Translation: To know that one does not know—this is the highest (wisdom); to not know yet think one knows—this is a flaw (of cognition).
Analysis: The core proposition. Laozi puts forward a fundamental distinction in epistemology: true wisdom is not about knowing a great deal, but about knowing that one does not know. "知不知" (knowing that one does not know) is the Socratic "knowing one's own ignorance"—the starting point of all cognition. "不知知" (not knowing yet claiming to know) is self-deception—passing off ignorance as knowledge, and is the greatest obstacle to cognition.
Similar views: Heshanggong's commentary: "知道言不知，是乃德之上。不知道言知，是乃德之病。" ("To know the Tao yet say one does not know—this is the highest virtue. To not know the Tao yet say one knows—this is a flaw of virtue.")
Translation: To know (the Tao) yet say "I do not know"—this is the highest virtue; to not know (the Tao) yet say "I know"—this is a flaw of character.
Analysis: Heshanggong's self-cultivation interpretation. "知不知" is not merely a cognitive attitude but a matter of moral cultivation—a person who possesses the Tao, even when knowing, humbly says they do not know, because the Tao is ineffable. A shallow person, with only a superficial understanding, parades their knowledge everywhere. This interpretation transforms an epistemological statement into a moral one.
Similar views: Heshanggong's commentary: "知道言不知，是乃德之上。" ("To know the Tao yet say one does not know—this is the highest virtue.")
Translation: Precisely because one regards "not knowing yet thinking one knows" as a flaw, one will not commit this flaw.
Analysis: An exquisite logical construction. "病病"—to treat the "flaw" as a "flaw," that is, to maintain vigilance against it. When a person can recognize the harm of self-deception and constantly guards against pretending to know what they do not, they can avoid making this mistake. This is a methodology of cognition through self-reflection.
Similar views: Heshanggong's commentary: "夫唯能病苦众人有强知之病，是以不自病也。" ("Only by being troubled that people have the flaw of feigning knowledge can one avoid this flaw oneself.")
Translation: The Sage (圣人) is free from this flaw, because he treats this flaw as a flaw, and therefore does not commit it.
Analysis: The summation of the entire chapter. The reason the Sage does not have the flaw of "not knowing yet thinking he knows" is precisely because he always remains vigilant against it. Herein lies a profound truth: a truly wise person is not one who knows everything, but one who maintains full alertness to their own ignorance. Being "free from the flaw" is not because one's nature is perfect, but because of continuous self-reflection.
Similar views: Wang Bi's commentary: "不知知之不足任则病也。" ("Not knowing that knowledge is insufficient to be relied upon—that is the flaw.")
Translation: The Sage (圣人) is free from the flaw of feigning knowledge, because he is constantly troubled by others having this flaw, and therefore does not commit it himself.
Analysis: Heshanggong extends "病病" to the social dimension—the Sage not only reflects on his own cognitive deficiencies but also grieves over the world's flaw of "feigning knowledge" (pretending to know and acting recklessly). From this emerges a brilliant contrast: the Sage "怀通达之知，托于不知" ("holds penetrating knowledge yet entrusts himself to not-knowing"), while the petty person "不知道意，妄行强知以自显著，内伤精神，减寿消年" ("does not know the meaning of the Tao, yet recklessly feigns knowledge to make himself conspicuous, inwardly injuring his spirit and shortening his lifespan").
Similar views: Heshanggong's commentary: "圣人怀通达之知，托于不知者，欲使天下质朴忠正，各守纯性。" ("The Sage possesses penetrating knowledge yet entrusts himself to not-knowing, wishing to make all under heaven simple, loyal, upright, and true to their pure nature.")
This chapter contains 5 interpretation combinations.
[Core Divergences]
Chapter 71 is Laozi's epistemological masterpiece, resonating with the Greek philosopher Socrates' "knowing one's own ignorance." The entire chapter unfolds through an exquisite play on words—three layers of the character "病" (flaw/affliction) form a self-reflexive cognitive structure: (1) "不知知" is a flaw—pretending to know what one does not; (2) "病病"—treating the flaw as a flaw, i.e., maintaining vigilance against self-deception; (3) the Sage "以其病病，是以不病"—continuous self-reflection is the only method for overcoming cognitive deficiencies. Heshanggong further extends this, linking the epistemological issue to self-cultivation: "妄行强知以自显著，内伤精神，减寿消年" ("recklessly feigning knowledge to make oneself conspicuous inwardly injures the spirit and shortens one's lifespan")—pretending to know is not merely an intellectual deficiency but also harms one's physical and mental well-being.