The Usefulness of the Empty
The Text
三十辐共一毂，当其无，有车之用。埏埴以为器，当其无，有器之用。凿户牖以为室，当其无，有室之用。故有之以为利，无之以为用。
Thirty spokes share one hub; it is the hole that makes the wheel useful. Clay is shaped into a pot; it is the hollow that makes the pot useful. Doors and windows are cut for a room; it is the empty space that makes the room useful. So advantage comes from what is there; usefulness comes from what is not.
Reading it
The most practical chapter in the book for anyone who owns things. Everything we call a product is bought for its hole: the wheel turns on nothing, the pot holds nothing, the room shelters nothing. Things are useful exactly where they are absent.
对拥有物品的人最实用的一章。一切产品买的是它的「空」：轮转于无、器盛于无、室居于无。物的用处恰在它缺席之处。
Clear one surface at home until it is completely empty. Leave it for a week and watch what it does to the room.
把家里一个台面清到全空，放一周。看它对整个房间做了什么。