How to read these texts

Classical texts are not physiological evidence. They record what people in the past noticed and valued over long experience of living, and the concepts they used to explain what they saw. Reading them beside the research of the previous chapters shows which modern claims are in fact very old, and also where ancient ideas differ fundamentally from modern science. This chapter does not claim that the ancients “already discovered” hormesis, autophagy or the Gompertz law; the ancient notions of jing (essence), qi and yin–yang belong to a different conceptual system and cannot be translated item by item into molecules or cells. All English translations of the classical passages are the author’s own.

Chapter 7 of Book 5 and Chapter 7 of Book 17 of this series have already read the Zhuangzi on “not eating the five grains”, Ge Hong’s criticism of grain avoidance, the Mawangdui manuscript Quegu shiqi, the Suwen’s “Great Treatise on the Five Regular Policies” on “grains, meat, fruit and vegetables”, the Lingshu chapter “Ordinary People Cut Off from Grain” and the Analects chapter “Xiang dang”. This chapter does not repeat them. It reads other passages on movement, measure and balance, and ends with the price paid in antiquity for the pursuit of long life.

Lüshi chunqiu, “Fulfilling One’s Years”: “everything can benefit, everything can harm”

The Lüshi chunqiu was compiled at the end of the Warring States period by the retainers of Lü Buwei, chancellor of Qin. “Fulfilling One’s Years” (Jin shu), a chapter of the “Almanac of the Last Month of Spring”, is about how to live out one’s natural span.

Two points deserve notice. First, “none fails to bring benefit, none fails to bring harm” says that the same thing can help or harm depending on what is “fitting”, and a modern reader readily thinks of dose–response relationships. But this is general practical wisdom, with no doses, no curves and no suggestion that low doses act in the opposite direction; it cannot be equated with the hormesis of Chapter 3. Second, “lengthening does not mean adding to what is short; it means completing one’s allotted number” understands long life as living out the span one is due, not breaking through a limit. This is structurally similar to Fries’s picture in Chapter 1 of a fixed upper limit with premature deaths postponed, but the “number” of Jin shu is a notion of destiny and due measure, not an estimate of a biological limit; and Fries’s picture itself has not been supported by the data.

Next comes the chapter’s most frequently quoted passage.

The text goes on to list the illnesses that stagnant qi causes in the head, ears, eyes, nose, abdomen and feet. Health as flow and illness as stagnation points the same way as the modern finding that sitting still is a risk in its own right, but the former rests on analogy and experience, the latter on measurement and statistics.

Hua Tuo: “but it should not be pushed to the limit”

Hua Tuo is speaking to his disciple Wu Pu; the biography goes on to say that he taught the “Frolics of the Five Animals” as daoyin exercise. The sentence comes closest to the “pulse and recovery” of Chapter 3, saying not only “move” but “do not push to the limit”; yet it defines neither dose nor intensity and is not the result of a controlled comparison, and “illness cannot arise” is an idealisation.

The Suwen: rhythm and “yin calm, yang sealed”

The sentence from the Suwen chapter “Treatise on the Heavenly Truth of High Antiquity” (Shanggu tianzhen lun), “they ate and drank in measure, kept regular hours and did not labour recklessly, and so body and spirit stayed together”, has already been quoted and discussed in Chapter 7 of Book 5 (as grounds for “measure rather than fasting”). Here we read the other half that follows it:

The passage attributes the pace of decline to drinking, indulgence and irregular hours, stressing rhythm and restraint rather than any single “tonic”. But “declining at fifty” against “living past a hundred” is an idealised contrast, not demography: low life expectancy in antiquity was driven mainly by infant deaths and infection. Infant and child mortality falls with age and lies outside the adult Gompertz–Makeham model of Chapter 1; deaths from infection among adults correspond roughly to its age-independent Makeham term.

“Yin calm, yang sealed” is often read today as “homeostasis” and linked with the “critical point” of proteostasis in Chapter 4. As rhetoric this is understandable, but yin and yang here describe the body’s functional state as a whole, with no one-to-one link to measurable variables, while the “collapse” and “hysteresis” of Chapter 4 are mathematical properties derived from equations, which the classical text does not contain. The two can be read side by side; they cannot confirm each other.

The harm of elixirs: the other side of the quest for long life

The ancient pursuit of long life was not only about “measure” and “movement”. Another strand was ingesting elixirs: “golden elixirs” refined from cinnabar (mercury sulphide), lead, arsenic and other minerals, taken in the hope of immortality. This strand left clear records of poisoning.

In this epitaph Han Yu lists several scholar-officials he knew who died after taking elixirs, including Li Yu, the subject of the epitaph himself. The Tang court was no exception. The Zizhi tongjian records that in his last years Emperor Xianzong took the drugs prepared by the alchemist Liu Mi: “the emperor took golden elixirs and became irritable and quick to anger; the eunuchs around him were often punished” (上服金丹，多躁怒，左右宦官往往获罪) (司马光 编著，胡三省 音注 1956). Records of several Tang emperors taking elixirs late in life recur in the histories, but historians disagree about whether elixir poisoning was the cause of death in each case (the histories record that Xianzong was killed by eunuchs), and the book makes no medical judgement.

This history is a direct warning. Elixir-taking rested on a self-consistent theory (metals do not decay, so whoever ingests them will not decay) and a few experiences of “feeling light”, not on controlled comparison. Today’s “anti-ageing” drugs and supplements are not elixirs, but the reasoning is sometimes similar: a mechanism in animals or cells, plus personal experience, stretched into “prolonging life”.

Reading together, and the boundaries

Putting this chapter’s passages together, classical thought on nourishing life shows at least two strands:

• One is movement and measure: “flowing water does not go foul”, “do not push to the limit”, “eat and drink in measure, keep regular hours”, “yin calm, yang sealed”. These summarise long experience of living and stress regularity, moderation and balance. Modern epidemiological findings that point the same way (the inverse association of fitness with mortality, the value of regular routines) have their own evidence and limitations; the classics cannot add evidence to them, and they cannot “prove” the classics.
• The other is ingesting elixirs to become immortal: seeking long life through mineral drugs. It has clear records of harm and was criticised even in its own time, by Han Yu among others.

The book’s position is that the first strand deserves to be valued as practical wisdom about the rhythms of life, but that it is a summary of experience, neither a molecular mechanism nor clinical evidence; the second strand is a historical lesson, reminding us to ask for controlled evidence behind any claim that something “taken, prolongs life”.

Chapter summary

“Fulfilling One’s Years” says that all things “can benefit and can harm”, that long life means “completing one’s number”, and that the body must move like flowing water; Hua Tuo’s “do not push to the limit” comes closest to modern ideas of dose and recovery; the Suwen blames “declining at fifty” on irregular living. These summarise experience of the rhythms of life; they can be read beside modern research but cannot confirm it. Mineral elixirs left clear records of poisoning. The next chapter returns to practice.