Xu (虚): Emptiness
The Zhuangzi's working term for the state of stillness: 'the Dao gathers in emptiness' — and the one warning attached to it: stillness without emptiness is just sitting while racing (zuochi).
The term
虚 (xū) — empty, insubstantial, hollowed out. In the Zhuangzi it is the working state of contemplative practice: the mind’s condition when it has stopped imposing and begun receiving. It is the single most important technical term behind both xinzhai and zuowang.
The original text
The term is defined in the xinzhai passage of Renjian shi (ch. 4), which closes its instruction in three stages:
“Unify your intention. Listen not with the ears but with the mind; listen not with the mind but with qi. Listening stops at the ears; the mind stops at matching. Qi is what is empty and awaits things. The Dao gathers in emptiness. Emptiness is the fasting of the mind.”
And moments later, the passage’s most quoted image:
“Look into the closed room: the empty room gives rise to white light, and good fortune rests there. If the mind does not rest there, this is called sitting while racing (坐驰).”
What the text claims
- Emptiness is receptivity. Qi is defined as “what is empty and awaits things” (虚而待物) — the ability to receive without pre-forming. The Dao “gathers” (集) where this receptivity is present: emptiness is not the absence of content but the condition that lets content arrive unforced.
- Emptiness is the definition of xinzhai. The passage makes the terms identical: 虚者，心斋也 — fasting of the mind is emptiness. The discipline of fasting (removing) and the state of emptiness (having removed) are one movement.
- The white light. 虚室生白 — “the empty room gives rise to white light” — is the passage’s image of the settled state: clarity arising of itself in the emptied mind. Traditional readings treat it as an image of the mind’s natural luminosity in stillness; some modern commentators read it more concretely as a description of visual phenomena arising in deep quiet. Both readings are recorded here; the text supports the image without settling its interpretation.
- The named failure: 坐驰. “Sitting while racing” — the body still, the mind galloping. This is the Zhuangzi’s own term for counterfeit sitting: posture without emptiness. It matters because it is the earliest warning that sitting alone is not the practice — emptiness is.
Historical development
- Zhuangzi (ch. 4): emptiness as the state where the Dao gathers; the origin of the term’s contemplative use.
- Later Daoist manuals (Qingjing Jing, Zuowang lun): the term becomes the standard description of the goal-state — “empty and clear,” “still and empty” — with the same claim: clarity arises from removal, not acquisition.
- Neo-Confucian usage: Zhu Xi and his school borrow the vocabulary cautiously — quiet sitting “empties” the mind of scattered thought, though the Confucian goal (moral clarity) differs from the Daoist one (release of self).
Modern research boundary
No clinical research addresses “emptiness” as a contemplative state; the modern literature’s nearest constructs (non-attachment, decentering, reduced self-referential processing) are correlates of other meditation forms and are not evidence about xu as described here. The claim that emptiness produces clarity is traditional; it is not tested, and this page does not present it as tested.
Editorial synthesis
Xu is the tradition’s answer to the question “what should the mind do in sitting?” — and the answer is: stop doing, become empty, and the Dao gathers. The image-pair the tradition left us — the empty room’s white light, and the seated racer — remains the most economical diagnosis tool in Chinese contemplative literature: light in the room means the mind rests; racing while seated means it doesn’t.
Sources
- Zhuangzi ch. 4 (Renjian shi): 'The Dao gathers in emptiness. Emptiness is the fasting of the mind' (唯道集虚。虚者，心斋也)
- Zhuangzi ch. 4: 'Look into the closed room — the empty room gives rise to white light' (瞻彼阕者，虚室生白，吉祥止止)