埏埴以為器,當其無,有器之用。
鑿戶牖以為室,當其無,有室之用。
故有之以為利,無之以為用。
Translation
Thirty spokes share one hub;
It is the empty space that makes the wheel useful.
Knead clay into a vessel;
It is the empty space that makes the vessel useful.
Cut doors and windows for a room;
It is the empty space that makes the room useful.
Therefore, while "being" provides the benefit,
"Non-being" provides the utility.