That Works Very Well in Practice, But How Does It Work In Theory?

Heidelberg Professor? Chairman of an Irish Company? Claude T. Bissell? Sean MacReamoinn? Walter Heller? Garret FitzGerald? Ernest Hollings? Anonymous?

Quote Investigator: There is a fundamental distinction between theory and practice. Sometimes a strategy that should work based on theoretical considerations fails when implemented in practice. This insight has been comically twisted to generate the following quip:

That works very well in practice, but how does it work out in theory?

The speaker of the line above has commonly been identified as an economist. Would you please examine the history of this witticism?

Quote Investigator: The earliest strong match for this joke located by QI was published in a 1911 issue of a magazine titled “The Youth’s Companion: For All the Family” which was based in Boston. Massachusetts. The humorous anecdote was set in Germany. Boldface has been added to excerpts: 1

A Professional Paradox.

The study of science is not necessarily all gray; it may have its rosy patches. It is said that a learned professor of Heidelberg forbade his students the repetition of a certain experiment.

“But,” they protested, “it has always been successful.”
“Nevertheless,” he said, “its position among experiments is absolutely untenable from an intellectual point of view.”
The boys stared.
“The thing may answer very well in practise,” said the professor, “but it is not sound in theory.”

In the following month the item above was further disseminated when it was reprinted in newspapers such as the “The Daily Herald” of Gulfport, Mississippi 2 and the “Springfield Daily News” of Springfield, Massachusetts. 3 This jest was not an exact match for the quip being explored, but later expressions would have been easily derivable from the tale either directly or indirectly.

Here are additional selected citations in chronological order.

Continue reading That Works Very Well in Practice, But How Does It Work In Theory?


  1. 1911 October 5, The Youth’s Companion: For All the Family, Volume 85, Number 40, A Professional Paradox, Quote Page 515, Column 2, Perry Mason Company, Boston. Massachusetts.(HathiTrust Full View) link link
  2. 1911 November 24, The Daily Herald (Gulfport Daily Herald), A Professional Paradox, Quote Page 4, Column 6, Gulfport, Mississippi. (GenealogyBank)
  3. 1911 November 24, Springfield Daily News, A Professional Paradox, Quote Page 18, Column 5, Springfield, Massachusetts. 9GenealogyBank)