Chapter XX.--In What Respect Philosophy Contributes to the Comprehension of Divine Truth.
As many men drawing down the ship, cannot be called many causes, but one cause consisting of many;--for each individual by himself is not the cause of the ship being drawn, but along with the rest;--so also philosophy, being the search for truth, contributes to the comprehension of truth; not as being the cause of comprehension, but a cause along with other things, and co-operator; perhaps also a joint cause. And as the several virtues are causes of the happiness of one individual; and as both the sun, and the fire, and the bath, and clothing are of one getting warm: so while truth is one, many things contribute to its investigation. But its discovery is by the Son. If then we consider, virtue is, in power, one. But it is the case, that when exhibited in some things, it is called prudence, in others temperance, and in others manliness or righteousness. By the same analogy, while truth is one, in geometry there is the truth of geometry; in music, that of music; and in the right philosophy, there will be Hellenic truth. But that is the only authentic truth, unassailable, in which we are instructed by the Son of God. In the same way we say, that the drachma being one and the same, when given to the shipmaster, is called the fare; to the tax-gatherer, tax; to the landlord, rent; to the teacher, fees; to the seller, an earnest. And each, whether it be virtue or truth, called by the same name, is the cause of its own peculiar effect alone; and from the blending of them arises a happy life. For we are not made happy by names alone, when we say that a good life is happiness, and that the man who is adorned in his soul with virtue is happy. But if philosophy contributes remotely to the discovery of truth, by reaching, by diverse essays, after the knowledge which touches close on the truth, the knowledge possessed by us, it aids him who aims at grasping it, in accordance with the Word, to apprehend knowledge. But the Hellenic truth is distinct from that held by us (although it has got the same name), both in respect of extent of knowledge, certainly of demonstration, divine power, and the like. For we are taught of God, being instructed in the truly "sacred letters"  by the Son of God. Whence those, to whom we refer, influence souls not in the way we do, but by different teaching. And if, for the sake of those who are fond of fault-finding, we must draw a distinction, by saying that philosophy is a concurrent and cooperating cause of true apprehension, being the search for truth, then we shall avow it to be a preparatory training for the enlightened man (tou gnostikou); not assigning as the cause that which is but the joint-cause; nor as the upholding cause, what is merely co-operative; nor giving to philosophy the place of a sine quâ non. Since almost all of us, without training in arts and sciences, and the Hellenic philosophy, and some even without learning at all, through the influence of a philosophy divine and barbarous, and by power, have through faith received the word concerning God, trained by self-operating wisdom. But that which acts in conjunction with something else, being of itself incapable of operating by itself, we describe as co-operating and concausing, and say that it becomes a cause only in virtue of its being a joint-cause, and receives the name of cause only in respect of its concurring with something else, but that it cannot by itself produce the right effect.
Although at one time philosophy justified the Greeks,  not conducting them to that entire righteousness to which it is ascertained to cooperate, as the first and second flight of steps help you in your ascent to the upper room, and the grammarian helps the philosopher. Not as if by its abstraction, the perfect Word would be rendered incomplete, or truth perish; since also sight, and hearing, and the voice contribute to truth, but it is the mind which is the appropriate faculty for knowing it. But of those things which co-operate, some contribute a greater amount of power; some, a less. Perspicuity accordingly aids in the communication of truth, and logic in preventing us from falling under the heresies by which we are assailed. But the teaching, which is according to the Saviour, is complete in itself and without defect, being "the power and wisdom of God;"  and the Hellenic philosophy does not, by its approach, make the truth more powerful; but rendering powerless the assault of sophistry against it, and frustrating the treacherous plots laid against the truth, is said to be the proper "fence and wall of the vineyard." And the truth which is according to faith is as necessary for life as bread; while the preparatory discipline is like sauce and sweetmeats. "At the end of the dinner, the dessert is pleasant," according to the Theban Pindar. And the Scripture has expressly said, "The innocent will become wiser by understanding, and the wise will receive knowledge."  "And he that speaketh of himself," saith the Lord, "seeketh his own glory; but He that seeketh His glory that sent Him is true, and there is no unrighteousness in Him."  On the other hand, therefore, he who appropriates what belongs to the barbarians, and vaunts it is his own, does wrong, increasing his own glory, and falsifying the truth. It is such an one that is by Scripture called a "thief." It is therefore said, "Son, be not a liar; for falsehood leads to theft." Nevertheless the thief possesses really, what he has possessed himself of dishonestly,  whether it be gold, or silver, or speech, or dogma. The ideas, then, which they have stolen, and which are partially true, they know by conjecture and necessary logical deduction: on becoming disciples, therefore, they will know them with intelligent apprehension.