"The appearance of the Great De follows only the Dao. When describing the Dao as an object, it is ambiguous whether it is there or not. Though it is ambiguous, it seems there is an image; though it is indistinct, it seems there is an object; though it is so profound and obscure, it seems there is an essence; its essence is so real and truthful, it gives faith. From ancient times till present, its name has never been forgotten; so observe the initiation and derivation of all objects. How do I know the nature of all objects? Because of this."

— Dr. Yang, Jwing-Ming, The Dao De Jing, A Qigong Interpretation