Certain words of Augustine raise a difficulty in this matter. Thus he says (De Trinitate, IX, vii) : "In the eternal truth, whence all corporeal creatures are, we see with our mind's eye the form according to which we are, and according to which we execute anything truly and rightly either in ourselves or in corporeal things." Also he says (Confess. I, xxv) : "If both of us see that what you say is true, and we both see that what I say is true, where, I pray, do we see it? Neither I in you, nor you in me, but both of us in that unchangeable truth which is above our minds." And to the like effect (De Trin. XII, ii) : " It belongs to the higher reason to judge of these bodily things according to aspects (rationes) eternal and everlasting, which certainly would not be unchangeable, were they not above the human mind." But aspects unchangeable and everlasting cannot be elsewhere than in God, since, according to Catholic faith,* God alone is eternal. It seems to follow that we can see God in this life, and that by seeing Him, and aspects of things in Him, we judge of the rest of things.* On the other hand it is incredible that in the above words Augustine should mean to assert that in this life we can understand God as He essentially is, seeing that in his book De videndo Deum he says the contrary.* It remains to enquire how in this life we can see that unchangeable truth or those everlasting aspects. That truth is in the soul, Augustine himself confesses:* hence he proves the immortality of the soul from the eternity of truth. But truth is not in the soul alone as God is said to be 'essentially' (per essentiam) in all things; nor as He is by His likeness in all things, inasmuch as everything is called 'true' so far as it approaches to the likeness of God: for from those points of view the soul stands in no better position than other beings: truth then is in the soul in a special manner, inasmuch as the soul knows truth. As then the soul and other beings are called 'true' in their natures, as bearing some likeness to the supreme nature of God, -- which is truth itself, as being its own fulness of actual understanding (suum intellectum esse),* -- so what is known by the soul is manifestly known, inasmuch as there exists in the soul a likeness of that divine truth which God knows. Hence on the text (Ps. xi, 2) truths are diminished from the sons of men, the Gloss [Augustine, Enarrationes in h.l.] says: "The truth is one, whereby holy souls are illumined: but since there are many souls, there may be said to be in them many truths, as from one face many images appear in as many mirrors." Though different things are known and believed to be true by different minds, yet there are some truths in which all men agree, for instance, the primary intuitions of intellect as well speculative as practical, because, so far as these go, an image of divine truth comes out universally in the minds of all. As then whatever any mind knows for certain, it knows it by virtue of these intuitions, which are the canons of all judgements, and into which all judgements may be resolved, the mind is said to see all things in the divine truth, or in everlasting aspects, and to judge of all things according to those aspects. This explanation is confirmed by the words of Augustine (Soliloq. I, viii, 15): "Even the truths taught in the schools, which every one, who understands them, unhesitatingly allows to be true, we must believe, could not possibly be understood, were they not lit up by the light of another, what I may call a sun proper to them (nisi ab alio quasi sole suo illustrantur)." He says then that the theories of science are seen in the divine truth as visible objects are seen in the light of the sun: but certainly such objects are not seen in the very body of the sun, but by the light which is a likeness of the solar brightness, remaining in the air and similar bodies. From these words then of Augustine it cannot be gathered that God is seen in His substance in this life, but only as in a mirror, which the Apostle also confesses of the knowledge of this life, saying (1 Cor. xiii, 12): We see now as in a glass darkly.
Though the human mind represents the likeness of God more closely than lower creatures, still such knowledge of God as can be gathered from the human mind does not transcend that kind of knowledge which is borrowed from sensible objects, since the soul knows her own essential nature by understanding the nature of things of sense (Chap. XLVI).* Hence neither by this method can God be known in any higher way than as the cause is known by the effect.*
3.46 : That the Soul in this Life does not understand itself by itself
3.48 : That the Final Happiness of Man is not in this Life