The source of all light is in the eye. If there were no eyes in this world the sun would not be light. You evoke light out of the universe. In the same way, you, by virtue of having a soft skin, evoke hardness out of wood. Wood is only hard in relation to a soft skin. It's your ear drum that evokes noise out of the air. You, by being this organism call into being the whole universe of light and color and hardness and heaviness and everything.