The dominant theory of classical elements, held by the Hindu, Japanese, and Greek systems of thought, is that there are five elements, namely Earth, Water, Air, Fire, and a fifth element known variously as Idea, Void "quintessence" or Aether (the term "quintessence" derives from "quint" meaning "fifth"). In Greek thought the philosopher Aristotle added aether as the quintessence, reasoning that whereas fire, earth, air, and water were earthly and corruptible, since no changes had been perceived in the heavenly regions, the stars cannot be made out of any of the four elements but must be made of a different, unchangeable, heavenly substance.[1]. The Greek five elements are sometimes associated with the five platonic solids.
The
Greek
classical elements are fire
(
),
earth
(
),
air
(
),
and water
(
).
They represent in Greek
philosophy, science,
and medicine
the realms of the cosmos
wherein all things exist and whereof all things consist. The ancient
Greek word for element (stoicheion)
literally meant "letter (of the alphabet)", the basic unit
from which a word is formed.
Plato mentions the elements as of pre-Socratic origin, a list created by the Ionian philosopher Empedocles (ca. 450 BC). Empedocles called these the four "roots"; Plato seems to have been the first to use the term "element (stoicheion)" in reference to air, fire, earth, and water.[2] According to Aristotle in his Physics:
Air is primarily wet and secondarily hot.
Fire is primarily hot and secondarily dry.
Earth is primarily dry and secondarily cold.
Water is primarily cold and secondarily wet.
One classic diagram (right) has one square inscribed in the other, with the corners of one being the classical elements, and the corners of the other being the properties. The opposite corner is the opposite of the these properties, "hot - cold" and "dry - wet". Of course, some of these qualities are predicated on a Mediterranean climate; those living further north would be a lot less likely to describe air as being hot, or earth as being dry.
According to Galen, these elements were used by Hippocrates in describing the human body with an association with the four humours: yellow bile (fire), black bile (earth), blood (air), and phlegm (water).
The concept of the classical elements proved extremely persistent in Europe, lasting through the Middle Ages to the early modern era. Just as the Aristotelian dogma was related to the Greek world view, the idea of classical elements in the Middle Ages composed a large part of the medieval world view. The Roman Catholic Church supported the Aristotelian concept of aether because it supported the Christian view of earthly life as impermanent and heaven as eternal.
In the philosophy of the Seven Chakras there are correspondences to the five elements as shared by both Hinduism and Buddhism as well as two other elements:
Sahasrara (Crown): Thought/Space
Ajña (Third Eye): Light/Dark
Vishuddhi (Throat): Ether/Sound
Anahata (Heart): Air
Manipura (Navel): Fire
Svadhisthana (Sacral): Water
Muladhara (Root): Earth
Main article: Wu Xing

In Taoism there is a similar system of elements, which includes metal and wood, but excludes air, which is replaced with qi, which is a force or energy rather than an element. In Chinese philosophy the universe consists of heaven and earth, heaven being made of qi and earth being made of the five elements (in the Chinese view, the attributes and properties of the Western and Indian Air element are equivalent to that of Wood, where the element of Ether is often seen as a correspondent to Metal). The five major planets are associated with and named after the elements: Venus is gold, Jupiter is wood, Mercury is Water, Mars is Fire, and Saturn is Earth. Additionally, the Moon represents Yin, and the Sun represents Yang. Yin, Yang, and the five elements are recurring themes in the I Ching, the oldest of Chinese classical texts which describes an ancient system of cosmology and philosophy. The five elements also play an important part in Chinese astrology and the Chinese form of geomancy known as Feng shui.
The doctrine of five phases describes two cycles of balance, a generating or creation (生, shēng) cycle and an overcoming or destruction (克/剋, kè) cycle of interactions between the phases.
Generating
Wood feeds fire;
Fire creates earth (ash);
Earth bears metal;
Metal collects water;
Water nourishes wood.
Overcoming
Wood parts earth;
Earth absorbs water;
Water quenches fire;
Fire melts metal;
Metal chops wood.
There are also two cycles of imbalance, an overacting cycle (cheng) and an insulting cycle (wu).