Wu (无) is regarded as the original source or ontological existence of the world in classical Chinese thinking. Laozi claimed that “you (有) is born out of wu.” This concept was further developed by He Yan（？-249）, Wang Bi（226-249）, and other thinkers of the Wei and Jin dynasties, who maintained that heaven, earth, and all things in the world originate from wu. No specific being, they argued, can be the original source or ontological existence of another being, much less of the world. The formation and existence of everything depend on wu, which is the fundamental source that transcends all tangible beings. Only an intangible and unidentifiable ontological existence gives countless specific beings their functions.

All things under heaven exist by means of you. The formation and existence of you originate from wu. To maintain you we must return to wu. (Wang Bi: Annotations on Laozi)