What are Emptiness and Non-Being in Taoism? 什么是虚无

It is synonymous with Wu (Non-Being).

Sound Categories, as quoted in Pronunciation and Meaning of All Scriptures, states: "Wu is Emptiness and Non-Being."

The concept of Wu originated with Laozi.

What are Emptiness and Non-Being in Taoism?

Laozi’s The Dao is formless, nameless, soundless, colorless and boundless; it generates all things and is infinite. The Dao is equivalent to Wu. Chapter 40 of the Dao De Jing states: "All things under heaven are born of Being, and Being is born of Non-Being." Wu and the Dao share a similar meaning.

Zhuangzi referred to the Dao as Wu.

Being and Non-Being are relative, yet the Dao is absolute and unconditioned; as the ontology, the Dao is Wu Wu (Non-Non-Being). Based on Daoist thought, Taoism evolved the theory of taking Non-Being as the ontology into its fundamental theological tenet.

Baopuzi: Inner Chapters·The Ultimate Principle states: "Being is born of Non-Being, and form is established by the spirit." All things under heaven are but dwellings with no abode, manifestations of Non-Being, which is the primal origin. Cheng Xuanying regarded all the diverse phenomena in the world as illusory: all things are born of the Dao, whose essence is void, emptiness and non-being, the profound mystery. Chen Jingyuan interpreted emptiness and non-being with the primordial Qi: Being is the One, and the One is the primordial Qi—all things under heaven are born of the primordial Qi. The primordial Qi belongs to Being; it has radiance yet no form, and though it has light and vision, it emerges from emptiness and non-being. Emptiness and non-being are the very essence of the Dao.

Taoist cultivation and nourishment theories embody the doctrine of taking emptiness and non-being as the foundation in their cultivation principles. Emptiness and non-being being the essence of the Dao, abiding in emptiness and non-being becomes a vital content of learning the way of immortals and attaining the Dao. The Classic of the Supreme Lord Laozi on the Origin of Emptiness and Spontaneous Nature states: A virtuous person learning the Dao must thoroughly understand emptiness, non-being and spontaneity. Those who abide in emptiness and non-being can attain the way of spontaneity; they no longer ascend to heaven, but remain in the mortal world to transform, witness life and death, and be teachers to all people.

There is the doctrine of the "Thirteen Emptinesses and Non-Beings" in Taoist cultivation and nourishment theories, consisting of thirteen principles: emptiness, non-being, purity, stillness, subtlety, frugality, softness, weakness, humility, diminution, timeliness, harmony and moderation, with emptiness and non-being as the essence of health preservation. The Dao has no physical form; being calm and serene as if non-existent is called emptiness. Diminishing the mind and abandoning intention, casting away hypocrisy and renouncing desire is called non-being.

See the entry on "Thirteen Emptinesses and Non-Beings".