That this is little comprehended is evident from the common saying “What is love?” What it is, is not known for the reason that love is not manifest to the understanding, and the understanding is the receptacle of the light of heaven. What comes into that light is interiorly seen, for what a man thinks, that he has knowledge of? For this reason, a man says that this or that is in the light of his understanding, also that he sees this to be so; likewise, he prays that he may be enlightened and illumined by God. Moreover, there is spiritual light to which natural light corresponds, and it is from this that one says, with reference to his understanding, that he sees. and a wise man prays to be enlightened and to be illumined by God, that is, that he may understand. Man, therefore, can form no idea concerning love, for this reason, that although the understanding, by means of the thought, presents itself to be seen, love does not. And yet love is the very soul or life of thought, and if love be taken away thought grows cold and dies, like a flower deprived of heat; for love enkindles, vivifies, and animates thought. Set your mind at work and consider whether you can think apart from some affection that is of love; and you will find in your own case that it is impossible. From this it is plain that love is the life of the understanding and of thought therefrom; and what is the life of the understanding and of thought therefrom is also the life of the whole man; for it is the life of all the senses and of all motions, thus the life of the organs by means of which senses and motions exist. That it is also the life of the rest of the viscera, will be seen in what follows.