On The Holy Trinity by St. Augustine
Chapter 8.--How the Soul Inquires into Itself. Whence Comes the Error of the Soul Concerning Itself.
11. It is then a wonderful question, in what manner the soul seeks and finds itself; at what it aims in order to seek, or whither it comes, that it may come into or find out. For what is so much in the mind as the mind itself? But because it is in those things which it thinks of with love, and is wont to be in sensible, that is, in corporeal things with love, it is unable to be in itself without the images of those corporeal things. And hence shameful error arises to block its way, whilst it cannot separate from itself the images of sensible things, so as to see itself alone. For they have marvellously cohered with it by the close adhesion of love. And herein consists its uncleanness; since, while it strives to think of itself alone, it fancies itself to be that, without which it cannot think of itself. When, therefore, it is bidden to become acquainted with itself, let it not seek itself as though it were withdrawn from itself; but let it withdraw that which it has added to itself. For itself lies more deeply within, not only than those sensible things, which are clearly without, but also than the images of them; which are indeed in some part of the soul, viz., that which beasts also have, although these want understanding, which is proper to the mind. As therefore the mind is within, it goes forth in some sort from itself, when it exerts the affection of love towards these, as it were, footprints of many acts of attention. And these footprints are, as it were, imprinted on the memory, at the time when the corporeal things which are without are perceived in such way, that even when those corporeal things are absent, yet the images of them are at hand to those who think of them. Therefore let the mind become acquainted with itself, and not seek itself as if it were absent; but fix upon itself the act of [voluntary] attention, by which it was wandering among other things, and let it think of itself. So it will see that at no time did it ever not love itself, at no time did it ever not know itself; but by loving another thing together with itself it has confounded itself with it, and in some sense has grown one with it. And so, while it embraces diverse things, as though they were one, it has come to think those things to be one which are diverse.