We join spokes together in a wheel,
but it is the center hole that makes the wagon move.
We shape clay into a pot,
but it is the emptiness inside that holds whatever we want.
We hammer wood for a house,
but it is the inner space that makes it livable.
We work with being,
but non-being is what we use.
–Lao Tzu, Tao te Ching, verse 11 translated by Stephen Mitchell
