Reciprocity and Divisibility in Yin/Yang Theory

Reciprocity and Divisibility in Yin/Yang Theory
by Ziki Dekel, ATH Editor of Acupuncture/TCM

The law of yin and yang is the natural order of the universe, the foundation of all things, mother of all changes, the root of life and death.

Chinese medicine is replete with numbered systems: the three treasures, the five elements, the eight principles, the fifteen types of qi. These multiplicities account for the variety of ways in which psychic and physiological phenomena manifest in the human body and help to define the medical system as a whole.

Underlying each one of these groups is the binary at the basis of Taoist philosophy and, in turn, Chinese medicine: yin and yang. Yin/Yang theory has it roots outside of medicine. It is unclear when the dichotomy was first formulated, but it is safe to assume that humans created a system of opposites based on their observations of cosmic events—day turned into night, summer into winter, young into old. Over time, yin/yang grew to encompass every sphere of human existence, from the physical to the spiritual life, ultimately reaching medicine.

The Yijing and the Daodejing, both early canonical Taoist works, describe yin/yang as a system of reciprocity and of infinite division, respectively. In applying yin/yang theory to Chinese medicine, it is helpful to focus on these two aspects. The language of reciprocity dispels the notion that yin/yang is a system of pure opposites: yin is not the antidote to yang, and yang is not the antidote to yin. Instead the two work together to make the whole of human existence. Chapter 5 of the Neijing Suwen reads: “Yang is the energy, the vital force, the potential, while yin is the substance, the foundation, the mother that gives rise to all this potential.” In biomedical terms, yin/yang in the human body manifests as structure and function. Just as there is no structure in the body without its function, there is no yin aspect in the body without its yang counterpart. The two balance each other, but they do not negate each other. 

While the structure/function binary is an important and useful application of yin/yang theory to medicine, there are many other ways in which we can understand how reciprocity applies to the theory. The Eight Principles of Chinese medicine include the yin/yang pairing along with three other pairs, each of which have a yin aspect and a yang aspect: interior (yin)/exterior (yang), empty (yin)/full (yang), and cold (yin)/hot (yang). Just as with structure/function, these pairings are considered as a unity. In their discussion of interior/exterior, which they translate as face (exterior) and interface (interior), Larre et al. write, “Looking at the fabric one must not take the face and interface separately but must see each as the articulation of the other. They are used to discern the two aspects of the same phenomenon—one superficial and the other deep.” One aspect has no meaning unless it is joined or connected with its other because both aspects are describing the same thing.

Infinite division or divisibility in yin/yang theory is not as clear cut as reciprocity, because it requires us to constantly reposit that which is being divided. By drawing a transverse plane, the human body can be divided into equal yin and yang parts; the lower body is yin and the upper body is yang. Yet, if we take the yin part by itself, it too can be divided by a transverse plane into upper yang and lower yin parts. Ted Kaptchuk write, “…within each Yin and Yang category, another Yin and Yang category can be distinguished. It is an extension of the logic that divides all phenomena into Yin and Yang aspects, allowing further division within aspects ad infinitum.” Through this process, the number of yin and yang parts grows exponentially and infinitely.

This example is rudimentary, but it offers a succinct entry into the application of yin/yang theory to the human body as it is applied in Chinese medicine. What makes yin/yang theory so useful and so fascinating is that any part of the body and any physiological phenomenon occurring within the body can be explained in yin/yang terms. In upcoming articles we will consider how yin and yang apply to basic anatomy and to the body’s organ systems.

About the Author

Ziki Dekel, L.Ac., our ATH Editor of Acupuncture/TCM, is a licensed New York State acupuncturist, nationally certified in acupuncture and Chinese herbal medicine. He came to acupuncture as a patient of the medicine, which propelled him to complete his training and apprenticeship in Chinese medicine. Prior to becoming an acupuncturist, Ziki received his B.A. from Brown University.Ziki is currently the Director of Galapagos Acupuncture, where he offers comprehensive care to patients in New York City. His research and practice interests focus on the treatment of cancer and autoimmune disorders with acupuncture and herbal medicine.