“Capitalism is a great idea in theory, but in practice it just doesn't work.”
The News Quiz, BBC Radio 4, November 2008
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Jeremy Hardy 18
British comedian 1961–2019Related quotes
The Times, Sidney Morgenbesser: Erudite and influential American linguistic philosopher with the analytical acuity of Spinoza and the blunt wit of Groucho Marx https://www.thetimes.co.uk/article/sidney-morgenbesser-5cz8gg8qfvm, September 8, 2004.

“Canada is a country that works better in practice than in theory.”
As quoted in "One nation or many?" https://web-beta.archive.org/web/20170522044424/http://www.economist.com/node/8173164 (16 November 2006), The Economist
Hayek's Journey: The Mind of Friedrich Hayek (2003)
Cited in: Tom Butler-Bowdon (2010), 50 Prosperity Classics. p. 133
The E-Myth Revisited, 1995

“God is a great concept, [but it] doesn't work”
Interview from the movie Fuck (2005)

“In theory there is no difference between theory and practice; in practice there is.”
Attributed in Nassim Nicholas Taleb, Antifragile - Things that Gain From Disorder (2012), p. 213.
The earliest known appearance of this quote in print is Walter J. Savitch, Pascal: An Introduction to the Art and Science of Programming (1984), where it is attributed as a "remark overheard at a computer science conference". It circulated as an anonymous saying for more than ten years before attributions to Jan L. A. van de Snepscheut and Yogi Berra began to appear (and later still to various others).
Disputed, Misattributed
“In theory, there is no difference between theory and practice. But, in practice, there is.”
The earliest known appearance in print of this quote is Benjamin Brewster in the October 1881 - June 1882 issue of "The Yale Literary Magazine." Brewster asks, "What does his lucid explanation amount to but this, that in theory there is no difference between theory and practice, while in practice there is?" See page 202. https://books.google.com/books?id=iJ9MAAAAMAAJ&printsec=frontcover&vq=%22no+difference%22#v=onepage&q&f=false It has also been attributed by Doug Rosenberg and Matt Stephens (2007) Use Case Driven Object Modeling with UMLTheory and Practice p. xxvii as well as Walter J. Savitch, Pascal: An Introduction to the Art and Science of Programming (1984), where it is attributed as a "remark overheard at a computer science conference". It circulated as an anonymous saying for more than ten years before attributions to van de Snepscheut and Yogi Berra began to appear (and later still to various others).
Misattributed

“Just because you know a thing is true in theory, doesn't make it true in fact.”
Source: Deathworld (1960), p. 151
Context: Just because you know a thing is true in theory, doesn't make it true in fact. The barbaric religions of primitive worlds hold not a germ of scientific fact, though they claim to explain all. Yet if one of these savages has all the logical ground for his beliefs taken away — he doesn't stop believing. He then calls his mistaken beliefs 'faith' because he knows they are right. And he knows they are right because he has faith. This is an unbreakable circle of false logic that can't be touched. In reality, it is plain mental inertia. A case of thinking 'what always was' will also 'always be.' And not wanting to blast the thinking patterns out of the old rut.