Chapter 11
11.
11. The thirty spokes unite in the one nave; but it is on the empty space (for the axle), that the
use of the wheel depends. Clay is fashioned into vessels; but it is on their empty hollowness, that their use depends. The door and windows are cut out (from the walls) to form an apartment; but it is on the empty space (within), that its use depends. Therefore, what has a (positive) existence serves for profitable adaptation, and what has not that for (actual) usefulness.
, 'The Use of what has no Substantive Existence.' The three illustrations serve to set forth the freedom of the Tâo from all pre-occupation and purpose, and the use of what seems useless.