28. And what did it profit me that, when I was scarcely twenty years old, a book of Aristotle's entitled The Ten Categories fell into my hands? On the very title of this I hung as on something great and divine, since my rhetoric master at Carthage and others who had reputations for learning were always referring to it with such swelling pride. I read it by myself and understood it. And what did it mean that when I discussed it with others they said that even with the assistance of tutors--who not only explained it orally, but drew many diagrams in the sand--they scarcely understood it and could tell me no more about it than I had acquired in the reading of it by myself alone? For the book appeared to me to speak plainly enough about substances, such as a man; and of their qualities, such as the shape of a man, his kind, his stature, how many feet high, and his family relationship, his status, when born, whether he is sitting or standing, is shod or armed, or is doing something or having something done to him--and all the innumerable things that are classified under these nine categories (of which I have given some examples) or under the chief category of substance.
29. What did all this profit me, since it actually hindered me when I imagined that whatever existed was comprehended within those ten categories? I tried to interpret them, O my God, so that even thy wonderful and unchangeable unity could be understood as subjected to thy own magnitude or beauty, as if they existed in thee as their Subject--as they do in corporeal bodies--whereas thou art thyself thy own magnitude and beauty. A body is not great or fair because it is a body, because, even if it were less great or less beautiful, it would still be a body. But my conception of thee was falsity, not truth. It was a figment of my own misery, not the stable ground of thy blessedness. For thou hadst commanded, and it was carried out in me, that the earth should bring forth briars and thorns for me, and that with heavy labor I should gain my bread.
30. And what did it profit me that I could read and understand for myself all the books I could get in the so-called "liberal arts," when I was actually a worthless slave of wicked lust? I took delight in them, not knowing the real source of what it was in them that was true and certain. For I had my back toward the light, and my face toward the things on which the light falls, so that my face, which looked toward the illuminated things, was not itself illuminated. Whatever was written in any of the fields of rhetoric or logic, geometry, music, or arithmetic, I could understand without any great difficulty and without the instruction of another man. All this thou knowest, O Lord my God, because both quickness in understanding and acuteness in insight are thy gifts. Yet for such gifts I made no thank offering to thee. Therefore, my abilities served not my profit but rather my loss, since I went about trying to bring so large a part of my substance into my own power. And I did not store up my strength for thee, but went away from thee into the far country to prostitute my gifts in disordered appetite. And what did these abilities profit me, if I did not put them to good use? I did not realize that those arts were understood with great difficulty, even by the studious and the intelligent, until I tried to explain them to others and discovered that even the most proficient in them followed my explanations all too slowly.
31. And yet what did this profit me, since I still supposed that thou, O Lord God, the Truth, wert a bright and vast body and that I was a particle of that body? O perversity gone too far! But so it was with me. And I do not blush, O my God, to confess thy mercies to me in thy presence, or to call upon thee--any more than I did not blush when I openly avowed my blasphemies before men, and bayed, houndlike, against thee. What good was it for me that my nimble wit could run through those studies and disentangle all those knotty volumes, without help from a human teacher, since all the while I was erring so hatefully and with such sacrilege as far as the right substance of pious faith was concerned? And what kind of burden was it for thy little ones to have a far slower wit, since they did not use it to depart from thee, and since they remained in the nest of thy Church to become safely fledged and to nourish the wings of love by the food of a sound faith.
O Lord our God, under the shadow of thy wings let us hope--defend us and support us. Thou wilt bear us up when we are little and even down to our gray hairs thou wilt carry us. For our stability, when it is in thee, is stability indeed; but when it is in ourselves, then it is all unstable. Our good lives forever with thee, and when we turn from thee with aversion, we fall into our own perversion. Let us now, O Lord, return that we be not overturned, because with thee our good lives without blemish--for our good is thee thyself. And we need not fear that we shall find no place to return to because we fell away from it. For, in our absence, our home--which is thy eternity--does not fall away.