“Je pense pouvoir dire sans trop me tromper que personne ne comprend la mécanique quantique.”
I think I can safely say that nobody understands quantum mechanics
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Richard Phillips Feynman est un physicien américain, l'un des plus influents de la seconde moitié du XXe siècle, en raison notamment de ses travaux sur l'électrodynamique quantique, les quarks et l'hélium superfluide.
Il reformula entièrement la mécanique quantique à l'aide de son intégrale de chemin qui généralise le principe de moindre action de la mécanique classique et inventa les diagrammes qui portent son nom et qui sont désormais largement utilisés en théorie quantique des champs .
Pendant la Seconde Guerre mondiale, il fut impliqué dans le développement de la bombe atomique américaine. Après la Seconde Guerre mondiale, il enseigna à l'université Cornell puis au Caltech où il effectua des travaux fondamentaux notamment dans la théorie de la superfluidité et des quarks. Sin-Itiro Tomonaga, Julian Schwinger et lui sont colauréats du prix Nobel de physique de 1965 pour leurs travaux en électrodynamique quantique. Vers la fin de sa vie, son action au sein de la commission d'enquête sur l'accident de la navette spatiale Challenger l'a fait connaître du grand public américain.
Pédagogue remarquable, il est le rédacteur de nombreux ouvrages de vulgarisation reconnus. Parmi ces livres, les Feynman lectures on physics, un cours de physique de niveau universitaire qui, depuis sa parution, est devenu un classique pour tous les étudiants de premier cycle en physique et leurs professeurs. Il raconte aussi ses nombreuses aventures dans plusieurs ouvrages : Surely You're Joking, Mr. Feynman! et What Do You Care What Other People Think?. Ce tome est lié au soutien moral que sa première épouse Arline lui donnait, l'encourageant par ce biais dans sa poursuite intellectuelle en tant que libre-penseur.
Wikipedia
“Je pense pouvoir dire sans trop me tromper que personne ne comprend la mécanique quantique.”
I think I can safely say that nobody understands quantum mechanics
en
If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atoms little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.
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[...] we have always had (secret, secret, close the doors!) we have always have had a great deal of difficulty in understanding the world view that quantum mechanics represents. At least I do, because I'm an old enough man that I haven't got to the point that this stuff is obvious to me. Okay, I still get nervous with it. And therefore, some of the youngest students...you know how it always is, every new idea, it takes a generation or two until it becomes obvious that there's no real problem. It has not yet become obvious to me that there is no real problem. I cannot define the real problem, therefore I suspect there's no real problem, but I'm not sure there's no real problem.
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“il s’agit en quelque sorte d’une caractéristique de la simplicité de la nature.”
sur le fait qu'il existe de nombreuses manières de formuler une même théorie, Discours de réception du prix Nobel.
Citation rapportée
“The same equations have the same solutions”
volume II; lecture 12, "Electrostatic Analogs"; p. 12-1
The Feynman Lectures on Physics (1964)
Source: The Character of Physical Law (1965), chapter 2, “ The Relation of Mathematics to Physics http://www.youtube.com/watch?v=M9ZYEb0Vf8U”
volume I; lecture 22, "Algebra"; section 22-1, "Addition and multiplication"; p. 22-1
The Feynman Lectures on Physics (1964)
lecture II: "The Uncertainty of Values"
The Meaning of It All (1999)
lecture III: "This Unscientific Age"
The Meaning of It All (1999)
lecture III: "This Unscientific Age"
The Meaning of It All (1999)
From Omni interview, "The Smartest Man in the World" (1979) or from the book p. 194.
The Pleasure of Finding Things Out (1999)
From Omni interview, "The Smartest Man in the World" (1979) or from the book p. 195.
The Pleasure of Finding Things Out (1999)
“I had too much stuff. My machines came from too far away.”
Reflecting on the failure of his presentation at the "Pocono Conference" of 30 March - 1 April 1948.
interview with Sylvan S. Schweber, 13 November 1984, published in QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga (1994) by Silvan S. Schweber, p. 436
“A very great deal more truth can become known than can be proven.”
"The Development of the Space-Time View of Quantum Electrodynamics," Nobel Lecture http://nobelprize.org/physics/laureates/1965/feynman-lecture.html (11 December 1965)
Comment to psychiatrist who examines Feynman and states he (the psychiatrist) has studied medicine.
Part 3: "Feynman, The Bomb, and the Military", "Uncle Sam Doesn't Need <u>You</u>", p. 159
Surely You're Joking, Mr. Feynman! (1985)
last words (15 February 1988), recalled by sister Joan Feynman, in Christopher Sykes, editor, No Ordinary Genius: The Illustrated Richard Feynman (1994), p. 254
“What I cannot create, I do not understand.Know how to solve every problem that has been solved.”
on his blackboard at the time of death in February 1988; from a photo in the Caltech archives http://archives.caltech.edu/pictures/1.10-29.jpg
The Value of Science (1955)
" New Textbooks for the "New" Mathematics http://calteches.library.caltech.edu/2362/1/feynman.pdf", Engineering and Science volume 28, number 6 (March 1965) p. 9-15 at p. 14
Paraphrased as "Precise language is not the problem. Clear language is the problem."
It is not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge and you really don't know what it is all about, or what the purpose of the world is, or know a great deal of other things. It is possible to live and not know.
from lecture "What is and What Should be the Role of Scientific Culture in Modern Society", given at the Galileo Symposium in Italy (1964)
The Pleasure of Finding Things Out (1999)
The Value of Science (1955)
“The philosophy of science is as useful to scientists as ornithology is to birds.”
Attributed to Feynman, many times, by the British historian of science Brian Cox.
Disputed and/or attributed
address " What is Science? http://www.fotuva.org/feynman/what_is_science.html", presented at the fifteenth annual meeting of the National Science Teachers Association, in New York City (1966), published in The Physics Teacher, volume 7, issue 6 (1969), p. 313-320
“Do not keep saying to yourself, if you can possibly avoid it, "But how can it be like that?"”
because you will get "down the drain", into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.
Concerning the apparent absurdities of quantum behavior.
Source: The Character of Physical Law (1965), chapter 6, “Probability and Uncertainty — the Quantum Mechanical View of Nature,” p. 129
Even if we knew every rule, however, we might not be able to understand why a particular move is made in the game, merely because it is too complicated and our minds are limited. If you play chess you must know that it is easy to learn all the rules, and yet it is often very hard to select the best move or to understand why a player moves as he does. So it is in nature, only much more so.
volume I; lecture 2, "Basic Physics"; section 2-1, "Introduction"; p. 2-1
The Feynman Lectures on Physics (1964)
remarks (2 May 1956) at a Caltech YMCA lunch forum http://calteches.library.caltech.edu/49/2/Religion.htm
lecture II: "The Uncertainty of Values"
The Meaning of It All (1999)
I might think about it a little bit, and if I can't figure it out then I go on to something else. But I don't have to know an answer. I don't feel frightened by not knowing things, by being lost in the mysterious universe without having any purpose — which is the way it really is, as far as I can tell. Possibly. It doesn't frighten me.
Source: No Ordinary Genius (1994), p. 239, from interview in "The Pleasure of Finding Things Out" (1981): video http://www.youtube.com/watch?v=NEwUwWh5Xs4&t=48m10s
I too can see the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination — stuck on this carousel my little eye can catch one-million-year-old light. A vast pattern — of which I am a part... What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little about it. For far more marvelous is the truth than any artists of the past imagined! Why do the poets of the present not speak of it? What men are poets who can speak of Jupiter if he were a man, but if he is an immense spinning sphere of methane and ammonia must be silent?
volume I; lecture 3, "The Relation of Physics to Other Sciences"; section 3-4, "Astronomy"; p. 3-6
The Feynman Lectures on Physics (1964)
Source: Curious Character
excerpt from letter to J. M. Szabados (30 November 1965), quoted in "Perfectly Reasonable Deviations from the Beaten Track The Letters of Richard P. Feynman" (2005) by Michelle Feynman and Carl Feynman, p. 206