Yin Yang represents the world as the fruit of two opposing and complementary forces, one rather active and emitting (Yang), the other more passive and receptive (Yin). All movement, all life would result from the inexorable passage from Yin to Yang, from Yang to Yin. (See Foundations.) The Yin Yang Theory has deeply influenced Traditional Chinese Medicine (TCM). It would be impossible to talk about physiology, pathology, diagnosis or treatment without referring to Yin Yang. This theory fits intimately with the Qi paradigm and with a Taoist worldview.

The paradigm of Qi consists in describing the universe as being the product of a fundamental energy made up of moving Breaths, varying in their states of condensation or expansion. (See Qi – Energy.)

The Taoist vision proposes a universe of which the part perceptible by the senses is:

• in an eternal process of experimentation;
• a theater where two forces interpenetrate, oppose and influence each other mutually and cyclically:
  • Dynamic Breaths, transformers, separators, multipliers that we associate with the Yang principle, more masculine; and
  • Passive, stable, structuring, condensing, unifying breaths that we associate with the Yin principle, more feminine.

These powers or principles, present since the origin of the world, and active until each of us, also bear the name of:

• YuanYang, the original Yang associated with the creative force of the Spirits; and
• YuanYin, the original Yin associated with the material web of the Essences.

The interaction of the forces of Yin and Yang creates the multiplicity of observable phenomena, which are the external and ephemeral manifestations of the Tao.

A universal duality

Both ambitious and simple, the Yin Yang Theory embraces all observable phenomena, from the interaction of stars and planets to the delicate organization of the smallest forms of life. In fact, this theory stems directly from how we view the world through our five senses. What we perceive is the surface of the world; we decode it and organize it in our mind, proceeding by categorization. We define and qualify everything – shapes, objects, living things, our relationships, our moods, the symptoms of our illnesses – by comparison. Thus, it is difficult to speak of heat without knowing the cold, to recognize the light if one ignores the darkness, to define the dryness without having felt the humidity, etc.

Just as energy and matter are inseparable, just as a leaf has a front and a back, Yin Yang encompasses the two components of all that is manifested.

Yin and Yang are opposed.

Yin and Yang complement each other.

Yin and Yang are inseparable.

Everything is either Yin or Yang … temporarily

The human brain is constantly generating categories that allow us to generalize and better understand our environment. This hypothesis has also been confirmed, among others, by studies of accident victims who, following a cerebrovascular accident (CVA), can, for example, remember the names of the fruits, but not those of the fruits. vegetables 1.

The Yin Yang Theory did not wait for these studies to assert that whatever we perceive through the senses can be classified as being (at a specific time) more Yang or more Yin. The Chinese character for Yang represents the side of a mountain exposed to light, heat and wind. The Yin character represents the side of the mountain in the shadow of the clouds, where it is cooler, darker and wetter. Yin and Yang, however, do not represent a fixed reality, but a particular trend.

To better understand, imagine that on a beautiful summer day we went down into a cave. The deeper we go into the earth, the more we notice that the cave is cool, dark, damp and silent. It is the qualities of the opaque and interior world of the earth which obstruct light and noise, which collect the water which sinks there, and which preserve a cool and constant temperature. If we turn off the lights on our helmets and avoid making noise, time will seem suspended; the only temporal benchmarks we will have left are the rhythms of our heartbeats and our breathing.

If we go up into the open air under the outside sun, we will be inundated with light and heat, and the noise of the intense activity of wildlife and humans can become overwhelming.

The dense, opaque, interior, dark, humid, silent and stable world of the Earth is Yin like the opacity of the clouds which filter light and bring rain to the coldest face of the mountain. The outer, aerial, hot, dry, luminous and changing world of the Sky is Yang like the face of the mountain exposed to the wind, and which transforms throughout the course of the sun from east to west.

Heaven is above, the purer Breaths rise and diffuse there. These are Yang qualities.

The Earth is below, the coarser and murkier Breaths descend and gather there. These are Yin qualities.

The classification in Yin or Yang of everything that surrounds us is the result of a division of the reality specific to Chinese culture.

The list could go on and on …

This classification is of course quite relative. We judge that a phenomenon is more Yin or more Yang according to certain criteria, but nothing is Yin or Yang in an absolute way. For example, in the month of April, it will seem to us that the days are more Yang than those of January, but if we compare them to the beautiful days of July, they really look Yin!

Yin and Yang: a perpetual movement

The expression of Yin or Yang polarities is never stable, it only exists as dynamism. Yin and Yang are constantly opposed and gradually go through different phases of growth and decline, in generally predictable cycles. The darkness and cold of night and winter alternate with the light and heat of day and summer. The cold and the darkness favor condensation, contraction, rest, the fold inwards… while the light and the heat promote the expansion, the activity and the exchanges.

The transition from Yin to Yang is done gradually and when the growth of one or the other reaches its peak, the movement is reversed. The cycles fit into each other: global warming and cooling cycles, annual cycles, daily cycles, etc. Together, they define the characteristics of eras and seasons which, in turn, influence the life of flora and fauna, and ours.

The relations between Yin and Yang are inconstant and always in opposition, but the cyclical alternation gives an impression of balance of Yin and Yang. All in all, Yin and Yang seem to be of equal strength… but their relationship resembles the succession of peaks and troughs of a roller coaster!

Living organisms can be described as the agglomeration of a set of Yin Yang phenomena:

• The human is ordered in different oppositions (head / trunk, hands / feet, left / right, back / front, Surface / Depth) which constitute as many Yin Yang parameters.
• Human life arises from the tension between the original Yin and Yang (Essences and Spirits) which must be supported by the stimuli of Flavors (Yin) and Perfumes (Yang), and by the Qi contained in the Air (Yang) and Food (Yin).
• Among Foods, some have hot dynamic characteristics (Yang), others cold (Yin).
• Qi acquired through Food, Air and visual, auditory and tactile stimuli enters the body through the upper openings (Yang), including the mouth and nose. Residues (stool and urine) are evacuated through the bottom openings (Yin).
• The transformation of Food and Air supposes a settling of the pure and the impure inside the body. The pure takes on various appearances: in the form of Blood and Organic Liquids, it is Yin, material, nourishing, humidifying; in the form of Qi, he is Yang, rapidly circulating, nourishing, warming and protecting.
• Qi itself is called YangQi when it protects and warms and YinQi when it nourishes.
• The pure is preserved by the Yin Viscera (the Organs) and the elimination of the impure comes under the Yang Viscera (the Entrails).
• All Viscera are contained in the Depth of the body (Yin). Opposing the Depth, the Surface is made up of skin, muscles and openings: the Yang part of the body.
• Yin Substances (Essences, Organic Liquids and Blood), in addition to shaping the material structures of the body, allow their development and growth, nourish, repair and moisten them. Yang Substances (Spirits, Qi) use these same material structures to perform a variety of functions: consciousness (perceptions, thinking, judgment, memorization, etc.), visceral activities, circulation, protection, warming, muscle movements, etc.

Yin and Yang in action in the body

The action of the Viscera spreads throughout the body, through an abundant network of Meridians which allows Qi and Substances to nourish and protect the organism. These Meridians are themselves polarized in Yin and Yang depending on whether they are rooted in the Organs or the Entrails, and depending on whether they circulate on the antero-median (Yin) or postero-lateral sides of the body (Yang).

As in nature, the role of the Yin and Yang components of the body varies according to the phases of activity and rest and according to the cycles defined by the environment:

• Breathing is faster and more jerky during the day, full and regular at night.
• We eat and digest during the day. Growth takes place at night, at rest.
• Muscles are active during the day, passive at night.
• Sensory Openings are primarily based on the daytime, allowing us to receive a large amount of stimuli and fuel our body, mind, and consciousness.
• At night, the Sensory Openings are closed and only the hearing is used as an alarm. Memory is consolidated. Dreams express unresolved conflicts.
• Yang energy, defensive, mobilizes on the Surface during the day to protect skin and muscles against climatic changes. It circulates in the Depth at night when we are asleep, well sheltered, protecting the Organs.
• Yin energy, nourishing, although it travels the body constantly, supports the activity of muscles and sensory openings during the day, it allows the Organs to refuel and store excess at night, at rest.
• The Yang factors in the environment stimulate the Yang in the body and deplete the Yin components. For example, outdoor heat stimulates the heart rate and decreases fluids through sweating.
• Conversely, the Yin factors in the environment stimulate the Yin in the body and weaken the Yang components. For example, Cold and Humidity help preserve liquids, but deplete the heating functions, interfere with the circulation of Substances and disrupt the processing of Food.

When external phenomena (heat, humidity, stress, food, etc.), failing our ability to adapt, create Excess Yin or Yang in our body, we see symptoms of imbalance appear. These can be analyzed in terms of Yin Yang, which will help us to determine whether the disease is due either to the Excess of a pathogenic factor (Yin or Yang), or from the insufficiency of a normal function of the body or of its underlying structure, themselves also Yin or Yang.

The classification of disease symptoms has long been dominated by a Yin Yang analysis grid called the Eight Rules (BaGang). (See Examinations.) Still used today, this grid allows the practitioner to determine if the condition is:

• Surface (Yang) or Depth (Yin);
• of the Excess type (Yang) with an acute character and an abundance of pathological factors; Where
• Void-type (Yin) with chronic character and weakness of normal functions;
• Heat (Yang) type with signs of inflammation or infection; Where
• Cold type (Yin) with signs of cold, stasis, etc .;
• finally, other characteristics are united under the Yin or Yang banner (hyperactivity, restlessness, drought are Yang, etc.).

The treatments advocated by Chinese medicine are often based on Yin Yang principles and the law of opposites. Traditionally, the Eight Methods (BaFa) respond to the eight types of ailments. To restore balance, you may need to:

• tonify where there is Void;
• disperse where there is Excess;
• free the Surface;
• reheat to chase away the cold (circulate, cauterize, etc.);
• clarify to drive out Heat (cool, reduce inflammation, drive out poison, etc.);
• disperse accumulations from above (vomiting);
• disperse accumulations from below (purgation);
• to harmonize the relations between two viscera.

All these pictorial terms refer to the search for a balance between opposing, dynamic and changing forces. The various therapeutic interventions aim, among other things, to relaunch the movement in the relations between Yin and Yang, so as to prevent one or the other from dominating unduly or suffering a blockage in its relations with its complement. They can also help the body adapt when the Yin Yang changes in the environment are extreme.