Man knows that love is but he does not know what love is. He knows from common speech that love is, as when it is said, he loves me, the king loves his subjects and the subjects love their king, the husband loves his wife, and the mother her children, and conversely; also, this or that man loves his country, his fellow-citizens, his neighbour; similarly, about things abstracted from person, as for example, one loves this or that thing. But although [the word] love is so generally used in speech, scarcely anyone knows what love is. Because one is unable, when he reflects upon love, to form for himself any idea of thought about it, he says either that it is not anything, or that it is merely something inflowing as a result of sight, hearing, touch and conversation, and thus affecting him. He is quite unaware that love is his very life, not only the common life of his whole body and of all his thoughts, but also the life of all their individual things. A wise man can perceive this, as for instance when it is said: "If you remove the affection which is of love, can you think anything or do anything? Do not thought, speech and action grow cold to the extent that the affection which is of love grows cold? And do they not grow warm to the extent that this affection grows warm?" But a wise man perceives these things, not from knowledge that love is the life of man, but from experience that this is what happens.