…that the purer and clearer the supernatural and divine light the more dark is it in the soul, and that it is less so when less pure.
But this may be easily explained; if we keep in mind the saying of the philosopher that supernatural things are more dark to the understanding the more clear and evident they are in themselves. A likeness taken from ordinary natural light will make this quite clear. A sunbeam coming in by the window is perceived the less distinctly the more pure and free from atoms and motes the air is, but the more of these there are, the more distinct is the beam to the eye. The reason is that we do not see light itself, but by means of it we see the objects on which it falls, and these reflecting it, the light itself becomes a visible object; had it not struck them it would itself remain invisible. On the contrary, if we think well of it, the line of the beam would be plunged in deeper darkness, for not only would it not be visible but it would absorb what faint light there might be, for as we suppose there are no objects whatever to reflect it. Thus this ray of divine contemplation, transcending as it does the natural powers, striking the soul with its divine light, makes it dark, and deprives it of all the natural affections and apprehensions which is previously entertained in its own natural light. Under these circumstances, the soul is left not only in darkness but in emptiness also, as to its powers and desires, both natural and spiritual, and in this emptiness and darkness is purified and enlightened by the divine spiritual light, but it does not imagine that it has it; yea, rather, it thinks itself to be in darkness, as we have said of the sunbeam which, though passing through the middle of a room, cannot be seen if the air is quite pure and there are no objects on which it may fall.
However, the spiritual light falling on the soul if there is anything to reflect it, that is, upon any matter, however small, of perfection, which presents itself to the understanding or a decision to be made as to the truth or falsehood of anything, the soul sees it at once and understands the matter more clearly than it ever did before it entered into this darkness. In the same way the soul discerns the spiritual light which is given it that it may easily recognize its own imperfection; thus, the ray of light in a room, which we said was of itself not so visible, but when the hand or any other object is held before it, the hand is seen forthwith, and the light of the sun is known to be there.