We’re blogging through St. Thomas Aquinas’ Compendium Theologiae, sometimes called his Shorter Summa. Find the previous posts here.
Today’s post is from Chapter 67: “The Divine Properties Not Externally Affixed.”
In this final chapter on the Trinity, Thomas deals with a significant controversy of the previous century. Gilbert of Poitiers was a philosopher and theologian; his works on Aristotelian logic were the most influential of his day. Like Thomas, he held that all things derive their being from God, who sustains them in being; but unlike Thomas he held that God was so ultimately unknowable that the Trinity must be distinct from God-as-ultimate-being. (No doubt I am doing violence to Gilbert's position with this brief summary.) This was contrary to the teachings of the Church. He was brought before an ecclesiastical court (for he was bishop of Poitiers) prosecuted by St. Bernard of Clairvaux, and was not convicted; but nevertheless agreed to change his book.
First, Thomas casts the dispute into the terms he's been using in the previous chapters. Gilbert, he says, claims that the relations or properties by which the Father, the Son, and the Holy Spirit are distinguished are external to the Godhead; and this is mistaken.
The view proposed by Gilbert de la Porrée and some of his followers, that the properties under discussion are not in the persons, but are external to them, cannot be defended.
Real relations must be in the things that are related. This is evident in the case of creatures, for real relations are in them as accidents in their subjects.
I am my son's father. It isn't simply a label the world hangs on me; rather, it's a metaphysical truth. If you look at the causes of my son's existence on this earth, I'm one of them. However, being my son's father is not part of my essence; I could have lived and died without fathering a child at all. Thus, though real, it is accidental in Thomas' terms.
But the relations whereby the persons are distinguished within the Godhead are real relations, as was demonstrated above.” Hence they must be in the divine persons; but not, of course, as accidents.
Thomas has shown that the relations that distinguish the Father, Son, and Holy Spirit are real; but they cannot be accidents, because there are no accidents in God. God is, simple and unchanging. And this is a general pattern:
Other perfections, too, which in creatures are accidents, cease to be accidents when transferred to God, as was shown above; such are wisdom, justice, and the like.
Further, these relations are, in principle, the only way in which the Divine Persons can be distinguished from each other; because anything else we might say of God is common to all three.
Besides, there can be no distinction in God except through the relations; all perfections that are predicated absolutely are common. Therefore, if the relations were external to the persons, no distinction would remain among the persons themselves.
Thus, to summarize: there are the relative properties that distinguish the Divine Persons; and these are the Divine Persons; and these are the Godhead. But we can also say that God is wisdom, and goodness, and I might add truth and beauty; and these apply to all three.
And so there are relative properties in the persons; but they are the persons themselves, and also the divine essence itself. In the same way wisdom and goodness are said to be in God, and are God Himself, as well as the divine essence, as was said above.
Having now spent many chapters on who God is, Thomas will now turn his attention to what God does.