Orthodoxus. Well, then, I do not suppose you are ignorant that it is impossible for two uncreated things to exist together, although you seem to have expressed nearly as much as this in an earlier part of the conversation. Assuredly we must of necessity say one of two things: either that God is separate from matter, or, on the other hand, that He is inseparable from it. If, then, one would say that they are united, he will say that that which is uncreated is one only, for each of the things spoken of will be a part of the other; and as they are parts of each other, there will not be two uncreated things, but one composed of different elements. For we do not, because a man has different members, break him up into many beings. But, as the demands of reason require, we say that a single being, man, of many parts, has been created by God. So it is necessary, if God be not separate from matter, to say that that which is uncreated is one only; but if one shall say that He is separate, there must necessarily he something intermediate between the two, which makes their separation evident. For it is impossible to estimate the distance of one thing from another, unless there be something else with which the distance between them may be compared. And this holds good, not only as far as the instance before us, but also to any number of others. For the argument which we advanced in the case of two uncreated things would of necessity be of equal force, were the uncreated things granted to be three in number. For I should ask also respecting them, whether they are separate from each other, or, on the other hand, are united each to its neighbour. For if any one resolve to say that they are united, he will be told the same as before; if, again, that they are separate, he will not escape the necessary existence of that which separates them.
If, then, any one were to say that there is a third account which might fitly be given of uncreated things, namely, that neither is God separate from matter, nor, again, are they united as part of a whole; but that God is locally situate in matter, and matter in God, he must be told as the consequence, that if we say that God is placed in matter, we must of necessity say that He is contained within limits, and circumscribed by matter. But then He must, equally with matter, be carried about without order. And that He rests not, nor remains by Himself, is a necessary result of that in which He is being carried, now this way, and now that. And besides this, we must say that God was in worse case still.
For if matter were once without order, and He, determining to change it for the better, put it into order, there was a time when God was in that which had no order. And I might fairly ask this question also, whether God filled matter completely, or existed in some part of it. For if one resolve to say that God was in some part of matter, how far smaller than matter does he make Him; that is, if a part of it contained God altogether. But if he were to say that He is in all of it, and is extended through the whole of matter, he must tell us how He wrought upon it. For we must say that there was a sort of contraction of God, which being effected, He wrought upon that from which He was withdrawn, or else that He wrought in union with matter, without having a place of withdrawal. But if any one say that matter is in God, there is equal need of inquiry, namely, whether it is by His being separated from Himself, and as creatures exist in the air, by His being divided and parted for the reception of the beings that are in Him; or whether it is locally situated, that is to say, as water in land; for if we were to say, as in the air, we must say that God is divisible; but if, as water in earth—since matter was without order and arrangement, and besides, contained what was evil—we must say, that in God were to be found the disorderly and the evil. Now this seems to me an unbecoming conclusion, nay, more a dangerous one. For you wish for the existence of matter, that you may avoid saying that God is the author of evil; and, determining to avoid this, you say that He is the receptacle of evil.
If, then, under the supposition that matter is separate from created substances, you had said that it is uncreated, I should have said much about it, to prove that it is impossible for it to be uncreated; but since you say that the question of the origin of evil is the cause of this supposition, it therefore seems to me right to proceed to inquire into this. For when it is clearly stated how evil exists, and that it is not possible to say that God is the cause of evil, because of matter being subject to Him, it seems to me to destroy such a supposition, to remark, that if God created the qualities which did not exist, He equally created the substances. Do you say then, that there co-exists with God matter without qualities out of which He formed the beginning of this world?
Valentinian. So I think.
Orthodoxus. If, then, matter had no qualities, and the world were produced by God, and qualities exist in the world, then God is the maker of qualities?
Valentinian. It is so.
Orthodoxus. Now, as I heard you say some time ago that it is impossible for anything to conic into being out of that which has no existence, answer my question: Do you think that the qualities of the world were not produced out of any existing qualities?
Valentinian. I do.
Orthodoxus. And that they are something distinct from substances? Valentinian. Yes.
Orthodoxus. If, then, qualities were neither made by God out of any ready at hand, nor derive their existence from substances, because they are not substances. we must say that they were produced by God out of what had no existence. Wherefore I thought you spoke extravagantly in saying that it was impossible to suppose that anything was produced by God out of what did not exist.
But let our discussion of this matter stand thus. For truly we see among ourselves men making things out of what does not exist, although they seem for the most part to be making them with something. As, for instance, we may have an example in the case of architects; for they truly do not make cities out of cities, nor in like manner temples out of temples.
But if, because substances underlie these things, you think that the builders make them out of what does exist, you are mistaken in your calculation. For it is not the substance which makes the city or the temples, but art applied to substance. And this art is not produced out of some art which lies in the substances themselves, but from that which is not in them.
But you seem likely to meet me with this argument: that the artificer makes the art which is connected with the substance out of the art which he has. Now I think it is a good reply to this to say, that in man it is not produced from any art lying beneath; for it is not to be granted that substance by itself is art. For art is in the class of accidents, and is one of the things that have an existence only when they are employed about some substance. For man will exist even without the art of building, but it will have no existence unless man be previously in being. Whence we must say that it is in the nature of things for arts to be produced in men out of what has no existence. If, then, we have shown that this is so in the case of men, why was it improper to say that God is able to make not only qualities, but also substances, out of that which has no existence? For as it appears possible for something to be produced out of what exists not, it is evident that this is the case with substances. To return to the question of evil. Do you think evil comes under the head of substances, or of qualities of substances?
Valentinian. Of qualities.
Orthodoxus. But matter was found to be without quality or form?
Valentinian. It was.
Source: Concerning Free Will (New Advent)