May 2, 2013 by mattwilcoxen
Book 5 of De Trinitate is the first part of what appears to be a distinct section constituted by books 5-7. We might say that Augustine’s concern in books 1-4 has been with the holy faith and the creedal scriptures. He has been engaged in laying out before us the faith of the church, and in proving it from scripture. As he moves into books 5-7 he will analyze the language which we use in articulating our faith in the Trinity, and the metaphysical implications this language does or does not have.
The prologue to book 5 is especially important for understanding how Augustine approaches the terms that we use in Trinitarian theology. He says:
“From now on I will be attempting to say things that cannot altogether be said as they are thought by a man–or at least as they are thought by me. In any case, when we think about God the trinity we are aware that our thoughts are quite inadequate to their object, and incapable of grasping him as he is”.
This does not mean that Augustine is a skeptic or altogether agnostic about the quest to understand God. In fact, he thinks the desire is good, and beneficial if the right path is followed. The path to be followed is that of avoiding materialistic conceptions of God. We must always read the divine economy in light of God’s aseity, eternality, immutability, and simplicity. If we do this, we may not be able to grasp what God is like, he says, but we will at least be able to guard our minds against saying anything about God that is not true.
The first real issue of speech about God that Augustine takes up here has to do with the language of “substance” or “being”. He reiterates his conviction that “being” is something that belongs most properly to God because God does not change. The Arian heretics used this principle too, apparently, and argued that it entails that everything we predicate of God must be predicated of God’s substance. This is so because any talk about a God that does not change is talk about God’s most essential being. This would mean, the Arians said, that when we refer to the “Father” and “Son” that we are therefore referring to two different substances. In other words, the Father and the Son are not equal. Augustine easily demolishes this argument by showing how many verses in scripture, if read this way, would entail exactly what the principle is designed to deny–the co-equality of the Father and the Son.
Normally, if we do not mean our predicate term in reference to a thing’s substance, we mean it in reference to some sort of “modification” of a substance. However, neither option will work for Father and Son (or Spirit), since one would entail denying the equality of substance and the other would entail attributing change to God. Instead, when we refer to “Father” and “Son” we are speaking “relation-wise”. One is defined in relation to the other, but the relation just is eternally.
To this the Arians would make another objection, arguing that while such logic might work for “Father” and “Son”, it would never suffice for terms like “unbegotten” and “begotten”. These two terms, the Arians think, clearly refer to substance, indicating that the substance of the Father and Son are fundamentally different. Not so, Augustine says. He argues that the meaning of negative terms like “unbegotten” do not actually affirm anything substance-wise. In fact, they are denials of a relation. And the term “begotten” is essentially equivalent to “Son”. So that we can logically translate these two terms to “not Son” and “Son”. This means that the Arians do not have an argument that holds.
So Augustine says that there are “substance-wise” statements and “relation-wise” statements. Substance-wise statements must be said “three times over about each of the three”, whereas relation-wise statements refer only to one of the three. Substance wise statements are said to refer to the one divine “ousia”, whereas relation-wise statements are said of the three “persons”. Augustine goes out of his way that there is nothing inherently referential about “person” language, but that we need some term and this one, correctly understood, will do.
The relation-wise terms are pretty easy to spot–“Father” and “Son” being the prime examples. But we can get tripped up when it comes to the Holy Spirit. It seems that “Holy Spirit” could easily be a title for the Father or the Son, since God is Spirit and “holy” is a predicate that applies in other places substance-wise. Augustine finds another term for the third person: “gift”. There are also some tricky cases: “origin” can refer to the Father as the begetter, or it can refer to the Trinity as the creator of all that exists. This means that in addition to “substance-wise” and “relation-wise” statements, there are also statements that refer to creation’s relation to God, but imply no change in God or in God’s eternal self-relating. Another example of this is “Lord”. Augustine closes by drawing out an implications of this last concept: changes in our language in relation to God (e.g. when he becomes our Lord) are changes in our epistemological status, but not at all changes in God.