Summa contra Gentiles1.29 Chapter XXIX. Of the likeness of creatures

In sequence to the above we may consider in what way it is possible to find in things a likeness to' God, and in what way it is impossible.

For effects that fall short of their causes do not agree with them in name and ratio, and yet there must needs be some likeness between them, because it is of the nature of action that a like agent should produce a like action, since every thing acts according as it is in act. Wherefore the form of the effect is found in its transcendent cause somewhat, but in another way and another ratio, for which reason that cause is called equivocal. For the sun causes heat in lower bodies by acting according as it is in act; wherefore the heat generated by the sun must needs bear some likeness to the sun's active power by which heat is caused in those lower bodies and by reason of which the sun is said to be hot, albeit in a different ratio. And thus it is said to be somewhat like all those things on which it efficaciously produces its effects, and yet again it is unlike them all in so far as these effects do not possess heat and so forth in the same way as they are found in the sun. Thus also God bestows all perfections on things, and in consequence He is both like and unlike all.

Hence it is that Holy Writ sometimes recalls the likeness between Him and His creatures, as when it is said (Gen. i. 26): Let Us make man to Our image and likeness: while sometimes this likeness is denied, according to the words of Isa. xl. 18: To whom then have you likened God; or what image will you make for Him? and of the psalm:? O God, who shall be like to Thee?

Dionysius is in agreement with this argument, for he says (Div. Nom. ix.): The same things are like and unlike to God; like, according as they imitate Him, as far as they can, Who is not perfectly imitable; unlike, according as effects fall short of their causes.

However, according to this likeness, it is more fitting to say that the creature is like God than vice versa. For one thing is like another when it possesses a quality or form thereof. Since then what is in God perfectly is found in other things by way of an imperfect participation, that in which likeness is observed is God's simply but not the creature's. And thus the creature has what is God's, and therefore is rightly said to be like God. But it cannot be said in this way that God has what belongs to His creature: wherefore neither is it fitting to say that God is like His creature; as neither do we say that a man is like his portrait, although we declare that his portrait is like him.

And much less properly can it be said that God is assimilated to the creature. For assimilation denotes movement towards similarity, and consequently applies to one that receives its similarity from another. But the creature receives from God its similarity to Him, and not vice versa. Therefore God is not assimilated to His creature, but rather vice versa.