After reading a round of Trinitarian debates between Bill Vallicella and Chad M (started a week ago, the latest was today), I went back to re-read the Scholastics again (in this case Aquinas and Petrus de Aquila). I’ve spent a week thinking about a response Aquinas gave to the following dilemma:
God begets (as Father)
God is begotten (as Son)
A begetter is a different being from something begotten
Therefore there are two Gods
A part of the response:
The unity or community of [for example] human nature is not a reality, but is only in the consideration of the mind. Hence this term “man” does not stand for the common nature, unless this is required by some adjunct, as when we say, “man is a species”; but the form signified by the name “God”–that is, the divine essence–is really one and common. So of itself it stands for the common nature, but by some adjunct it may be restricted so as to stand for the person.
ST 1.39.4 ad 3
A created nature is common only in the mind, but the divine nature is not. The relevance of this to the dispute between Nominalism and realism is unmistakable, and we can see the Platonic idea anticipates a mode of existence which is proper to the Trinity so far as it is a single reality really common to many. Could it be that the Platonic ideas are not best Christianized by putting the ideas of things in the mind of God (the universale ante rem) but by the unity of the nature in the Trinity? Nevertheless, the Aristotelian critique of Platonism is also totally verified: not only because the reality of universals is not possible in the created order but also, more profoundly, because the absolute reality of the possessor of the nature is preserved. The Father is not a “participation” in divinity. The opposition of realisms to nominalism was based on the sense of an opposition between the community of nature and the substantial existence of what possessed the nature, which is equivalent to saying it was based on the implicit denial that anything could be consubstantial.*
This strikes me as a possible third way around the problem of realism and nominalism through a bona fide Christian philosophy. It might also help us to push the discussion further among Analytic philosophers over the “‘is’ of numerical identity” which creates so many apories** in their discussion of the Trinity. Thesis: To make the opposition between the is of identity and predication somethign that reflects the reality of the Trinity as opposed to being a feature of how we have to talk about that reality requires an implicit denial that anything is consubstantial or homoousian (St. Thomas would say that the Trinitatian apories arising from thigns said with the “is of numberical identity” arise from not distinguishing what we can say from what can be).
Of course, we Thomists are prone to seeing the Trinity as beyond the laws of Logic…
*Neither the Platonist, Aristotelian, nor Nominalist can say that Plato and Socrates, or two frogs, or any two hypostases are “consubstantial”. For the Platonist, there is only one substance for a multitude of similar things, sc. “man itself” or “frog itself”. For the Aristotelian, there are only the various substances, and the only consubstantiality (though it makes little sense to call it this) is in the mind. Nominalism is a version of Aristotle’s theory which does not add any Augustinian paradigms for substances outside of creation (like divine ideas, say.)
**That’s the plural. I looked it up.