The words are not Plato’s. They paraphrase his Protagoras (360d), where Socrates argues that “the knowledge of what is and is not dangerous is courage”; the tidy modern sentence was written by classicist Werner Jaeger in Paideia, Vol. II, and later trimmed to this one-liner on quotation sites.
“Courage is knowing what not to fear” Not a real Plato quote. “Courage is knowing what not to fear” is a one-liner trimmed from classicist Werner Jaeger's paraphrase of Plato's Protagoras (360d) in Paideia, Vol. II — via Quotle.info
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Evoking the world of Werner Jaeger — German-American classical scholar. Theme: "Courage is knowing what not to fear". 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 the words actually come from
Actually phrased by
Werner Jaeger (trans. Gilbert Highet)
In
Paideia: The Ideals of Greek Culture, Vol. II
Location
p. 122, footnote referencing Protagoras 360d5
Genuine root
Plato, Protagoras 360d (Jowett translation)
Courage is knowing what to fear and what not to fear.
↑ the popular one-liner keeps only the second half — “what not to fear”
Plato’s actual line at Protagoras 360d, in Jowett’s translation, reads: “the knowledge of that which is and is not dangerous is courage, and is opposed to the ignorance of these things.” The neat aphorism is Jaeger’s condensation of that argument, not Plato’s own wording.
The exact modern wording — “knowing what to fear and what not to fear” — is traced by Wikiquote to Werner Jaeger’s Paideia, Vol. II, p. 122, not to any line Plato wrote.
Jaeger’s footnote points to Plato’s Protagoras 360d, where Socrates argues “the knowledge of what is and is not dangerous is courage.”
The tidy modern wording is Werner Jaeger’s, from Paideia, Vol. II (English translation, 1940s) — still under copyright. Plato’s underlying Protagoras and Jowett’s 1871 translation are long in the public domain.
Fact-check
Why it’s pinned on Plato
The line circulates as a word-for-word Plato quotation. It is not one — and the fuller version is not even purely Plato’s idea in that form.
✕
Presented as a verbatim quote from Plato
Plato wrote no such sentence. The phrasing is a 20th-century paraphrase; Wikiquote traces it to Werner Jaeger’s Paideia, Vol. II, p. 122, whose footnote in turn points back to Protagoras 360d.
✕
Circulated as the full Jaeger line, further shortened common
Jaeger’s phrase is “knowing what to fear and what not to fear”; the viral one-liner drops the first half, subtly shifting the emphasis from balanced judgment to mere fearlessness.
✓The genuine root is Plato’s Protagoras 360d — “the knowledge of what is and is not dangerous is courage” — recast into a quotable sentence by Werner Jaeger, per Wikiquote.
Context
The idea is Plato’s; the sentence isn’t
The thought behind the quote is genuinely Platonic. In the Protagoras, Socrates presses toward the conclusion that courage is a form of knowledge — specifically the knowledge of what truly is and is not to be feared — while cowardice is ignorance of the same. Getting your fears right, on this view, is an act of understanding, not just nerve.
What travels around the internet, though, is not Plato’s wording but a scholar’s gloss. Writing on this very passage in Paideia, Werner Jaeger compressed the argument into “Courage is knowing what to fear and what not to fear.” Detached from his footnote and trimmed to half its length, the sentence was re-labelled as a direct Plato quotation — which it never was.
The idea is Plato’s. The sentence is Jaeger’s.
A note on the Protagoras argument
The move is contested even within the dialogue: when Socrates offers “the knowledge of that which is and is not dangerous is courage,” Protagoras pointedly declines to assent. The identification of courage with knowledge is the conclusion Socrates is driving at, not a settled maxim Plato hands down — which is part of why turning it into a tidy motto flattens the philosophy.
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Filed under
More provenance-checked quotes on the same theme, each with its reuse status.
Werner Wilhelm Jaeger (1888–1961) was a German-American classicist, one of the most influential Plato and Aristotle scholars of the 20th century, who taught at Berlin, Chicago, and Harvard. His three-volume masterwork Paideia: The Ideals of Greek Culture (German 1933–1947; English translation by Gilbert Highet) traced how the Greeks shaped character through education. It is in Volume II, discussing Plato’s Protagoras, that his crisp gloss on courage — later mistaken for a direct Plato quotation — appears.
For writers & researchers
Cite this
Primary / earliest documented
Werner Jaeger, Paideia: The Ideals of Greek Culture, vol. 2, trans. Gilbert Highet (New York: Oxford University Press, 1943), 122 — paraphrasing Plato, Protagoras 360d (Jowett tr.).
This verification page
Quotle.info. “Who really said ‘Courage is knowing what not to fear’?” Last verified 7 Jul 2026. https://quotle.info/who-said/courage-is-knowing-what-not-to-fear