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.
LaoziWhen a country is in harmony with the Tao, the factories make trucks and tractors. When a country goes counter to the Tao, warheads are stockpiled outside the cities. There is no greater illusion than fear, no greater wrong than preparing to defend yourself, no greater misfortune than having an enemy. Whoever can see through all fear will always be safe.
Laozi