“You have no proof of this,” I said.
“No. But a theory must be tested to be disproved, Mr Bastable.”
Book 1, Chapter 8 “A Decision in Cold Blood” (p. 233)
Oswald Bastable, The Land Leviathan (1974)
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Michael Moorcock 224
English writer, editor, critic 1939Related quotes

Youtube, Other, Reason Rally Ra Rant https://www.youtube.com/watch?v=isrST6wOUJA (March 28, 2012)
“One test of good theory is that it have practical implications.”
Source: 1970s, Organizational Analysis: A Sociological View, 1970, p. vii
Context: It is surprising how much discipline is imposed upon theory by requiring that it ‘make a difference’ and provide guidance or useful illumination. I learned long ago from students in professional schools that questions of ‘so what’ or ‘what relevance does this have’ do not signify impatience with theory per se, much less anti-intellectualism, but only impatience with the obvious, general, remote, and vague statements that often parade as social science theory. One test of good theory is that it have practical implications.

"Reincarnation of the Reds," http://www.ilanamercer.com/phprunner/public_article_list_view.php?editid1=108 WorldNetDaily.com, December 29, 2006, The Colorado Springs Gazette, January 17, 2007, and The Orange County Register, "The Reds Have Become Greens," January 19, 2007.
2000s, 2007

Philosophy in the Twentieth Century (1982) p. 133.
p. 1078 of "The discovery of forcing." http://www.logic.univie.ac.at/~ykhomski/ST2013/The%20Discovery%20of%20Forcing.pdf Rocky Mountain Journal of Mathematics 32, no. 4 (2002): 1071–1100.

“The proof of a theory is in its reasoning, not in its sponsorship”
Theory of Money and Credit http://www.econlib.org/library/Mises/msT1.html (1912)
Source: http://www.econlib.org/library/Mises/msT2.html#I.5.12 | Theory of Money and Credit

“Existence proofs always trump theory. That’s engineering.”
Source: Short fiction, The Man Who Sold The Moon (2014), p. 135