Adage Origin: Assumption Is the Mother of All Foul-Ups

Posted byquoteresearch

Glenn Curtiss? Angelo Donghia? Stephen Robbins? Eugene Lewis Fordsworthe? Caroline Leaf Carol? Bill Gatter? Anonymous?

Train wreck disaster in 1895 at Montparnasse in Paris, France

Question for Quote Investigator: Relying on false assumptions leads to serious blunders. Here are two versions of a pertinent adage:

(1) Assumption is the mother of all mistakes.
(2) Assumption is the mother of all screw-ups.

This saying has been attributed to U.S. interior designer Angelo Donghia, U.S. military parachutist Bill Gatter, and others. Would you please explore the provenance of this maxim?

Reply from Quote Investigator: There are several versions of this saying which makes it difficult to trace. The earliest match found by QI appeared in “The Sun” newspaper of Baltimore, Maryland in July 1972. A political operative in a U.S. presidential campaign employed the saying. Boldface added to excerpts by QI:1

They would not be traveling anywhere if it were not for Stephen Robbins, 30, the chief advance and scheduling man, who breezily advises his even younger aides: “Don’t assume: assumption is the mother of foul-ups.”

The above citation suggests that Stephen Robbins may have coined the adage, but QI believes it is more likely that the saying was already in circulation, and the creator was anonymous. Future researchers may uncover earlier evidence.

Below are additional selected citations in chronological order.

Variant statements describing the “mother of all errors” have a very long history. For example, the 1612 book titled “A Glasse for the Godly. Contayning many Comfortable Treatises” included the following statement:2

For Ignorance is the Mother of all errors.

A variant adage which asserted that “necessity” was the “mother of all mistakes” appeared in the 1903 book “A Rosary” by John Davidson:3

NECESSITY.
The mother of invention? Yes; and the mother of all mistakes, and the prophetess of failure.

In 1957 a thematically related pun based on the word “assume” appeared in a newspaper in Espanola, New Mexico:4

. . . I urge you, as a driver, to observe the rules of traffic and highway safety in the operation of your car.

Don’t ass-u-me anything, when you drive because, you’ll make an ass of u and me—ass-u-me.

A separate Quote Investigator article about the wordplay above is available here.

The earliest close match found by QI appeared in a Maryland newspaper in 1972 as mentioned previously:

… Stephen Robbins, 30, the chief advance and scheduling man, who breezily advises his even younger aides: “Don’t assume: assumption is the mother of foul-ups.”

In 1973 an article about skydiving appeared in the adventure magazine “True”. Bill Gatter, a member of the U.S. Army Golden Knights Parachute Team, was interviewed in the piece, and Gatter employed the adage:5

If I have any apprehension before a jump, it’s apprehension about not doing my best. I’m a professional. There’s no excuse for blowing a maneuver. If it happens I don’t want it to be because of me.

This is a mentally demanding sport involving a great deal of concentration. There is no room for assumption. Assumption is the mother of all screw-ups.

In September 1977 the aviation magazine “Flight Operations” published a piece by flight instructor Bill Gabella about piloting helicopters in poor weather conditions under IFR (Instrument Flight Rules). While discussing this very difficult task, Gabella credited the adage to U.S. aviation pioneer Glenn Curtiss:6

It is well to remember the sterling advice Glenn Curtiss gave to Orville Wright during the first James Gordon Bennett Trophy Race nearly 70 years ago: “Orville, in aviation assumption is the mother of all screw-ups.”

Glenn Curtiss died in 1930, and QI has not yet found convincing evidence that he employed the adage.

In October 1977 “The Alabama Review: A Quarterly Journal of Alabama History” published an article about an excavation conducted at the site of a former dormitory on the campus of the University of Alabama, Tuscaloosa. The excavators incorrectly assumed that no firearms would be found:7

Such assumptions are the mother of all foul-ups. Almost immediately upon the opening of excavations, books were uncovered, charred and completely carbonized … Almost immediately following this exciting discovery a well-preserved derringer came to view.

In 1978 Paul Dickson published a compilation titled “The Official Rules” which contained the following entry:8

Tylk’s Law. Assumption is the mother of all foul-ups.

The accompanying note stated that Dickson found the adage listed in a Xeroxed collection of sayings with uncertain provenance.

In October 1978 “The Daily Register” of Shrewsbury, New Jersey printed the adage while describing it as an “old Army maxim”:9

There is no way to screen the quality of journalists before issuing credentials to them. To do so would be discrimination, which is abominable in principle, let alone in practice. Unfortunately, the quality of journalists is assumed to be high when credentials are issued. And, to use the old Army maxim, assumption is the mother of all foulups.

In 1980 Arthur Bloch published a compilation titled “Murphy’s Law Book Two” which contained the following entry:10

WETHERN’S LAW OF SUSPENDED JUDGMENT:
Assumption is the mother of all screw-ups.

In 1981 “The New York Times” applied the adage to pugilists:11

In boxing, however, assumption is the mother of foul-up.

In 1983 “The New York Times” published a piece about U.S. interior designer Angelo Donghia who employed the adage:12

“It was disaster,” he said. “I, who had always checked everything out, discovered too late that I had signed a contract in which I had no control of production. The samples I saw in every city were like nothing I had developed. I had assumed the quality would be there and it wasn’t. Assumption is the mother of screw-up and I learned never to assume again.”

In 1985 the “Los Angeles Times” printed a variant of the adage using the word “disaster”:13

Assumption can often be the mother of disaster.

In 1992 the compilation “Quotable Business: Over 2,500 Funny, Irreverent, and Insightful Quotations About Corporate Life” included the following entry:14

Assumption is the mother of screw-up.
Angelo Donghia (1935-85) American designer

In 2011 the adage appeared in a message on the community website of the software company SAP:15

Mr Eugene Lewis Fordsworthe initially said assumption is the mother of all mistakes. He later said his earlier philosophy that assumption is the mother of all mistakes was flawed, and he recognized that sometimes good comes from assumptions.

In 2018 the adage appeared within an advertisement for a family counselor:16

“In a relationship do not assume to know what the other person is thinking. You will most likely be wrong and can make matters worse. Assumptions are the mother of all mess ups!”
~Dr. Caroline Leaf Carol

In conclusion, the earliest match in July 1972 used the word “foul-ups” and was spoken by political campaigner Stephen Robbins. QI believes the saying was already in circulation, and the creator remains anonymous. Aviation pioneer Glenn Curtiss received credit in 1977, but that date was many years after his death in 1930. Interior designer Angelo Donghia used the adage in 1983, but he did not coin it.

Image Notes: Picture of a train wreck disaster in 1895 at Montparnasse in Paris, France. This image has been cropped and resized.

Acknowledgement: Great thanks to Joshua Gross whose inquiry led QI to formulate this question and perform this exploration. Gross noted the lack of credible evidence supporting the linkage to Eugene Lewis Fordsworthe.

  1. 1972 July 1, The Sun, Youth image follows candidate on trips by Adam Clymer (Washington Bureau of The Sun), Quote Page A9, Column 1, Baltimore, Maryland. (ProQuest) ↩︎
  2. 1612, A Glasse for the Godly. Contayning many Comfortable Treatises by R. W., A Minister of Gods Word (Robert Wolcomb), Section: A Ghest for the Sovle, Quote Page 499, Printed by T. P. for Arthur Iohnson, London. (Google Books Full View) link ↩︎
  3. 1903, A Rosary by John Davidson, Section 70, Quote Page 191, Grant Richards, London. (Google Books Full View) link ↩︎
  4. 1957 December 26, Rio Grande Sun, (Advertisement from Horace DeVargas Agency, auto insurance company), Quote Page 10, Column 6, Espanola, New Mexico. (Newspapers_com) ↩︎
  5. 1973 June, True: For Today’s Active Man, Skydiving: A Lifetime Thrill Packed into a Few Moments by William Albert Allard, Start Page 55, Quote Page 95, Column 1, Fawcett Publications, Inc., Greenwich, Connecticut. (Verified with scans) ↩︎
  6. 1977 September, Flight Operations, Volume 66, Number 9, Helicopter IFR techniques by Bill Gabella, Start Page 41, Quote Page 42, Aviation Publishing Corporation: A Subsidiary if Macro Communications Inc., New York. (Verified with scans) ↩︎
  7. 1977 October, The Alabama Review: A Quarterly Journal of Alabama History, Volume 30, Number 4, Historical Archaeology on The University of Alabama Campus by Jerry C. Oldshue, Start Page 266, Quote Page 272, Published in cooperation with the Alabama Historical Association by The University of Alabama Press. (Verified with scans) ↩︎
  8. 1978, The Official Rules by Paul Dickson, Quote Page 178 and 197-198, Delacorte Press, New York. (Verified with scans) ↩︎
  9. 1978 October 9, The Daily Register, The mouth-flapping fool who fooled no one at all by Bill Zapcic, Quote Page 11, Column 3, Shrewsbury, New Jersey. (Newspapers_com) ↩︎
  10. 1980, Murphy’s Law Book Two: More Reasons Why Things Go Wrong, Compiled and Edited by Arthur Bloch, Quote Page 34, Price/Stern/Sloan Publishers Inc., Los Angeles, California. (Verified with scans) ↩︎
  11. 1981 January 19, New York Times, Lopsided Hagler Bout Delights Antuofermo by Michael Katz (Special to The New York Times), Quote Page C12, Column 5, New York. (ProQuest) ↩︎
  12. 1983 January 20, New York Times, Behind Angelo Donghia’s Gray Flannel Success by John Duka, Start Page C1, Quote Page C6, Column 4, New York. (ProQuest) ↩︎
  13. 1985 June 29, Los Angeles Times, Getting a Boarding Pass in Advance Makes Sense by Peter S. Greenberg, Quote Page Y8, Column 4, Los Angeles, California. (Newspapers_com) ↩︎
  14. 1992, Quotable Business: Over 2,500 Funny, Irreverent, and Insightful Quotations About Corporate Life by Louis E. Boone, Section 1: The Art and Science of Managing, Chapter 8: Decision Making, Quote Page 83, Random House, New York. (Verified with scans) ↩︎
  15. Website: community.sap.com, Section: Additional Blog Posts by Members, Article title: Is assumption the mother of all mistakes?, Article author: Former Member, Timestamp on website: 2011 May 30 2:36 AM, Website description: Messages from the SAP Software Community. (Accessed community.sap.com on September 27, 2025) link ↩︎
  16. 2018 February 22, Kearney Hub, Section: Bravo Guide to Entertainment, (Advertisement for Family Life Counseling from Dr. Caroline Leaf), Quote Page 8, Column 3, Kearney, Nebraska. (Newspapers_com) ↩︎