Qi or, as spelled in Wade-Giles, ch'i (氣 ; in pinyin: qì; ki in Japanese; gi in Korean), in English very often spelled as chi. Qi is a fundamental concept of everyday Chinese culture, most often defined as "breath" (for example, the colloquial Mandarin Chinese term for "weather" is tiān qi, or the "breath of heaven") and, by extension, "life energy" or "spiritual energy" that is part of everything that exists. References to it or similar philosophical concepts as a type of metaphysical energy that sustains living beings are used in many belief systems, especially in Asia.
Philosophical conceptions of qi date from the earliest recorded times in Chinese thinking. One of the most important early figures in Chinese mythology is Huang Di or the Yellow Emperor. He is storied to have been the culture hero who collected and formalized much of what subsequently became known as Traditional Chinese Medicine. Although the concept of qi has been very important within all Chinese philosophies, the way that these philosophies describe qi have been very different and conflicting.
One basic difference has been the question of whether qi exists as a force separate from matter or whether qi arises from matter. Buddhists and Taoists have tended toward the former belief, with Buddhists in particular, believing that matter is an illusion.
By constrast, the Neo-Confucians sharply criticized the notion that qi exists separate from matter, and viewed qi as a arising from the properties of matter. Most of the theories of qi as a metaphor for the fundamental physical properties of the universe that we are familiar with today were systematized and promulgated in the last thousand years or so by the school known as the Neo-Confucians. Knowledge of the theories they espoused was eventually required by subsequent Chinese dynasties to pass their civil service examinations.
Theories of Traditional Chinese Medicine assert that the body has natural patterns of metabolic energy associated with it that circulate in channels called meridians in English. Symptoms of various illnesses are seen many times as the product of disrupted or unbalanced energy movement through such channels. Traditional Chinese Medicine attempts to relieve these symptoms by balancing the flow of qi in the body using various techniques. Some of these techniques include herbal medicines, special diets, physical training regimens (qigong) and acupuncture, which uses fine metal needles inserted into the skin to reroute or balance qi.
Traditional Asian martial arts theories also discuss qi. For instance, internal systems attempt to cultivate and direct this energy during combat as well as to ensure proper health. Many other martial arts include some concept of qi in their philosophies.
The nature of qi is highly controversial, and the old controversy among Chinese philosophy as to the nature of qi still exists. Among some TCM practitioners, qi is merely a metaphor for biological processes similar to the Western concept of the soul, and there is no need to invoke new biology, much less new physics, to account for its effects. Others argue that qi involves requires some new physics or biology. Attempts to directly connect qi with some scientific phenonomenon have been attempted since the mid-nineteenth century. The philosopher Kang Youwei argued that qi was synonymous with the later abandoned concept of lumeniferous ether. Some in the early 21st century are attempting to link the concept of qi to biophotons. As of yet, science considers these claims of qi as an independent force to be unconvincing. Claims that control of qi allows one to transcend normal physical and biological processes are widely regarded as pseudoscience by the scientific establishment.
Views of qi as an esoteric force tend to be more prominent in the West, where it is often associated with New Age spritualism. They are less prominent in China, where traditional Chinese medicine is often practiced and considered effective, but in which esoteric notions of qi are considered to contradict Marxist notions of dialectic materalism.
The consensus among scientists is that the results claimed by martial arts students and patients of traditional Chinese medicine practitioners while real can be explained without invoking esoteric processes. In answer, most proponents of the effects of the cultivation of qi maintain that since modern scientific technologies have to this point been unable to create life out of organic chemicals in their laboratories, and that as qi is a metaphor for the energy of life itself, it is to be thereby demonstrated that the mechanisms of how the subject of such a metaphor would work so far elude the abilities of the scientific community to describe. Opponents argue that qi is merely a form of vitalism, a theory that was largely abandoned in the early 19th century.
The concept of qi appears often in Chinese fiction, in which a stock character is that of the kung fu master who has gained control of qi, to the point that he can alter the forces of nature. This character has entered Western consciousness through the martial arts film. Many have also remarked on the similarity between the concept of qi and that of the Jedi's Force in the Star Wars movies, and have suggested that George Lucas may have borrowed the concept.