This is RD’s third point in response to our book review of Colin Gunton, detailing Gunton’s critique of Augustine’s teaching on the Trinity.
Once again, The Grit’s advice is, read it slowly, and maybe a couple of times over – it’ll come clear gradually.
3. THE ONE ESSENCE, AND THE THREE PERSONS – THE PRIORITY OF THE FATHER IN AUGUSTINE
Augustine constantly refers his trinitarian thinking back to the ‘simple essence’ of God. He is not alone in thinking this way. The emphasis on ‘essence’ is not just Latin or Western way of thinking. We see in both the Nicene creed with its description of the Son and the Spirit in homoousial terms (‘of the same substance’), as well as the writings of both Greek and Latin Fathers, that they tend to think ‘ousially/substantially/essentially’ as well as ‘personally’ with respect to the Trinity.
The Cappadocian Fathers in the East, along with Augustine in the West, used the term ‘essence’ or ‘substance’ or ‘being/ousia’ to supply the grammar or terminology of trinitarian unity. By saying that the Son, in his particularity as one of the three members of the Trinity, is ‘of the same substance’ (homoousion) with the Father, they are safeguarding the unity of God, his oneness with the Father, and also confessing that the Son is also truly God, and a distinct, personal particular of God.
There is a contemporary trend which stress the three persons as the starting point, and downplays the importance of the one-substance informing our trinitarian thinking. This loses what the Fathers gained by thinking ‘substantially’ about the persons and their equality and unity (homoousion of the Son and the Spirit). By ignoring, or even pillaring this focus on ‘substance’, the three Persons are made to bear all the weight in affirming their equality and unity, especially their equality. So, as with Volf and others, any hierarchical order in the relations between the three Persons (the priority of the Father in being and authority), must imply inferiority in ‘godness’ or being.
In assessing Augustine’s work, we need to ask whether he so conceives of “oneness” to make it a thing prior to “threeness” so that the threeness may collapse back in the one essence and a sort of modalism occur.
We have already noted that Augustine has been accused of beginning with the unity of the divine essence before going on to the three Persons. The charge that Augustine saw the oneness as a substrate below the three persons, and thus had Modalist tendencies, is an old one, and has been common until recently. H. A. Wolfson saw it in 1956 in his analysis of the philosophy of the Church Fathers. ‘Unlike Tertullian and like Aristotle, . . he identifies the substratum not with the Father but with something underlying both the Father and the Son.’
Further, Augustine insists in Sermon 52 (410) that in this unity the 3 members are irreducible – that is, you cannot go behind the three in their unity to a fourth thing, like an underlying substance. ‘Augustine clearly rejects the idea of a common divinity as in any way separable from the person.’
 If we ask what is the ‘essence’ of this unity, the answer comes, ‘the inseparability of their operations’. But Augustine can push the question further. We observe that in the operation of God in the incarnation, although all three members are involved, yet only the Son and not the Father or the Holy Spirit are incarnate. If three are inseparable in operation, why did not the whole Trinity become incarnate? The question is important, for Augustine has very much located the unity of God in the inseparability of operation of the three members. Unity would seem to dictate they all ought become incarnate. Augustine answer solves his problem by not only thinking about who God is, but also at the same time reflecting on the process of thinking theologically in an appropriate way. As he answers the question about who was incarnate, he at the same time indicates yet another way, a deeper way if you like, of accounting for the oneness of God: the priority of the Father:
This [right theological thinking] has been established by the dispensation of the Incarnation, which is properly attributed to the Son, so that there proceeds from the Father himself, as from the single principle from whom are all things, both understanding through the Son and to a certain interior and ineffable sweetness and delight in that understanding . . . , which is rightly ascribed to the Holy Spirit.
But the question remains, so acutely raised by Gunton’s observation on De Trinitate books 5 and 7, has Augustine satisfactorily tied the three persons, and thus the Father and his priority, back to the one essence? You will see that Augustine at least does so by his strong emphasis on the inseparable actions of the three persons, and that the Son, the Word of God, is appropriate to both his relations to the Father and also to the fact that God’s one essence has the attribute of ‘wisdom’. However, his repeated insistence on seeing the relations only relatively to the three persons and not ontologically to the one substance is unsatisfactory. It can leave God’s essence as something inherently impersonal.
T F Torrance points out that amongst the Greek Fathers, it was Didymus the Blind who came up with the most satisfactory solution: the Son receives his existence of sonship not from the person of the Father (as with the Cappadocians), but from the being of the Father. This at once acknowledges that the persons are to be conceived of of the one essence and not just against the essence, and that God’s essence is inherently and ineluctably personal. To acknowledge the ontological nature of the relations between the three Persons, which makes them what they are, and at the same time to honour the importance of the “one essence” is thinking truly about God, we then ought say: God’s one being and the three Persons arise together. Real being then, as God undoubtedly has, is not monism but a personal sharing in being.