It is well known that Platonism was a much more powerful philosophical force in the fourth century than Aristotelianism (this judgment must, of course, be modified somewhat due to the incorporation of elements of Aristotelian philosophy in later strands of Platonism; but that modification is not going to happen in this short post). 1 Many images used by Plato and later Platonists proved to be very fruitful for early Christian theologians.
One place in which this can be seen is the twenty-first Oration of Gregory of Nazianzus, “On the Great Athanasius, Bishop of Alexandria.” There, he writes:
For many and great as are our blessings— none can say how many and how great— which we have and shall have from God, this is the greatest and kindliest of all, our inclination and relationship to Him. For God is to intelligible things what the sun is to the things of sense. The one lightens the visible, the other the invisible, world. The one makes our bodily eyes to see the sun, the other makes our intellectual natures to see God. And, as that, which bestows on the things which see and are seen the power of seeing and being seen, is itself the most beautiful of visible things; so God, who creates, for those who think, and that which is thought of, the power of thinking and being thought of, is Himself the highest of the objects of thought, in Whom every desire finds its bourne, beyond Whom it can no further go. For not even the most philosophic, the most piercing, the most curious intellect has, or can ever have, a more exalted object. For this is the utmost of things desirable, and they who arrive at it find an entire rest from speculation. (Oration 21.1)
This might sound familiar to readers of Plato’s Republic, for it seems plausible to suggest that this way of describing knowledge of the sensible and the intelligible was borrowed (in summary form) nearly wholesale from the “Allegory of the Sun” (the main principles of which are reprised again in the “Analogy of the Divided Line” and the “Allegory of the Cave”) in Republic 507b-509c (Book 6), where Socrates engages Glaucon in discussion about the apprehension of the good. Though the selection is long, I include the whole thing here.
…[T]here is a many beautiful and a many good, and so of other things which we describe and define; to all of them the term ‘many’ is applied.
True, he said.
And there is an absolute beauty and an absolute good, and of other things to which the term ‘many’ is applied there is an absolute; for they may be brought under a single idea, which is called the essence of each.
The many, as we say, are seen but not known, and the ideas are known but not seen.
And what is the organ with which we see the visible things?
The sight, he said.
And with the hearing, I said, we hear, and with the other senses perceive the other objects of sense?
No, I never have, he said.
Then reflect: has the ear or voice need of any third or additional nature in order that the one may be able to hear and the other to be heard?
Nothing of the sort.
No, indeed, I replied; and the same is true of most, if not all, the other senses—you would not say that any of them requires such an addition?
But you see that without the addition of some other nature there is no seeing or being seen?
How do you mean?
Sight being, as I conceive, in the eyes, and he who has eyes wanting to see; colour being also present in them, still unless there be a third nature specially adapted to the purpose, the owner of the eyes will see nothing and the colours will be invisible.
Of what nature are you speaking?
Of that which you term light, I replied.
True, he said.
Noble, then, is the bond which links together sight and visibility, and great beyond other bonds by no small difference of nature; for light is their bond, and light is no ignoble thing?
Nay, he said, the reverse of ignoble.
And which, I said, of the gods in heaven would you say was the lord of this element? Whose is that light which makes the eye to see perfectly and the visible to appear?
You mean the sun, as you and all mankind say.
May not the relation of sight to this deity be described as follows?
Neither sight nor the eye in which sight resides is the sun?
By far the most like.
And the power which the eye possesses is a sort of effluence which is dispensed from the sun?
Then the sun is not sight, but the author of sight who is recognised by sight?
True, he said.
And this is he whom I call the child of the good, whom the good begat in his own likeness, to be in the visible world, in relation to sight and the things of sight, what the good is in the intellectual world in relation to mind and the things of mind:
Will you be a little more explicit? he said.
Why, you know, I said, that the eyes, when a person directs them towards objects on which the light of day is no longer shining, but the moon and stars only, see dimly, and are nearly blind; they seem to have no clearness of vision in them?
And the soul is like the eye: when resting upon that on which truth and being shine, the soul perceives and understands, and is radiant with intelligence; but when turned towards the twilight of becoming and perishing, then she has opinion only, and goes blinking about, and is first of one opinion and then of another, and seems to have no intelligence?
Now, that which imparts truth to the known and the power of knowing to the knower is what I would have you term the idea of good, and this you will deem to be the cause of science, and of truth in so far as the latter becomes the subject of knowledge; beautiful too, as are both truth and knowledge, you will be right in esteeming this other nature as more beautiful than either; and, as in the previous instance, light and sight may be truly said to be like the sun, and yet not to be the sun, so in this other sphere, science and truth may be deemed to be like the good, but not the good; the good has a place of honour yet higher.
What a wonder of beauty that must be, he said, which is the author of science and truth, and yet surpasses them in beauty; for you surely cannot mean to say that pleasure is the good?
God forbid, I replied; but may I ask you to consider the image in another point of view?
In what point of view?
You would say, would you not, that the sun is not only the author of visibility in all visible things, but of generation and nourishment and growth, though he himself is not generation?
In like manner the good may be said to be not only the author of knowledge to all things known, but of their being and essence, and yet the good is not essence, but far exceeds essence in dignity and power.
Glaucon said, with a ludicrous earnestness: By the light of heaven, how amazing!
Yes, I said, and the exaggeration may be set down to you; for you made me utter my fancies.
And pray continue to utter them; at any rate let us hear if there is anything more to be said about the similitude of the sun.
Yes, I said, there is a great deal more.
Then omit nothing, however slight. (tr. Benjamin Jowett)
Ancient philosophy was of course not a straitjacket for the Fathers, but it did provide material that was useful to think with–mental furniture, as it were, that could be creatively redeployed in a new context. As we see over and over again in the history of Christian thought, anyone who wants to keep Christians from plundering the Egyptians is going to need a better security system–but if put into place, that system, far from protecting the Christian inheritance, would paradoxically rob the church of much that could be tweaked and put to good use.