Yin Yang Theory

The Yin Yang theory is a fundamental concept, not only for understanding Chinese medicine but within the entire culture. You can apply the idea of yin and yang everywhere. Although the basic concept may seem simple to many of us, it is ultimately a complex way of viewing human existence in a dynamic world. It is a way to understand the world around us, a world that emerges from the relationships between opposites, the yin and yang symbols.

Initially, the theory is a way of categorization. It is a collection of associations and categorizations. We often see lists of yin and yang elements, but because the principle can be applied to all elements in this universe, it would be an impossible task to provide a complete classification. The list would be endless. However, we must always introduce a nuance, and that is that of relativity. Every classification is relative. Therefore, it would also be wrong to say that something is absolutely Yin or Yang. Each object of categorization is related to what it is compared to, in this case, its opposite. Everything is relative, and we can only know things in relation to something else. Yin and yang are extremes of the same continuum. In addition, each object has the potential to become its opposite.

The yin and yang theory is a philosophical school of thought, a form of naturalism in which Nature is approached in a positive way. It is an inclusive way of looking at things, where the focus is not on controlling or subduing Nature but on acting in harmony with its inherent laws. The principle of complementarity leads to an alternating and pulsating interaction between the two principles, where something is never perfectly yin or perfectly yang. There is always a form of dominance of one over the other. Because yin and yang both have the same origin, they are equal to each other, and there can be no notion of one being better than the other.

You cannot see these concepts as purely logical entities or simple cosmological principles. It is not just a way of categorizing but also a way of qualifying. This means that there is a degree of gradation possible. It is not a static concept but a dynamic process. It is rarely a static 50-50 relationship; this is only a snapshot of the ongoing process. This dynamic process is at the core of the whole concept and can be found in the Book of Changes – the Yijing. In that sense, you could say that knowledge of the Yijing, and thus of the transformation and dynamic interplay between yin and yang, forms the basis of Chinese medicine.

Differentiation can be seen in the light of qualitative and quantitative overlap. Qualitatively, this means that in the classification of yang and yin, yang can be further subdivided into yang and yin, then further into yang and yin, and so on. The same applies to yin. An example of this is that the upper body is yang and the lower body is yin. Within this upper body (yang), the front is yin, and the back is yang. The right arm is yang, and the left arm is yin. The inside of the arm is yin, and the outside is yang. Quantitatively, on the other hand, is more about the degree of yin and yang seen from the perspective of cyclic phases. For example, 1 a.m. in the morning has less yang than 4 a.m. in the morning and less yang than 11 a.m. in the morning. The transition from one polarity to another is gradual and continuous.

Initially, this was a fourfold categorization of yang in yin, yin in yin, yin in yang, and yang in yang. Also known as young yin, full yin, young yang, and full yang. Yin and yang can form connections with each other. Something can be both yin and yang. How yin and yang further differentiate can be found in the Wuji – Taiji – YinYang – Wuxing – 10,000 things schema. After the four forms of pairing of yin and yang, you get the trigrams. Combined, these trigrams form the hexagrams, and there are 64 combinations of them. These hexagrams, that’s what the Yijing is. You could say that the Yijing is a language built from combinations of yin and yang.

If one thing should be clear, it’s that yin and yang are not fixed entities but are in a continuous play of change. It is not a static concept. The Taiji symbol does not stand still but is in continuous motion. Similar to the Hellenistic concept of ‘panta rhei,’ where everything flows. There is a permanent movement; everything is in a state of change. The only constant in the universe is that everything changes. This dynamism, that way of change, is what you want to learn to understand.

Of course, there are also processes that are more complex than can be described with a fourfold division. That’s why there has been further development into trigrams and hexagrams. With the 64 hexagrams being the ultimate differentiation, everything in our world can be described. Because everything in the universe can be described in terms of these hexagrams, you could say that everything is based on yin and yang. Yin and yang are phases in a cyclic movement where one is continually transformed into the other. It is a process of transformation. The relationship between these two is what you find in the Taiji symbol, and it symbolizes what is called the ‘interdependence’ of yin and yang. The Taiji symbolizes perfection and, by encompassing both pairs, possesses all the possibilities of the cosmos while emphasizing their interrelational nature.

Chinese medicine assumes that the human body has arisen from the blending of yin and yang. The Huang Di Nei Jing says: two types of qi attract each other to blend and form a physical entity. These yin-yang relationships can be found in the categorization of all phenomena and also of the aspects of the body. In addition to the regions of the body (see the example above of front and back / upper and lower), there is a classification of internal organs: the solid organs are yin (liver, heart, kidneys, spleen, lungs), and the hollow organs are yang (large and small intestine, gallbladder, stomach, bladder). This is known as the ZhangFu. Mapping the body in this way allowed a doctor to categorize the nature of a disease as active in a yin or yang region, influencing their approach to treatment.

Chinese traditional medicine ancient book

This covers the simple dichotomy of opposites. An example of a more complex differentiation is the classification of the body’s 12 channels, where 2×3 channels are yin and 2×3 channels are yang. This is known as the six divisions. Another excellent example of how the principles of yin and yang are used in medicine is the basic diagnostic method of the Ba Gang, or 8 principles. This method distinguishes the following themes: Is it yin or yang – is it external or internal – is it hot or cold – is it full or empty.

The principle is applied in various ways within Chinese medicine. It allows for the classification of the histological structures of the human body. It represents the relationship between structures and their functions. It categorizes pathogenesis, where we have a subdivision into excess of yin or yang and deficiency of yin or yang. It not only provides guidance in diagnosis.


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