It appeared also to him that he apprehended this supreme being, and that he gained a firm knowledge of it by that which was his own essence. It was therefore clear to him that his essence was something incorporeal without any material quality; and whatever material thing he apprehended by his outward sense, was not in reality his essence; but that it was something of an incorporeal substance, whereby he apprehended that absolute and perfect being that is necessarily and of itself existent. Having thus learnt that his real essence was not a corporeal substance perceived by his senses and compassed about by his skin, his body seemed to him something altogether contemptible, and so he wholly addicted himself to the contemplation of that noble essence whereby he apprehended that noble and necessarily existent being. Then he considered within himself, whether this noble essence could possibly be dissolved, corrupted, and vanish altogether, or whether it were of perpetual duration. Now he knew that corruption and dissolution were properties of bodies, and consisted in putting off one form and putting on another; as for instance when water is changed into air and air into water, or when herbs are turned into earth or ashes, and earth into herbs--for this is the true notion of corruption. But an incorporeal being, independent of body and altogether free therefrom, cannot be liable to corruption. Having thus quite assured himself that his real essence could not be corrupted, he desired to know in what condition it would be itself when it left the body and was separated therefrom; but now he knew that it was not so, until the body was no longer a fit instrument for its use. Therefore weighing in his mind all his apprehensive faculties, he saw that every one of them apprehended its object, sometimes potentially, sometimes actually--as when the eye is shut or turns itself away from the visible object, it is potentially apprehensive--which means, though it does not actually apprehend it at present, yet is able to do so for the time to come. And when the eye is open and turned toward the effect, it is actually apprehensive, which means, it apprehends it at present. And so it is with all the other faculties. Furthermore he saw that if any of these faculties never actually apprehended its proper object, yet so long as it is potentially apprehensive, it has no desire to apprehend any particular object, because it has no knowledge thereof, as is seen in a man who is born blind. But if it did ever actually apprehend, and becomes afterwards potentially apprehensive, it is inclined to apprehend its object actually, because it has been acquainted with the object and is intent upon it, as a man, who has before enjoyed his sight, continually desires visible objects after he is blind; and the more glorious, perfect, and beautiful the object is, the more his desire increases and the greater is his grief for the loss.