Now let us hear what it is that he invites us to learn, that we may ascertain from him how we are to know God, although he thinks that his words are beyond the capacity of all Christians. “Let them hear,” says he, “if they are able to do so.” We have then to consider what the philosopher wishes us to hear from him. But instead of instructing us as he ought, he abuses us; and while he should have shown his goodwill to those whom he addresses at the outset of his discourse, he stigmatizes as “a cowardly race” men who would rather die than abjure Christianity even by a word, and who are ready to suffer every form of torture, or any kind of death.
He also applies to us that epithet “carnal” or “flesh-indulging,” “although,” as we are wont to say, “we have known Christ after the flesh, yet now henceforth we know Him no more,” and although we are so ready to lay down our lives for the cause of religion, that no philosopher could lay aside his robes more readily. He then addresses to us these words: “If, instead of exercising your senses, you look upwards with the soul; if, turning away the eye of the body, you open the eye of the mind, thus and thus only you will be able to see God.”
He is not aware that this reference to the two eyes, the eye of the body and the eye of the mind, which he has borrowed from the Greeks, was in use among our own writers; for Moses, in his account of the creation of the world, introduces man before his transgression as both seeing and not seeing: seeing, when it is said of the woman, “The woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise;” and again not seeing, as when he introduces the serpent saying to the woman, as if she and her husband had been blind, “God knows that on the day that you eat thereof your eyes shall be opened;” and also when it is said, “They ate, and the eyes of both of them were opened.” The eyes of sense were then opened, which they had done well to keep shut, that they might not be distracted, and hindered from seeing with the eyes of the mind; and it was those eyes of the mind which in consequence of sin, as I imagine, were then closed, with which they had up to that time enjoyed the delight of beholding God and His paradise.
This twofold kind of vision in us was familiar to our Saviour, who says, “For judgment I have come into this world, that they which see not, might see, and that they which see might be made blind,” — meaning, by the eyes that see not, the eyes of the mind, which are enlightened by His teaching; and the eyes which see are the eyes of sense, which His words do render blind, in order that the soul may look without distraction upon proper objects. All true Christians therefore have the eye of the mind sharpened, and the eye of sense closed; so that each one, according to the degree in which his better eye is quickened, and the eye of sense darkened, sees and knows the Supreme God, and His Son, who is the Word, Wisdom, and so forth.
Source: Against Celsus (New Advent)