The beautiful appearance of the world of dreams, in whose creation each man is a complete artist, is the condition of all plastic art, indeed, as we shall see, an important half of poetry. We enjoy the form with an immediate understanding, all shapes speak to us, nothing is indifferent and unnecessary. - Nietzsche, The Birth of Tragedy (1871) Aristotle thought the blood in our veins just sat there. He wrote long before it was discovered that blood pumps through our veins. He thought the blood was still - except when we were moving, it sort-of splashed around inside us a bit. Like when you're holding a cup of water and walking. When we fall asleep, our bodies are still. The blood settles. He also thought our sensations caused reflections of the surface of the blood in our brains. When we look at a flower, our senses perceive the flower not as if the actual object was in our mind but as it reflects itself on our blood. When we are asleep and still, the left-ov...