Yin & Yang Theory
The logic underlying Chinese medical theory-a logic which assumes that a part can be understood only in its relation to the whole-can also be called synthetic or dialectical. In Chinese early naturalist and Taoist thought, this dialectical logic that explains relationships, patterns, and change is called Yin-Yang theory.
The Chinese characters for Yin and Yang are written here in the old style. Other characters in this book are simplified modern characters.
Although the Chinese identify the relationships between phenomena primarily by the patterns of Yin and Yang, another system of categorization, known as the Five Phases, was also in use in early China. In this system, Wood, Fire, Earth, Metal, and Water were seen as a set of emblems by which all things and events in the universe could be organized. Although the Five Phases categories permeate virtually every aspect of traditional Chinese thought, leaving a significant impression on Chinese medical theory, this influence is for the most part formal and linguistic in nature. The Five Phases proved too mechanical, while Yin-Yang theory, because of its greater flexibility, was much more practical for the Chinese physician. It accommodated clinical changes and theoretical developments that the tradition required in order to grow.
Yin-Yang theory is based on the philosophical construct of two polar complements, called Yin and Yang. These complementary opposites are neither forces nor material entities. Nor are they mythical concepts that transcend rationality. Rather, they are convenient labels used to describe how things function in relation to each other and to the universe. They are used to explain the continuous process of natural change. But Yin and Yang are not only a set of correspondences; they also represent a way of thinking. In this system of thought, all things are seen as parts of a whole. No entity can ever be isolated from its relationship to other entities; no thing can exist in and of itself. There are no absolutes. Yin and Yang must, necessarily, contain within themselves the possibility of opposition and change.
The character for Yin originally meant the shady side of a slope. It is associated with such qualities as cold, rest, responsiveness, passivity, darkness, interiority, downwardness, inwardness, and decrease.
The original meaning of Yang was the sunny side of a slope. The term implies brightness and is part of one common Chinese expression for the sun. Yang is associated with qualities such as heat, stimulation, movement, activity, excitement, vigor, light, exteriority, upwardness, outwardness, and increase.
Working with these ideas, Chinese thought and Chinese medical tradition have developed five principles of Yin and Yang.
1. All things have two aspects: a Yin aspect and a Yang aspect.
Thus, time can be divided into night and day, place into earth and heaven, season into inactive periods (fall and winter) and active periods (spring and summer), species into female and male, temperature into cold and hot, weight into light and heavy, and so on. Inside and outside, down and up, passive and active, empty and full are all examples of Yin-Yang categories. These qualities are opposites, yet they describe relative aspects of the same phenomena. Yin and Yang qualities exist in relation to each other.
In terms of the body, the front is considered Yin and the back Yang. The upper part of the body is considered more Yang than the lower part; the outer parts of the body (skin, hair, etc.) are more Yang than the inner Organs. The Yin and Yang of the body are often described metaphorically as the body's Water and Fire. Illnesses that are characterized by weakness, slowness, coldness, and underactivity are Yin; illnesses that manifest strength, forceful movements, heat, and overactivity are Yang.
The philosopher Zou Yen (c. 305-240 B.C.E.) describes this idea this way: "Heaven is high, the earth is low, and thus [Heaven and Earth] are fixed. As the high and low are thus made clear, the honorable and humble have their place accordingly. As activity and tranquillity have their constancy, the strong and the weak are thus differentiated.... Cold and hot season take their turn.... [Heaven] knows the great beginning, and [Earth] acts to bring things to completion.... [Heaven] is Yang and [Earth] is Yin."
2. Any Yin or Yang aspect can be further divided into Yin and Yang.
This means that 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. For example, temperature can be divided into cold (Yin) and hot (Yang), but cold can be divided further into icy cold (Yin) and moderately cold (Yang). In the body, the front of the trunk is Yin compared with the back, but the front can be divided further so that the abdomen is Yin in relation to the chest. Within a Yin illness characterized by Coldness there may be aspects of Yang such as sharp, forceful contractions. Within a Yang illness of Heat and hyperactivity there may be weakness and loss of weight, both Yin qualities.
Chuang Tzu (Zhuang Zi), the Taoist philosopher, (fl. probably between 400 and 300 B.C.E.) describes the unfolding of Yin and Yang, and the notion of the unity of opposites, in a radical paradoxical way: "There is nothing in the world greater than the tip of a hair that grows in the autumn, while Mount Tai is small. No one lives a longer life than a child who dies in infancy, but Peng Zu (who lived many hundred years) died prematurely."
3. Yin and Yang mutually create each other.
Although Yin and Yang can be distinguished, they cannot be separated. They depend on each other for definition. And the things in which Yin and Yang are distinguished could not be defined without the existence of Yin and Yang qualities. For instance, one cannot speak of temperature apart from its Yin and Yang aspects, cold and heat. Similarly, one could not speak of height unless there were both tallness and shortness. Such opposite aspects depend on and define each other.
Another example might be the relationship between a couple in which one partner can be (relatively) passive only if the other partner is (relatively) aggressive, and vice versa. Passivity and aggression can be measured only in comparison with each other. The activity (Yang) of the body is nourished by its physical form (Yin), and the physical form is created and maintained by the activity of the body. In illness, overactivity has meaning only in relation to a condition of underactivity, and vice versa.
Lao Tzu (Lao Zi), the reputed founder of Taoism, declares in the Tao-te Ching (or Dao-de Jing-the Classic of the Tao and Its Virtue):
Being and non-being produce each other;
Difficult and easy complete each other;
Long and short contrast each other;
High and low distinguish each other;
Sound and voice harmonize each other;
Front and back follow each other.
4. Yin and Yang control each other.
If Yin is excessive, then Yang will be too weak, and vice versa. If the temperature is neither too cold nor too hot, then both cold and hot aspects are mutually controlled and held in check. If it is too cold, then there is not enough heat, and vice versa. Yin and Yang balance each other.
In our example of the couple, the extent to which one partner can be aggressive depends on the extent to which the other is passive, and vice versa. They exert mutual control over each other. An illness of Fire in the body may be due to insufficient Water; an illness of Water may be due to insufficient Fire.
Lao Tzu alludes to this concept when he says:
He who stands on tiptoe is not steady.
He who strides forward does not go.
He who shows himself is not luminous.
He who justifies himself is not prominent.
He who boasts of himself is not given credit.
He who brags does not endure for long.
5. Yin and Yang transform into each other.
This principle is a formula for the nature of organic process. It suggests two types of transformations: changes that occur harmoniously, in the normal course of events, and the sudden ruptures and transformations characteristic of extremely disharmonious situations.
Because Yin and Yang create each other in even the most stable relationships, Yin and Yang are always subtly transforming into each other. This constant transformation is the source of all change. It is a give-and-take relationship that is life activity itself. In the dynamics of the body, the nature of transformation can be illustrated by the manner in which inhalation is followed by exhalation, or periods of activity and exertion must be succeeded by nourishment and rest. In normal life such regular transformations occur smoothly, maintaining a proper, healthy balance of Yin and Yang in the body.
In a relationship in which Yin and Yang are unbalanced for prolonged periods of time or in an extreme manner, the resulting transformations may be quite drastic. Harmony means that the proportions of Yin and Yang are relatively balanced; disharmony means that the proportions are unequal and there is imbalance. A deficiency of one aspect implies an excess of the other. Extreme disharmony means that the deficiency of one aspect cannot continue to support the excess of another aspect. The resulting change may be rebalancing or, if that is not possible, either the transformation into opposites or the cessation of existence.
To return to the couple, let's assume a disharmonious relationship in which one partner is excessively aggressive and the other excessively passive. This situation can have three possible outcomes: Either they sit down and talk it out, agreeing to a rearrangement of attitudes (i.e., they rebalance their relationship); or one day the passive partner gets fed up and waits for the other with an ax (i.e., a radical transformation of Yin into Yang occurs); or they separate, putting an end to the relationship.
In clinical practice, one of these three kinds of transformation is always possible. For example, when a patient has a pattern with very high fever and much sweating (considered an excess of Yang, or Fire), the patient may be in danger of suddenly going into shock (an extreme Yin, or Cold, condition). This is because Yang cannot continue to exist in such extreme relation to Yin without some transformation occurring. Either a gradual transformation, a rebalancing, must take place-medication and healing; or a radical transformation will occur-shock; or Yin and Yang will separate and existence will cease-death.
Lao Tzu describes the transformation process poetically:
In order to contract,
It is necessary first to expand.
In order to weaken,
It is necessary first to strengthen.
In order to destroy,
t is necessary first to promote.
In order to grasp,
It is necessary first to give.
And also:
People hate to be orphaned, the lonely ones, and the unworthy.
And yet kings and lords call themselves by these names.
Therefore it is often the case that things gain by losing and lose by gaining.
Yin-Yang theory is well illustrated by the traditional Chinese Taoist symbol (Figure 1). The circle representing the whole is divided into Yin (black) and Yang (white).
The small circles of opposite shading illustrate that within the Yin there is Yang and vice versa. The dynamic curve dividing them indicates that Yin and Yang are continuously merging. Thus Yin and Yang create each other, control each other, and transform into each other.
FIGURE 1
Traditional Yin-Yang Symbol
Because of the pervasive influence of Yin-Yang theory on Chinese thought and culture, the Chinese understand and explain events differently than does the West. The idea of causation, central to Western thinking, is almost entirely absent. Aristotle (384-322 B.C.E.), in his Physics (one of the basic works of Western philosophy), pens the archetypal formulation of this Western notion: "Men do not think they know a thing till they have grasped the 'why' of it (which is to grasp its primary cause)." For the Chinese however, phenomena occur independently of an external act of creation, and there is no great need to search for a cause.
Tao produced the One.
The One produced the two.
The two produced the three.
And the three produced the ten thousand things.
The ten thousand things carry the Yin and embrace the Yang and through the blending of the Qi they achieve harmony.