A Comprehensive Review of "Metal" (Jin) in Philosophy, Politics, and Medicine (Pre-Qin to Han Dynasty)

Abstract

As a pivotal component of the Five Phases (Wuxing) system, "Metal" (Jin) underwent a profound transformation from the Pre-Qin era to the Han Dynasty. It evolved from denoting material properties into a complex symbol encompassing Cosmology, Ethics, and Pathology. This review, based on core texts such as the Book of Documents (Shangshu), Lüshi Chunqiu, Huainanzi, Luxuriant Dew of the Spring and Autumn (Chunqiu Fanlu), and the Yellow Emperor's Inner Canon (Huangdi Neijing), explores the multifaceted construction of Metal regarding contraction, sternness, transformation, and righteousness.

I. Origins and Ontology: From Casting to "Compliance and Transformation"

In the Shang and early Western Zhou periods, before the systematization of Wuxing, "Metal" primarily referred to bronze and metallic weaponry.

1.1 Definition in the Hong Fan (Book of Documents)

The classical definition of the Five Phases first appears in the Hong Fan chapter. It states: "Metal means compliance and transformation (Cong Ge)."

Cong (Compliance): Refers to the metal's malleability when heated, obeying the shape of the mold.
Ge (Transformation/Change): Refers to the process where ores are smelted and forged into tools, changing their form and nature to become hard and sharp. During this period, the philosophical core of Metal was established as "transformation in accordance with the Dao." It implies a process of removing impurities and achieving utility through external force (Fire), laying the groundwork for the later Confucian association with "Yi" (Righteousness/Duty—the act of correction).

1.2 The Source of Weapons and Punishment

In Pre-Qin thought, Metal was inextricably linked to weaponry and penal codes. Texts like Guoyu and Guanzi mention that the Qi of Metal governs killing. The hardness and sharpness of metal made it a natural carrier of violence. Cosmologically, this translated into a "necessary destructive force"—the power to trim redundancy and curb excessive growth to maintain order.

II. Spacetime and Cosmology: Autumnal Qi and Withering

By the late Warring States period and early Han, with the compilation of Lüshi Chunqiu and Huainanzi, Metal was locked into a "spacetime isomorphism."

2.1 Metal in the "Monthly Ordinances" (Yueling)

In the Lüshi Chunqiu and Book of Rites, Metal is assigned to Autumn and the West.

The Month of Mengqiu (Early Autumn): Heaven and Earth begin to contract; excessive growth is forbidden. At this time, "Virtue resides in Metal." The Son of Heaven wears white, eats hemp and dog meat, and wears white jade to align with the Qi of Metal.
The Qi of Sternness/Killing (Su Sha): In the season governed by Metal, the Yang Qi of nature begins to retract, and Yin Qi ascends. This is an "inward-pulling" movement.
Taboos and Decrees: Because Metal governs killing, Autumn is the season for executing criminals and strictly prohibiting the felling of living trees (to avoid damaging the remaining life force, or because Metal destroys Wood, and Wood is already weak).

2.2 Position in Yin-Yang Fluctuation

In the Huainanzi, Metal is formed from the condensation of "Earth Qi." Although it belongs to Yin (relative to the Yang of Fire), it contains a hard, Yang nature within. The core function of Metal is "Collection" (Lian)—gathering the energy dispersed in Summer to store it for Winter. Without the contraction of Metal, life energy would dissipate and vanish.

III. Confucian Ethics: The Judgment of Righteousness and Virtue

Dong Zhongshu, the great Han Confucian scholar, synthesized the natural "Metal" into a moral "Metal" in his Luxuriant Dew of the Spring and Autumn, cementing the "Virtue of Metal" in imperial ideology.

3.1 The Dialectic of Metal and Wood / Benevolence and Righteousness

Dong Zhongshu proposed a correlation:

Wood governs Benevolence (Ren); Metal governs Righteousness (Yi): Wood represents growth and love (Spring); Metal represents judgment, duty, and rectification (Autumn).
The System of Heaven: Heaven is not purely giving; it possesses both the virtue of birth and the authority of execution. Metal is not just the destroyer of Wood but its corrector. If things only grow without restraint (unchecked Wood), chaos ensues; Metal acts as the pruning shear.
Political Metaphor: Metal symbolizes the rigidity of law and punishment. A ruler cannot govern by grace (Wood) alone but must use punishment (Metal) as a supplement. However, Dong emphasized "Wood as primary, Metal as auxiliary," correcting the Legalist tendency to overemphasize harsh laws.

3.2 Bureaucracy and Color

The Bohutong (Comprehensive Discussions in the White Tiger Hall) further solidified Metal's symbolism. Metal corresponds to White, symbolizing purity, clarity, and selflessness. In the Five Sacrifices, it corresponds to the Gate, implying Autumn as the gateway through which all things enter storage/hibernation.

IV. Medical Body View: The Physiology and Pathology of Lung-Metal

The Huangdi Neijing (Suwen & Lingshu) internalized the macro-narrative of Wuxing into a microcosmic body map, constructing a system centered on the Lungs.

4.1 Viscera Manifestation: The Lungs as the Canopy

Lungs belong to Metal: The Lungs are located in the highest part of the thorax, covering the other organs, hence called the "Canopy" or "Florid Canopy." The nature of Metal is clear and descending; thus, Lung Qi functions best when clearing and descending.
Governing Qi and Respiration: Just as Metal corresponds to the cool wind of nature, the Lungs govern the Qi of the entire body and regulate respiratory rhythm.
Regulating Water Passages: "Metal generates Water." The descending function of the Lungs dredges body fluids and sends them down to the Bladder. If the "Metal" system fails, water passages become blocked, leading to edema.

4.2 Body Tissues and Orifices

Governing Skin and Hair: The hardness of metal forms an outer shell, corresponding to the human skin and body hair. This is the first line of defense against external pathogens (Wei Qi).
Opening at the Nose: The nose is the gateway of respiration; the Qi of Lung-Metal connects directly to the nose.

4.3 Emotions, Sounds, and Tastes

Emotion is Grief/Sorrow (You/Bei): As Autumn sees the withering of nature, the Qi of Metal induces sadness. Excessive grief consumes Lung Qi.
Sound is Weeping: The sound of Metal is like the striking of bells—clear but piercing, associated with crying.
Taste is Pungent (Acrid): Pungent flavors enter the Lungs. Pungency disperses and moves Qi, preventing the constricting nature of Metal from causing stagnation. However, the Neijing warns: "When sick in Metal, do not eat too much pungent food," lest it disperse the Qi too severely.

4.4 Pathology and Generation-Control in the Han Era

The Classic of Difficult Issues (Nanjing) further elaborated on Metal's role in disease transmission:

Deficiency: Supplement the Mother (Earth/Spleen).
Excess: Drain the Child (Water/Kidney).
Metal controlling Wood: If Lung-Metal Qi is too strong (excessive killing energy), it will over-suppress Liver-Wood, leading to stagnation of Liver Qi, rib pain, or anger.

V. Conclusion

From the Pre-Qin to the Han Dynasty, "Metal" bridged the gap from instrumental rationality (weapons, tools) to value rationality (Righteousness, Law) and biological rationality (Lungs, Qi).

Taoism viewed Metal as the inevitable phase of "Collection" in the cosmic energy cycle.
Confucianism saw Metal as the majesty and legal standard essential to sovereignty, a rational check on boundless benevolence.
Medicine defined Metal as the critical system for maintaining purity, regulating fluid metabolism, and defending against pathogens. The synthesis of these three perspectives under the unified Han ideology established "Metal" as a stable paradigm representing the West, Autumn, Whiteness, Contraction, and Reformation, influencing Chinese philosophy and science for the next two millennia.

Metal