Category Archives: Paul Samuelson

When the Facts Change, I Change My Mind. What Do You Do, Sir?

John Maynard Keynes? Paul Samuelson? Winston Churchill? Joan Robinson? Apocryphal?


Dear Quote Investigator: John Maynard Keynes was an enormously influential economist, but some of his detractors complained that the opinions he expressed tended to change over the years. Once during a high-profile government hearing a critic accused him of being inconsistent, and Keynes reportedly answered with one of the following:

When events change, I change my mind. What do you do?

When the facts change, I change my mind. What do you do, sir?

When my information changes, I alter my conclusions. What do you do, sir?

When someone persuades me that I am wrong, I change my mind. What do you do?

Because there are so many different versions of this rejoinder I was hoping you might determine if any of them is real. Is there any truth to this anecdote?

Quote Investigator: No direct evidence that Keynes made a comment of this type has been located by QI or other researchers. The earliest statement found by QI that fits this template was not spoken by Keynes but by another prominent individual in the same field, Paul Samuelson who was awarded the 1970 Nobel Prize in economics. He was well-known to students for creating a best-selling economics textbook.

On December 20, 1970 he was interviewed by a panel on the television program “Meet the Press.” The transcript of the show was published the next day in the “Daily Labor Report” from the Bureau of National Affairs, Washington. Austin Kiplinger of Kiplinger Publications asked Samuelson about inflation. Boldface has been added to excerpts [PSDR]:

KIPLINGER: Returning to this matter of how much inflation we can absorb effectively, you may remember that Dr. Sumner Schlicter at Harvard shocked, I guess, the American Public after World War II when he said some inflation was not only inevitable but perhaps also desirable to promote growth. My question is do you agree with that general assessment and if so, how much should we have and how much is acceptable?

DR. SAMUELSON: I do agree with it and I suffer for expressing my agreement. Different editions of my textbook have been quoted. In the first edition I said a five percent rate is tolerable. Then I worked it down to three percent and then down to two percent and the AP carried a wire “Author Should Make Up His Mind.” Well when events change, I change my mind. What do you do?

Intriguingly, in 1978 Samuelson used a version of this expression again, and this time he credited the words to Keynes. His statement was reported in the Wall Street Journal in an article by Lindley H. Clark Jr. [PSWJ]:

Paul Samuelson, the Nobel laureate from the Massachusetts Institute of Technology, recalled that John Maynard Keynes once was challenged for altering his position on some economic issue. “When my information changes,” he remembered that Keynes had said, “I change my mind. What do you do?”

It is possible that Samuelson was consciously or unconsciously echoing a remark of Keynes when he spoke in 1970, but there is no compelling support for this because he did not credit Keynes during the television interview.

Here are some additional selected citations in chronological order.

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