Yin-Yang

In physiological activities, the transformation of substances into function or vice versa verifies the theory of the interdepending relation of yin and yang. Substance pertains to yin and function to yang, the former being the basis of the latter, while the latter is the reflection of the existence of the former and also the motive force for the production of the former. Only when there are ample nutrient substances can the functional activities of the zang-fu organs be healthy. Contrariwise, only when the functional activities of the zang-fu organs are sound are they able constantly to stimulate the production of nutrient substances. The coordination and equilibrium between substance and function are the vital guarantee of physiological activities. Hence we find in Neijing: "Yin is installed in the interior as the material foundation of yang, while 'yang remains on the exterior as the manifestation of the function of yin."

2.The inter-consuming-supporting and the inter-transforming relation of yin and yang

Consuming implies losing or weakening; supporting implies gaining or strengthening. The two aspects of yin and yang within a thing are not fixed, but in a state of constant motion. Owing to their mutual conflict and support, the losing or gaining of one aspect will inevitably influence the other. For instance, consuming of yin leads to gaining of yang, while