“We do not always know what we are talking about.... Troubles... can be made to arise whenever what is being said includes itself—a self-referral situation.”
Methods of Mathematics Applied to Calculus, Probability, and Statistics (1985)
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Richard Hamming 90
American mathematician and information theorist 1915–1998Related quotes

Original German: Man könnte den ganzen Sinn des Buches etwa in die Worte fassen: Was sich überhaupt sagen lässt, lässt sich klar sagen; und wovon man nicht reden kann, darüber muss man schweigen.
Introduction
1920s, Tractatus Logico-Philosophicus (1922)

Rejoinder when told that he couldn't talk about physics, because "nobody [at this table] knows anything about it."
Part 5: "The World of One Physicist", "Alfred Nobel's Other Mistake", p. 310.
Quoted in Handbook of Economic Growth (2005) by Philippe Aghion and Steven N. Durlauf.
Surely You're Joking, Mr. Feynman! (1985)

Source: 2010s, Free Will (2012), p. 13

Remarks (20 May 1992), quoted in Esquire (August 1992) and Ann Beatts (23 November 1997) "ABSURDUM; Murphy Brown's Got Dan All Fired Up Again," Los Angeles Times
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