The end or term of the production of man
Objection 1. It would seem that the image of God is not only in man's mind. For the Apostle says (1 Corinthians 11:7) that "the man is the image... of God." But man is not only mind. Therefore the image of God is to be observed not only in his mind.
Objection 2. Further, it is written (Genesis 1:27): "God created man to His own image; to the image of God He created him; male and female He created them." But the distinction of male and female is in the body. Therefore the image of God is also in the body, and not only in the mind.
Objection 3. Further, an image seems to apply principally to the shape of a thing. But shape belongs to the body. Therefore the image of God is to be seen in man's body also, and not in his mind.
Objection 4. Further, according to Augustine (Gen. ad lit. xii, 7,24) there is a threefold vision in us, "corporeal," "spiritual," or imaginary, and "intellectual." Therefore, if in the intellectual vision that belongs to the mind there exists in us a trinity by reason of which we are made to the image of God, for the like reason there must be another trinity in the others.
On the contrary, The Apostle says (Ephesians 4:23-24): "Be renewed in the spirit of your mind, and put on the new man." Whence we are given to understand that our renewal which consists in putting on the new man, belongs to the mind. Now, he says (Colossians 3:10): "Putting on the new" man; "him who is renewed unto knowledge" of God, "according to the image of Him that created him," where the renewal which consists in putting on the new man is ascribed to the image of God. Therefore to be to the image of God belongs to the mind only.
I answer that, While in all creatures there is some kind of likeness to God, in the rational creature alone we find a likeness of "image" as we have explained above (1,2); whereas in other creatures we find a likeness by way of a "trace." Now the intellect or mind is that whereby the rational creature excels other creatures; wherefore this image of God is not found even in the rational creature except in the mind; while in the other parts, which the rational creature may happen to possess, we find the likeness of a "trace," as in other creatures to which, in reference to such parts, the rational creature can be likened. We may easily understand the reason of this if we consider the way in which a "trace," and the way in which an "image," represents anything. An "image" represents something by likeness in species, as we have said; while a "trace" represents something by way of an effect, which represents the cause in such a way as not to attain to the likeness of species. For imprints which are left by the movements of animals are called "traces": so also ashes are a trace of fire, and desolation of the land a trace of a hostile army.
Therefore we may observe this difference between rational creatures and others, both as to the representation of the likeness of the Divine Nature in creatures, and as to the representation in them of the uncreated Trinity. For as to the likeness of the Divine Nature, rational creatures seem to attain, after a fashion, to the representation of the species, inasmuch as they imitate God, not only in being and life, but also in intelligence, as above explained (2); whereas other creatures do not understand, although we observe in them a certain trace of the Intellect that created them, if we consider their disposition. Likewise as the uncreated Trinity is distinguished by the procession of the Word from the Speaker, and of Love from both of these, as we have seen (28, 3); so we may say that in rational creatures wherein we find a procession of the word in the intellect, and a procession of the love in the will, there exists an image of the uncreated Trinity, by a certain representation of the species. In other creatures, however, we do not find the principle of the word, and the word and love; but we do see in them a certain trace of the existence of these in the Cause that produced them. For in the fact that a creature has a modified and finite nature, proves that it proceeds from a principle; while its species points to the (mental) word of the maker, just as the shape of a house points to the idea of the architect; and order points to the maker's love by reason of which he directs the effect to a good end; as also the use of the house points to the will of the architect. So we find in man a likeness to God by way of an "image" in his mind; but in the other parts of his being by way of a "trace."
Reply to Objection 1. Man is called to the image of God; not that he is essentially an image; but that the image of God is impressed on his mind; as a coin is an image of the king, as having the image of the king. Wherefore there is no need to consider the image of God as existing in every part of man.
Reply to Objection 2. As Augustine says (De Trin. xii, 5), some have thought that the image of God was not in man individually, but severally. They held that "the man represents the Person of the Father; those born of man denote the person of the Son; and that the woman is a third person in likeness to the Holy Ghost, since she so proceeded from man as not to be his son or daughter." All of this is manifestly absurd; first, because it would follow that the Holy Ghost is the principle of the Son, as the woman is the principle of the man's offspring; secondly, because one man would be only the image of one Person; thirdly, because in that case Scripture should not have mentioned the image of God in man until after the birth of the offspring. Therefore we must understand that when Scripture had said, "to the image of God He created him," it added, "male and female He created them," not to imply that the image of God came through the distinction of sex, but that the image of God belongs to both sexes, since it is in the mind, wherein there is no sexual distinction of sex, but that the image of God belongs to both sexes, since it is in the mind, wherein there is no sexual distinction. Wherefore the Apostle (Colossians 3:10), after saying, "According to the image of Him that created him," added, "Where there is neither male nor female" [these words are in reality from Galatians 3:28 (Vulg. "neither Gentile nor Jew").
Reply to Objection 3. Although the image of God in man is not to be found in his bodily shape, yet because "the body of man alone among terrestrial animals is not inclined prone to the ground, but is adapted to look upward to heaven, for this reason we may rightly say that it is made to God's image and likeness, rather than the bodies of other animals," as Augustine remarks (QQ. 83, qu. 51). But this is not to be understood as though the image of God were in man's body; but in the sense that the very shape of the human body represents the image of God in the soul by way of a trace.
Reply to Objection 4. Both in the corporeal and in the imaginary vision we may find a trinity, as Augustine says (De Trin. xi, 2). For in corporeal vision there is first the species of the exterior body; secondly, the act of vision, which occurs by the impression on the sight of a certain likeness of the said species; thirdly, the intention of the will applying the sight to see, and to rest on what is seen.
Likewise, in the imaginary vision we find first the species kept in the memory; secondly, the vision itself, which is caused by the penetrative power of the soul, that is, the faculty of imagination, informed by the species; and thirdly, we find the intention of the will joining both together. But each of these trinities falls short of the Divine image. For the species of the external body is extrinsic to the essence of the soul; while the species in the memory, though not extrinsic to the soul, is adventitious to it; and thus in both cases the species falls short of representing the connaturality and co-eternity of the Divine Persons. The corporeal vision, too, does not proceed only from the species of the external body, but from this, and at the same time from the sense of the seer; in like manner imaginary vision is not from the species only which is preserved in the memory, but also from the imagination. For these reasons the procession of the Son from the Father alone is not suitably represented. Lastly the intention of the will joining the two together, does not proceed from them either in corporeal or spiritual vision. Wherefore the procession of the Holy Ghost from the Father and the Son is not thus properly represented.
Source: Summa Theologica (New Advent)