Following on the heels of Part 7 in this series, here begins section 4 of MMA’s aforementioned Ch. 5. It’s heavy lifting. I apologize for those who have no patience for philosophical speculation. But I think she provides a coherent model for understanding the Incarnation.
4 Medieval metaphysics, Aristotle revised again!
4.1 Real distinction and characterization
Like Aristotle but contrary to Swinburne, medieval Latin school theologians take human being for a real, not a nominal essence, one that is — in all non-miraculous cases — contemporary-sense essential to the primary substances that have it (e.g., to Socrates, to Plato, and to each of us). That meant that for them — unlike Swinburne — their endorsement of (T10) carried with it the claim that a given natural kind might be essential to some, but only contingently characterize others.
Not only do they treat natural kinds as susceptible of real definition[, T]hey reify the natures by treating them as really constitutive of the things to which they belong. They read Aristotle to be claiming
(T12) a primary substance (e.g., Socrates) is necessarily identical with the individual substance nature (Socrates’ humanity) that is contemporary-sense essential to it.
Their endorsement of (T10) drove them to draw a further distinction that never entered Aristotle’s mind, to contemplate Aristotle’s contrast between primary and secondary substances by positing two types of concrete individual substance things: primary substances (e.g., Socrates or Beulah the cow) and individual substance natures (Socrates’ humanity; Beulah’s bovinity). They needed to claim that it was possible for something that is not essentialy human (preeminently, a Divine person, the Divine Word, Who is essentially Divine) to unite itself to a really distinct concrete individual human nature in such a way as to be characterized by it and to be the ultimate subject of the actions and passions that are done and suffered through it.
Faced with an analogous problem — how to unite really distinct Divine and human souls — Swinburne throws up his hands, insists that it is impossible. If the only type of union available between really distinct substance things were aggregation, then Swinburne would appear to be right. Mere aggregation can unite any really distinct things into a whole (e.g., the Taj Mahal and the honey bee in the hive), but the union would be too loose for Christological purposes, because it does not support any literal sharing of attributes (communicatio idiomatum) — any literal denomination or naming of one part from another (e.g., the Taj Mahal is not truly said to be a honey–maker, nor is the bee truly called a beautiful building).
Medievals recognized three ways in which one thing might be named from or denominated from something:
(a) per se denomination: the Divine Word is Divine per se and Socrates is human per se; the Divine Word couldn’t exist without being Divine, and Socrates couldn’t exist without being human;
(b) per accidens denomination: Socrates is white per accidens. Socrates is really distinct from whiteness and is contingently white in the sense that Socrates could exist without being white;
(c) extrinsic denomination: Socrates is older than Plato and shorter than Aristotle and uglier than Alcibiades.
By [T9] the Divine Word as essentially Divine could not be human per se and essentially. But extrinsic denomination seems too loose to reflect human nature’s actually belonging to the Divine Word as Its own. Accordingly, Scotus and Ockham take as analogy denomination per accidens.
Medieval Latin Aristotelians reify not only substance natures, but some or all accident natures, qualities chief among them. Yet, from their Aristotelian point of view, white Socrates is not a mere aggregation of Socrates and whiteness; whiteness inheres in Socrates. Likewise, they want to say, the Word made flesh is not a mere aggregate of Divinity and humanity; the individual human nature is assumed by the Divine Word.
But what is the metaphysical difference between mere aggregation and inherence? Medieval Latin Aristotelians cite three features:
(a) co-location: Socrates and his whiteness are in the same place at the same time;
(b) potency-actualization: the whiteness actualizes a potency for being white in Socrates;
(c) ontological dependence: the whiteness essentially depends on Socrates for its existence in a non-efficient-causal way.
(a) does not seem relevant to angels (as essentially immaterial substances) and their inhere accidents. Likewise, it is of no help in understanding the Divine Word’s relations to the human nature, because the Divine Word is either nowhere (because immaterial) or everywhere (by virtue of Divine knowledge and power) and no more where the human nature is than where everything else is.
Medievals rules out (b) on the philosophical ground that the Divine Word as simple cannot be a subject of inherence. They also excluded it on philosophico-theological grounds. Philosophy tells us that, when whiteness actualizes a substance’s potency for being white, it affects how it is qualified; and when a substantial form actualizes matter’s potency to receive it, it affects the substance-kind to which its subject belongs. Medievals reasoned that human nature is a substance-kind. If it actualized the potency of some subject to receive it, it would affect the substance-kind to which its subject belonged. Since the Divine Word is essentially Divine, such potency-actualization would result in a metaphysically impossible and theologically impermissible confusion of natures! Likewise, the other way around, if the Divine Word were supposed to inhere in the human nature!
Scotus concludes that the most relevant relations is (c), an accident’s ontological dependence on its subject. Scotus emphasizes that this relation is not to be identified with (although it bears some analogies to) efficient causal dependence. All creatures are efficient causally dependent on all three persons of the Trinity as their first efficient cause. But not all creatures are assumed by the Divine persons. Likewise, a subject (e.g., the intellect) may be an efficient partial cause of some of its accidents (e.g., an act of understanding), but this is a different relation from the ontological dependence the accident has on it as its subject. Scotus declares that ontological dependence of a broad-sense property thing on a subject is sufficient for characterization. Even if whiteness did not actualize a potency in Socrates, Socrates would be the subject on which the whiteness ontologically depended and that would be enough to make it true that Socrates is white. Likewise, ontological dependence by the assumed human nature on the Divine Word is sufficient for the Divine Word to be contingently denominated from the human nature.
Even if the Divine Word had no potency to be actualized by the individual human nature, it might seem that, if the Divine Word is first not-related and then related, the Divine Word undergoes a change—contrary to Divine simplicity and immutability. To avoid this, Scotus invokes the doctrine of non-mutual relations. Sometimes the truth of “aRb” requires a relation thing R in a and a co-relation thing R’ in b (e.g., where this wall is similar in color to that wall). But other times it is enough if a is the term of a relation-thing R’ that inheres in b (i.e., if bR’a). Scotus imagines that the Divine Word (a) will be the term of such a dependence relation (R’) that inheres in the assumed human nature (b) without any corresponding R-thing inhering in It (a), and that this will be enough to make “the Divine Word assumes the human nature” true.
Although this idea of non-mutual relations was widely accepted among medieval Aristotelians, anyone who — like Swinburne — denied immutability and impassibility to be essential to Godhead could allow that the Divine Word acquires a new relation of assuming when it assumes the human nature. Nor would this necessarily renew their worry about the fusion of natures, for it is one thing to suppose that human nature inheres in by actualizing a potency in Divinity or Divinity inheres in by actualizing a potency in humanity. It is another to suppose that Divinity is first not inhered in and then inhered in by the co-relative of the ontological dependence relation in the human nature — that is, by the relation of sustaining or supporting or suppositing the human nature.
What is key is that the ontological dependence relation that Scotus identifies be sufficient for characterization. Scotus says that it is: the ontological dependence of whiteness on Socrates suffices for the truth of “Socrates is white,” and the ontological dependence of the human nature on the Divine Word would suffice for the truth of “The Divine Word is human” and be enough to license the further creedal predications: “born of the Virgin Mary, suffered under Pontius Pilate, was crucified, dead, buried, but rose on the third day.”