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Who really said it

It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so

Not Ronald Reagan — an anonymous saying rooted in Josh Billings Josh Billings (Henry Wheeler Shaw) 1818–1885 · American humorist
Disputed Rights unconfirmed

This exact wording is not Ronald Reagan’s, and its true author is anonymous. Per Quote Investigator, the earliest documented root is humorist Josh Billings, who wrote in 1874, “I honestly believe it is better to know nothing than to know what ain’t so.” The polished modern sentence evolved anonymously and has been serially pinned on Mark Twain, Will Rogers, and Kin Hubbard. Reagan did voice a related idea in his 1964 “A Time for Choosing” speech — “the trouble with our liberal friends… is just that they know so much that isn’t so” — but that is a different line, and he claimed no authorship of this saying.

Last verified 10 Jul 2026 · how we verify · spot an error?

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Disputed credit — copy with the correction

“It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so” Not Ronald Reagan. This exact wording is anonymous; its earliest documented root is Josh Billings (1874): "I honestly believe it is better to know nothing than to know what ain't so." Reagan said only a related line in 1964. Source: Quote Investigator.

The slide-ready mistake: crediting this to Ronald Reagan. Use the credit shown above instead.

Can you use it?

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.

Image direction — grounded in this quote’s real context; paste into your image tool

In context

Evoking the world of Josh Billings (Henry Wheeler Shaw) — American humorist and lecturer. Theme: "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so". 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.

Minimalist

Minimalist editorial slide for the quote "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so". Clean background, a single muted accent color, generous negative space, subtle paper or linen texture, no literal illustration — let the words carry it. Reserve clear space for a serif quote and a small credit line. No lettering in the image itself.

Provenance

The documented root, and the Reagan connection

Earliest root
Everybody's Friend, Or; Josh Billings's Encyclopedia and Proverbial Philosophy of Wit and Humor
Author
Josh Billings (Henry Wheeler Shaw), 1874
Modern wording
Anonymous — no identified author
Reagan's variant
“A Time for Choosing,” 27 Oct 1964

It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.

The polished modern form above is anonymous. The nearest genuine ancestor is Josh Billings’s 1874 line: “I honestly believe it is better to know nothing than to know what ain’t so.”

Quote Investigator: full chronology of this saying

How we verified this

  • The definitive study is Quote Investigator, which finds the creator “remains anonymous” and traces the earliest matching form to Josh Billings’s 1874 collection.
  • QI documents the wandering credits: Mark Twain (1899), Artemus Ward (1911), Josh Billings (1913), Kin Hubbard (1958), and Will Rogers (1978) — none with substantive support, per Quote Investigator.
  • Reagan’s genuine, and different, line appears in the Reagan Library transcript of “A Time for Choosing” (27 Oct 1964): “The trouble with our liberal friends is not that they’re ignorant; it’s just that they know so much that isn’t so.”

The exact modern wording has no identifiable author or first-publication, so no copyright status can be asserted for it. Its 1874 Josh Billings ancestor is long in the public domain, whereas Reagan’s separate 1964 “A Time for Choosing” wording is in copyright — but neither is the sentence quoted here.

Fact-check

A quote that proves its own point

Fittingly for a line about believing things that just ain’t so, this saying is one of the most misattributed in English. Quote Investigator finds no evidence any of its famous claimants wrote it.

Mark Twain No evidence

The single most popular credit online, but scholars at the Center for Mark Twain Studies find no support, and QI records the Twain ascription only from 1899 onward — long after the idea was circulating. Quote Investigator.

Ronald Reagan Different line

Reagan said a related thought in 1964 — “they know so much that isn’t so” — but not this sentence, and he claimed no authorship. Crediting him with this exact wording is a modern mix-up. Reagan Library.

Will Rogers, Kin Hubbard, Artemus Ward Unsupported

All picked up the line at various points (Rogers in a 1978 magazine, Hubbard via Laurence J. Peter in 1977), with no substantive evidence any coined it. Quote Investigator.

The nearest genuine author is Josh Billings, whose 1874 “better to know nothing than to know what ain’t so” is the earliest documented form; the crisp modern sentence itself is anonymous, per Quote Investigator.

Context

Why this line keeps getting a new author

A pithy, folksy aphorism with no famous name attached is unstable: retellers reach for a recognizable humorist to lend it authority. Over 150 years the same sentence has been handed to Twain, Ward, Billings, Hubbard, Rogers — and, more recently, to Reagan, whose 1964 “they know so much that isn’t so” gave the sentiment a memorable political home.

A saying about false certainty that nobody can say for sure who wrote.

Explore

Filed under

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

Wisdom Truth Doubt

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.

Quote Investigator: It Ain't What You Don't Know…quoteinvestigator.com

The definitive chronology, earliest-attestation, and misattribution history.
Reagan Library: “A Time for Choosing” (1964)reaganlibrary.gov

Official transcript containing Reagan's genuine, different variant.
Wikiquote: Ronald Reaganen.wikiquote.org

Documents the 1964 speech line; does not list this exact saying as Reagan's.
Talk:Mark Twain (Wikiquote)en.wikiquote.org

Editors' discussion of the unsupported Twain attribution.
The New Republic: The Big Short's fake Twain quotenewrepublic.com

On the film that opened with this line falsely credited to Twain.

The author

About Josh Billings (Henry Wheeler Shaw)

Josh Billings (Henry Wheeler Shaw)

1818–1885 · American humorist and lecturer

Henry Wheeler Shaw, writing as Josh Billings, was one of 19th-century America’s most popular humorists, famous for aphorisms in comic phonetic spelling. His 1874 Everybody’s Friend carried the line — “better to know nothing than to know what ain’t so” — that Quote Investigator identifies as the earliest documented root of this saying. He is credited here as its nearest genuine ancestor, though the polished modern wording is anonymous.

For writers & researchers

Cite this

Earliest documented in Josh Billings, 1874

Josh Billings [Henry Wheeler Shaw], Everybody's Friend, Or; Josh Billings's Encyclopedia and Proverbial Philosophy of Wit and Humor (Hartford, CT: American Publishing Company, 1874) — earliest documented form; the modern wording is anonymous. See “Quote Origin: It Ain't What You Don't Know That Gets You Into Trouble,” Quote Investigator, Nov. 18, 2018.

This verification page

Quotle.info. “Who really said ‘It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so’?” Last verified 10 Jul 2026. https://quotle.info/who-said/it-aint-what-you-dont-know-that-gets-you-into-trouble-its

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