The reason why the ill and weak and people physically delicate generally see visions is that by the lack of flesh, fat and blood the veins and tubes of the body and the organs of all the senses are free and not blocked as they are in a muscular person. Therefore, naturally, the senses become keen and man perceives more than what is within the ordinary range of perception. Also such a person, when asleep, perceives the impressions from the inner world, because during sleep the inner sense, which may be called the root of the senses, turns its back, so to speak, on the external world and so begins to see the world within.