Yin-yang is a frame of thinking that can be considered a fundamental basis of Eastern philosophy. In ancient Far East Asia, people categorised everything of nature as yin or yang, including natural phenomenon such as human physiology. Yang(陽) is a masculine element, yin(陰) is a feminine element and the two represent the countless symmetries found in nature. Just as there is a sky for the earth, a sun for the moon, a man for a woman and strength for softness, every phenomena in human societies and the universe can be identified in relative terms. The concept of reducing these to a plus and a minus to explain natural events is the concept of yin and yang.
For example, consider a hill in the sunlight. The bright side is called the “yang place” and the opposite, dark side is called the “yin place”. Thus, light is yang, darkness is yin. That is not all. The air that is heated by sunlight becomes warm and rises, while cold air sinks because it is heavy. Yang symbolises heat, lightness and upward, active movement while yin symbolises cold, heaviness and downward, sluggish movement. But that does not mean that yin is bad and yang is good. The reason being, everything that counters each other in nature coexists and forms a balance. Also, as time passes, the sun will move from the east to the west, making the sunny place dark and the dark place sunny. Yin-yang is a law that shows the relativity of nature very well. It shows that everything is relative to each other even if they seem like opposites, forming a harmonious balance and cycle.
Balance forms harmony and nature always seeks harmony. For example, traditional Korean and Chinese medicine is based on the concept that the reason why diseases occur is because of the balance of yin and yang in the human body being broken. To restore the balance, acupuncture and herbal remedies are used, restoring good health. A broken harmony is due to one side being greater than the other as yin and yang form a zero-sum game. This means that as one side waxes, the other side wanes and vice versa, with the sum of the two being equal at all times. But this does not mean that yin and yang oppress and fight each other. Instead, the two rely on each other despite being opposites. In this world, there is no light without darkness. There is no forwards without backwards and no life without death. For instance, if there were only men (yang) in this world, the human race would be wiped out in one generation. But if yin and yang coexist to help each other and form a union, they give birth to a new generation. Nature always exists as a perfectly balanced coexistence of two polarities. When yin and yang form a balance they form something even greater than their sum, which is harmony.
In ancient China and Korea, there are five, not four, basic elements (Japan also has five but they are slightly different). In the East, these five elements are called “oh hang (오행, 五行)” in Korean and “wu xing” in China. These are (read in Korean): hwa (火, fire), su (水, water), mok (木, wood), geum (金, metal), and toh (土, earth). When you combined with the theory of Yin and Yang, the concept is known as the Yin-Yang and the Five Elements theory (eum yang oh hang sul, 음양오행설). Wu Xing is quite different from the Four Elements of ancient Greece in that it explains the changes in life and the universe rather than being the building blocks of matter (“wu xing” translates to “five ways”). To first understand Wu Xing, one must understand that each element is more of an abstract concept than the actual object. For example, “mok” does not mean wood per se, but rather a symbol for the life force of a growing tree.
There are two relationships between the elements in Wu Xing: Creation (상생, 相生) and Destruction (상극, 相剋). Creation refers to the cyclic principle of what generates what, and Destruction refers to what overcomes and represses what. The Creation and Destruction of Wu Xing are as follows:
목생화(木生火): Wood creates Fire. Wood feeds Fire.
화생토(火生土): Fire creates Earth. Fire makes ash which becomes Earth.
토생금(土生金): Earth creates Metal. Earth bears Metal.
금생수(金生水): Metal creates Water. Metal carries Water.
수생목(水生木): Water creates Wood. Water nourishes Wood.
목극토(木剋土): Wood beats Earth. Wood takes roots in Earth.
Human beings have believed that all matter can be divided into basic elements for a very long time. Although we now know that the basic building block of the universe is atoms, what did ancient people believe matter was made of?
In ancient Greece, the seat of Western culture, it was believed that everything was made from the four elements: earth, fire, water and air. According to Aristotle, every element has a primary and secondary characteristic, with the four characteristics being hot, cold, dry and wet. Air is primarily wet and secondarily hot, fire is primarily hot and secondarily dry, earth is primarily dry and secondarily cold and water is primarily cold and secondarily wet. He also spoke of a fifth element (quintessence) beyond the four elements. The name of the fifth element is aether and it is a pure and heavenly element that cannot be corrupted like the earthly four elements. Furthermore, it was thought that aether was the element of the sky and stars were composed of it as they were heavenly, not earthly.
The four classic elements of ancient Greece had an impact not only on physics and chemistry, but also on philosophy and culture (the concept of the four elements is popular in modern games too). The most interesting example of these is a theory by Hippocrates, the father of Western medicine, that states that the human body is composed of four bodily fluids (humours) and an imbalance between the humours caused diseases. The four humours are yellow bile (fire), black bile (earth), blood (air) and phlegm (water). Furthermore, he believed that the four humours affected personalities too. For example, an excess of black bile (“melan chole” in Greek) would cause a person to become introspective and think negatively, leading to depression or “melancholy”. This is quite possibly the first medical records on clinical depression.
The four classic elements of ancient Greece can also be found in ancient Egypt and many other ancient civilisations. It also had a significant influence on alchemy in the Middle Ages.