Most people know the 5 elements as: metal ('Jin'), water ('Shui'), wood ('Mu'), fire ('Huo') and earth ('Tu').
The usage and understanding of 5 elements are subject to the different era of human history and of course subject to one's interpretation. Well, your mileage might be different from mine. One can view the 5 elements as in their physical stage or in the metaphysics stage or mere symbols. As the 5 elements represent a lot of things.
For example:
1. Astronomers consider it as the 5 planets, namely: Jupiter (wood - Xing), Venus (metal - Jin Xing), Mercury (water - Shui Xing), Mar (fire - huo xing) and Saturn (earth - tu xing).
2. Strategists consider it as the direction. Namely: east (wood), west (metal), south (fire), north (water) and centre (earth).
3. Of course, 4 pillars of destiny practitioners would consider 5 elements as seasons, namely: wood belongs spring, fire belongs summer, earth belongs to the 4 seasons, metal belongs to autumn and waster belongs to winter.
4. In terms of colour: wood is green, fire is red, earth is yellowish brown, metal is white, and water is black.
5. In terms of the 4 celestial animals and Feng Shui, wood represents green dragon, fire represents scarlet bird, metal represents white tiger and water represents tortoise.
6. Chinese medicine practitioners would consider 5 elements as:
a. wood represents eye, fire represents tongue, earth represents mouth, metal represents nose, and water represents ear;
b. wood represents liver, fire represents heart, earth represents spleen, metal represents lung, water represents kidney;
c. wood represents gallbladder, fire represents small intestine, earth represents stomach, metal represents large intestine, and water represents urinary bladder;
d. wood represents tendon, fire represents vein, earth represents flesh, metal represents skin and hair, and water represents marrow.
7. In term of behaviour, wood represents happiness, fire represents joy, earth represents desire, metal represents angry, and water represents sadness.
8. In term of Chinese musical notes, wood represents 'jue', fire represents 'zhi', earth represents 'gong', metal represents 'shang', and water represents 'yu'. (Note: Chinese has 5 notes pentatonic musical scales rather than the 7 notes normal musical scales, and gong-shang-jue-shi-yu is equivalent to 1 Do, 2 Re, 3Mi ,5 So ,6 La of modern musical note - yes, 4 Fa and 7 Si are missing)
9. In terms of favours, wood represents sour, fire represents spicy, earth represents sweet, metal represents bitter, and water represents salty.
10. The Chinese scholar statesman, Dong Zhong Shu (2nd Century B.C.), considered them as humanity ('Ren' - wood) , righteousness ('Yi' - metal), manner ('Li' - fire), wisdom ('zhi' - water) and trust ('xin' - earth) - the 5 virtues .
11. Another Chinese scholar Wang An Shi (1021-1086) considered them as the contradiction phenomenon among general affairs that shows both mutually generating and controlling.
How can't the Chinese believe in and derive the 5 elements? I tried to offer one of the solutions here.
In Yi Xici Zhuan:
Ancient Chinese were great observers and they have been doing just
that. By looking up at the sky and the movement of Sun, moon and
stars; by looking down here on earth, the presence of day and night -
all these lead to the belief in Yin and Yang. Of course, not to
mention:
Moon vs. Sun
Man vs. Woman
Hard vs. Soft
Tall vs. short
Light vs. darkness
Similarly, 5 elements are also like this. By examining the sky and
earth, we can notice that when the Big Dipper/Plow points to the
East, then it is spring on Earth.
What would happen in spring? One can feel the warm spring breeze, and
witness the growth of plant. By this, ancients observed all these
study and concluded that: the movement of 'qi' in spring is a kind
of spreading/stretching out. Plants and animals stretching out and
wake up from hibernation.
In winter, the Plow points to the North, the climate is cold, and
animal goes into hibernation. The movement of winter is a kind of
contrasting inward.
Looking up at the sky at the change of pointing direction of the Big
Dipper/Plow which corresponds with the change of season on earth and
the observation of plants and animals behaviour have lead the Chinese
to deduce that in a year, there are changes in term of 'spreading
out', 'up-rising', 'smooth and steady', 'gathering inward' and
'descending' - all these lead the Chinese to come up with the idea
of the symbolic 5 elements.
Of course, the study and observation of ancient Chinese on the 5
elements are not scientific but base on metaphysics, that is why the
5 elements are really symbols. There are of course wrong or mistaken
concept in the Chinese belief of the 5 elements, and the Chinese
tends to view the explanation 5 elements as too simplified. Well, in
a time where scientific knowledge is not available yet, we cannot
blame the ancient Chinese for being too simple.