Yin and yang
Yin and yang (, ), also yinyang or yin-yang, is a concept that originated in Chinese philosophy, describing an opposite but interconnected, self-perpetuating cycle. Yin and yang can be thought of as complementary and at the same time opposing forces that interact to form a dynamic system in which the whole is greater than the assembled parts and the parts are as important for the cohesion of the whole.In Chinese cosmology, the universe creates itself 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 and contractive in nature, while "yang" is repelling, active and expansive in principle; this dichotomy in some form, is seen in all things in nature—patterns of change and difference. For example, biological, psychological and 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 traits and Yang as sharp and masculine.
''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