Yin and yang

Originating in ancient Chinese philosophy, yin and yang (, , ) or yin-yang is the concept that there exist cosmic principles or forces that are opposite but complementary, which interact, interconnect, support and perpetuate each other. Together they form a dynamic system in which the whole is greater than the interdependent components, and both parts are essential for the cohesion of the whole.

In Chinese creation theory, the universe develops out of a primary chaos of primordial qi or material energy, organized into the cycles of yin and yang, force and motion leading to form and matter. "Yin" is retractive, passive, contractive and receptive in nature in a contrasting relationship to "yang" that is repelling, active, expansive and repulsive in principle; this dichotomy in some form, is seen in all things in nature and their patterns of change, difference and transformations. For example, biological, psychological and cosmological seasonal cycles, the historical evolution of landscapes over days, weeks, years to eons. The original meaning of yin was depicted as the northerly shaded side of a hill and yang being the bright southerly aspect. When pertaining to human gender, yin is associated to more rounded feminine characteristics and yang as sharp and masculine traits.

''Taiji'' is a Chinese cosmological term for the "Supreme Ultimate" state of undifferentiated absolute and infinite potential, the oneness before duality, from which yin and yang originate. It can be contrasted with the older ''wuji'' (). In the cosmology pertaining to yin and yang, the material energy which this universe was created from is known as ''qi''. It is believed that the organization of qi in this cosmology of yin and yang is the formation of the 10 thousand things between Heaven and Earth.

Included among these forms are humans. Many natural dualities (such as light and dark, fire and water, expanding and contracting) are thought of as physical manifestations of the duality symbolized by yin and yang. This duality, as a unity of opposites, lies at the origins of many branches of classical Chinese science, technology and philosophy, as well as being a primary guideline of traditional Chinese medicine, and a central principle of different forms of Chinese martial arts and exercise, such as baguazhang, tai chi, daoyin, kung fu and qigong, as well as appearing in the pages of the ''I Ching'' and the famous Taoist medical treatise called the ''Huangdi Neijing''.

In Taoist metaphysics, distinctions between good and bad, along with other dichotomous moral judgments, are perceptual, not real; so, the duality of yin and yang is an indivisible whole. In the ethics of Confucianism on the other hand, most notably in the philosophy of Dong Zhongshu ( 2nd century BC), a moral dimension is attached to the idea of yin and yang. The Ahom philosophy of duality of the individual self ''han'' and ''pu'' is based on the concept of the hun 魂 and po 魄 that are the yin and yang of the mind in the philosophy of Taoism. Provided by Wikipedia