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Who really said it

Real knowledge is to know the extent of one's ignorance

Attributed to Confucius 551–479 BCE · Chinese philosopher and teacher, Spring and Autumn period
Attributed Rights unconfirmed

Widely credited to Confucius and genuinely Confucian in spirit — it compresses a real passage in the Analects (Book II, ch. 17), where the Master tells his disciple Zi Lu that true knowledge is to know what you know and to admit what you do not. But the catchy English wording “Real knowledge is to know the extent of one’s ignorance” appears in no standard scholarly translation, and no primary source pins that exact phrasing.

Last verified 7 Jul 2026 · how we verify · spot an error?

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Unconfirmed quote & credit

“Real knowledge is to know the extent of one's ignorance” Real knowledge is to know the extent of one's ignorance. — attributed to Confucius; a modern paraphrase of Analects 2.17

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We couldn’t verify where this wording comes from, so there’s no rights status to give. Safe to present as an unverified or anonymous line — just don’t assert a specific author or source.

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In context

Evoking the world of Confucius — Chinese philosopher and teacher. Theme: "Real knowledge is to know the extent of one's ignorance". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.

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Provenance

Where it really comes from

Attributed to
Confucius
Genuine basis
The Analects, Book II (Wei Zheng), ch. 17
Status
Loose modern paraphrase of a real passage
Composed
Sayings 6th–5th c. BCE; compiled later by disciples

You, shall I teach you what knowledge is? When you know a thing, to hold that you know it; and when you do not know a thing, to allow that you do not know it — this is knowledge. ↑ the popular one-liner is a paraphrase of this passage

James Legge’s translation of Analects 2.17 (Chinese: “知之為知之，不知為不知，是知也”). The popular one-liner — “Real knowledge is to know the extent of one’s ignorance” — is a compressed paraphrase of this idea, not a sentence Confucius is recorded as saying in any scholarly rendering.

Analects 2.17 at the Chinese Text Project

How we verified this

  • The genuine source is Analects, Book II (Wei Zheng), ch. 17, where Confucius tells Zi Lu that knowledge is to hold what you know and admit what you do not — James Legge’s translation at ctext.org ↗.
  • Wikiquote ↗ lists the authentic “to know what you know and what you do not know” passage in its sourced section, but does not carry “Real knowledge is to know the extent of one’s ignorance” as a genuine Confucius line.
  • Popular quote databases and even academic blurbs (e.g. Columbia’s ICCCR ↗) print the paraphrase as if verbatim, without citing any passage of the Analects.

The underlying Analects text is ancient and long in the public domain, as is James Legge’s 19th-century translation. The modern paraphrase “Real knowledge is to know the extent of one’s ignorance” has no identified author or copyright and is too short to protect.

Context

Why it resonates

The line has become shorthand for intellectual humility — the idea that wisdom begins with mapping the edges of what you don’t know. It sits comfortably beside Socrates’ “I know that I know nothing,” which is part of why it circulates so freely in classrooms, boardrooms and LinkedIn posts.

What Confucius actually said in Analects 2.17 is subtler and more practical: not to measure your ignorance, but to be honest about the boundary in each case — claim what you genuinely know, and openly concede what you don’t. The popular wording keeps the spirit while sharpening it into an aphorism the Master never quite phrased.

Confucius taught the honesty; the epigram is ours.

On paraphrase vs. quotation

Ancient Chinese aphorisms rarely survive translation as fixed English sentences. Different translators — Legge, Arthur Waley, D. C. Lau — render 2.17 in noticeably different words, none of which match the popular epigram. That mismatch is the tell that a memorable quote-card line is a modern gloss rather than a direct citation.

Treating it as ‘attributed’ rather than ‘fabricated’ is the fair call: the thought is demonstrably Confucius’, even if the sentence is not his.

Explore

Filed under

More provenance-checked quotes on the same theme, each with its reuse status.

Wisdom Humility Knowledge

Go further

Dig deeper

Trusted places to keep pulling the thread — primary archives, fact-checks, and scholarship. We show how we used each one before you leave.

Analects 2.17 (Wei Zheng), Chinese + Leggectext.org

The primary passage the quote paraphrases, in classical Chinese with James Legge’s translation.
Confuciusen.wikiquote.org

Lists the authentic ‘know what you know’ passage as sourced; does not carry the popular paraphrase as genuine.
‘The Master Said’: Confucius as a Quoteresearchgate.net

Scholarship on how loose sayings get attached to Confucius’ name in Western quotation culture.
‘Real knowledge…’ Confucius says (essay)icccr.tc.columbia.edu

Academic use that prints the paraphrase as a Confucius quote with no primary citation — typical of how it spreads.
Confucius quote pagebrainyquote.com

Representative popular database crediting the exact wording to Confucius without a source.
Quote by Confuciusgoodreads.com

High-traffic aggregator entry driving the attribution, again with no textual reference.

The true author, in substance

About Confucius

Confucius

551–479 BCE · Chinese philosopher and teacher

Confucius (Kǒng Fūzǐ) was a teacher, editor and political thinker of the Spring and Autumn period whose ethics of virtue, ritual and reciprocity shaped East Asian civilization for two millennia. He wrote no books himself; his sayings survive as the Analects (Lunyu), compiled by disciples after his death. Because that text is a patchwork of remembered aphorisms, many lines later ‘quoted’ from him — including this one — are paraphrases rather than his exact words.

For writers & researchers

Cite this

Primary source — Chicago

Confucius, The Analects, Book II (Wei Zheng), ch. 17, trans. James Legge (London, 1861): “When you know a thing, to hold that you know it… this is knowledge.” The wording “Real knowledge is to know the extent of one’s ignorance” is a modern paraphrase of no fixed source.

MLA (9th ed.)

Confucius. The Analects. Translated by James Legge, 1861, bk. 2, ch. 17.

APA (7th ed.)

Confucius. (1861). The analects (J. Legge, Trans.). (Original work composed 6th–5th c. BCE)

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Quotle.info. “Who really said ‘Real knowledge is to know the extent of one’s ignorance’?” Last verified 7 Jul 2026. https://quotle.info/who-said/real-knowledge-is-to-know-the-extent-of-ones-ignorance

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