413. (xiii) Wisdom or the understanding, from power given it by love, can be elevated, and can receive such things as are of light out of heaven, and perceive them. It has been shown in several places above that man has the power to perceive arcana of wisdom when he hears them. This faculty of man is what is called rationality and is the heritage of every man by creation. It is the faculty of understanding things interiorly and of forming opinions on what is just and right, and on what is good and true; and by it man is distinguished from beasts. This therefore is the meaning where it is said "the understanding can be elevated and can receive such things as are of light out of heaven, and perceive them". That this is so can be seen also in a certain image in the lungs, since the lungs correspond to the understanding. It may be evident in the lungs from their cellular substance, which is made up of bronchial tubes continued even to the minutest air-cells, which are receptacles for the air used in breathing; these are the things with which the thoughts act in conjunction by correspondence. This cell-like substance is such that ii. can be expanded and contracted in twofold fashion, in one with the heart, and in the other almost separate from the heart, in the former by arteries and veins which come from the heart alone, in the latter by the bronchial arteries and veins which come from the vena cava and aorta; these vessels are outside the heart. This takes place in the lungs because the understanding can be raised above its own particular love corresponding to the heart and can receive light from heaven. Yet when the understanding is raised above its own particular love, it does not go away from it, but derives therefrom an affection for knowing and understanding for the sake of some reward of honour, glory, or gain in the world. This quality clings to every love like a surface, on account of which love shines out to the surface, and with the wise shines through. These things concerning the lungs are brought forward to prove that the understanding may be elevated, and receive and perceive things that are of the light from heaven, for the correspondence is plenary. To see from correspondence is to see the lungs in accordance with the understanding, and the understanding from the lungs and so from both together to perceive proof.