The Formation of Visceral Manifestation Theory (Zang-Xiang)

The formation of visceral manifestation theory is marked by the completion of the Neijing (Inner Canon), with successive generations of physicians continuously supplementing and developing it. Its formation rests primarily on the following four foundations:

1. The Accumulation of Ancient Anatomical Knowledge

As early as the Spring and Autumn and Warring States periods, the ancients had already attained a certain understanding of the morphology of the zang-fu organs. For example, the Shiji · Bian Que Cang Gong Liezhuan (Records of the Grand Historian: Biographies of Bian Que and the Duke of Cang) records the legendary high-antiquity physician Yu Fu treating disease: "He would cut open the skin and dissect the muscles, sever the vessels and bind the sinews, manipulate the brain and marrow, separate the membranes and fascia, rinse and wash the stomach and intestines, and flush and cleanse the five zang." While this account is legendary and may seem insufficient as evidence, if one focuses on the anatomical procedures it describes, it is not difficult to discern a solid foundation of anatomical knowledge behind this legend, indicating that a certain amount of anatomical understanding had already accumulated by that time.

The Lingshu · Jing Shui (Spiritual Pivot: On the Meridians and Waterways) states: "As for a man of eight chi in height, his skin and flesh are present on the exterior; they can be measured, palpated, and traced. After his death, he can be dissected and examined. The firmness or fragility of his zang organs, the size of his fu organs, the capacity of his stomach, the length of his vessels, the clarity or turbidity of his blood... all have their general measures." This shows that at the time, the method of anatomy was a fundamental approach to understanding the structure of the human body. The Lingshu · Chang Wei (Spiritual Pivot: On the Intestines and Stomach) and the Nanjing (Classic of Difficult Issues), the 42nd Difficulty, describe in detail the anatomical morphology, weight, color, volume, and other aspects of the body's zang-fu organs. According to the research of the Japanese scholar Yamada Keiji, these descriptions are records of the results of "the condemnation and execution of Zhai Yi and his followers, whereupon the imperial physicians and skilled butchers were ordered to dissect and flay them together, measure the five zang, and use bamboo strips to guide through their vessels, in order to know their beginnings and ends" (Hanshu · Wang Mang Zhuan, History of the Former Han: Biography of Wang Mang). Thus, its understanding and description of human anatomical structure were, at that time, far more detailed and accurate than those of other medical systems.

The significance of the anatomical method in the formation of visceral manifestation theory lies, first, in that it was through anatomical observation that the very concepts of the zang-fu organs were established. Although the visceral manifestation theory that was ultimately constructed did not take the anatomical forms of the zang-fu organs as its guiding principle, its theoretical construction nonetheless took these initial anatomical concepts as its starting point. Second, anatomical practice promoted understanding of the physiological functions of the zang-fu organs. For example, the heart governing the blood vessels, the lung governing respiration, the kidney governing water and fluids, the stomach governing reception and ripening, the large intestine governing the conveyance of waste — all of these were based on anatomical knowledge.

2. Long-Term Observation of Human Physiological and Pathological Phenomena

Because ancient anatomical knowledge was crude and insufficient to meet the medical need of revealing the high complexity of life, it was difficult to construct a complete system of medical theory through anatomical methods alone. Against the cultural background of ancient Chinese philosophy — the theories of qi essence, yin-yang, and the five elements, together with their modes of thinking — ancient medical practitioners adopted the cognitive method of "knowing the interior from the exterior" (yi biao zhi li) and "inspecting the exterior to infer the interior" (si wai chuai nei). That is, by observing and analyzing the functional changes of the living body, they constructed a medical theoretical system that placed primary importance on functional states.

Based on the principle that "whatever exists internally must manifest itself externally," by using the methods of "inspecting the exterior to infer the interior," "observe the external correspondences to know the internal organs," and "analogy by image" (qu xiang bi lei), and through holistic observation of the living body, they analyzed the different responses of the human body to various environmental conditions and external stimuli, thereby understanding the laws of human physiology and pathology. This became the primary basis for the formation of visceral manifestation theory. For instance, building upon the known fact that the lung governs respiration, they observed that when the body surface is exposed to cold, respiratory symptoms such as nasal congestion, sneezing, coughing, and hoarseness appear, and from this deduced the tenets that "the lung governs the skin and body hair," "the nose is the orifice of the lung," and "the lung governs the voice." Similarly, on the basis of knowing that the heart governs the blood vessels, they discovered that emotional tension, anger, and shame are often accompanied by changes such as increased heart rate and pulse, and sweating, and from this derived the conclusions that "the heart governs the spirit and brightness" and "its associated fluid is sweat."

3. The Accumulation and Synthesis of Medical Practice Experience

Using therapeutic effects to explore and verify — or falsify — the body's physiology and pathology was an important basis for continuously enriching the concrete content of visceral manifestation theory and developing it into a foundational theory with universal clinical guiding significance. For example, the repeated experience that eating animal liver could treat night blindness gave rise to the therapeutic method of "supplementing the organs with the corresponding animal organs," and also provided evidence for the theory that "the liver opens into the eyes." The use of the method of tonifying the kidney and replenishing essence to treat growth and development disorders, diminished reproductive function, and to promote the healing of bone fractures served to corroborate the kidney's functions of storing essence, promoting growth, development, and reproduction, and governing the bones. In another example, when external contractions enter the interior and transform into heat, symptoms such as abdominal distention, fever, rapid breathing, nasal flaring, and constipation often appear. Treatment with herbs that guide out stagnation and drain downward often results in bowel movements, abatement of fever, and relief of dyspnea. From this, it was deduced that "the lung and the large intestine are internally-externally paired," and that when the zang organ is excess, treatment by draining the corresponding fu organ may be applied. Naturally, hypotheses or theories that were falsified by clinical practice were discarded or revised. For example, in the relationships among the zang organs, according to the sequential generation order of the five elements, fire generates earth, meaning that heart fire warms spleen earth. However, this did not entirely conform to clinical reality. Therefore, after the rise of the mingmen (life gate) theory, it came to be widely held that the fire of the mingmen has the function of warming spleen earth, and clinically, the therapeutic principle of warming kidney yang to fortify and transport spleen earth came to be extensively applied.

4. The Permeation of Ancient Philosophical Thought

The construction of visceral manifestation theory underwent a process of evolution from an emphasis on physical substance toward a paradigm of functional states. The philosophical theory of qi monism and the doctrines of yin-yang and the five elements played a critically important role in this evolutionary process. They not only determined the theoretical form of visceral manifestation theory but also defined its fundamental approaches and methods for analyzing problems. Qi theory, as a view of nature, focused on exploring the origin of the material world. It used the concepts of the gathering and dispersal of formless qi to explain the intrinsic connection between tangible things and intangible "void," revealing the holistic, process-oriented, and unified nature of all things. Yin-yang theory emphasized the viewpoint of "one divides into two," employing the attributes of yin and yang and the theories of opposition, mutual dependence, waxing and waning, and mutual transformation to study the nature of things and their relationships of opposition and unity. Five elements theory regarded the natural world as a unified systemic whole, using the attributes of wood, fire, earth, metal, and water and the laws of generation, restraint, overbearing, and rebellion to investigate the interrelationships among things and their interactions. Guided by this philosophical thought, the construction of visceral manifestation theory inevitably emphasized studying the functions of the zang-fu organs and their structural relationships from a holistic, macroscopic, and dynamic perspective. In this way, the functional images of the zang-fu organs, their yin-yang images, and their five-element images were formed. At the same time, this also led to a conceptual divergence in understanding the morphological locations of the zang-fu organs. For instance, the controversy over whether the liver should be assigned to the middle or lower burner transcended the scope of anatomical study; its essence lay in better elucidating the functional relationships between the liver and the spleen-stomach on the one hand, and the liver and the kidney on the other.

In summary, visceral manifestation theory is a theoretical system constructed by ancient medical practitioners over the course of long-term life and medical practice. Based on ancient anatomical knowledge and influenced by the ancient Chinese philosophical theories of qi essence, yin-yang, and the five elements along with their modes of thinking, they employed methods such as holistic observation, "inspecting the exterior to know the interior," and "analogy by image" to build this system. It is the product of the ancients' integration of objectively observed forms with knowledge obtained through subjective reasoning.