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Who really said it

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

Not Garret FitzGerald — an anonymous joke Anonymous Origin anonymous · earliest strong match 1911 · attached to FitzGerald only from 1985
Disputed Rights unconfirmed

This is a long-running joke about economists, not a FitzGerald original. Quote Investigator ↗ traces its earliest strong match to an unsigned 1911 magazine anecdote about a Heidelberg professor and concludes that the originator was anonymous, with later instances popularised by W. R. Rodgers, Claude T. Bissell, Sean MacReamoinn and Walter Heller. FitzGerald enters the story only in 1985, when the businessman Tony O’Reilly put a version of the line in his mouth during a comic impersonation — and his 2011 obituary in The New York Times then reported it as something FitzGerald had actually said.

Last verified 7 Sep 2026 · how we verify · spot an error?

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Disputed credit — copy with the correction

“That Works Very Well in Practice, But How Does It Work In Theory?” Not Garret FitzGerald. The joke is anonymous: Quote Investigator's earliest strong match is an unsigned 1911 item, "A Professional Paradox," in The Youth's Companion (5 October 1911), and it concludes the originator cannot be identified. Close matches follow in The New Statesman and Nation (1951), Varsity Graduate (1959), The Irish Times (1972) and The Washington Star (1979, credited to economist Walter W. Heller). FitzGerald was first linked to the line on 6 July 1985, when The Irish Times reported Tony O'Reilly delivering it as part of a comic impersonation of him; his New York Times obituary of 20 May 2011 then printed a version as FitzGerald's own remark.

The slide-ready mistake: crediting this to Garret FitzGerald. Use the credit shown above instead.

Can you use it?

We couldn’t verify where this wording comes from, so there’s no rights status to give. Safe to present as an unverified or anonymous line — just don’t assert a specific author or source.

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In context

Evoking the themes of knowledge, doubt and wisdom. Theme: "That Works Very Well in Practice, But How Does It Work In Theory?". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.

Minimalist

Minimalist editorial slide for the quote "That Works Very Well in Practice, But How Does It Work In Theory?". Clean background, a single muted accent color, generous negative space, subtle paper or linen texture, no literal illustration — let the words carry it. Reserve clear space for a serif quote and a small credit line. No lettering in the image itself.

Provenance

The 1985 moment the line became ‘his’

Earliest strong match
“A Professional Paradox,” unsigned, 5 October 1911
First linked to FitzGerald
The Irish Times, 6 July 1985 — reporting an impersonation, not a speech
Hardened into fact
New York Times obituary, 20 May 2011
Originator
Anonymous, per Quote Investigator

“That’s a very good idea,” said Garret. “I know it will work very well in practice, but tell me John, how will it work in theory?” As impersonated, not as spoken

This is not Garret FitzGerald speaking. It is Tony O’Reilly performing FitzGerald — sketching an imaginary cabinet meeting in which John Bruton, then a minister in FitzGerald’s government, proposes a solution to the balance of payments problem. The Irish Times reported the routine on 6 July 1985 and noted the audience laughed. It is the earliest connection between this joke and FitzGerald that anyone has documented, and it is a joke about him, not by him.

Quote Investigator: the full chronology, 1911 to 2015

How we verified this

  • 1911 — the earliest strong match located by Quote Investigator ↗ is an unsigned filler item, “A Professional Paradox,” in The Youth’s Companion of 5 October 1911. A Heidelberg professor forbids an experiment that has always succeeded: “The thing may answer very well in practise, but it is not sound in theory.”
  • 1951 & 1959 — the modern shape arrives. W. R. Rodgers, writing in The New Statesman and Nation of 6 January 1951, tells of an Irish company chairman greeting record dividends with “this is all very well in practice. But how does it work out in theory?” Claude T. Bissell, president of the University of Toronto, retold the same Irish-boardroom story in Varsity Graduate, volume 8 (1959) ↗.
  • 1979 — the joke is recast as a definition of economists and credited to Walter W. Heller, adviser to Presidents Kennedy and Johnson. Barry Popik ↗ collects the newspaper run from the Seattle Daily Times of 4 July 1979 onward; FitzGerald appears nowhere in it.
  • 1985 → 2011 — Tony O’Reilly’s impersonation puts the line in FitzGerald’s mouth, and FitzGerald’s New York Times obituary of 20 May 2011 reports a version of it as his own remark. Quote Investigator ↗ documents both, and still concludes the originator was anonymous.

No rights status can honestly be asserted, because the popular wording has no identifiable author or first publication. The 1911 anecdote that supplies the joke’s earliest strong match is unsigned and long out of copyright, but it uses different words; the wordings that most resemble the modern form appear in works still under copyright — The New Statesman and Nation (1951), The Irish Times (1985) and The New York Times (2011). The exact string usually quoted matches none of them.

Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.

Fact-check

Everyone this joke has been pinned on

This is a travelling gag, not a quotation. It attaches itself to whichever public figure best fits the caricature of the theorist, and the record shows it changing hosts roughly once a decade.

Garret FitzGerald the popular credit

The earliest FitzGerald instance found by Quote Investigator ↗ is The Irish Times of 6 July 1985, reporting Tony O’Reilly giving “a superb imitation of Garret FitzGerald” and sketching an imaginary cabinet meeting in which FitzGerald’s minister John Bruton proposes a fix for the balance of payments. The words are O’Reilly’s comic invention. FitzGerald’s 2011 obituary in The New York Times later printed a version as his own line, and quote aggregators have repeated it since with no source at all ↗.

Walter W. Heller six years earlier

Credited to the former chairman of the US Council of Economic Advisers in The Washington Star of 28 June 1979, per Quote Investigator ↗, and repeated in newspapers through the 1980s as collected by Barry Popik ↗. The joke was already in print decades before he used it, and Quote Investigator concludes the originator was anonymous.

Ernest Hollings recycled

Attributed to the US senator in The Plain Dealer of Cleveland on 8 May 1988, as documented by Quote Investigator ↗ — nine years after the Heller version was already in print.

W. R. Rodgers, Claude T. Bissell and Sean MacReamoinn tellers, not authors

Rodgers told it in The New Statesman and Nation in January 1951 about an unnamed Irish company chairman; Bissell retold the same story in the University of Toronto’s Varsity Graduate, volume 8 (1959) ↗; MacReamoinn was quoting it on Irish radio by 1972. Quote Investigator ↗ names all three as popularisers, not originators.

Quote Investigator’s conclusion ↗ is explicit: “this quip evolved over many decades, and its originator was anonymous.” Garret FitzGerald is one of the later names it was handed to — and the only one who got it by way of a comedian doing an impression of him.

Context

How a joke about economists found a Taoiseach

The gag works by inverting a sturdy old complaint. “That’s fine in theory, but will it work in practice?” is the ordinary sceptic’s objection; reversing it produces an instant caricature of the theorist who cannot accept good news until the model agrees. That is why it has been handed round for a century, landing on whoever the era’s most conspicuous theorist happened to be — a Heidelberg professor in 1911, an Irish company chairman in 1951, a university president’s alumni-magazine essay in 1959, an economic adviser to two US presidents in 1979.

Garret FitzGerald was an unusually good fit. He was a doctorate-holding economist who became head of government, and his public image ran to the professorial. When Tony O’Reilly wanted a laugh at a 1985 event, doing FitzGerald chairing a cabinet meeting, the line was already sitting there waiting. The impersonation is the point: O’Reilly was not reporting something FitzGerald said, he was writing a joke in FitzGerald’s voice. Twenty-six years later, an obituary printed a version of it as FitzGerald’s own remark, and the loop closed.

The line was never FitzGerald’s. It was O’Reilly’s — doing FitzGerald.

One more wrinkle: the wording everybody quotes isn’t in any of the sources

Compare the documented wordings and none of them is the popular form. 1951 gives “this is all very well in practice. But how does it work out in theory?”; 1959, “That is all very well in practice, but how will it work out in theory?”; 1972, “It’s all very well in practice. How is it in theory?”; the 1985 O’Reilly impersonation, “I know it will work very well in practice, but tell me John, how will it work in theory?”; the 2011 obituary, “That’s fine in practice, but will it work in theory?”

The string circulating today — “That Works Very Well in Practice, But How Does It Work In Theory?” — is in fact the headline of Quote Investigator’s 2015 article ↗ on the subject. That is a researcher’s summary of a family of jokes, not a sentence anyone is recorded as speaking. It is worth saying plainly, because a quotation that exists only in its investigator’s title is about as far from a sourced utterance as a quotation can get.

Explore

Filed under

More provenance-checked quotes on the same theme, each with its reuse status.

Knowledge Doubt Wisdom

Go further

Dig deeper

Trusted places to keep pulling the thread — primary archives, fact-checks, and scholarship. We show how we used each one before you leave.

Quote Investigator: the full chronologyquoteinvestigator.com

The anchor investigation. Ten dated citations from 1911 to 2015, with exact wordings, and the conclusion that the quip evolved over decades from an anonymous origin.
Barry Popik on the economist versionbarrypopik.com

Newspaper instances of the “an economist is someone who…” form from July 1979 onward, associated with Walter Heller. FitzGerald is not mentioned.
Garret FitzGeralden.wikipedia.org

Life dates, both terms as Taoiseach, and his economics career at Aer Lingus, The Economist and UCD. The article does not carry the quip.
Varsity Graduate, volume 8 (1959)archive.org

The University of Toronto alumni volume in which Claude T. Bissell retold the Irish-boardroom version, scanned in full.
Tony O’Reillyen.wikipedia.org

Background on Sir Anthony John Francis O’Reilly (1936–2024), the Irish businessman whose 1985 impersonation first put the line in FitzGerald’s mouth.
The quote as it circulates, unsourcedgoodreads.com

A typical aggregator entry crediting FitzGerald with no citation of any kind — the mechanism by which the obituary line became ‘his’ quote.

The man the joke landed on

Why it stuck to him

Garret FitzGerald

1926–2011 · Taoiseach of Ireland and academic economist

Garret FitzGerald (9 February 1926 – 19 May 2011) was a Fine Gael politician who served two terms as Taoiseach, from June 1981 to March 1982 and from December 1982 to March 1987. Before politics he built a career in economics — working in transport planning at Aer Lingus, acting as Irish correspondent for The Economist, lecturing at University College Dublin and taking a UCD doctorate in economics in 1968, published as Planning in Ireland. That combination — a working economist running a country, with a public reputation for professorial abstraction — is precisely what made him a plausible host for a joke that had been circulating, unowned, for decades before he reached office.

For writers & researchers

Cite this

Earliest documented in

“A Professional Paradox.” The Youth’s Companion: For All the Family 85, no. 40 (October 5, 1911): 515 — the earliest strong match located by Quote Investigator, which concludes the quip’s originator was anonymous. The line was first attached to Garret FitzGerald in Anthony O’Reilly’s comic impersonation of him, reported in The Irish Times (Dublin), July 6, 1985, 14.

This verification page

Quotle.info. “Who really said ‘That Works Very Well in Practice, But How Does It Work In Theory?’?” Last verified 7 Sep 2026. https://quotle.info/who-said/that-works-very-well-in-practice-but-how-does-it-work-in/

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