He is not ashamed, moreover, to say, in addition to these statements (that the unseemly character of his opinions may be manifest to those who will live after him): “Come now, if one were to look down from heaven upon earth, in what respect would our actions appear to differ from those of ants and bees?” Now does he who, according to his own supposition, looks from heaven upon the proceedings of men and ants, look upon their bodies alone, and not rather have regard to the controlling reason which is called into action by reflection; while, on the other hand, the guiding principle of the latter is irrational, and set in motion irrationally by impulse and fancy, in conjunction with a certain natural apparatus? But it is absurd to suppose that he who looks from heaven upon earthly things would desire to look from such a distance upon the bodies of men and ants, and would not rather consider the nature of the guiding principles, and the source of impulses, whether that be rational or irrational.
And if he once look upon the source of all impulses, it is manifest that he would behold also the difference which exists, and the superiority of man, not only over ants, but even over elephants. For he who looks from heaven will see among irrational creatures, however large their bodies, no other principle than, so to speak, irrationality; while among rational beings he will discover reason, the common possession of men, and of divine and heavenly beings, and perhaps of the Supreme God Himself, on account of which man is said to have been created in the image of God, for the image of the Supreme God is his reason.
Source: Against Celsus (New Advent)