Ying and Yang

In Chinese philosophy the yin and yang (Simplified Chinese: 阴阳; traditional Chinese: 陰陽; pinyin: yīnyáng) are generalized descriptions of the antitheses or mutual correlations in human perceptions of phenomena in the natural world, combining to create a unity of opposites in the theory of the Taiji. The term liang yi (Simplified Chinese: 两仪; traditional Chinese: 兩儀; pinyin: liǎngyí, lit. "two mutually correlated opposites"), also known as yin and yang or heaven and earth, has a similar meaning.

The dual concepts of yin and yang which describe two primal opposing but complementary principles or cosmic forces said to be found in all non-static objects and processes in the universe. This seemingly paradoxical concept is the cornerstone of most branches of Chinese philosophy, as well as traditional Chinese medicine.