individuals or properties, are really distinct if and only if they are either mutually separable or unilaterally separable. According to Alan B. Wolter ("The Formal Distinction" in John Duns Scotus, 1265-1965, eds. Ryan and Bonansea, CUA Press, 1965, pp. 45-60),
In the works of Aquinas, for example, the term ['real distinction'] seems to have two basically different meanings, only one of which corresponds to the usage of Scotus, Ockham, or Suarez. For the latter, the real distinction is that which exists between individuals, be they substances or some individual accident or property. It invariably implies the possibility of separating one really distinct thing from another to the extent that one of the two at least may exist apart from the other. (p. 46)
Second Construal of 'Real Distinction'
On a Thomist view, my essence and my existence are not really distinct on the first construal of 'real distinction' because they are mutually inseparable: neither can be without the other. This strikes me as entirely reasonable. My individual essence is nothing without existence, and there are no cases of pure existence. I am not now and never have been an existence-less essence, nor a bit of essence-less existence. And yet Thomists refer to the distinction between (indvidual) essence and existence in finite concrete individuals as a real distinction. So 'real distinction' must have a second basic meaning, one that does not require that really distinct items be either mutually or unilaterally separable. What is this second basic meaning? And how does it differ from the Scotistic formal distinction?
Seeking an answer to the first question, I turn to Feser's manual where, on p. 74, we read:
But separability is not the only mark of a real distinction. Another is contrariety of the concepts under which things fall . . . . For example, being material and being immaterial obviously exclude one another, so that there must be a real distinction between a material thing and an immaterial thing. A third mark sometimes suggested is efficient causality . . . .
In this passage, Feser seems to be saying that there is one disinction called the real distinction, but that it has more than one mark. He does not appear to be maintaining that 'real distinction' has two different meanings, one that requires separability and another that does not. On the next page, however, Feser makes a distinction between a "real physical distinction" and a "real metaphysical distinction" where the former requires separability but the latter does not. He goes on to say that for Scotus and Suarez a necessary condition of any real distinction in created things is that the items distinguished be separable: "a distinction is real only when it entails separability." (75)
The Formal Distinction
I asked: "What is the second basic meaning of 'real distinction'?" The answer I glean from Feser is that the second meaning is real metaphysical distinction, a distinction that does not require separability. Now for my second question: How does this real metaphysical distinction differ from the formal distinction? According to Cross, "the formal distinction is the kind of distinction that obtains between (inseparable) properties on the assumption that nominalism about properties is false." (108) Feser describes it as a third and intermediate kind of disinction that is neither logical nor real. (75) Both what Cross and Feser say comport well with my understanding of the formal distinction.
Consider the distinction between a man's animality and his rationality. They are clearly distinct because there are animals that are not rational, and there are rational beings that are not animals. It is also clear that the distinction is not purely logical: the distinction is not generated by our thinking or speaking, but has a basis in extramental and extralinguistic reality. Is it then a real distinction? Not if such a distinction entails separability. For it is not broadly logically possible that the rationality of Socrates exist without his animality, or his animality without his rationality. Anything that is both animal and rational is essentially both animal and rational. (Whereas it is not the case that anything that is both sitting and speaking is essentially both sitting and speaking.) So the Scotist, for whom the reality of a real distinction entails separability, says that what we have here is a formal distinction, a distinction between two 'formalities,' animality and rationality, that are really inseparable but formally distinct.
My second question, again, is this: How does the real metaphysical distinction differ from the formal distinction? In both cases, the distinction is not purely logical, i.e., a mere distinctio rationis. So in both cases the distinction has a basis in reality. Further, in both cases there is no separability of the terms of the distinction. Socrates cannot be rational without being an animal, and he cannot be an animal without being rational. Similarly, he cannot exist without having an essence, and he cannot have an essence without existing.
So what is the difference between the real metaphysical distinction (that Feser distinguishes from the real physical distinction) and the formal distinction? If I understand Feser, his view is that the formal distinction collapses into the virtual distinction, which is a logical distinction, hence not a real distinction, whereas the real metaphysical distinction is a real distinction despite its not requiring separability. But what is the virtual distinction?
The Virtual Distinction
Feser tells us that a logical distinction is virtual "when it has some foundation in reality." (73) A virtual distinction is a logical distinction that is more than a merely verbal distinction. He gives the example of a man's nature which, despite its being one thing, can be viewed under two aspects, the aspect of rationality and the aspect of animality. The distinction between the two aspects is not real but virtual. The virtual distinction thus appears to be identical to the formal distinction.
Accordingly, the difference between the real metaphysical distinction and the formal distinction is that the first is real despite its not entailing separability while the second is logical despite having a foundation in reality. I hope I will be forgiven for not discerning a genuine difference between these two kinds of distinction. Feser suggests that the difference may only be a matter of emphasis, with the Thomist emphasizing the logical side of the virtual/formal distinction and the Scotist emphasizing the real side. (76)
Should we then irenically conclude that the metaphysical real distinction of the Thomists (or, to be cautious, of Feser the Thomist) is the same as the formal distinction of (some of) the Scotists?
Essence and Existence Again
I am afraid that matters are much messier. Suppose you agree that essence and existence in Socrates are neither mutually nor unilaterally separable. Suppose you also agree that Socrates is a contingent being: he exists (speaking tenselessly) but there is no broadly logical necessity that he exist. The second supposition implies that Socates does not exist just by virtue of his essence: his existence does not follow from his nature. Nor is his existence identical to his essence or nature, as it is in the ontologically simple God. So they must be distinct in reality. But -- and here comes trouble -- this real distinction in Socrates as between his essence and his existence cannot be a distinction between inseparable aspects. Animality and rationality are inseparable aspects of Socrates' nature; but essence and existence cannot be inseparable aspects of him. If they were inseparable, then Socrates would exist by his every nature or essence. This seems to imply that the metaphysical real distinction is not the same as the formal distinction. For the metaphysical real distinction between essence and existence requires separability of essence and existence in creatures.
It looks like we are in a pickle. We got to the conclusion that the real metaphysical distinction is the same as the formal distinction. But now we see that they cannot be the same. Some may not 'relish' it, but the 'pickle' can be savored as an aporetic polyad:
1. Socrates is a metaphysically contingent being.
2. Metaphysical contingency entails weak separability (as defined above) of essence and existence.
3. Nothing is such that its essence and existence are weakly separable.
The triad is logically inconsistent.
Solution by (1)-denial. One cannot of course maintain that Socrates is metaphysically necessary. But one could deny the presupposition upon which (1) rests, namely, the constituent-ontological assumption that Socrates is compounded of essence and existence. On a relation ontology, essence-existence composition makes no sense.
Solution by (2)-denial. One could try to show that contingency has an explanation that does not require weak separability of essence and existence.
Solution by (3)-denial. One could argue that the individual essence of Socrates can be wthout being exemplified along the lines of Plantinga's haecceity properties.
Each of these putative solutions brings trouble of its own.