John von Neumann? Oskar Morgenstern? W. Edwards Deming? Michael A. Jackson? Apocryphal?
Question for Quote Investigator: The brilliant polymath John von Neumann performed pioneering research in game theory, computer science, quantum physics, and other areas. His work was so original that he required the formulation of important new definitions. The following two similar remarks have been credited to him:
(1) There is no point in using exact methods where there is no clarity in the concepts and issues to which they are to be applied.
(2) There is no sense in being precise when you don’t know what you are talking about.
I am having difficulty finding supporting citations. Did John von Neumann actually say or write either of these statements?
Reply from Quote Investigator: In 1944 John von Neumann and Oskar Morgenstern published the trailblazing book “Theory of Games and Economic Behavior” which contained the following passage. Boldface added to excerpts by QI:1
To begin with, the economic problems were not formulated clearly and are often stated in such vague terms as to make mathematical treatment a priori appear hopeless because it is quite uncertain what the problems really are. There is no point in using exact methods where there is no clarity in the concepts and issues to which they are to be applied. Consequently the initial task is to clarify the knowledge of the matter by further careful descriptive work.
Thus, von Neumann and Morgenstern should receive credit for the first statement given above. However, QI conjectures that the second statement is an informal paraphrase of the second statement, and it should be credited to neither von Neumann nor Morgenstern.
Below are additional selected citations in chronological order.
A thematically related observation appeared in the 1908 book “The Problem of Logic” by W. R. Boyce Gibson and Augusta Klein:2
To define a word formally is to mark off its edges from the encroachments of other words, and there is no point in being precise about the edges if there is uncertainty about the centre. A definition, in fact, is rarely wanted unless the rough meaning of a word is already known.
In June 1945 the famous U.S. business theorist W. Edwards Deming reviewed “Theory of Games and Economic Behavior” in the “Journal of the American Statistical Association”. Deming noticed the quotation, and he repeated the idea with a different phrasing:3
The lack of real success of mathematics and economics is largely due to a combination of unfavorable circumstances, some of which can gradually be removed. For one thing it is often not certain just what the problems are, and there is no point in using exact methods under such circumstances. But this state of affairs is disappearing. Concepts are improving, and data are fast accumulating for subjecting theories to test . . .
In 1951 sociologist Gideon Sjoberg published an article titled “A Rationale for Descriptive Sociology” in the journal “Social Forces”. Sjoberg reprinted an excerpt from “Theory of Games and Economic Behavior” while crediting von Neumann and Morgenstern:4
There is no point in using exact methods where there is no clarity in the concepts and issues to which they are to be applied. Consequently the initial task is to clarify the knowledge of the matter by further careful descriptive work.
In 1987 Julio Cesar S. P. Leite published a computer science technical report, and he attributed to John von Neumann a close match to the second statement at the beginning of this article. Unfortunately, no supporting citation was specified:5
The reason why not much progress has been made is best synthesized by the following quotation from von Neumann: There’s no sense in being precise about something when you don’t even know what you are talking about.
In 1988 Hilliard B. Holbrook III completed a master’s thesis at the University of Florida. The statement in Leite’s 1987 technical report was repeated and credited to von Neumann. The accompanying footnote pointed to Leite’s work:6
The effect here is aptly described by von Neumann: “there’s no sense in being precise about something when you don’t even know what you’re talking about”.
In 1995 Michael A. Jackson published “Software Requirements & Specifications: A Lexicon of Practice, Principles and Prejudices” which included both of the statements attributed to von Neumann:7
As John von Neumann observed in The Theory of Games, ‘There is no point in using exact methods where there is no clarity in the concepts and issues to which they are to be applied’.
In a crisper conversational version he said more simply, ‘There is no sense in being precise when you don’t know what you are talking about’.
In 1999 the quotation collection “Murphy’s Law 2000” compiled by Arthur Bloch included the following item without citation:8
VON NEUMANN’S AXIOM:
There’s no sense in being precise when you don’t know what you’re talking about.
In 2011 “Numbers: Computers, Philosophers, and the Search for Meaning” by John Tabak contained the following passage:9
The mathematician and physicist John von Neumann, who was also a pioneer in the field of computer science, summed up the situation in these words, “There’s no sense in being precise when you don’t even know what you’re talking about”.
In 2016 “The Nobel Factor: The Prize in Economics, Social Democracy, and the Market Turn” by Avner Offer and Gabriel Soderberg contained the following:10
The mathematician, physicist and polymath John von Neumann is reputed to have said: ‘There is no sense in being precise when you don’t even know what you’re talking about’.
In conclusion, John von Neumann and Oskar Morgenstern deserve credit for crafting the first statement given at the beginning of this article. Von Neumann died in 1957, and he received credit for the second statement by 1987. However, QI has never seen a substantive supporting citation. Hence, QI conjectures that the first statement was paraphrased to generate the second which was subsequently incorrectly reassigned directly to von Neumann.
Image Notes: Picture of calipers from Steve Buissinne at Pixabay. The image has been cropped and resized.
Acknowledgement: Great thanks to Nick Radcliffe whose inquiry about the second statement led QI to formulate this question and perform this exploration.
- 1947 (1944 Copyright), Theory of Games and Economic Behavior by John von Neumann and Oskar Morgenstern, Second edition, Chapter 1: Formulation of the Economic Problem, Quote Page 4, Note: QI has verified the quotation in the second edition; QI has not seen the first edition, but the second edition preface says it only fixed misprints and added an appendix, Princeton University Press, Princeton, New Jersey. (Verified with scans) ↩︎
- 1908, The Problem of Logic by W. R. Boyce Gibson with the co-operation of Augusta Klein, Chapter 2: Definition and the Predicables, Quote Page 18, Adam and Charles Black, London. (Google Books Full View) link ↩︎
- 1945 June, Journal of the American Statistical Association, Volume 40, Number 230, Book Review by W. Edwards Deming of “Theory of Games and Economic Behavior” by John von Neumann and Oscar Morgenstern, Start Page 263, Quote Page 264, American Statistical Association, Washington DC. (Verified with scans) ↩︎
- 1951 March, Social Forces, Volume 29, Number 3, A Rationale for Descriptive Sociology by Gideon Sjoberg (University of Texas), Start Page 251, Quote Page 255, Published for The University of North Carolina Press by The Williams & Wilkins Company, Baltimore, Maryland. (Verified with scans) ↩︎
- Technical Report RTP-071, Date: June 21, 1987, Department of Information and Computer Science, University of California, Irvine. Title: A Survey on Requirements Analysis, Author: Julio Cesar S. P. Leite, Part 1: Introduction, Quote Page 3, Advanced Software Engineering Project. (Accessed via www-di.inf.puc-rio.br on February 13, 2025) ↩︎
- 1988, A Methodology for Scenario-Based Requirements Exploration by Hilliard B. Holbrook III, A Thesis Presented to the Graduate School of the University of Florida in partial fulfillment of the requirements of the Degree of Master of Science, Quote Page 5, Major Department: Computer and Information Sciences, University of Florida. (Verified with scans) ↩︎
- 1995 (1998 reprint), Software Requirements & Specifications: A Lexicon of Practice, Principles and Prejudices by Michael A. Jackson, Entry: Designations, Start Page 61, Quote Page 65, ACM Press, New York and Addison-Wesley, New York. (Verified with scans) ↩︎
- 1999, Murphy’s Law 2000: What else can go wrong in the 21st century!, Compiled by Arthur Bloch, Chapter: Expertsmanship & Academiology, Quote Page 15, Price Stern Sloan: Penguin Putnam, New York. (Verified with scans) ↩︎
- 2011, Numbers: Computers, Philosophers, and the Search for Meaning by John Tabak, Revised Edition, Chapter 4: Analytical Engines, Quote Page 64, Facts On File, New York. (Verified with scans) ↩︎
- 2016, The Nobel Factor: The Prize in Economics, Social Democracy, and the Market Turn by Avner Offer and Gabriel Soderberg, Chapter 1: Imaginary Machines, Quote Page 41, Princeton University Press, Princeton, New Jersey. (Verified with scans) ↩︎