Thirty spokes meet in the hub,
but the empty space between them
is the essence of the wheel.
Pots are formed from clay,
but the empty space within it
is the essence of the pot.
Walls with windows and doors
form the house,
but the empty space within it
is the essence of the home.
The tao that can be told is not the eternal Tao The name that can be named is not the eternal Name. The unnamable is the eternally real. Naming is the origin of all particular things. Free from desire, you realize the mystery. Caught in desire, you see only the manifestations. Yet mystery and manifestations arise from the same source. This source is called darkness. Darkness within darkness. The gateway to all understanding.