The seeds of plants, the food we need to sustain our lives, sprout in the dark earth. Life begins and grows within the darkness of a mother's womb. Light, as well as dark, can be a giver and sustainer of life. Light reflects on the lenses of our eyes so that we may see the world in which we live. It nourishes plants, animals, and humans, which all have a place within the cycle of life.
Light provides warmth, and, as fire, it both destroys and cleanses.
In effect, it aids nature in her process of reclamation back into the dark by illuminating physical and amorphous images which may block the path to self realization. Too much light can be the blinding flame of many nuclear explosions. If cast in total darkness a plant will wither and die. Darkness marks the inner road of the psyche and leads us on the path of self reclamation, yet light illuminates the truth and characterizes the moment of self discovery. As the Taoist said, any extreme becomes its own opposite, in the end.