"Qi" is Not a Metaphysical Concept – The Physical Underpinnings and Cognitive Revolution of Pre-Qin Theories of Qi

Author: Xuanji Editorial Department

Zhuangzi's "A Complete Understanding of the World is but Qi" (通天下一气耳) is often cited as an endorsement of Eastern mysticism. Yet, few question: If "qi" were merely a vague figment of imagination, why did the Pre-Qin thinkers—from physicians to politicians, Confucians to Daoists—unanimously choose it as the core category to explain the world$1 How could an empty metaphysical concept bear the entire weight of cosmology, ontology, epistemology, and political philosophy$2

Chapter 1: Introduction: A Concept Read Backwards

Today, when we discuss the character "qi" (气), we tend to preemptively categorize it as belonging to the realm of metaphysics or mysticism. The root of this judgment lies less in a close reading of Pre-Qin texts and more in a cognitive inertia—projecting the various mystical connotations later appended to "qi" back onto its original context in Pre-Qin thought.

However, if we return to the Pre-Qin classics themselves, to the very sites where "qi" was first used, we discover a starkly different picture: "Qi" was never an abstract philosophical invention, but rather a high-level abstraction by the Pre-Qin people of observable, perceptible, and verifiable natural phenomena. It sought to unify and explain what we today distinguish as "matter," "energy," and "information."

Why do we say this$3 This requires us to elaborate from three perspectives:

First, the etymology of "qi" itself points to physical experience. The qi of breathing, the qi of steam, the qi of wind and rain—what the Pre-Qin people referred to as "qi" began with the most intuitive bodily sensations and observational records of natural phenomena, rather than abstract contemplation.

Second, the core propositions of Pre-Qin theories of qi—that qi gathers to become life, and dissipates to become death; that the qi of heaven and earth does not lose its order—are essentially Pre-Qin expressions of the laws of conservation of matter and transformation of energy. These propositions are not poetic metaphors but serious answers to the fundamental physical question: "From whence do all things come, and to where do they go$4"

Third, the concept of "qi" served the function of information theory in the hands of the Pre-Qin thinkers. From the "essence qi" (精气) discussed in Guanzi's Neiye to Master Mencius's "vast, flowing qi" (浩然之气), "qi" was not only the fundamental substance constituting the world but also the carrier of information that connected heaven and humanity, and pervaded the inner and outer realms—it explained epistemological questions like "How does one perceive the world$5" and "How does the mind correspond with things$6"

Therefore, the central thesis of this paper is: Pre-Qin theories of qi are not metaphysics but a cognitive revolution that occurred over two thousand years ago. Through the unified abstraction of "qi," they attempted to break down the barriers between the material and spiritual worlds, and between natural and humanistic orders. The depth and ambition of this thinking deserve our re-examination with a serious scholarly attitude.

Below, we will begin from the origins in ancient myths and folklore, follow the evolutionary trajectory of Pre-Qin thought, and peel back layer by layer the physical underpinnings of "qi."

Chapter 2: Origins: From Ancient Experience to Rational Germination

Section 1: Wind, Clouds, and Breath – The Primitive Experiential Field of "Qi"

To understand the original nature of any concept, one must inquire into its origins. Historically, the character "qi" has been explained as either "cloud and vapor" (云气) or "fodder for guests" (馈客刍米). Regardless of the interpretation, it points to something perceptible and fluid—either the ever-changing clouds and mists in the sky or the rising steam from cooking rice.

This point is crucial. From its inception, "qi" was not a purely speculative product but a naming of bodily experiences and natural observations.

The Pre-Qin people lived in a world deeply connected to nature. They breathed daily, feeling the air enter and exit their chests; they observed celestial phenomena, seeing clouds gather and disperse, winds rise and storms brew; they lit fires for cooking, seeing water boil and steam rise, and firewood burn to ash; they cultivated fields, feeling the alternation of the four seasons. These experiences formed the raw material for the concept of "qi."

Master Zhuangzi, in his Discourse on the Equality of Things (齐物论), offers a brilliant description:

"The Great Expanse exhales and its name is Wind. It is only when it is not acting that it is so. When it acts, the myriad openings roar. And do you not hear it whistling$7 The crevices of mountains and forests, the hollows of great trees a hundred spans around, are like noses, like mouths, like ears, like cleavages, like holes, like depressions, like basins, like pools. They whistle, they shriek, they bluster, they sigh, they cry, they wail, they moan, they howl. The former sings out, and the latter answers with a hum. When the wind is gentle, the harmony is slight; when the wind is strong, the harmony is great; when the fierce wind passes, the myriad openings become empty."

This passage is often read as literature, but its physical insights are not to be overlooked. Master Zhuangzi says, "The Great Expanse exhales and its name is Wind"—the earth exhales a breath, and this is wind. The wind passes through various-sized openings in the mountains and forests, producing different sounds; the strength of the wind determines the volume of the sound—"When the wind is gentle, the harmony is slight; when the wind is strong, the harmony is great."

Is this not a simple acoustic observation$8 Sound is the result of the vibration of gases, the shape of the openings determines the nature of the sound, and the strength of the wind determines its volume. Master Zhuangzi uses "qi" to unify the explanation of the cause of wind and the production of sound, the underlying mode of thinking is entirely physical: starting from observable phenomena to find a unified principle of explanation.

Section 2: The Doctrine of Six Qi – The Earliest Classification System of Natural Forces

If Master Zhuangzi's description carried the grand air of a philosopher, then the medical diagnosis of Yi He (医和) recorded in Zuo Zhuan reveals a more precise and analytical aspect of Pre-Qin theories of qi.

In Zuo Zhuan, during the first year of Duke Zhao (昭公元年), the Marquis of Jin fell ill, and Yi He was sent from the state of Qin to diagnose him. After his diagnosis, Yi He offered a judgment of profound theoretical depth:

"Heaven has six qi, which descend to generate the five flavors, manifest as the five colors, are signaled by the five sounds, and when excessive, cause the six diseases. The six qi are: Yin, Yang, Wind, Rain, Darkness, and Brightness. They are divided into four seasons, ordered into five junctures, and when exceeding their bounds, become disasters. Excessive Yin causes cold diseases; excessive Yang causes heat diseases; excessive Wind causes diseases of the extremities; excessive Rain causes abdominal diseases; excessive Darkness causes confused diseases; excessive Brightness causes heart diseases."

This passage is rich in information and deserves careful analysis.

First Level: Classification. Yi He divides the fundamental forces of nature into six categories—Yin, Yang, Wind, Rain, Darkness, and Brightness. These six "qi" are not randomly listed but are a systematic compilation of the primary physical factors in the natural environment perceptible to the human body: the two poles of temperature (Yin cold and Yang heat), atmospheric movement (wind), the water cycle (rain), and the two poles of illumination (darkness and brightness).

Second Level: Order. "They are divided into four seasons, ordered into five junctures"—the six qi are not chaotic; they have temporal order, operating according to the rhythm of the seasons. A crucial realization is implied here: natural forces are regular and predictable.

Third Level: Causality. "When exceeding their bounds, become disasters; when excessive, cause the six diseases"—if any qi is in excess ("excessive" meaning "excessive"), it will lead to corresponding diseases. Excessive Yin qi causes cold diseases, excessive Yang qi causes heat diseases, and so on. This is a clear causal reasoning model: environmental physical factors are the cause of diseases, and there is a correspondence between the type of disease and the causative factor.

Let us ask: Is this metaphysics$9

A metaphysical system might say, "Heaven's mandate is unknowable" or "Ghosts and spirits send diseases." What Yi He established, however, is a framework for explaining diseases that is entirely based on natural causality. In this framework, there is no intervention of gods or spirits, no unknowable fate—only the orderly operation of natural forces and its disordered consequences. "Qi" here is the rational naming of natural forces.

Section 3: Boyang Fu on Earthquakes – A Mechanical Model of Qi

Earlier than Yi He's discussion of the six qi is the account of Boyang Fu (伯阳父) on earthquakes, recorded in Guoyu (Discourses of the States). In the second year of King You of Zhou (780 BCE), the three rivers all trembled, and Boyang Fu commented:

"The qi of Heaven and Earth does not lose its order. If it exceeds its order, the people have disturbed it. Yang is suppressed and cannot emerge, Yin is pressed and cannot steam. Thus, there are earthquakes. Now the three rivers are indeed trembling, which means Yang has lost its place and presses down Yin. If Yang is lost and within Yin, the river sources will be blocked; if the sources are blocked, the state will surely perish."

This discourse deserves extreme attention, as it may be one of the earliest records in Chinese intellectual history to explain geological phenomena using "qi."

Boyang Fu's reasoning is as follows:

1. The qi of Heaven and Earth has its normal operational order ("does not lose its order").
2. The cause of earthquakes is "Yang is suppressed and cannot emerge, Yin is pressed and cannot steam"—Yang qi is trapped underground and cannot vent upwards; Yin qi is compressed and cannot circulate. The two forces mutually press each other and cannot be released, thus causing earthquakes.
3. The consequence of earthquakes is the blockage of river sources, which in turn affects the survival of the state.

What is the core of this explanatory model$10 It is the accumulation and release of force. Yang qi (which can be understood as underground heat, active subterranean energy) is blocked by Yin qi (which can be understood as the oppressive force of the Earth's crust). Energy cannot circulate normally, accumulates to a certain point, and then erupts as an earthquake. While the specific mechanisms differ entirely, the basic model of "energy accumulation—exceeding a threshold—sudden release" is shared, showing a striking similarity in the structural thinking with modern plate tectonics and elastic rebound theories.

Even more noteworthy is Boyang Fu's methodological premise: "The qi of Heaven and Earth does not lose its order." This statement implies that the workings of nature are orderly and regular, and earthquakes are not punishments from deities but the result of disturbances in the natural order. This is a thoroughly naturalistic stance.

Thus, we can preliminarily conclude: In the origins of Pre-Qin theories of qi—whether in observations of daily experience, the construction of medical theories, or the explanation of geological phenomena—"qi" played the role of a unified name for natural forces. It was not metaphysical speculation but a tool for the Pre-Qin people to rationally grasp the perceptible and observable physical world.

Chapter 3: "A Complete Understanding of the World is but Qi" – The Physical Underpinnings of Daoist Theories of Qi

Section 1: Master Laozi: The Cosmology of "Interacting Qi Harmonizes Them" (冲气以为和)

Daoism is a core developer of Pre-Qin theories of qi. Master Laozi's Daodejing provides a cosmological framework for qi.

Daodejing, Chapter 42:

"The Dao gives birth to One; One gives birth to Two; Two gives birth to Three; Three gives birth to the myriad things. The myriad things carry Yin and embrace Yang; the interacting qi harmonizes them."

This passage is one of the most famous cosmological outlines in Chinese philosophy. Let us inquire into each phrase.

"The Dao gives birth to One" – What is "One"$11 Commentators throughout history have offered various interpretations, but if placed within the context of Pre-Qin theories of qi, the most reasonable understanding of "One" is "primordial qi" (元气)—the unified, undifferentiated original qi of the universe. This "One" is not the number "1" in a mathematical sense but signifies "wholeness and unity": the unified state before the differentiation of all things.

"One gives birth to Two" – What is "Two"$12 Yin and Yang. The unified primordial qi differentiates into two opposing yet complementary forces or tendencies.

"Two gives birth to Three" – What is "Three"$13 The key here lies in "the interacting qi harmonizes them" (冲气以为和). "Chong" (冲) means vigorous interaction. Yin and Yang interact and stimulate each other, producing a third state—"He" (和), harmony. "Three" is the qi of harmony produced by the interaction of Yin and Yang.

"Three gives birth to the myriad things" – Under the joint action of Yin, Yang, and the qi of harmony, all things are generated.

"The myriad things carry Yin and embrace Yang; the interacting qi harmonizes them"—the state of existence of all things is to carry Yin, embrace Yang, and maintain their own harmonious unity through the vigorous interaction of qi.

What are the physical implications of this cosmological model$14

It describes an evolutionary process from a unified state to a differentiated state and then to a complex state. The original unified "qi" (One) differentiates into two basic opposing forces (Two). The interaction of these two forces produces a new dynamic balance (Three), from which the diversity of all things emerges (myriad things).

If we temporarily set aside specific material carriers and focus solely on this mode of thinking—from uniformity to symmetry breaking, from symmetry breaking to interaction, from interaction to the emergence of complex systems—it shares a profound structural isomorphism with the basic logic of the universe's evolution after the Big Bang as described by modern cosmology.

Of course, we are not suggesting that Master Laozi "predicted" modern physics. What we are saying is: Master Laozi's theory of qi has a physical mode of thinking—it focuses on the process of generation from simplicity to complexity, from unity to multiplicity, and "qi" is the unified medium and driving force of this process.

Even more worthy of reflection is the word "He" (和) in "interacting qi harmonizes them." "He" is not static balance but dynamic coordination—Yin and Yang constantly interact and clash, maintaining a flowing stability amidst conflict. This is precisely the simple expression of "dynamic equilibrium" or "dissipative structure" in modern physics.

Section 2: Master Zhuangzi: The Unifying Field of "A Complete Understanding of the World is but Qi"

If Master Laozi provided a cosmological framework for theories of qi, then Master Zhuangzi pushed them towards a deeper unity—not just the unity of cosmic generation, but unity in an ontological sense.

In Zhuangzi's "A Complete Understanding of the World" (知北游), there is a passage that can be considered the highest programmatic statement of Pre- Qin theories of qi:

"The birth of man is the aggregation of qi; aggregation becomes life, dispersion becomes death. If death and life were strangers, what would I have to worry about! Therefore, the myriad things are one. That which people consider marvelous they call spirits and marvels; that which they consider foul they call stench and rottenness. Stench and rottenness are reborn as spirits and marvels; spirits and marvels are reborn as stench and rottenness. Therefore it is said: 'A complete understanding of the world is but qi.' The sage therefore esteems unity."

Every sentence in this passage is worthy of repeated contemplation.

"The birth of man is the aggregation of qi; aggregation becomes life, dispersion becomes death."

What is life$15 It is the aggregation of qi. What is death$16 It is the dispersion of qi. This is not a poetic metaphor but a serious ontological proposition: the essence of life does not lie in some mysterious soul or independent spiritual entity, but in a specific mode of aggregation of matter-energy. When this mode of aggregation is maintained, it is "life"; when this mode of aggregation disintegrates, it is "death."

There is a key physical insight here that is often overlooked: Master Zhuangzi did not say "qi aggregates to become life, qi extinguishes to become death," but rather "qi aggregates to become life, qi disperses to become death." "Disperse" is not "extinguish." After life perishes, the qi does not vanish but merely disperses, returning to the great qi that pervades heaven and earth. What does this mean$17 It means that matter-energy neither arises from nothing nor perishes into nothing; it merely transforms between aggregation and dispersion.

Is this not precisely the Pre-Qin expression of the conservation of matter and conservation of energy$18

"That which people consider marvelous they call spirits and marvels; that which they consider foul they call stench and rottenness. Stench and rottenness are reborn as spirits and marvels; spirits and marvels are reborn as stench and rottenness."

People consider beautiful things "marvels" and ugly things "stench and rottenness." But foul things can be reborn as marvelous things, and marvelous things will eventually be reborn as foul things.

This is not a lament of nihilism but a profound recognition of the natural law of material circulation and transformation. Flowers bloom as "marvels," wither and rot as "stench and rottenness"; but rotten flowers and leaves turn into soil nutrients, nourishing new life to bloom again—"stench and rottenness are reborn as spirits and marvels." This is a complete closed loop of material circulation in nature.

"Therefore it is said: 'A complete understanding of the world is but qi.'"

Therefore, what permeates the entire world is but qi.

The power of this statement lies in the character "yi" (一, one). "One qi" means: the foundation of all things is the same; there is no ontological断裂 (discontinuity) between life and death, beauty and ugliness, marvels and stench and rottenness; they are merely transformations of the same fundamental substance between different states.

This is the Pre-Qin "unified field theory." Contemporary physics attempts to explain the four fundamental forces with a unified theory; the Pre-Qin people, with the single concept of "qi," unified matter (the substance of qi), energy (the flow and transformation of qi), and information (the resonance and transmission of qi). Although the scale and precision are incomparable, the theoretical impulse to seek a unified explanation is entirely consistent.

Section 3: Qi Transformation and Flow – A Worldview of Process Philosophy

Master Zhuangzi's theory of qi also has an extremely important aspect that is often overlooked: it understands the world as a constantly flowing process, rather than a collection of static entities.

In Zhuangzi's "Autumn Floods" (秋水), the North Sea Sage says:

"Things have measure without limit, time without cessation, divisions without fixedness, ends and beginnings without fixed cause."

The measure of things is infinite, time never stops, the divisions of things are not fixed, and there is no fixed cause between ends and beginnings. This is a complete process cosmology: there are no eternally unchanging entities, only constantly flowing processes.

Zhuangzi's "The Great and Venerable Teacher" (大宗师) further elaborates:

"He is there, together with the Creator, wandering in the one qi of Heaven and Earth."

The true person is one who is friends with the Creator, wandering in the one qi of Heaven and Earth. The word "wandering" (游) here is deeply meaningful—it implies not "settling" in a fixed state of existence, but "wandering" within the flow of qi.

In Zhuangzi's "The Joy of Life" (至乐), there is a striking passage about the origin of life:

"Intermingled between the faint and the obscure, it transforms and there is qi; qi transforms and there are forms; forms transform and there is life. Now, again..."