Yin and Yang Theory
The theory of yin and yang is the most fundamental concept of traditional Chinese medicine. One of the major beliefs of TCM is that all things in the universe are either yin or yang. However, there are no absolutes: nothing is ever all yin or all yang, but a balance between the two forces. For example, when day changes into night, it is an example of a yang object changing into a yin object; when winter turns into spring; it is considered a changing from yin to yang.
These forces are opposite and yet complementary, and share an interdependent relationship without yin, there would be no yang, and without yang, no yin
Yang is generally associated with items or concepts that are bright, warm, and in motion. Yin is generally associated with objects or ideas that are dark, still and cold. Any given frame of reference can be divided into opposite factors, i.e. a yin side and a yang side. For instance, a human body can be divided into exterior and interior sections; the temperature can be divided into hot or cold; time can be divided into day or night; animals can divided into hot-blooded or cold-blooded, and so on.
