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Yin–Yang Theory: a Basis of Traditional Chinese Medicine

As a grounding principle in Traditional Chinese Medicine (TCM), yin-yang theory is an important diagnostic tool that addresses balance and health in a person’s whole system (body-mind-spirit) in clinical practice. Often Yin and Yang are distilled into a system of opposites, vying for dominance. However, the principle of yin and yang in TCM is much more dynamic than the simple relationship opposition may suggest. There are four key aspects of yin and yang relationality:

  • Opposition
  • Interdependence
  • Mutually Consuming
  • Intertransformational

First, let's take a look at the idea of yin and yang as opposites to each other. Yin relates to dense matter, while yang relates to energy. Yin is connected with night, the moon, depth, darkness, earth and soil, the northern direction, to name just a few associations. Yang, on the other hand is associated with day, sun, the surface of things, light, heavens and air, and the southern direction. In Chinese Medicine, various parts of the body are considered more yin or yang. Below the waist is said to be yin in nature, while above the waist is yang. This correlates with proximity to the earth or the heavens. A yin-type person tends to be introverted, restful, quiet, and thin, while a yang individual is more active, outgoing, boisterous, and robust.

While yin and yang are in opposition, they are also interdependent upon each other. It is a system of counterbalance. Try this exercise: find a partner, stand facing each other with approximately one step between you, then grasp each other's hands or wrists. Now, keeping your feet planted on the ground, lean away from each other . To make this even more dynamic, continue facing each other and grasping hands or wrists, but start turning in a circle with your bodies still leaning away from each other. As you lean back, it is the opposition of your partner's weight that helps you to remain upright. If your partner dominates in strength, you will both fall in that person's direction; should you dominate, then you are likely to fall in your direction. Instead, your opposite forces make it possible for each other to continue standing or spinning, as the case may be. (This is a great exercise to do with a loved one to remind yourselves of how much you rely upon one another!) Yin and yang are very much like this counterbalancing activity: south cannot exist without north, nor dark without light. It is the existence of one that even allows us to differentiate and define the other. Similarly, the surface of an object is understood in light of its depth. The sun makes it possible for us to see the moon in its many phases.

Although interdependent, yin and yang weave a delicate balance in which one is capable of consuming the other. Yang is not more apt to consume yin, nor is yin more able to consume yang. Either can be weaker or stronger than the other. However, the relationship that occurs when one is weak or strong sheds light on the interdependence of yin and yang qualities. When yin is dominant, it forces yang into weakness; a dominance of yang forces yin into a state of weakness. If there is a weakness of yin, yang appears dominant; similarly, if yang is weak, then yin will appear stronger. When yin dominates an individual, s/he will tend to be apathetic, exhibit a weak voice, lack expression, and show signs of cold and/or damp. The person displaying weakness of yang will be pale in complexion and show a strong dislike or even fear of cold because the internal fire is damaged and unable to warm the system adequately. When yang is preponderant, the individual may be very aggressive, prone to yelling, red in the eyes and complexion, hot headed with cold feet. If yin is weak, the individual may experience spontaneous sweating (especially at night), insomnia, restlessness, a persistent low-grade sore throat, and inappropriate weight loss; in this instance yin is unable to cool the yang fire sufficiently.

Finally, yin and yang are each capable of transforming into the other. Night turns to day, cold turns to warm, matter turns to energy, so on and so forth. It is important to note that these states of transformation require very important circumstances. First, the seed for change must exist in order for an external factor to have an impact on the system. Secondly, the seed must be ready for the change: it must be ready for gemination. So, for the lethargic person to become active, s/he must have the physical energy necessary, as well as the desire to turn that energy in movement.

It is clear from the dynamic relationship of yin and yang, that TCM conceives of the human body as an intricately woven system of balance, displayed in the turning of day into night, activity into rest, superficial into deep, upper into lower. Our bodies are not systems of opposites vying for dominance, but rather aspects that feed, nurture, and create space for the other, with each part connected to the whole. It is in this way that I approach individuals with whom I work: always looking at the whole system as it relates to each part and each part as it relates to the system. Whether it be how your calf muscles relate to your feet, quadriceps, abdominal muscles, or neck, how your shoulders relate to your wrists, or how your emotions relate to your physical self, it is all connected in these extraordinary things we call bodies!

May peace and health be upon you!