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Home > Dictionary of Science Quotations > Scientist Names Index V > John von Neumann Quotes

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John von Neumann
(28 Dec 1903 - 8 Feb 1957)

Hungarian-American mathematician who made significant contributions in diverse fields, including quantum physics, logic, meteorology, game theory and computer science.

Science Quotes by John von Neumann (4 quotes)

Neumann, to a physicist seeking help with a difficult problem: Simple. This can be solved by using the method of characteristics.
Physicist: I'm afraid I don’t understand the method of characteristics.
Neumann: In mathematics you don't understand things. You just get used to them.
— John von Neumann
Attributed, as related by Dr. Felix Smith (Head of Molecular Physics, Stanford Research Institute) to author Gary Zukav, who quoted it in The Dancing Wu Li Masters: An Overview of the New Physics (1979, 2001), 208, footnote. The physicist (a friend of Dr. Smith) worked at Los Alamos after WW II. It should be noted that although the author uses quotation marks around the spoken remarks, that they represent the author's memory of Dr. Smith's recollection, who heard it from the physicist. Therefore the fourth-hand wording is very likely not verbatim. Webmaster finds Zukav's book seems to be the only source for this quote.
Science quotes on:  |  Characteristic (66)  |  Mathematics (587)  |  Method (154)  |  Solution (168)  |  Understanding (317)

Anyone who considers arithmetical methods of producing random digits is, of course, in the state of sin.
— John von Neumann
Remark made at a symposium on the Monte Carlo method. 'Various Techniques Used in Connection with Random Digits', Journal of Research of the National Bureau of Standards, Appl. Math. Series (1951), 3, 36-38; Collected Works, Vol. 5, 5. As quoted in Herman Heine Goldstine, The Computer from Pascal to von Neumann (2nd Ed. 1993), 297.
Science quotes on:  |  Arithmetic (68)  |  Random Number (2)  |  Sin (27)

The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work—that is, correctly to describe phenomena from a reasonably wide area.
— John von Neumann
'Method in the Physical Sciences', in The Unity of Knowledge, editted by L. Leary (1955), 158. Reprinted in John Von Neumann, F. Bródy (ed.) and Tibor Vámos (ed.), The Neumann Compendium (2000), 628.
Science quotes on:  |  Construct (25)  |  Explanation (161)  |  Interpretation (61)  |  Justification (33)  |  Mathematics (587)  |  Model (64)  |  Observation (418)  |  Phenomenon (218)  |  Science (1699)

What is important is the gradual development of a theory, based on a careful analysis of the ... facts. ... Its first applications are necessarily to elementary problems where the result has never been in doubt and no theory is actually required. At this early stage the application serves to corroborate the theory. The next stage develops when the theory is applied to somewhat more complicated situations in which it may already lead to a certain extent beyond the obvious and familiar. Here theory and application corroborate each other mutually. Beyond lies the field of real success: genuine prediction by theory. It is well known that all mathematized sciences have gone through these successive stages of evolution.
— John von Neumann
'Formulation of the Economic Problem' in Theory of Games and Economic Behavior (1964), 8. Reprinted in John Von Neumann, F. Bródy (ed.) and Tibor Vámos (ed.), The Neumann Compendium (2000), 416.
Science quotes on:  |  Application (117)  |  Corroborate (2)  |  Fact (609)  |  Prediction (67)  |  Problem (362)  |  Theory (582)

Quotes by others about John von Neumann (3)

The spectacular thing about Johnny [von Neumann] was not his power as a mathematician, which was great, or his insight and his clarity, but his rapidity; he was very, very fast. And like the modern computer, which no longer bothers to retrieve the logarithm of 11 from its memory (but, instead, computes the logarithm of 11 each time it is needed), Johnny didn't bother to remember things. He computed them. You asked him a question, and if he didn't know the answer, he thought for three seconds and would produce and answer.
From interview with Donald J. Albers. In John H. Ewing and Frederick W. Gehring, Paul Halmos Celebrating 50 Years of Mathematics (1991), 9.
Science quotes on:  |  Answer (201)  |  Compute (10)  |  Computer (84)  |  Logarithm (4)  |  Mathematician (177)  |  Memory (81)  |  Question (315)  |  Remember (53)  |  Thinking (222)

There was a seminar for advanced students in Zόrich that I was teaching and von Neumann was in the class. I came to a certain theorem, and I said it is not proved and it may be difficult. Von Neumann didn’t say anything but after five minutes he raised his hand. When I called on him he went to the blackboard and proceeded to write down the proof. After that I was afraid of von Neumann.
In George Pσlya and Gerald L. Alexanderson (ed.) The Pσlya Picture Album: Encounters of a Mathematician (1987), 154. Also footnoted in Matti Tedre, The Development of Computer Science: a Sociocultural Perspective (2006), 198, cited as from How to Solve It: A New Aspect of Mathematical Method (1957), xv.
Science quotes on:  |  Afraid (15)  |  Blackboard (6)  |  Difficulty (113)  |  Proof (192)  |  Student (131)  |  Teaching (99)  |  Theorem (46)  |  Writing (72)

Running overtime is the one unforgivable error a lecturer can make. After fifty minutes (one microcentury as von Neumann used to say) everybody's attention will turn elsewhere.
In 'Ten Lessons I Wish I Had Been Taught', Indiscrete Thoughts (2008), 197.
Science quotes on:  |  Attention (76)  |  Error (230)  |  Fifty (15)  |  Lecturer (7)  |  Minute (25)

See also:
  • 28 Dec - short biography, births, deaths and events on date of Neumann's birth.
  • John von Neumann - context of quote In mathematics you don't understand things. - Medium image (500 x 350 px)
  • John von Neumann - context of quote In mathematics you don't understand things. - Large image (800 x 600 px)
  • John von Neumann: The Scientific Genius Who Pioneered..., by Norman MacRae. - book suggestion.

Carl Sagan Thumbnail In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) -- Carl Sagan
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