It’s Difficult to Make Predictions, Especially About the Future

Niels Bohr? Samuel Goldwyn? K. K. Steincke? Robert Storm Petersen? Yogi Berra? Mark Twain? Nostradamus? Anonymous?

Dear Quote Investigator: There is a family of popular humorous sayings about the formidable task of successful prognostication. Here are five examples:

    1. It is difficult to make predictions, especially about the future.
    2. Predictions are hazardous, especially about the future.
    3. It is hard to prophecy, particularly about the future.
    4. It’s dangerous to prophesy, particularly about the future.
    5. Never make forecasts, especially about the future.

Of course, a prediction is inherently about the future, and the modifiers “especially” and “particularly” emphasize the comical redundancy of the statement. These expressions have been attributed to a diverse collection of individuals, including Niels Bohr, Sam Goldwyn, Robert Storm Petersen, and Yogi Berra. Would you please tell me who I should credit?

Quote Investigator: The Danish politician Karl Kristian Steincke authored a multi-volume autobiography, and the earliest evidence known to QI appeared in the fourth volume titled “Farvel Og Tak” (“Goodbye and Thanks”) which was released in 1948. Danish text is followed by an English rendering below. The saying appeared in a section with this title:

Og saa til Slut et Par parlamentariske Sprogblomster

And finally a couple of parliamentary howlers

The saying was spoken during the parliamentary year 1937-1938, and no attribution was specified. Boldface added to excerpts by QI: 1

Det er vanskeligt at spaa, især naar det gælder Fremtiden.

It is difficult to make predictions, especially about the future.

This citation was mentioned in the prominent reference “The Yale Book of Quotations”. 2 More information about Danish citations for this saying is presented in the addendum at the end of this article.

The first appearance in English located by QI was printed in a 1956 academic publication called the “Journal of the Royal Statistical Society. Series A”. This early citation 3 and several others remarked on the Danish language origin of the aphoristic joke: 4

Alas, it is always dangerous to prophesy, particularly, as the Danish proverb says, about the future.

In May 1961 “The Canadian Journal of Economics and Political Science” printed an instance of the saying using the word “hazardous” instead of “dangerous”. Indeed, the phrasing changed over time and was highly variable: 5

“Prediction,” goes an old Danish proverb, “is hazardous, especially about the future.” For the Canadian economy the hazard is especially great.

Here are additional selected citations in chronological order.

In September 1961 a version of the expression was published in “The Journal of Medical Education”, and the author of the article was identified as the Director of Institute for Experimental Research in Surgery at the University of Copenhagen, Denmark. The words were credited to an unidentified Danish humorist: 6

“It is difficult to prophesy, particularly about the future,” as one of our humorists once expressed himself.

The Spring 1962 issue of the literary magazine “The Kenyon Review” printed an instance of the saying: 7

It is hard to prophecy, particularly about the future, a Danish witticism goes, and I shall refrain from such rashness…

Also in 1962 a Danish geophysical journal publishing in English printed a version of the mock adage: 8

But, to quote a Danish clown philosopher: “It is difficult to prophesy, especially about the future.”

In 1963 the magazine “Computers and Automation” based in Newtonville, Massachusetts printed yet another variant of the saying: 9

“Prediction is difficult, especially when dealing with the future”. . .Danish Proverb

In 1969 the book “How to Use the Computer in Business Planning” included an instance of the quip without attribution: 10

Let us not forget the old adage, “Forecasting is very difficult, especially about the future.”

In 1971 a version of the saying was attributed to the famous physicist Niels Bohr in the pages of the “Bulletin of the Atomic Scientists”. This ascription occurs frequently in modern times: 11

We must test all intellectually respectable lines of inquiry, while keeping in mind that, as the great Danish physicist Niels Bohr said, “it is very difficult to predict — especially the future.”

In January 1973 the saying was credited to Niels Bohr again in a journal published by the Society for Industrial and Applied Mathematics (SIAM) by the mathematician Mark Kac of Rockefeller University: 12

While (to quote Niels Bohr) “it is difficult to predict, especially the future” it might be useful (and fun) to pick out some recent developments which might be the forerunner of things to come.

In July 1973 the periodical New Scientist printed an instance without attribution: 13

It is always very difficult to prophesy, particularly about the future, and extrapolation of the prices of common stock has ruined many a speculator.

In September 1975 the mathematician Mark Kac employed the quip again. He carefully noted the ascription to Bohr, but he also stated that the expression was “an old Danish proverb”: 14

A principal purpose of this conference, as I am given to understand, is to try to look into the future of mathematical statistics. Now, there is a saying, attributed to Niels Bohr but apparently an old Danish proverb, that it is difficult to predict, especially the future.

In 1976 the mathematician Stanislaw M. Ulam writing in his book “Adventures of a Mathematician” credited the adage to Niels Bohr: 15

As Niels Bohr said in one of his amusing remarks: “It is very hard to predict, especially the future.” But I think mathematics will greatly change its aspect. Something drastic may evolve, an entirely different point of view on the axiomatic method itself.

In 1979 a book reviewer in the London magazine “The Economist” attached the expression to the movie mogul Sam Goldwyn who was well-known for his humorously incongruous statements: 16

This is because, as Sam Goldwyn once said, it is difficult to make forecasts, especially about the future.

In 1980 a newspaper in New York reprinted a different article from “The Economist” that credited Samuel Goldwyn: 17

Every prognosis here should be salted with all the familiar cautionary phrases, from Samuel Johnson’s snort (when warned in 1770 of Britain’s supposed impending ruin) that “there is a great deal of ruin in a country”, to Samuel Goldwyn’s “never prophesy, especially about the future”

In 1984 the popular syndicated gossip columnist Liz Smith ascribed the adage to Goldwyn: 18

“Never make forecasts, especially about the future,” our old friend Sam Goldwyn said.

In 1988 an article in the journal “The Hastings Center Report” assigned the saying to Nostradamus who was well-known for his prophecies: 19

Nostradamus allegedly said, “Prediction is difficult, especially about the future.”

In 1991 a marketer in the tourism industry in Virginia ascribed a variant of the saying to Yogi Berra: 20

Randall Foskey, director of admissions marketing for Colonial Williamsburg, probably said it best last week at the legislative dinner sponsored by the Virginia Hospitality and Travel Association.

“In the words of Yogi Berra, ‘I never make predictions, especially about the future,'” Foskey said.

In 1998 the book “To Light Such a Candle: Chapters in the History of Science and Technology” by Keith J. Laidler suggested that Mark Twain used the saying: 21

As Mark Twain said, it is difficult to make predictions, particularly about the future.

In 2000 an article from the RAND Corporation thank tank mentioned ascriptions to Mark Twain and Yogi Berra: 22

Two familiar quotations are worth citing to clarify the objectives of this analysis. The first is President Eisenhower’s truistic observation that “the future lies before us”; the second has been variously attributed to Mark Twain and Yogi Berra: “It is dangerous to make forecasts, especially about the future.”

In conclusion, current evidence indicates that this comical proverb was first expressed in Danish, and the author remains unknown. The first written instance now known was dated 1948.

Niels Bohr died in 1962, and the first published linkage of his name to the expression known to QI appeared in 1971. Fellow scientist Stanislaw M. Ulam who knew and communicated with Bohr credited him in 1976. Thus, there is substantive evidence that Bohr employed the saying in 1962 or earlier, but the date remains uncertain.  Samuel Goldwyn died in 1974, and his first linkage to the saying known to QI was printed in 1979. Perhaps he used the expression, but the evidence is very weak, and it is very unlikely he crafted it. These dates will probably change as more citations are uncovered.

(Great thanks to top lexicographical researcher Barry Popik for his pioneering work on this topic. Many thanks to Egil Gersov of Åbo Akademis bibliotek for locating the saying in “Farvel Og Tak” and creating scans. Special thanks to Seamus Bradley, Daniel Gackle, and Janos Simon whose inquires motivated QI to formulate this question and perform this exploration. Thanks also to Douglas G. Wilson for his analysis of the supposed 1918 citation. Also, thanks to Esben Mølgaard for his willingness to help. In addition, thanks to Amory Lovins who told QI that some instances of “Niels” were misspelled as “Neils”.)

Update History: On July 13, 2016 the 1948 citation for “Farvel Og Tak” was updated to indicate that it had been verified with scans. Update History: On January 5, 2021 instances of “Neils” were changed to “Niels”. Also, some text was rewritten.

Image Notes: The Crystal Ball circa 1902 by John William Waterhouse. Pictures accessed via Wikimedia Commons. Pictures are cropped.

ADDENDUM: A kind person (mentioned in the acknowledgement) helped QI verify the 1948 citation. But there exist other potential Danish citations. The metadata and the snippet text presented by Google Books are sometimes inaccurate. Hence, citations must be verified on paper.

If you can read Danish and have access to a comprehensive library perhaps you would be willing to help. The QI email address is on the About page here. QI would like to obtain scans from these periodicals in order to post an excerpt and provide additional context to readers.

Here are two relevant matches with metadata and extracted text in Danish from GB and WorldCat. The saying was attributed Storm P (Robert Storm Petersen) in the following:

Periodical Title: LO-Bladet
Year: 1952 (approximate)
Volume: 48
Page: 185 (approximate)
Publisher: [København, Landsorganisationen i Danmark]
Link: here

Nu er det imidlertid, som Storm-P. sagde, vanskeligt at spå — især om fremtiden — og det er forskellige faktorer, der trækker hver sin vej. Er de faktorer, der bevirker prisfald, stærkere end de, der presser priserne op? Den store efterspørgsel …

Title: Byplan
Year: 1953 (approximate)
Volumes: 5-6
Page 101 (approximate)
Author: Dansk byplanlaboratorium; Norsk byplanforening.
Publisher: Kbhvn. [i.e. København] : Arkitektens forlag, 1948-
Link: here

… „Det er vanskeligt at spå, navnlig om fremtiden”? Da den kloge biskop Absalon i ellevehundredhvidkål grundlagde København, var han en meget fremsynet mand, alle datidens byplan teoretikere har sikkert stottet ham i overbevisningen om, …


  1. 1948, Farvel Og Tak: Minder Og Meninger by K. K. Steincke, (Farvel Og tak: Ogsaa en Tilvaerelse IV (1935-1939)), Quote Page 227, Forlaget Fremad, København. (Publisher Fremad, Copenhagen, Denmark) (Verified with scans; thanks to a kind librarian at Åbo Akademis bibliotek)
  2. 2006, The Yale Book of Quotations by Fred R. Shapiro, Section Niels Bohr, Quote Page 92, Yale University Press, New Haven. (Verified on paper)
  3. 2012, The Dictionary of Modern Proverbs, Compiled by Charles Clay Doyle, Wolfgang Mieder, and Fred R. Shapiro, Page 206, Yale University Press, New Haven. (Verified on paper)
  4. 1956, Journal of the Royal Statistical Society: Series A (General), “Proceedings of the Meeting”, [Speaker: Bradford Hill], Page 147, Volume 119, Number 2, Blackwell Publishing for the Royal Statistical Society. (JSTOR) link
  5. 1961 May, The Canadian Journal of Economics and Political Science / Revue Canadienne d’Economique et de Science politique, Volume 27, Number 2, “Canada’s Economic Prospects: A Survey of Ten Industries” by Jesse W. Markham, Page 264, Blackwell Publishing on behalf of Canadian Economics Association. (JSTOR) link
  6. 1961 September, The Journal of Medical Education, Volume 36, “Medical Education in Denmark” by H. H. Wandall, Start Page 1059, Quote Page 1069, Column 2, Association of American Medical Colleges. (Verified on paper)
  7. 1962 Spring, The Kenyon Review, Volume 24, Number 2, “Almost in the Family: IV. Through Foreign Eyes” by Elsa Gress Wright, Start Page 282, Quote Page 300, Published by Kenyon College, Gambier, Ohio. (JSTOR) link
  8. 1962, Journal Name: Geofysiske Publikasjoner: Geophysica Norvegica, Volume 24, Special Issue: In memory of Vilhelm Bjerknes on the 100th Aniversary of His Birth, Article Title: “Vilhelm Bjerknes, March 14, 1862 – April 19, 1951”, Authors: Tor Bergeron, Olaf Devik, and Carl Ludvig Godske, Article Section: “Back in Oslo” by Carl Ludvig Godske, Start Page 21, Quote Page 25, Published by Det Norske Videnskaps-Akademi i Oslo, Universitetsforlaget, Oslo, Published in cooperation with the American Meteorological Society, Boston, Massachusetts. (Accessed Archive at on October 19, 2013) link
  9. 1963 December, Computers and Automation, Volume 12, Number 12, Diebold Researchers Undertake Study of EDP Developments, Quote Page 10, Column 1, Published by Berkeley Enterprises, Inc, Newtonville, Massachusetts. (Internet Archive)
  10. 1969, How to Use the Computer in Business Planning by Henry F. Lande, Section: The Purpose of This Book, Quote Page ix, Prentice-Hall, Englewood Cliffs, New Jersey. (Verified on paper)
  11. 1971 December, Bulletin of the Atomic Scientists, Volume 27, Number 10, On the Social Deployment of Science by Alan G. Mencher, Page 37, Educational Foundation for Nuclear Science, Inc. (Google Books full view) link
  12. 1973 January, SIAM Review, Volume 15, Number 1, Chronicle, Start Page 243, Quote Page 256, (Synoptic description of talk entitled “Whither Stochastic Processes?” by Mark Kac of Rockefeller University), Published by Society for Industrial and Applied Mathematics. (JSTOR) link
  13. 1973 July 12, New Scientist, Exponential Living by Lord Bowden, (Book Review of “The Logarithmic Century”), Start Page 100, Quote Page 100, New Science Publications, London. (Now Published by Reed Business Information) (Google Books full view) link
  14. 1975 September, Advances in Applied Probability, Volume 7, Supplement: Proceedings of the Conference on Directions for Mathematical Statistics, Some Reflections of a Mathematician on the Nature and the Role of Statistics by Mark Kac, Start Page 5, Quote Page 5, Published by Applied Probability Trust. (JSTOR) link
  15. 1976, Adventures of a Mathematician by Stanislaw M. Ulam, Quote Page 286, Charles Scribner’s Sons, New York. (Verified on paper)
  16. 1979 September 8, The Economist, Section: Books, Kahn and his banzai, (Book review of “World Economic Development 1979 and Beyond” and “The Japanese Challenge”, Start Page 120, Quote Page 121, Column 1, Published by Economist Newspaper Ltd., London. (Verified on microfilm)
  17. 1980 August 26, Finger Lake Times Three Options for the Soviets, (Acknowledgement to Economist, London), Quote Page 5, Column 1, Geneva, New York. (Old Fulton)
  18. 1984 March 12, The Post (The Palm Beach Post), Actress Gears Up For Busy Schedule by Liz Smith (Syndicated Column), Quote Page B2, Column 1, Palm Beach, Florida. (Google News Archive)
  19. 1988 December, Journal title: The Hastings Center Report, Volume 18, Number 6, Article title: Precatory Prediction and Mindless Mimicry: The Case of Mary O’Connor, Author: George J. Annas, (Unnumbered page in database), Published by Hastings Center. (Questia)
  20. 1991 January 20, Richmond Times-Dispatch, Section: Area/State, “Tourist Visits to State Sites Up 0.1% IN ’90 – Blue Ridge Highlands Region has Biggest Gain, 6.1 Percent”, Author: Wilford Kale, Quote Page F-1, Richmond, Virginia. (NewsBank Access World News)
  21. 1998, Book title: To Light Such a Candle: Chapters in the History of Science and Technology, Author: Keith J. Laidler, Quote Page 3, Publisher: Oxford University Press, Oxford, UK. (Questia)
  22. 2000, Asian Economic Trends and Their Security Implications by Charles Wolf Jr., Anil Bamezai, K. C. Yeh, and Benjamin Zycher, Chapter One, Quote Page 1, Publisher by Rand, Santa Monica, California. (Questia)