Book VII of the Confessions recounts how Augustine was leant certain books of the platonists i.e. of the Neoplatonists (such as Plotinus), and the impact they had on his search for the way to think of the immutability of God.
What the books of the Platonists were to provide Augustine with, among other things, was a way of thinking about God that would free it of physical implications, implications about time and space, and so of the need for physical imagery, as well as providing him with an epistemological discipline, the ascent of the mind through which he could be certain of this God’s existence.
The books say that before all times and above all times your only-begotten Son immutably abides eternal with you, and that souls ‘receive their fullness (John 1.16) to be blessed, and that they are renewed to be wise by participation in wisdom abiding in them.
Eternal truth and true love and beloved eternity: you are my God.
I was certain that you are infinite without being infinitely diffused through finite space. I was sure that you truly are, and are always the same; that you never become other or different in any part or by any movement or position, whereas all other things derive from you, as is proved by the fact that they exist.
Note how immutability and eternity now come into focus.
There is another thread to this, for early on in his transition from his Manichean sympathies, Augustine seems to have become concerned with the Trinitarian godhead, and particularly the relation of the Father to the Son. One problem seems to be, how can the Father be the generator of the Son (as according to Nicene Christology he is), and not change? Platonism was of immediate help to him on that issue. He believed that the platonic thinking provided him with an answer compatible with divine immutability. But as far as the Incarnation itself is concerned, he more than once says rather dismissively that the books made no reference to that.
Here we shall focus on the first of these benefits, the acquisition of a way of reading the Church’s language about God’s threefoldness. This reading is better understood not as an hermeneutic for Scripture, but as a proposal for a translation, the development or appropriation of a cognitively equivalent language, which expressed ‘in different words, and in a variety of ways’, such dogmas as the only-begottenness of the Son by the Father, and the Johannine idea that wisdom comes by participation in the Son. But yet his reading of the books was not exactly cognitively equivalent to Scripture, for he relies on them to expand upon the biblical account. For one thing that they state is that ‘before all times and above all times your only begotten Son immutably abides in you’, which is certainly not to be found in the Prologue to John’s Gospel, though Augustine may have thought that it was implied by it, or at least consistent with it: he does not say.
But he is happy to take this filling out of the meaning of Scripture (as I call it) from the Platonists, citing the precedent of Moses spoiling the Egyptians, and (what is more apt) Paul’s appropriation of Aratus and Epimenides the Cretan in his address to the philosophers of Athens. So it seems that what he received from these books, at least, was a way of thinking about God as ‘before’ and ’above’ all times and places, an atemporality and non-spatiality shared, of course, by his only-begotten Son. This is the ‘immaterial truth’ that the books of the Platonists taught him.
So one significant gift of the platonists was the grammar of timeless eternity and immutability which Augustine readily applied to God, and which took him where Aristotle’s Categories could not go. Of course it was not the only gift of the platonists, but it is the one that chiefly matters to us here. There was also the matter of the ascent of the mind to God, the experience of which provided Augustine with direct ‘evidence’, or at least confirmation, of the divine eternality as being an intrinsic part of the conceptuality of the Creator-creature distinction. The light that he experienced was ‘utterly different from all our kinds of light’. It superiority lay in the fact that this light was the light of the Creator. And so ‘Eternal truth and true love and beloved eternity: you are my God’.
There is an interval of discussion in the Confessions between the accounts of two ‘ascents’, to be found in Confessions VII. x (16). ‘I entered and with my soul’s eye, such as it was, saw above that same eye of my soul the immutable light higher than any mind ….’ and then in Confessions VII xvi 22. ‘’So in the flash of a trembling glance it attained to that which is. At that moment I saw your ‘invisible nature understood through the things that are made (Rom.1:20) But I did not possess the strength to keep my vision fixed.’ These are either two accounts of the same thing, or of two different phases of experience. What Augustine says in that interval is crucial to our understanding. He tells us that in his Manichean phase his soul created for itself ‘a god pervading all places in infinite space’. This god he now cheerfully abandoned because another conceptuality was at hand. God is spirit, immutable and eternal, supremely good, giving all else its being which is also good. Augustine thought that as such God is incapable of pervading all places in infinite space like a gas, or luminosity, but that he is omnipresent in a deeper, more spiritual, non-sensous way. He had found an intellectually satisfactory way of appropriating the Church’s teaching about divine immutability.
So one of the fruits of his reading some books of the platonists is that Augustine is able to begin to develop a grammar of God about whom such questions as ‘Where is he?’ and ‘How long has he existed?’ and ‘How large is he?” and ‘What was he doing before the Creation?’ make no sense.
Yet Augustine is not totally carried away by his reading of the books. Just as Aristotle’s Categories took him so far, to the level of the creaturely, and no further, so the books of the platonists also took him so far, to the Father and his only-begotten Son, and no further.
For he is clear that there is no equivalent translation of the Incarnation of the Son or of his offering upon the Cross into platonic conceptuality. Nevertheless, the books most certainly given him a grammar of God, or the beginnings of one, of an immutable God who Is ‘before all times and above all times’, a true Creator. ‘I was sure that you truly are, and are always the same; that you never become other or different in any part of by any movement or position, whereas all other things derive from you, as if provided by the fact that they exist’. Parts, movement, position – these are Aristotelian categories. And the immutability of the Word of God means that he is not merely ‘a man of excellent wisdom’, nor that he is incarnate in a mere body, but that since change is ascribed to the incarnate Son he must have a human nature, body and soul.