Tie a string to an object. When you pull on a string, the object on the other end comes toward you.
But when you push on a string, the object at the other end of the string is unaffected, because the string just crumples up. For economists, "pushing on a string" refers to the idea that monetary policy may (in certain circumstances) be more effective at reducing inflation even at the cost of a recession than it is at stimulating an economy. Back in 2015, I posted about an early use of the "pushing on a string" metaphor during Congressional hearings in March 1935.
However, Samuel Demeulemeester has recently written to me with several example from the same time frame, but slightly earlier. Jeff Busby was at the time a Congressman from Mississippi. Willford King was a professor of economics at New York University, and a Fellow of the American Statistical Association. Irving Fisher is in the story, too. In short, the metaphor was not a one-off comment in 1935, but was demonstrably familiar to policy-makers and academics at this time. What follows is from Demeulemeester, with his permission (for ease of reading, I have not inserted additional indenting or quotation marks to his email):
I just came across your post of July 30, 2015, “Pushing on a String: An Origin Story”, in which you suggest that this metaphor might first have been used by Representative T. A. Goldsborough during hearings held on March 18, 1935.
Goldsborough actually seems to have gotten this metaphor from Willford King of New York University, who used it during hearings before a subcommittee (presided by Goldsborough) of the Committee on Banking and Currency, House of Representatives, on January 30, 1934. King had himself heard it from “somebody” else:
Mr. BUSBY. Therefore, I think it is more essential we go to the question of dealing with both the up and down amount of bank money that may be issued so as to control it.
Mr. KING. You can prevent overissuance of this bank-deposit currency, but it is very hard to prevent underissuance of the same thing. As somebody said, you can push on a string but it doesn’t produce very good results.
Mr. BUSBY. That is exactly what I have in mind, and I want to see some kind of scheme worked out where we are pushing on the string and you can see some effect on the other end of the string.
(See here, p. 71)
This Mr. Busby would himself use the metaphor in an exchange with Irving Fisher two days later, on February 1, 1934, before the same subcommittee:
Mr. BUSBY. As Dr. King said yesterday, you can pull on a string and feel the effect of it. Therefore, you can pull down the fixed media of exchange, but you can’t push it up, just as you can push on a string and feel no effect at the other end. So in adverse times when property prices are falling the only remedy I see to get efficiency out of the arrangement is for the Government to step in and supply where this by-product of the banks' activities is wiped out.
(Ibid., p. 85)
And Fisher himself would use a variation of the “pushing on a string” metaphor in the following passage of his book 100% Money (1935):
Such must often be our predicament so long as we have a system under which our circulating medium is a by-product of private debt. The time when nobody wants to go into debt is the very time when we most need money and so most hope that somebody will kindly accommodate us by going into debt. Few will do so, despite all the official urging and coaxing and despite the low rates of interest. It is a case of leading a horse to water without being able to make him drink. Or it is like “pushing on the lines” to make the horse go.
(1935, 1st ed., p. 94;  1936, 2nd ed., p. 105; this passage already appeared in a 1934 draft version of the book)
As Demeulemeester points out in a follow-up email: `By the way, King's statement, as I re-read it, only says that he did not originate the phrase "you can push on a string but it doesn't produce very good results'. This leaves open the possibility that he was the first to apply this metaphor to monetary policy."
Timothy Taylor is an American economist. He is managing editor of the Journal of Economic Perspectives, a quarterly academic journal produced at Macalester College and published by the American Economic Association. Taylor received his Bachelor of Arts degree from Haverford College and a master's degree in economics from Stanford University. At Stanford, he was winner of the award for excellent teaching in a large class (more than 30 students) given by the Associated Students of Stanford University. At Minnesota, he was named a Distinguished Lecturer by the Department of Economics and voted Teacher of the Year by the master's degree students at the Hubert H. Humphrey Institute of Public Affairs. Taylor has been a guest speaker for groups of teachers of high school economics, visiting diplomats from eastern Europe, talk-radio shows, and community groups. From 1989 to 1997, Professor Taylor wrote an economics opinion column for the San Jose Mercury-News. He has published multiple lectures on economics through The Teaching Company. With Rudolph Penner and Isabel Sawhill, he is co-author of Updating America's Social Contract (2000), whose first chapter provided an early radical centrist perspective, "An Agenda for the Radical Middle". Taylor is also the author of The Instant Economist: Everything You Need to Know About How the Economy Works, published by the Penguin Group in 2012. The fourth edition of Taylor's Principles of Economics textbook was published by Textbook Media in 2017.