Now that He did not teach us such things by some visible operation, Himself presiding over the work, as we may see in matters of bodily teaching, no one would gainsay whose nature is not altogether animal and brutish. But still it has been said that our first knowledge of such arts is from Him, and, if such is the case, surely He Who endowed our nature with such a faculty of conceiving and finding out the objects of our investigation was Himself our Guide to the arts. And by the law of causation, whatever is discovered and established by conception must be ascribed to Him Who is the Author of that faculty. Thus human life invented the Art of Healing, but nevertheless he would be right who should assert that Art to be a gift from God. And whatever discovery has been made in human life, conducive to any useful purposes of peace or war, came to us from no other quarter but from an intelligence conceiving and discovering according to our several requirements; and that intelligence is a gift of God. It is to God, then, that we owe all that intelligence supplies to us. Nor do I deny the objection made by our adversaries, that lying wonders also are fabricated by this faculty. For their contention as to this makes for our own side in the argument. For we too assert that the science of opposites is the same, whether beneficial or the reverse; e.g. in the case of the arts of healing and navigation, and so on. For he who knows how to relieve the sick by drugs will also know, if indeed he were to turn his art to an evil purpose, how to mix some deleterious ingredient in the food of the healthy. And he who can steer a boat with its rudder into port can also steer it for the reef or the rock, if minded to destroy those on board. And the painter, with the same art by which he depicts the fairest form on his canvas, could give us an exact representation of the ugliest. So, too, the wrestling-master, by the experience which he has gained in anointing, can set a dislocated limb, or, should he wish to do so, dislocate a sound one. But why encumber our argument by multiplying instances? As in the above-mentioned cases no one would deny that he who has learned to practise an art for right purposes can also abuse it for wrong ones, so we say that the faculty of thought and conception was implanted by God in human nature for good, but, with those who abuse it as an instrument of discovery, it frequently becomes the handmaid of pernicious inventions. But although it is thus possible for this faculty to give a plausible shape to what is false and unreal, it is none the less competent to investigate what actually and in very truth subsists, and its ability for the one must in fairness be regarded as an evidence of its ability for the other.