Under heaven all can see beauty as beauty only because there is ugliness. All can know good as good only because there is evil. Therefore having and not having arise together. Difficult and easy complement each other. Long and short contrast each other. High and low rest upon each other. Voice and sound harmonize each other. Front and back follow one another.
By following this simple path, you become extraordinary, unfathomable, a being of profound cosmic subtlety. You outlive time and space by realizing the subtle truth of the universe.
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.
In order to contract, It is necessary first to expand. In order to weaken, It is necessary first to strengthen. In order to destroy, It is first necessary to promote. In order to grasp, It is necessary first to give. This is called subtle light. The weak and the tender overcome the hard and the strong.
Clay is fashioned into vessels; it is on their empty hollowness that their use depends. Doors and windows are cut out to make a dwelling, and on the empty space within, its use depends. Thus, while the existence of things may be good, it is the non-existence in them that makes them serviceable.
The master does his job and then stops. He understands that the universe is forever out of control, and that trying to dominate events goes against the current of the Tao.