Thirty spokes share a single hub;
it is the empty space in the center that makes the wheel useful.
Clay is shaped into a vessel;
it is the empty space inside that makes the vessel useful.
Doors and windows are cut to make a room;
it is the empty space within that makes the room useful.
Thus, being is what we work with,
non-being makes it useful.
Considering the physical body and shen (soul/consciousness), the physical body represents existence and being. It is like a wheel, vessel, or room. In contrast, shen is like air, empty space, and non-being. The physical body is what we work with when we feel and do, but shen (our mental state) is the most useful. In other words, we cultivate shen through our body.
Translated by Chiyan Wang
