Sclera other species share, but also to the fact that the human iris is relatively small and comprises a significantly smaller portion of the exposed eye surface compared to other animals. It is theorized that this adaptation evolved because of our social nature as the eye became a useful communication tool in addition to a sensory organ. It is believed that the conspicuous sclera of the human eye makes it easier for one individual to infer where another individual is looking, increasing the efficacy of this particular form of nonverbal communication. Animal researchers have also found that, in the course of
The Description of the Human Body soul. A sick or injured body does not do what we want or moves in ways we do not want. He believed the death of the body stopped it from being fit to bring about movement. This did not necessarily happen because the soul left the body. René Descartes believed the body could exist through mechanical means alone. This included digestion, blood circulation, muscle movement and some brain function. He felt we all know what the human body is like because animals have similar bodies and we have all seen them opened up. He saw the body as a machine.