# John von Neumann

Truth … is much too complicated to allow anything but approximations.

John von Neumann (28 December 19038 February 1957) was a Hungarian-American-German-Jewish mathematician and computer scientist, generally regarded as one of the foremost mathematicians of the 20th century.

## Quotes

Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin.
When we talk mathematics, we may be discussing a secondary language built on the primary language of the nervous system.
In mathematics you don't understand things. You just get used to them.
With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.
You wake me up early in the morning to tell me that I'm right? Please wait until I'm wrong.
If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.
There probably is a God. Many things are easier to explain if there is than if there isn't.
• I think that it is a relatively good approximation to truth — which is much too complicated to allow anything but approximations — that mathematical ideas originate in empirics. But, once they are conceived, the subject begins to live a peculiar life of its own and is … governed by almost entirely aesthetical motivations. In other words, at a great distance from its empirical source, or after much "abstract" inbreeding, a mathematical subject is in danger of degeneration. Whenever this stage is reached the only remedy seems to me to be the rejuvenating return to the source: the reinjection of more or less directly empirical ideas.
• "The Mathematician", in The Works of the Mind (1947) edited by R. B. Heywood, University of Chicago Press, Chicago
• Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin. For, as has been pointed out several times, there is no such thing as a random number — there are only methods to produce random numbers, and a strict arithmetic procedure of course is not such a method.
• On mistaking pseudorandom number generators for being truly "random" — this quote is often erroneously interpreted to mean that von Neumann was against the use of pseudorandom numbers, when in reality he was cautioning about misunderstanding their true nature while advocating their use. From "Various techniques used in connection with random digits" by John von Neumann in Monte Carlo Method (1951) edited by A.S. Householder, G.E. Forsythe, and H.H. Germond
• A large part of mathematics which becomes useful developed with absolutely no desire to be useful, and in a situation where nobody could possibly know in what area it would become useful; and there were no general indications that it ever would be so. By and large it is uniformly true in mathematics that there is a time lapse between a mathematical discovery and the moment when it is useful; and that this lapse of time can be anything from 30 to 100 years, in some cases even more; and that the whole system seems to function without any direction, without any reference to usefulness, and without any desire to do things which are useful.
• "The Role of Mathematics in the Sciences and in Society" (1954) an address to Princeton alumni, published in John von Neumann : Collected Works (1963) edited by A. H. Taub ; also quoted in Out of the Mouths of Mathematicians : A Quotation Book for Philomaths (1993) by R. Schmalz
• 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.
• "Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
• It is exceptional that one should be able to acquire the understanding of a process without having previously acquired a deep familiarity with running it, with using it, before one has assimilated it in an instinctive and empirical way… Thus any discussion of the nature of intellectual effort in any field is difficult, unless it presupposes an easy, routine familiarity with that field. In mathematics this limitation becomes very severe.
• As quoted in "The Mathematician" in The World of Mathematics (1956), by James Roy Newman
• When we talk mathematics, we may be discussing a secondary language built on the primary language of the nervous system.
• As quoted in John Von Neumann, 1903-1957' (1958) by John C. Oxtoby and B. J. Pettis, p. 128
• It is just as foolish to complain that people are selfish and treacherous as it is to complain that the magnetic field does not increase unless the electric field has a curl. Both are laws of nature.
• As quoted "John von Neumann (1903 - 1957)" by Eugene Wigner, in Year book of the American Philosophical Society (1958); later in Symmetries and Reflections : Scientific Essays of Eugene P. Wigner (1967), p. 261
• You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, no one really knows what entropy really is, so in a debate you will always have the advantage.
• Suggesting to Claude Shannon a name for his new uncertainty function, as quoted in Scientific American Vol. 225 No. 3, (1971), p. 180
• Young man, in mathematics you don't understand things. You just get used to them.
• Reply as reported by Dr. Felix T. Smith of Stanford Research Institute to a physicist friend who had said "I'm afraid I don't understand the method of characteristics." —as quoted in footnote of pg 226, in The Dancing Wu Li Masters: An Overview of the New Physics (1991) by Gary Zukav.
• The goys have proven the following theorem…
• Statement at the start of a classroom lecture, as quoted in 1,911 Best Things Anyone Ever Said (1988) by Robert Byrne
• The calculus was the first achievement of modern mathematics and it is difficult to overestimate its importance. I think it defines more unequivocally than anything else the inception of modern mathematics; and the system of mathematical analysis, which is its logical development, still constitutes the greatest technical advance in exact thinking.
• As quoted in Bigeometric Calculus: A System with a Scale-Free Derivative (1983) by Michael Grossman, and in Single Variable Calculus (1994) by James Stewart.
• If one has really technically penetrated a subject, things that previously seemed in complete contrast, might be purely mathematical transformations of each other.
• As quoted in Proportions, Prices, and Planning (1970) by András Bródy
• If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.
• Remark made by von Neumann as keynote speaker at the first national meeting of the Association for Computing Machinery in 1947, as mentioned by Franz L. Alt at the end of "Archaeology of computers: Reminiscences, 1945--1947", Communications of the ACM, volume 15, issue 7, July 1972, special issue: Twenty-fifth anniversary of the Association for Computing Machinery, p. 694.
• There probably is a God. Many things are easier to explain if there is than if there isn't.
• As quoted in John Von Neumann : The Scientific Genius Who Pioneered the Modern Computer, Game Theory, Nuclear Deterrence and Much More (1992) by Norman Macrae, p. 379
• If you say why not bomb them tomorrow, I say why not today? If you say today at five o' clock, I say why not one o' clock?
• As quoted in "The Passing of a Great Mind" by Clay Blair, Jr., in LIFE Magazine (25 February 1957), p. 96

A mind of von Neumann's inexorable logic had to understand and accept much that most of us do not want to accept and do not even wish to understand. ~ Eugene Wigner
Sorted alphabetically by author or source
• Bennie decided to approach Johnnie on the matter and arranged to travel to Princeton’s Institute for Advanced Study, headed up at the time by Oppenheimer, where Johnnie (and lesser geniuses such as Albert Einstein) was stationed.
• I have sometimes wondered whether a brain like von Neumann's does not indicate a species superior to that of man.
• Nobel Laureate Hans Bethe of Cornell University, as quoted in LIFE Magazine (1957), pages 89-104
• He was a really remarkable man. He listened to me talk about this rather obscure subject and in ten minutes he knew more about it than I did. He was extremely quick.
• David Blackwell, as quoted in Out of the Mouths of Mathematicians : A Quotation Book for Philomaths (1993) by Rosemary Schmalz, Mathematical Association of America, ISBN: 9780883855096, p. 213
• The only student of mine I was ever intimidated by. He was so quick. There was a seminar for advanced students in Zürich 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.
• Quite aware that the criteria of value in mathematical work are, to some extent, purely aesthetic, he once expressed an apprehension that the values put on abstract scientific achievement in our present civilization might diminish: "The interests of humanity might change, the present curiosities in science may cease, and entirely different things may occupy the human mind in the future." One conversation centered on the ever accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue.
• A deep sense of humor and an unusual ability for telling stories and jokes endeared Johnny even to casual acquaintances. He could be blunt when necessary, but was never pompous. A mind of von Neumann's inexorable logic had to understand and accept much that most of us do not want to accept and do not even wish to understand. This fact colored many of von Neumann's moral judgments. … Only scientific intellectual dishonesty and misappropriation of scientific results could rouse his indignation and ire — but these did — and did almost equally whether he himself, or someone else, was wronged.
• Eugene Wigner, in "John von Neumann (1903 - 1957)" in Year book of the American Philosophical Society (1958); later in Symmetries and Reflections : Scientific Essays of Eugene P. Wigner (1967), p. 261