My Medical Thoughts 8: The Core Mission of Medicine: Addressing "Excess" and "Deficiency" in the Human Body
The Core Mission of Medicine: Addressing "Excess" and "Deficiency" in the Human Body
Is the way of Heaven not like drawing a bow?
The high is brought down; the low is raised.
What is in excess is reduced; what is deficient is supplemented.
Such is the way of Heaven: it reduces the excess and supplements the deficiency.
The way of man is not so: it reduces the deficient to offer to the excess.
Who can offer their surplus to the world?
Only those who follow the Way.
Therefore, the sage acts without presumption,
Achieves success without resting upon it,
And does not desire to display his worthiness.
— Excerpt from Tao Te Ching
- The Concepts of "Excess" and "Deficiency" in Traditional Chinese Medicine and the Western Theory of Homeostasis
The ultimate mission of medicine is not merely to eradicate specific pathogens, but to restore order within the life system. Whether in traditional Eastern medicine or modern Western medicine, the core task can be distilled into the precise intervention and correction of the body's states of "excess" and "deficiency." Rectifying such imbalances is not only the pathway to curing diseases but also the fundamental principle for safeguarding human dignity and quality of life.
In the philosophical context of Traditional Chinese Medicine (TCM), "excess" and "deficiency" are regarded as the fundamental pathogenesis of disease. The Huangdi Neijing (Yellow Emperor's Inner Canon) highly summarizes this pathological state, stating, "When Yin is in excess, Yang becomes diseased; when Yang is in excess, Yin becomes diseased." This means that the preponderance or decline of the opposing forces of Yin and Yang within the body disrupts the original harmony.
To address this imbalance, TCM established the therapeutic principle of "carefully examining the location of Yin and Yang to regulate them, aiming for equilibrium." Here, "equilibrium" does not imply absolute stillness, but rather a dynamic balance—the ideal state of health described in the Suwen: Treatise on the Vitality and Communication with Heaven as "Yin in peace and Yang in firmness, so that spirit and essence are governed."
When the body exhibits "excess," the surplus must be reduced; when it shows "deficiency," the insufficiency must be supplemented. This wisdom of correction is deeply rooted in ancient Chinese philosophy. As the Tao Te Ching states, "The way of Heaven reduces the excess and supplements the deficiency." Medicine emulates this natural order; through human intervention, it guides the body back to the path of "ultimate harmony," ensuring the smooth flow of Qi and blood and the tranquil functioning of the Zang-fu organs.
Coincidentally, in its exploration of the laws of life, modern Western medicine has arrived at a core concept highly congruent with "excess" and "deficiency," albeit by a different route: Homeostasis.
The development of homeostasis theory is a scientific history of deepening human cognition. As early as the mid-19th century, French physiologist Claude Bernard introduced the concept of the "internal environment." He pointed out that the internal environment of multicellular organisms (such as blood and tissue fluid) must remain relatively constant, which is the prerequisite for a free and independent life. This idea laid the cornerstone for homeostasis theory.
In the 1920s, American physiologist Walter Cannon built upon Bernard's work, formally coining the term "homeostasis" and systematically elaborating on it in his 1932 book, The Wisdom of the Body.
Cannon noted that homeostasis is not a rigid fixation, but a dynamic regulatory state of "similarity but not sameness." When the body is disturbed by internal or external environments, causing physiological variables like body temperature, blood sugar, and blood pressure to deviate from their normal ranges (i.e., exhibiting "excess" or "deficiency"), the body automatically initiates negative feedback mechanisms. Through the coordinated action of the nervous and endocrine systems, these variables are brought back to their set normal intervals.
For example, when blood sugar is too high, insulin secretion increases to promote the utilization and storage of glucose; when blood sugar drops too low, glucagon prompts the breakdown of liver glycogen, thereby maintaining blood sugar homeostasis.
With the introduction of cybernetics in the mid-20th century, Norbert Wiener's theory of negative feedback provided precise mathematical and engineering language for homeostasis, elevating the medical understanding of "excess" and "deficiency" from qualitative descriptions to quantitative models.
Today, the concept of homeostasis has expanded from a single internal environment to systemic and even molecular-level network regulation. Many modern medical treatments are, in essence, assisting the body in restoring homeostasis: antihypertensive drugs correct the "excess" of blood pressure; insulin supplementation compensates for the endocrine "deficiency"; and anti-infective treatments eliminate external disruptive factors that destroy homeostasis.
In conclusion, whether it is the Eastern wisdom of "aiming for equilibrium" in the Huangdi Neijing or the Western science of "negative feedback regulation" in modern medicine, both articulate the same truth: life is a complex system striving to maintain its own balance in a dynamic environment. The core mission of medicine is to act as an assistant and restorer of this system, keenly perceiving and correcting the "excesses" and "deficiencies" in the body's structure and function, ultimately guiding life back to harmony and homeostasis.