Historical illustration of Chinese metal casting. The Five Phases (wu xing)—metal, wood, fire, water, and earth—can be used to describe and classify relationships and processes at work in the realm of science.

Four kinds of organizing principles formed the basis of traditional science in China: Heaven and Man, yin–yang duality, the wu xing or Five Phases, and qi. They were combined to build a complex theoretical structure for the relationships and patterns that Chinese doctors and scientists found in nature.

Just as it did elsewhere in the premodern world, scientific thought in China emerged with early attempts to think about the natural world abstractly and systematically. One of the earliest attempts to organize the phenomenological and natural world was the ancient divination text known today as the Book of Changes (I Ching). Although today writers find antecedents for many modern scientific ideas in this text, to early Chinese science and many other areas of Chinese philosophy, the Book of Changes was a way to organize and classify natural phenomena—the first step in any scientific tradition.

Because many of the terms used in this system of classification came from ancient mystical traditions of shamanism and divination (the practice that seeks to foresee future events or discover hidden knowledge, usually by the interpretation of omens or by the aid of supernatural powers), assigning them strict definitions is particularly challenging for Western students of Chinese life and science. The terms yin and yang, wu xing, and qi have been the subject of much debate in the vain quest for precise Western equivalents. But the fact that these terms are still used in schools of traditional medicine in China testifies to their usefulness in Chinese science.

Organizing Principles

From these beginnings emerged four kinds of organizing principles to form the basis of all premodern Chinese scientific thought: Heaven and Man, yin–yang duality, the wu xing or Five Phases, and qi.

The relationship between Heaven and Man is central in Chinese scientific thought and is expressed in several ways. In astrology and astronomy not only is man part of the natural world, but also heaven reflects and responds to the human world below. The fenshu (field allocation theory maps) of the second century BCE divided the heavens first into political regions in the human world and then into specific agencies within the imperial government. Specific constellations corresponded to specific government ministries, and the unpredicted appearance of an object in a ministry’s constellation was interpreted as an ominous sign.

Chinese medicine interprets the relationship between nature and man in terms of both microcosm and macrocosm. The human body can be interpreted as both a natural world in miniature and as an integral part of a larger natural world. As a result, ailments are diagnosed as either dysfunctional imbalances within the microcosm of the human body or as imbalances between the human body and the external world.

Light and Dark, Male and Female

Yin and yang were terms used in early Chinese thought to express the basic duality of all phenomena. The earliest examples can be found in the Book of Changes, and some scholars claim that conscious expression of the notion of polar dualities can be seen in the art of the Shang dynasty (1766–1045 BCE). The terms yin and yang are used to express the observation that many things have a dual nature: both light and dark, hot and cold, male and female. The Chinese characters for yin and yang literally describe the dark and light sides of a hill. In medicine the terms are used most frequently as adjectives, qualifying things based on their observed qualities, such as yin qi or yang qi.

Metal, Wood, Water, Fire, and Earth

Chinese science uses the Five Phases (wu xing) to further describe and classify phenomena, especially processes. An emphasis on process and interaction is a distinguishing characteristic of Chinese science and medicine. Whereas much of early Western medicine stressed the mechanical relationships of organs and other body parts, Chinese medicine looked at how the many characteristics of the body and nature interact and sought ways to describe and classify these interactions. The Five Phases, often confused with the Aristotelian “elements,” are the metal phase, wood phase, water phase, fire phase, and earth phase. The word xing means “to do or act, action, activity.” The Five Phases or activities of qi are often used to explain cyclical transformations found in medicine and elsewhere.

The Five Phases and Qi

Qi is the most important term in Chinese science and one of the most difficult to translate. Today most scholars choose not to translate the term, but some of the better Western equivalents for the term qi include “vital energy or substance” or “matter-energy.” The science scholar Nathan Sivin explains that qi is simultaneously “what makes things happen in stuff” and “stuff in which things happen” (Sivin, 1977). Qi can either take form and become visible and substantial or can be an agent that activates processes and influences their development. As a result, the concept of qi is central to Chinese medicine. Qi circulates through the body as a kind of vital energy, but, unlike blood, it has no substance. Qi instead activates and influences how blood and the organs function. Often qi is beneficial, but sometimes qi, especially from an outside source, can upset the balance within the body to create an ailment. The responsibility of the Chinese doctor is to diagnose this imbalance and take corrective measures.

The Five Phases describe five aspects of qi and their cyclical relationship. The wood phase does not describe the texture of qi but rather qi that is growing and developing a certain potential. When qi moves on to the next phase, fire, it realizes this potential and becomes active. The fundamental sequence of the Five Phases is sometimes called the “cycle of mutual production.” The sequence of the cycle is based on early empirical observations, but in practice its use is much more theoretical. When wood is burned it produces fire; fire produces ash (earth); ores from the earth become metal; water condenses on cold metal; and wood can grow with water. The logic behind this sequence is more mnemonic than practical. What was important to the Chinese doctor or scientist was the relationship between the different aspects of qi.

All of these basic concepts—Heaven and Man, yin and yang, the Five Phases, and qi—can be combined to build a complex theoretical structure for the relationships and patterns that Chinese doctors and scientists found in nature. Even though Chinese and Western thinkers confronted the same physical universe—human bodies in China differ only superficially from bodies elsewhere in the world—Chinese science and medicine developed a unique theoretical structure for understanding the phenomena in the universe, a system of understanding that Chinese scientists refined for almost two thousand years.

Further Reading

Ho Peng Yoke. (1985). Li, qi, and shu: An introduction to science and civilization in China. Seattle: University of Washington Press.

Nakayama, S., & Sivin, N. (Eds.). (1973). Chinese science: Explorations of an ancient tradition. Cambridge, MA: MIT Press.

Needham, J. (1969.) The grand titration: Science and society in East and West. Toronto: University of Toronto Press.

Needham, J., Wang Ling, & de Solla Price D. (1986). Heavenly clockwork: The great astronomical clocks of medieval China (2nd ed.). Cambridge, U.K.: Cambridge University Press.

Sivin, N. (Ed.). (1977). Science and technology in East Asia. New York: Science History.

Temple, R. (1986). The genius of China: 3,000 years of science, discovery, and invention. New York: Simon & Schuster.

Source: Forage, Paul. (2009). Science, Traditional. In Linsun Cheng, et al. (Eds.), Berkshire Encyclopedia of China, pp. 1929–1931. Great Barrington, MA: Berkshire Publishing.

The yin–yang symbol evokes the dark and light sides of a hill; the yin–yang theory is one of four principles that helped to shape the study of science in China.

Science, Traditional (Chuánt?ng k?xué ????)|Chuánt?ng k?xué ???? (Science, Traditional)

Download the PDF of this article