Without a doorway, the room cannot be entered; and without windows light cannot enter, and is therefore full of darkness. Such is the utility of existence and non-existence. Through sight colours may be seen, but too much colour blinds us. Apprehending the tones of sound, too much sound might make us deaf, as too much flavour deadens taste.
Though thirty spokes may form the wheel, it is the hole within the hub which gives the wheel utility. So shall the Seventh High Caulbearer be according to his position. It is not the clay the potter throws, which gives the pot its usefulness, but the space within the shape from which the pot is made. Neither is it the clay nor the shape, nor the design that gives the pot is value; but that which it contains, or does not contain. Even the air within the empty vessel must be considered.