Chinese five elements

In Chinese Daoism thought, things in nature can be classified in five types: metal, wood, water, fire, earth (金、木、水、火、土) (generally referred in that order). These five elements (五行) are not just the materials that the names refer to, but rather metaphors for describing how things interact and relate to each other.

Daoism promotes a production chain between the elements, as well as a control chain between them. In the production chain, wood produces fire; fire produces earth; earth produces metal; metal produces water; water produces wood. In the control chain, wood controls earth; earth controls water; water controls fire; fire controls metal; metal controls wood. If one lays out these circular chains in a circle, then one chain outlines a pentagon and the other chain outlines a five pointed star pattern. These interactions and relationships form a framework for different schools of philosophy, belief and discipline. The interaction of five elements becomes a tool that helps scholars sort out observations and empirical data. Based on observations of how things interact, things are classified into one of the five elements so that they fit into the observed pattern. Then one can draw high level conclusions or predictions based on the element types.

In Chinese medicine, each organ of the human body is associated with an element. The liver, tendon, eyes are of the wood element type; heart, blood vessels, tongue are fire element type; spleen, muscle, mouth are earth element type; lungs, skin, hair, nose are metal element type; kidney, bone, ears are water element type; etc. This classification helps in adjusting the balance in the body.

The study of herbal therapy classified the properties and effects of each herb according to empirical observations on how the herb affects the body. For example, if one herb causes dry mouth and chapped skin, it would be classified as "fire" type. The element type of the herbs can serve a useful purpose when designing a herbal cocktail remedy because the "fire" ingredient can be controlled by adding some "water" ingredients; or addition of "metal" ingredients can assist the "water" ingredients to do their job in controlling the "fire" etc. A "water" type herb or food is believed to benefit a "wood" type organ etc. The principle of the five elements is used extensively in Chinese medicine.

The study of Feng Shui focuses on how the five elements type of people, objects, landscapes etc. affects the harmony of the environment. Even Chinese astrology are based on the five elements. The five major planets are named after the five elements: Venus is metal; Jupiter is wood; Mercury is water; Mars is fire; Saturn is earth. The model is used in attempts to make sense out of the unknowns, such as fortune telling and many other things. Of course, if there is not a pattern in the data, the result is unreliable regardless of how good the sorting tool is.