This is not a comedian’s one-liner; it is a famous demonstration of why computers find English hard. The two sentences look identical in structure and are not — in the first, “flies” is a verb and “like” a preposition; in the second, “flies” is a noun and “like” a verb. Wikiquote ↗ files it under Misattributed for Groucho with no known citation to Marx, noting it “first appears unattributed in mid-1960s logic/computing texts”. The Harvard computer scientist Anthony Oettinger ↗ is the earliest named user, contrasting the two sentences by 1963 and giving a fuller version with the banana in Scientific American in September 1966.
“Time flies like an arrow. Fruit flies like a banana” Not Groucho Marx. A syntactic-ambiguity example from 1960s computational linguistics; the Marx attribution dates only to 1982. Via quotle.info
⚠ The slide-ready mistake: crediting this to Groucho Marx. Use the credit shown above instead.
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In context
Evoking the themes of knowledge, creativity and doubt. Theme: "Time flies like an arrow. Fruit flies like a banana". 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 actually comes from
Popular credit
Groucho Marx — listed under Misattributed on Wikiquote
Actual home
Machine translation and parsing literature, 1960s
Earliest named user
Anthony Oettinger, Harvard — the contrast by 1963, the banana version in Scientific American, September 1966
Earliest Groucho attribution
A Usenet post dated 9 July 1982, per the Yale Book of Quotations — and it has never been located
Time flies like an arrow. Fruit flies like a banana.
The point of the pair is grammatical, not comic. Read the first sentence and you parse “flies” as a verb and “like” as a preposition; the second sentence has the identical shape and requires you to parse “flies” as a noun and “like” as a verb. A human re-reads and laughs. A machine has to be told how to choose — which is exactly the difficulty, “handling ambiguous syntactic structures”, that the pair was used to illustrate.
Wikiquote ↗ places the line in its Misattributed section for Groucho and states the position in five words: “No known citation to Marx.” It adds that the sentence pair “first appears unattributed in mid-1960s logic/computing texts as an example of the difficulty of machine parsing of ambiguous statements”.
Both Wikiquote and Wikipedia’s article on the sentence ↗ report the same finding from the Yale Book of Quotations (2006, p. 498): there is no reason to believe Marx said it, and the earliest Marx attribution YBQ could date is a post to the Usenet group net.jokes on 9 July 1982 — five years after Groucho’s death. Both sources add that no matching post has ever been found in the Google Groups archives.
Wikipedia ↗ traces the linguistic pedigree instead: Anthony Oettinger contrasted “fruit flies like bananas” with “time flies like an arrow” as an example of syntactic ambiguity as early as 1963 (Harvard Alumni Bulletin 66:205), with a fuller exposition using the banana in his September 1966 Scientific American article “The Uses of Computing in Science”.
No copyright status is asserted. The sentence pair circulated as an unattributed teaching example before anyone claimed it, and no first publication has been established that would fix either a date or a rights holder — Wikiquote describes it only as appearing “unattributed in mid-1960s logic/computing texts”. The specific 1963 and 1966 publications in which Anthony Oettinger used it are separate copyrighted works and are cited here as evidence, not as the origin of the wording.
Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.
Fact-check
Often misattributed
A pun this clean looks like it must have a famous author. This one has a discipline instead.
✕
Credited as the authorGroucho Marx No primary source
Wikiquote ↗ states there is “no known citation to Marx”, and the Yale Book of Quotations traces the attribution only to a Usenet post of 9 July 1982 — five years after he died. Wikipedia adds ↗ that the closest post anyone has since found in the Google Groups archive is dated September 8 and does not mention Marx at all.
~
Where it really lived1960s machine-translation research Early user
Wikiquote records the pair appearing “unattributed in mid-1960s logic/computing texts” as a standard illustration of parsing ambiguity. It was a worked example passed between researchers, which is exactly the kind of text that reaches the public with no author attached.
~
The earliest name attached to itAnthony Oettinger, Harvard Early user
Per Wikipedia ↗, Oettinger used the time-flies/fruit-flies contrast by 1963 and published a fuller banana version in Scientific American in September 1966. He is the earliest named user on record — which is not the same as being the author, and Wikipedia does not claim he coined it.
✓Nobody can name who first wrote the pair. What is documented is that it was circulating in computational-linguistics work in the mid-1960s, and that Groucho’s name was not attached to it until 1982 ↗, five years after his death.
Context
Why it mattered
The sentence pair became famous because it is a genuinely hard problem wearing a joke’s clothing. Early machine-translation researchers had assumed that grammar could be mechanised: feed in the rules, get out the parse. These eleven words demonstrate that identical surface structures can demand completely different analyses, and that choosing between them requires knowing what fruit and arrows actually are.
That is also why attributing it to Groucho is more than a footnote error. Read as a Marx Brothers gag, it is a pun. Read as what it is, it is one of the tidiest statements of why natural language is hard — a problem the field spent the following sixty years on.
Eleven words that showed grammar alone cannot parse English.
Read the full story
The joke did not escape the linguists’ notice either. Wikipedia records that Oettinger’s 1966 Scientific American article prompted a reader to send in a poem, “An Ode to Oettinger”, published in the magazine’s correspondence column that November.
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The author
About Unknown (a syntactic-ambiguity example)
??
Unknown (a syntactic-ambiguity example)
In print by 1963 · from machine-translation and parsing research
No one has ever been identified as the author of this sentence pair. It surfaced in the 1960s inside computational-linguistics teaching material, where it was used to show that two sentences with identical surface structure can require completely different grammatical analyses. The Harvard computer scientist Anthony Oettinger is the earliest named person to use it, from 1963 — but the sources that document him do not claim he invented it.
For writers & researchers
Cite this
The primary source (Chicago)
Earliest documented in mid-1960s computational-linguistics material; the contrast used by Anthony Oettinger by 1963 (Harvard Alumni Bulletin 66:205) and in fuller form in “The Uses of Computing in Science”, Scientific American 215:3 (September 1966). Attribution to Groucho Marx traced no earlier than 1982 (Fred R. Shapiro, ed., The Yale Book of Quotations, Yale University Press, 2006, p. 498).
This verification page
Quotle.info. “Who really said ‘Time flies like an arrow. Fruit flies like a banana’?” Last verified 11 Aug 2026. https://quotle.info/who-said/time-flies-like-an-arrow-fruit-flies-like-a-banana/