Although material force in the universe integrates and disintegrates, and attracts and repulses in a hundred ways, nevertheless the principle (li) according to which it operates has an order and is unerring. As an entity, material force simply reverts to its original substance when it disintegrates and becomes formless. When it integrates and assumes form, it does not lose the eternal principle (of Change). The Great Vacuity of necessity consists of material force. Material force of necessity integrates to become the myriad things. Things of necessity disintegrate and return to the Great Vacuity.

(Chang Tsai)