Source: Assigning Meanings to Programs http://www.cs.virginia.edu/~weimer/2007-615/reading/FloydMeaning.pdf (1967), pp. 19–20.
“Rigor is not a yes-no property of a proof… it is a vague standard of careful treatment that is currently acceptable to a particular group.”
Methods of Mathematics Applied to Calculus, Probability, and Statistics (1985)
Context: When you yourself are responsible for some new application in mathematics... then your reputation... and possibly even human lives, may depend on the results you predict. It is then the need for mathematical rigor will become painfully obvious to you.... Mathematical rigor is the clarification of the reasoning used in mathematics.... a closer examination of the numerous "hidden assumptions" is made.... Over the years there has been a gradually rising standard of rigor; proofs that satisfied the best mathematicians of one generation have been found inadequate by the next generation. Rigor is not a yes-no property of a proof... it is a vague standard of careful treatment that is currently acceptable to a particular group.
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Richard Hamming 90
American mathematician and information theorist 1915–1998Related quotes

“Group action -- yes; group thinking -- no”
Seventy faces: articles of faith (2002)

“The standard you walk past, is the standard you accept.”
Message regarding unacceptable behaviour (2013)
Context: I will be ruthless in ridding the army of people who cannot live up to its values. And I need everyone of you to support me in achieving this. The standard you walk past, is the standard you accept. that goes for all of us, but especially those, who by their rank, have a leadership role. NB While on Q & A, ABC TV on 1st February 2016, Australian of the Year, Lieutenant General David Lindsay Morrison attributed; "The standard you walk by is the standard you accept"; to David Hurley, former Chief, Australian Defence Force, explaining the quote; "... doesn't belong to me or [my former speechwriter] Cate McGregor, it belongs to the Governor of NSW, David Hurley."
Art History And Class Struggle (1978)

1980s and later, Knowledge, Evolution and Society (1983), "Coping with Ignorance", "Our Moral Heritage"

“Wide acceptance of an idea is not proof of its validity.”
Source: The Lost Symbol