Generality and Relativity of the Yin-Yand Property
The yin-yang property is referred to as possessing "generality," in that it is not limited to specific things. It exists generally in various things or phenomena in the natural world and represents the two aspects of mutual opposition as well as mutual relation. The sentence "The water and fire are the manifestations of yin and yang" (from Chapter 5 of Plain Questions) shows that the ancients wisely thought of the features of "water" and "fire," and took them as the standard or norm to distinguish the yin-yang property of things or phenomena, and used them to induce and classify these things.
All things or phenomena that are warm or heat-related, ascending, bright, excited,light, motional, functional, hyperfunctional, etc., pertain to the category of yang.Those that are cool or cold, descending, dim, depressive, heavy, static, material, hypofunctional, etc. , pertain to the category of yin. Heaven pertains to yang because of its upper position and earth to yin because of its lower position. Water pertains to yin because of its form, its cold nature and downward flowing, While fire relates to yang due to its lack of form, and because of its hot nature and upward flaming. In the body, yang transforms into qi while yin constitutes the form, this means the transformative functions pertain to yang, while the material body pertains to yin. Therefore, in TCM, the qi that has the function of promoting and warming the body is called "yang-qi" while the qi that has the functions of nourishing and moisturizing the body is called "yin-qi. " The visceral figured bodies are attributed to yin and the visceral functional activities are attributed to
yang.
It is clear that the movement of celestial bodies, the alternation of day and night and the four seasons, the changes of cold and hot or warm and cool, or the different organization and functional states of the body, all develop and change in mutual opposition and mutual relation, and can be attributed to yin and yang respectively according to their specific properties.
The relativity of the yin-yang property refers to the fact that the property is not absolute and unchangeable, but is relative and flexible for concrete things or phenomena. It can be determined by comparison with its opposite aspects, and be affected by certain conditions such as time, place, etc.
Generally speaking, the relativity of yin-yang is manifested in one of two ways.
First, yin and yang can be mutually transformed under certain circumstances. For example, in the body, material refers to yin while functionality refers to yang. Under certain physiological conditions, however, material can be transformed into energy in order to promote functional activities, and function can be transformed into material. Moreover,due to this transformation, it is then possible to ensure the normal development of life activities.
The other manifestation of yin-yang relativity is yin and yang's unlimited divisibility. Two aspects of the yin and yang of something can be divided as the scale of classification is changed i. e. , any aspect of yin or yang can also be divided into yin and yang. For example, daytime pertains to yang and night to yin. However, daytime or night also can be divided into yin and yang. In daytime, morning is the yang within yang, and afternoon is the yin within yang. At night, the former half of the night is the yin within yin,and the latter half of the night is the yang within the yin.
Another example comes from the heart and the kidney. According to the nature and features of the human body's visceral functional activities, the heart and kidney are of zang-viscera and pertain to yin. However, the heart is located in the upper and possesses the feature of fire, while the kidney is located in the lower and is attributed to water-organ. Thus, the heart pertains to yang and the kidney pertains to yin. Even the heart and kidney themselves can be sub-divided into yin and yang i. e. , heart-yin and heart-yang,and kidney-yin and kidney-yang.
The condition of dividing into yin and yang within yin and yang indicates that these properties exist not only in all things or phenomena generally, but also that they can be sub-divided within themselves. This relativity of yin-yang property reflects the regularity and complexity of the concept.
To summarize, things and phenomena in the natural world and universe can be generalized as two large classes, and the interior of things can be divided into two aspects of yin and yang. Furthermore, any aspect of yin or yang of a thing can be sub-divided again into yin and yang. This has great significance, as it assists in revealing the essentials and law of contradictions of things or phenomena by generalizing and analyzing the movement and change of things' occurrence and development. Thus, Chapter 5 in Plain Questions states. "Yin and yang can be divided down to ten, and then further down to one hundred, to a thousand, to ten thousand, and to a number so great as defies calculation; yet in essence all these are but one. "
The crux of the matter is that the various changes of all things can be generalized by the law of unity of opposites between yin and yang. The occurrence, development, and change of all things are the result of mutual struggle and movement change between the two aspects of yin and yang in the interior of things. Such mutual struggle and movement change are mainly manifested in the aspects of opposition and restriction, mutual dependence and utilization, wane-wax and equilibrium, and mutual transformation between yin and yang. In the application of the theory of yin-yang in TCM, the above-mentioned four relationships are to generalize and explain the body's physiological activities, pathological changes, and to guide clinical diagnosis and treatment.
