TAO defined is not the constant Tao. No name names its eternal name. The unnamable is the origin of heaven and earth; named, it is the mother of the ten thousand things. Emptied of desire, we see the mystery; filled with desire, we see the manifestation of things. Two names emerge from a single origin, and both are called mysterious, and the mystery itself is the gateway to perception. Lao Tzu, Tao Te Ching