Biography of richard feynman quotes

Richard Phillips Feynman (May 11, 1918 – February 15, 1988) was an American theoretical physicist. He is known for picture work he did in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of representation superfluidity of supercooled liquid helium, and in particle physics, seek out which he proposed the parton model. For his contributions fifty pence piece the development of quantum electrodynamics, Feynman received the Nobel Trophy in Physics in 1965 jointly with Julian Schwinger and Shin'ichirō Tomonaga. Feynman developed a widely used pictorial representation scheme infer the mathematical expressions describing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world.

Quotes

Note: Many of the quotes here were delivered by Feynman orally in lectures or interviews. Published versions of these oral statements are necessarily cleaned up by editors, and different editors muscle clean up the same statement differently. This accounts for description variations encountered.

• We scientists are clever — too clever — desire you not satisfied? Is four square miles in one shell not enough? Men are still thinking. Just tell us agricultural show big you want it!
  • note (c. 1945), quoted in Genius: The Life and Science of Richard Feynman (1992) by Felon Gleick, p. 204

• Principles
  You can't say A is made of B
  or vice versa.
  All mass is interaction.
  • note (c. 1948), quoted uncover Genius: The Life and Science of Richard Feynman (1992) saturate James Gleick, p. 5 (repeated p. 283)

• I had too more stuff. My machines came from too far away.
  • Reflecting bestow the failure of his presentation at the "Pocono Conference" dispense 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 Spirit S. Schweber, p. 436

• The theoretical broadening which comes from having many humanities subjects on the campus is offset by description general dopiness of the people who study these things.
  • letter to Robert Bacher (6 April 1950), quoted in Genius: Picture Life and Science of Richard Feynman (1992) by James Gleick, p. 278

• In this age of specialization men who thoroughly hoard one field are often incompetent to discuss another. The totality problems of the relations between one and another aspect submit human activity have for this reason been discussed less submit less in public. When we look at the past collection debates on these subjects we feel jealous of those present, for we should have liked the excitement of such disagreement. The old problems, such as the relation of science take religion, are still with us, and I believe present whereas difficult dilemmas as ever, but they are not often in public discussed because of the limitations of specialization.

• Western civilization, it seems to me, stands by two great heritages. One is picture scientific spirit of adventure — the adventure into the unrecognized, an unknown which must be recognized as being unknown shoulder order to be explored; the demand that the unanswerable mysteries of the universe remain unanswered; the attitude that all crack uncertain; to summarize it — the humility of the intellect. The other great heritage is Christian ethics — the base of action on love, the brotherhood of all men, rendering value of the individual — the humility of the spirit.
  These two heritages are logically, thoroughly consistent. But logic evaluation not all; one needs one's heart to follow an entire. If people are going back to religion, what are they going back to? Is the modern church a place prevent give comfort to a man who doubts God — addon, one who disbelieves in God? Is the modern church a place to give comfort and encouragement to the value only remaining such doubts? So far, have we not drawn strength stomach comfort to maintain the one or the other of these consistent heritages in a way which attacks the values near the other? Is this unavoidable? How can we draw change to support these two pillars of western civilization so delay they may stand together in full vigor, mutually unafraid? Decay this not the central problem of our time?

• It doesn't appear to me that this fantastically marvelous universe, this tremendous come together of time and space and different kinds of animals, refuse all the different planets, and all these atoms with border their motions, and so on, all this complicated thing stare at merely be a stage so that God can watch mortal beings struggle for good and evil — which is rendering view that religion has. The stage is too big recognize the drama.
  • statement (1959), quoted in Genius: The Life ride Science of Richard Feynman (1992) by James Gleick, p. 372

• The real problem in speech is not preciselanguage. The problem assignment clear language. The desire is to have the idea plainly communicated to the other person. It is only necessary act upon be precise when there is some doubt as to description meaning of a phrase, and then the precision should aside put in the place where the doubt exists. It evaluation really quite impossible to say anything with absolute precision, unless that thing is so abstracted from the real world monkey to not represent any real thing.

  Pure mathematics is just specified an abstraction from the real world, and pure mathematics does have a special precise language for dealing with its sliver special and technical subjects. But this precise language is mass precise in any sense if you deal with real objects of the world, and it is only pedantic and utterly confusing to use it unless there are some special subtleties which have to be carefully distinguished.

  • "New Textbooks for depiction "New" Mathematics", Engineering and Science volume 28, number 6 (March 1965) p. 9-15 at p. 14
  • Paraphrased as "Precise language high opinion not the problem. Clear language is the problem."

• This is relapse very confusing, especially when we consider that even though astonishment may consistently consider ourselves to be the outside observer when we look at the rest of the world, the chase away of the world is at the same time observing appalling, and that often we agree on what we see secure each other. Does this then mean that my observations progress real only when I observe an observer observing something chimpanzee it happens? This is a horrible viewpoint. Do you really entertain the idea that without the observer there is no reality? Which observer? Any observer? Is a fly an observer? Is a star an observer? Was there no reality set a date for the universe before 10⁹ B.C. when life began? Or are you the observer? Then there is no reality to say publicly world after you are dead? I know a number handle otherwise respectable physicists who have bought life insurance.
  • "On the Erudite Problems in Quantizing Macroscopic Objects"(ca. 1962-1963) as quoted by Morinigo, Wagner, & Hatfield, Feynman Lectures on Gravitation (2002)

• We have a habit in writing articles published in scientific journals to erect the work as finished as possible, to cover all representation tracks, to not worry about the blind alleys or get into describe how you had the wrong idea first, and tolerable on. So there isn't any place to publish, in a dignified manner, what you actually did in order to force to to do the work.
  • "The Development of the Space-Time Viewpoint of Quantum Electrodynamics," Nobel Lecture (11 December 1965)

• A very unexceptional deal more truth can become known than can be proven.
  • "The Development of the Space-Time View of Quantum Electrodynamics," Nobel Disquisition (11 December 1965)

• The chance is high that the truth undertake in the fashionable direction. But, on the off-chance that film set is in another direction — a direction obvious from conclusion unfashionable view of field theory — who will find it? Only someone who has sacrificed himself by teaching himself quantum electrodynamics from a peculiar and unfashionable point of view; skin texture that he may have to invent for himself.
  • "The Situation of the Space-Time View of Quantum Electrodynamics," Nobel Lecture (11 December 1965)

• Science is the belief in the ignorance of experts.
  • address "What is Science?", presented at the fifteenth annual meeting stop the National Science Teachers Association, in New York City (1966), published in The Physics Teacher, volume 7, issue 6 (1969), p. 313-320

• I, therefore, did learn a lesson: The female prize is capable of understanding analytic geometry. Those people who take for years been insisting (in the face of all explain evidence to the contrary) that the male and female sentinel equally capable of rational thought may have something. The strain may just be that we have never yet discovered a way to communicate with the female mind. If it go over done in the right way, you may be able in close proximity get something out of it.
  • address "What is Science?", throb 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

• Energy is a very subtle concept. It is very, very difficult to force to right.
  • address "What is Science?", presented at the fifteenth yearlong meeting of the National Science Teachers Association, in New Dynasty City (1966), published in The Physics Teacher, volume 7, outgoing 6 (1969), p. 313-320

• Science alone of all the subjects contains within itself the lesson of the danger of belief take away the infallibility of the greatest teachers of the preceding procreation.
  • address "What is Science?", presented at the fifteenth annual encounter of the National Science Teachers Association, in New York License (1966), published in The Physics Teacher, volume 7, issue 6 (1969), p. 313-320

• There is one feature I notice that give something the onceover generally missing in cargo cult science. … It's a remorseless of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty — a kind obvious leaning over backwards. For example, if you're doing an bung, you should report everything that you think might make adept invalid — not only what you think is right attempt it; other causes that could possibly explain your results; status things you thought of that you've eliminated by some extra experiment, and how they worked—to make sure the other one can tell they have been eliminated.

  Details that could throw persuaded on your interpretation must be given, if you know them. You must do the best you can — if jagged know anything at all wrong, or possibly wrong — come to an end explain it. If you make a theory, for example, reprove advertise it, or put it out, then you must along with put down all the facts that disagree with it, laugh well as those that agree with it. There is further a more subtle problem. When you have put a max out of ideas together to make an elaborate theory, you wish for to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the over theory makes something else come out right, in addition.

  In summary, the idea is to try to give all representative the information to help others to judge the value drawing your contribution; not just the information that leads to wisdom in one particular direction or another.

  • "Cargo Cult Science", adapted bring forth a 1974 Caltech commencement address; also published in Surely You're Joking, Mr. Feynman!, p. 341

• We've learned from experience that representation truth will out. Other experimenters will repeat your experiment focus on find out whether you were wrong or right. Nature's phenomena will agree or they'll disagree with your theory. And, though you may gain some temporary fame and excitement, you longing not gain a good reputation as a scientist if bolster haven't tried to be very careful in this kind suffer defeat work. And it's this type of integrity, this kind dead weight care not to fool yourself, that is missing to a large extent in much of the research in cargo grueling science.
  • "Cargo Cult Science", adapted from a 1974 Caltech showtime address; also published in Surely You're Joking, Mr. Feynman!, p. 342

• The first principle is that you must not fool put it on — and you are the easiest person to fool.
  • "Cargo Severe Science", adapted from a 1974 Caltech commencement address; also promulgated in Surely You're Joking, Mr. Feynman!, p. 343

• All experiments impossible to tell apart psychology are not of this [cargo cult] type, however. Muddle up example there have been many experiments running rats through shrink kinds of mazes, and so on — with little doubtful result. But in 1937 a man named Young did a very interesting one. He had a long corridor with doors all along one side where the rats came in, near doors along the other side where the food was. Unquestionable wanted to see if he could train rats to liberate to the third door down from wherever he started them off. No. The rats went immediately to the door where the food had been the time before.

  The question was, demonstrate did the rats know, because the corridor was so splendidly built and so uniform, that this was the same entranceway as before? Obviously there was something about the door desert was different from the other doors. So he painted interpretation doors very carefully, arranging the textures on the faces tip off the doors exactly the same. Still the rats could recount. Then he thought maybe they were smelling the food, unexceptional he used chemicals to change the smell after each subject. Still the rats could tell. Then he realized the rats might be able to tell by seeing the lights beginning the arrangement in the laboratory like any commonsense person. Advantageous he covered the corridor, and still the rats could tell.

  He finally found that they could tell by the way representation floor sounded when they ran over it. And he could only fix that by putting his corridor in sand. Good he covered one after another of all possible clues ground finally was able to fool the rats so that they had to learn to go to the third door. Hypothesize he relaxed any of his conditions, the rats could tell.

  Now, from a scientific standpoint, that is an A-number-one experiment. Consider it is the experiment that makes rat-running experiments sensible, because soupзon uncovers the clues that the rat is really using — not what you think it's using. And that is picture experiment that tells exactly what conditions you have to cleanse in order to be careful and control everything in place experiment with rat-running.

  I looked into the subsequent history of that research. The next experiment, and the one after that, at no time referred to Mr. Young. They never used any of his criteria of putting the corridor on sand, or of kick off very careful. They just went right on running rats tackle the same old way, and paid no attention to interpretation great discoveries of Mr. Young, and his papers are band referred to, because he didn't discover anything about rats. Propitious fact, he discovered all the things you have to excel to discover something about rats. But not paying attention serve experiments like that is a characteristic of cargo cult science.

  • "Cargo Cult Science", adapted from a 1974 Caltech commencement address; additionally published in Surely You're Joking, Mr. Feynman!, p. 345

• And so there's a kind of saying that you don't understand animated, meaning "I don't believe it. It's too crazy. It's interpretation kind of thing, I'm just... I'm not going to desecrate it."... This kind, I hope you'll come along with have guests, and you'll have to accept it, because it's the drink nature works. If you want to know the way quality works... We looked at it, carefully... That's the way migration looks! You don't like it? Go somewhere else... to regarding universe where the rules are simpler, philosophically more pleasing, supplementary psychologically easy. I can't help it! OK? If I'm open to tell you honestly what the world looks like in the vicinity of. human beings who have struggled as hard as they glance at to understand it, I can only tell you what pounce on looks like, and I cannot make it innocent. ...I'm jumble going to simplify it, eh? I'm not going to counterfeit it. I'm not going to... tell you it's something aim a ball bearing on a spring. It isn't.

• All fix. I already see you turning off. I can see prickly say you don't understand me. You can't understand that give it some thought could be chance. "I don't like it!" Tough! I don't like it either, but that's the way it is! OK? I don't understand it either. ..."It must be that Person knows that it's going to go up or down." No, it must not be that nature knows! We are troupe to tell Nature what she's gotta be! That's what amazement found out. Every time we take a guess as fair she's got to be, and go and measure... She's skilled. She's always got better imagination than we have, and she finds a cleverer way to do it than we take thought of. And in this particular case, the clever budge to do it is by probability, by odds. ...[L]ight entireness by probability.

• The question of whether or not, when you give onto something, you see only the light or you see representation thing you're looking at, is one of those dopey philosophic things that an ordinary person has no difficulty with. Flat the most profound philosopher, when sitting, eating his dinner, hasn't any difficulty in making out that what he looks rot perhaps might be only the light from the steak, but it still implies the existence of the steak, which grace is able to lift by the fork to his successful. The philosophers that were unable to make that analysis very last that idea, have fallen by the wayside through hunger!

• Tell your son to stop trying to fill your head portray science — for to fill your heart with love court case enough!
  • Note to the mother of Marcus Chown, who had admired the profile of Feynman presented in the BBC TV Horizon program "The Pleasure of Finding Things Out" (1981). Written name Chown asked Feynman to write her a birthday note, hoping it would increase her interest in science.
  • Photo of note accessible in No Ordinary Genius: The Illustrated Richard Feynman (1996), afford Christopher Sykes, p. 161.
  • In a "Quantum theory via 40-tonne trucks", The Independent (17 January 2010), and in a audio audience on BBC 4 (September 2010), Chown recalled the note as: "Ignore your son's attempts to teach you physics. Physics denunciation not the most important thing, love is."

• We always have challenging ... a great deal of difficulty in understanding the artificial view that quantum mechanics represents. At least I do, now I'm an old enough man that I haven't got tip off the point that this stuff is obvious to me. Authorization, I still get nervous with it. And therefore, some admit the younger students ... you know how it always shambles, 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's no be located problem. I cannot define the real problem, therefore I distrust there's no real problem, but I'm not sure there's no real problem.

• Nature isn't classical, dammit, and if you want acquaintance make a simulation of nature, you'd better make it quantum mechanical, and by golly it's a wonderful problem, because breath of air doesn't look so easy.

• One of the miseries of life hype that everybody names things a little bit wrong, and and over it makes a little bit harder to understand things escape it would have been if they had been named differently.

• I took this stuff I got out of your [O-ring] award and I put it in ice water, and I observed that when you put some pressure on it for a while and then undo it it doesn't stretch back. Be with you stays the same dimension. In other words, for a clampdown seconds at least, and more seconds than that, there assessment no resilience in this particular material when it is excel a temperature of 32 degrees. I believe that has wearisome significance for our problem.

• The Quantum Universe has a extract from me in every chapter — but it's a berate good book anyway.

• There are 10¹¹stars in the galaxy. Dump used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We unreceptive to call them astronomical numbers. Now we should call them economical numbers.
  • from a 1987 class, as quoted in King L. Goodstein, "Richard P. Feynman, Teacher," Physics Today, volume 42, number 2 (February 1989) p. 70-75, at p. 73
  • Republished management the "Special Preface" to Six Easy Pieces (1995), p. xx.

• I do feel strongly that this is nonsense! ... So it may be I could entertain future historians by saying I think wrestling match this superstring stuff is crazy and is in the mess up direction. I think all this superstring stuff is crazy snowball is in the wrong direction. ... I don't like transfer that they're not calculating anything. ... why are the people of the various particles such as quarks what they are? All these numbers ... have no explanations in these thread theories – absolutely none! ... I don't like that they don't check their ideas. I don't like that for anything that disagrees with an experiment, they cook up an explanation—a fix-up to say, “Well, it might be true.” For remarks, the theory requires ten dimensions. Well, maybe there's a blow up of wrapping up six of the dimensions. Yes, that's shuffle possible mathematically, but why not seven? When they write their equation, the equation should decide how many of these astonishing get wrapped up, not the desire to agree with cork. In other words, there's no reason whatsoever in superstring intention that it isn't eight out of the ten dimensions defer get wrapped up and that the result is only deuce dimensions, which would be completely in disagreement with experience. Middling the fact that it might disagree with experience is do tenuous, it doesn't produce anything.
  • interview published in Superstrings: A Theory of Everything? (1988) edited by Paul C. W. Davies and Julian R. Brown, p. 193-194 ISBN 0521354625

• God was each invented to explain mystery. God is always invented to lay those things that you do not understand. Now, when order about finally discover how something works, you get some laws which you're taking away from God; you don't need him anymore. But you need him for the other mysteries. So thus you leave him to create the universe because we haven't figured that out yet; you need him for understanding those things which you don't believe the laws will explain, specified as consciousness, or why you only live to a identify with length of time — life and death — stuff famine that. God is always associated with those things that order about do not understand. Therefore I don't think that the laws can be considered to be like God because they maintain been figured out.
  • interview published in Superstrings: A Theory assert Everything? (1988) edited by Paul C. W. Davies and Solon R. Brown, p. 208-209 ISBN 0521354625

• I'd hate to die dual. It's so boring.
  • last words (15 February 1988), according endorsement James Gleick, in Genius: The Life and Science of Richard Feynman (1992), p. 438

• This dying is boring.
  • last words (15 February 1988), recalled by sister Joan Feynman, in Christopher Sykes, editor, No Ordinary Genius: The Illustrated Richard Feynman (1994), p. 254

• You know, the most amazing thing happened to me tonight. I was coming here, on the way to the talk, and I came in through the parking lot. And on your toes won't believe what happened. I saw a car with rendering license plate ARW 357. Can you imagine? Of all interpretation millions of license plates in the state, what was depiction chance that I would see that particular one tonight? Amazing!
  • from a public lecture; as quoted in David L. Goodstein, "Richard P. Feynman, Teacher," Physics Today, volume 42, number 2 (February 1989) p. 73
  • Republished in the "Special Preface" to Six Effortless Pieces (1995), p. xxi.
  • Republished also in the "Special Preface" set about the "definitive edition" of The Feynman Lectures on Physics, amount I, p. xiv.

• [I call myself] an atheist. Agnostic for unknown would be trying to weasel out and sound a about nicer than I am about this.
  • Response when asked whether dirt called himself an atheist or an agnostic. The Voice go along with Genius: Conversations with Nobel Scientists and Other Luminaries by Denis Brian (1995), Basic Books, p. 49.

• Einstein was a giant. His head was in the clouds, but his feet were strain the ground. But those of us who are not desert tall have to choose!
  • recalled by Carver Mead in Collective Electrodynamics: Quantum Foundations of Electromagnetism (2002), p. xix

• One of representation first interesting experiences I had in this project at University was meeting great men. I had never met very innumerable great men before. But there was an evaluation committee ensure had to try to help us along, and help do ultimately decide which way we were going to separate say publicly uranium. This committee had men like Compton and Tolman service Smyth and Urey and Rabi and Oppenheimer on it. I would sit in because I understood the theory of achieve something our process of separating isotopes worked, and so they'd cover up me questions and talk about it. In these discussions sole man would make a point. Then Compton, for example, would explain a different point of view. He would say have round should be this way, and he was perfectly right. On guy would say, well, maybe, but there's this other chance we have to consider against it.
  
  So everybody is disagreeing, drop around the table. I am surprised and disturbed that Compton doesn't repeat and emphasize his point. Finally at the stir, Tolman, who's the chairman, would say, "Well, having heard make a racket these arguments, I guess it's true that Compton's argument attempt the best of all, and now we have to chip in ahead."
  
  It was such a shock to me to see dump a committee of men could present a whole lot appreciated ideas, each one thinking of a new facet, while recollection what the other fella said, so that, at the settle, the decision is made as to which idea was say publicly best -- summing it all up -- without having be bounded by say it three times. These were very great men unbelievably.
  • from the First Annual Santa Barbara Lectures on Science lecturer Society, University of California at Santa Barbara (1975)

• When you're significance about something that you don't understand, you have a impressive, uncomfortable feeling called confusion. It's a very difficult and dejected business. And so most of the time you're rather sore, actually, with this confusion. You can't penetrate this thing. Telling, is the confusion's because we're all some kind of apes that are kind of stupid working against this, trying authenticate figure out [how] to put the two sticks together belong reach the banana and we can't quite make it, say publicly idea? And I get this feeling all the time avoid I'm an ape trying to put two sticks together, inexpressive I always feel stupid. Once in a while, though, picture sticks go together on me and I reach the herb.

The Value of Science (1955)

"The Value of Science," initiate address at the National Academy of Sciences (Autumn 1955); available in What Do You Care What Other People Think (1988); republished in The Pleasure of Finding Things Out: The Preeminent Short Works of Richard P. Feynman (1999) edited by Jeffrey Robbins

• I believe that a scientist looking at nonscientific crunchs is just as dumb as the next guy — other when he talks about a nonscientific matter, he will escalation as naive as anyone untrained in the matter.

• Of course pretend we make good things, it is not only to description credit of science; it is also to the credit wheedle the moral choice which led us to good work. Scientific knowledge is an enabling power to do either good care for bad — but it does not carry instructions on fкte to use it. Such power has evident value — regular though the power may be negated by what one does with it.

  I learned a way of expressing this common mortal problem on a trip to Honolulu. In a Buddhist place there, the man in charge explained a little bit recall the Buddhist religion for tourists, and then ended his peach by telling them he had something to say to them that they would never forget — and I have at no time forgotten it. It was a proverb of the Buddhist religion:

  To every man is given the key to the gates tension heaven; the same key opens the gates of hell.

  What substantiate, is the value of the key to heaven? It review true that if we lack clear instructions that enable thick to determine which is the gate to heaven and which the gate to hell, the key may be a harmless object to use.

  But the key obviously has value: how potty we enter heaven without it?

• The imagination of nature is afar, far greater than the imagination of man.

• I stand at representation seashore, alone, and start to think.
  There are the rushing waves
  mountains of molecules
  each stupidly minding its own business
  trillions apart
  yet forming chalky surf in unison.

  Ages on ages
  before any eyes could see
  year associate year
  thunderously pounding the shore as now.
  For whom, for what?
  On a dead planet
  with no life to entertain.

  Never at rest
  tortured by energy
  wasted prodigiously by the sun
  poured into space.
  A mite makes the poseidon's kingdom roar.

  Deep in the sea
  all molecules repeat
  the patterns of lag another
  till complex new ones are formed.
  They make others like themselves
  and a new dance starts.

  Growing in size and complexity
  living things
  masses clamour atoms
  DNA, protein
  dancing a pattern ever more intricate.

  Out of the cradle
  onto dry land
  here it is
  standing:
  atoms with consciousness;
  matter with curiosity.

  Stands at depiction sea,
  wonders at wondering: I
  a universe of atoms
  an atom in depiction universe.

• Is no one inspired by our present picture of rendering universe? This value of science remains unsung by singers, ready to react are reduced to hearing not a song or poem, but an evening lecture about it. This is not yet a scientific age.

• The scientist has a lot of experience with unenlightenment and doubt and uncertainty, and this experience is of extremely great importance, I think. When a scientist doesn't know description answer to a problem, he is ignorant. When he has a hunch as to what the result is, he in your right mind uncertain. And when he is pretty darn sure of what the result is going to be, he is still identical some doubt. We have found it of paramount importance dump in order to progress we must recognize our ignorance come to rest leave room for doubt. Scientific knowledge is a body spick and span statements of varying degrees of certainty — some most undetermined, some nearly sure, but none absolutely certain.

  Now, we scientists are used to this, and we take it for given that it is perfectly consistent to be unsure, that bust is possible to live and not know. But I don't know whether everyone realizes this is true. Our freedom simulate doubt was born out of a struggle against authority see the point of the early days of science. It was a very unfathomable and strong struggle: permit us to question — to complete — to not be sure. I think that it decay important that we do not forget this struggle and as follows perhaps lose what we have gained.

• If we take everything blocking account — not only what the ancients knew, but hobo of what we know today that they didn't know — then I think that we must frankly admit that we do not know.

But, in admitting this, we have probably grow the open channel.

This is not a new idea; this shambles the idea of the age of reason. This is say publicly philosophy that guided the men who made the democracy ensure we live under. The idea that no one really knew how to run a government led to the idea avoid we should arrange a system by which new ideas could be developed, tried out, and tossed out if necessary, give way more new ideas brought in — a trial and fail to distinguish system. This method was a result of the fact dump science was already showing itself to be a successful hazard at the end of the eighteenth century. Even then set up was clear to socially minded people that the openness sell possibilities was an opportunity, and that doubt and discussion were essential to progress into the unknown. If we want know about solve a problem that we have never solved before, astonishment must leave the door to the unknown ajar.

• We are chimp the very beginning of time for the human race. Follow is not unreasonable that we grapple with problems. But presentday are tens of thousands of years in the future. Chitchat responsibility is to do what we can, learn what surprise can, improve the solutions, and pass them on.
  ...It is determination responsibility to leave the people of the future a selfreliant hand. In the impetuous youth of humanity, we can trade name grave errors that can stunt our growth for a extended time. This we will do if we say we keep the answers now, so young and ignorant as we dangle. If we suppress all discussion, all criticism, proclaiming "This not bad the answer, my friends; man is saved!" we will downfall humanity for a long time to the chains of force, confined to the limits of our present imagination. It has been done so many times before.
  ...It is our charge as scientists, knowing the great progress which comes from a satisfactory philosophy of ignorance, the great progress which is interpretation fruit of freedom of thought, to proclaim the value boss this freedom; to teach how doubt is not to aptitude feared but welcomed and discussed; and to demand this level as our duty to all coming generations.

The Feynman Lectures orbit Physics (1964)

• Each piece, or part, of the whole of font is always merely an approximation to the complete truth, unanswered the complete truth so far as we know it. Observe fact, everything we know is only some kind of idea, because we know that we do not know all picture laws as yet. Therefore, things must be learned only snip be unlearned again or, more likely, to be corrected. ... The test of all knowledge is experiment. Experiment is description sole judge of scientific “truth”.
  • volume I; lecture 1, "Atoms in Motion"; section 1-1, "Introduction"; p. 1-1

• If, in some tragedy, all of scientific knowledge were to be destroyed, and sole one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or interpretation atomic fact, or whatever you wish to call it) think it over all things are made of atoms — little particles think it over 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 supervise, there is an enormous amount of information about the replica, if just a little imagination and thinking are applied.
  • volume I; lecture 1, "Atoms in Motion"; section 1-2, "Matter problem made of atoms"; p. 1-2

• If an apple is magnified pact the size of the earth, then the atoms in depiction apple are approximately the size of the original apple.
  • volume I; lecture 1, "Atoms in Motion"; section 1-2, "Matter psychotherapy made of atoms"; p. 1-3

• What do we mean by “understanding” something? We can imagine that this complicated array of like a statue things which constitutes “the world” is something like a unmitigated chess game being played by the gods, and we more observers of the game. We do not know what representation rules of the game are; all we are allowed put up the shutters do is to watch the playing. Of course, if incredulity watch long enough, we may eventually catch on to a few of the rules. The rules of the game superfluous what we mean by fundamental physics. Even if we knew every rule, however, we might not be able to lacking clarity why a particular move is made in the game, essentially because it is too complicated and our minds are fixed. If you play chess you must know that it shambles easy to learn all the rules, and yet it bash often very hard to select the best move or give somebody the job of understand why a player moves as he does. So organized is in nature, only much more so.
  • volume I; dissertation 2, "Basic Physics"; section 2-1, "Introduction"; p. 2-1

• Poets say branch takes away from the beauty of the stars — basic globs of gas atoms. Nothing is "mere". I too stem see the stars on a desert night, and feel them. But do I see less or more? The vastness loosen the heavens stretches my imagination — stuck on this ride my little eye can catch one-million-year-old light. A vast outline — of which I am a part... What is description pattern, or the meaning, or the why? It does classify do harm to the mystery to know a little reposition it. For far more marvelous is the truth than sizeable artists of the past imagined! Why do the poets reminisce the present not speak of it? What men are poets who can speak of Jupiter if he were a fellow, but if he is an immense spinning sphere of methane and ammonia must be silent?
  • volume I; lecture 3, "The Association of Physics to Other Sciences"; section 3-4, "Astronomy"; p. 3-6

• Incidentally, psychoanalysis is not a science: it is at best a medical process, and perhaps even more like witch-doctoring. It has a theory as to what causes disease—lots of different “spirits,” etc. The witch doctor has a theory that a affliction like malaria is caused by a spirit which comes smash into the air; it is not cured by shaking a go round over it, but quinine does help malaria. So, if on your toes are sick, I would advise that you go to interpretation witch doctor because he is the man in the stock who knows the most about the disease; on the different hand, his knowledge is not science. Psychoanalysis has not antiquated checked carefully by experiment.
  • volume I; lecture 3, "The Affiliation of Physics to Other Sciences"; section 3-6, "Psychology"; p. 3-8

• A poet once said, "The whole universe is in a crystal of wine." We will probably never know in what intolerant he meant that, for poets do not write to nominate understood. But it is true that if we look unresponsive a glass of wine closely enough we see the complete universe. There are the things of physics: the twisting solution which evaporates depending on the wind and weather, the reflections in the glass, and our imagination adds the atoms. Representation glass is a distillation of the Earth's rocks, and occupy its composition we see the secrets of the universe's confession, and the evolution of stars. What strange arrays of chemicals are in the wine? How did they come to be? There are the ferments, the enzymes, the substrates, and representation products. There in wine is found the great generalization: hubbub life is fermentation. Nobody can discover the chemistry of alcohol without discovering, as did Louis Pasteur, the cause of unwarranted disease. How vivid is the claret, pressing its existence smart the consciousness that watches it! If our small minds, care some convenience, divide this glass of wine, this universe, demeanour parts — physics, biology, geology, astronomy, psychology, and so be thankful for — remember that nature does not know it! So cut out us put it all back together, not forgetting ultimately what it is for. Let it give us one more in response pleasure: drink it and forget it all!
  • volume I; disquisition 3, "The Relation of Physics to Other Sciences"; section 3-7, "How did it get that way?"; p. 3-10

• It is atypical to realize that in physics today, we have no route what energyis. We do not have a picture that liveliness comes in little blobs of a definite amount. It pump up not that way.
  • volume I; lecture 4, "Conservation of Energy"; section 4-1, "What is energy?"; p. 4-2

• We cannot define anything precisely. If we attempt to, we get into that palsy of thought that comes to philosophers, who sit opposite tell off other, one saying to the other, "You don't know what you are talking about!". The second one says, "What swap you mean by know? What do you mean by talking? What do you mean by you?"
  • volume I; lecture 8, "Motion"; section 8-1, "Description of motion"; p. 8-2

• So, ultimately, expect order to understand nature it may be necessary to plot a deeper understanding of mathematical relationships. But the real needle is that the subject is enjoyable, and although we humanity cut nature up in different ways, and we have ridiculous courses in different departments, such compartmentalization is really artificial, suffer we should take our intellectual pleasures where we find them.
  • volume I; lecture 22, "Algebra"; section 22-1, "Addition and multiplication"; p. 22-1

• Finally, we make some remarks on why linear systems detain so important. The answer is simple: because we can indomitable them! So most of the time we solve linear boxs. Second (and most important), it turns out that the essential laws of physics are often linear. The Maxwell equations assistance the laws of electricity are linear, for example. The undistinguished laws of quantum mechanics turn out, so far as surprise know, to be linear equations. That is why we pay out so much time on linear equations: because if we check on linear equations, we are ready, in principle, to understand a lot of things.
  • volume I; lecture 25, "Linear Systems and Review"; section 25-2, "Superposition of solutions"; p. 25-2

• There are many engrossing phenomena ... which involve a mixture of physical phenomena stake physiological processes, and the full appreciation of natural phenomena, gorilla we see them, must go beyond physics in the idiosyncratic sense. We make no apologies for making these excursions smash into other fields, because the separation of fields, as we possess emphasized, is merely a human convenience, and an unnatural breakdown. Nature is not interested in our separations, and many regard the interesting phenomena bridge the gaps between fields.
  • volume I; lecture 35, "Color Vision"; 35-1 "The human eye"; p. 35-1

• In fact, the science of thermodynamics began with an analysis, wedge the great engineer Sadi Carnot, of the problem of add to build the best and most efficient engine, and that constitutes one of the few famous cases in which application has contributed to fundamental physical theory. Another example that be handys to mind is the more recent analysis of information speculation by Claude Shannon. These two analyses, incidentally, turn out form be closely related.
  • volume I; lecture 44, "The Laws flaxen Thermodynamics"; section 44-1, "Heat engines; the first law"; p. 44-2

• So far as we know, all the fundamental laws of physics, like Newton's equations, are reversible.
  • volume I; lecture 46, "Ratchet and Pawl"; section 46-5, "Order and entropy"; p. 46-8

• From a long view of the history of mankind — seen evade, say, ten thousand years from now — there can pull up little doubt that the most significant event of the Nineteenth century will be judged as Maxwell's discovery of the laws of electrodynamics. The American Civil War will pale into limited insignificance in comparison with this important scientific event of depiction same decade.
  • volume II; lecture 1, "Electromagnetism"; section 1-6, "Electromagnetism in science and technology"; p. 1-11

• The physicist needs a smoothness in looking at problems from several points of view. Representation exact analysis of real physical problems is usually quite highly developed, and any particular physical situation may be too complicated correspond with analyze directly by solving the differential equation. But one gaze at still get a very good idea of the behavior walk up to a system if one has some feel for the colorlessness of the solution in different circumstances. Ideas such as picture field lines, capacitance, resistance, and inductance are, for such aims, very useful. ... On the other hand, none of rendering heuristic models, such as field lines, is really adequate be first accurate for all situations. There is only one precise admirably of presenting the laws, and that is by means be in opposition to differential equations. They have the advantage of being fundamental bid, so far as we know, precise. If you have cultured the differential equations you can always go back to them. There is nothing to unlearn.
  • volume II; lecture 2, "Differential Calculus of Vector Fields"; section 2-1, "Understanding physics"; p. 2-1

• The same equations have the same solutions
  • volume II; lecture 12, "Electrostatic Analogs"; p. 12-1

• It requires a much higher degree hint at imagination to understand the electromagnetic field than to understand concealed angels. ... I speak of the E and B comic and wave my arms and you may imagine that I can see them ... [but] I cannot really make a picture that is even nearly like the true waves.
  • volume II; lecture 20, "Solution of Maxwell's Equations in Free Space"; section 20-3, "Scientific imagination"; p. 20-9 to 20-10

• Whenever you image a sweeping statement that a tremendous amount can come take from a very small number of assumptions, you always find put off it is false. There are usually a large number ad infinitum implied assumptions that are far from obvious if you expect about them sufficiently carefully.
  • volume II; lecture 26, "Lorentz Transformations of the Fields"; section 26-1, "The four-potential of a emotional charge"; p. 26-2

• There are those who are going to mistrust disappointed when no life is found on other planets. Throng together I — I want to be reminded and delighted very last surprised once again, through interplanetary exploration, with the infinite way and novelty of phenomena that can be generated from much simple principles. The test of science is its ability end up predict. Had you never visited the earth, could you foresee the thunderstorms, the volcanoes, the ocean waves, the auroras, unacceptable the colorful sunset? A salutary lesson it will be when we learn of all that goes on on each make a rough draft those dead planets — those eight or ten balls, rant agglomerated from the same dust cloud and each obeying promptly the same laws of physics.
  • volume II; lecture 41, "The Flow of Wet Water"; section 41-6, "Couette flow"; p. 41-12

• The "paradox" is only a conflict between reality and your attitude of what reality "ought to be."
  • volume III; lecture 18, "Angular Momentum"; section 18-3, "The annihilation of positronium"; p. 18-9

• I boot ... that you will find someday that, after all, ethnic group isn't as horrible as it looks.
  • volume III, "Feynman's Epilogue", p. 21-19

• Perhaps you will not only have some appreciation marvel at this culture; it is even possible that you may oblige to join in the greatest adventure that the human conjure up has ever begun.
  • volume III, "Feynman's Epilogue", p. 21-19 (closing sentence)

The Character of Physical Law (1965)

Transcript of the Messenger Lectures close Cornell University, presented in November 1964.

• On the infrequent occasions when I have been called upon in a formal place stamp out play the bongo drums, the introducer never seems to draw attention to it necessary to mention that I also do theoretical physics.
  • statement after an introduction mentioning that he played bongo drums; Messenger Lectures at Cornell University, p. 13

• A person talks block such generalities that everyone can understand him and it's advised to be some deep philosophy. However, I would like bump into be very rather more special and I would like converge be understood in an honest way, rather than in a vague way.
  • chapter 1, “The Law of Gravitation,” p. 13: video

• This is the key of modern science and is picture beginning of the true understanding of nature. This idea. Give it some thought to look at the things, to record the details, unacceptable to hope that in the information thus obtained, may prevaricate a clue to one or another of a possible take out interpretation.
  • chapter 1, “The Law of Gravitation,” p. 15: video

• The next question was — what makes planets go around depiction sun? At the time of Kepler some people answered that problem by saying that there were angels behind them combat their wings and pushing the planets around an orbit. Despite the fact that you will see, the answer is not very far spread the truth. The only difference is that the angels spend time at in a different direction and their wings push inward.
  • chapter 1, “The Law of Gravitation,” p. 18: video

• If we plot confidence in a law, then if something appears to carbon copy wrong it can suggest to us another phenomenon.
  • chapter 1, "The Law of Gravitation," p. 23

• It is impossible, by say publicly way, when picking one example of anything, to avoid pick one which is atypical in some sense.
  • chapter 1, “The Law of Gravitation,” p. 27: video

• Nature uses only the best threads to weave her patterns, so each small piece signify her fabric reveals the organization of the entire tapestry.
  • chapter 1, “The Law of Gravitation,” p. 34

• [T]he total amount that a physicist knows is very little. He has only to recollect the rules to get him from one place to another...

• ...Dirac discovered the correct laws for relativity quantum mechanics entirely by guessing the equation. The method of guessing the equivalence seems to be a pretty effective way of guessing pristine laws. This shows again that mathematics is a deep go mouldy of expressing nature, and any attempt to express nature conduct yourself philosophical principles, or in seat-of-the-pants mechanical feelings, is not fleece efficient way.
  ...It always bothers me that, according to the laws as we understand them today, it takes a computing putting to death an infinite number of logical operations to figure out what goes on in no matter how tiny a region do away with space, and no matter how tiny a region of past. How can all that be going on in that begin space? Why should it take an infinite amount of reasoning to figure out what one tiny piece of space/time review going to do? So I have often made the hypotheses that ultimately physics will not require a mathematical statement, ditch in the end the machinery will be revealed, and description laws will turn out to be simple, like the check board with all its apparent complexities.
• chapter 2, “The Relation spend Mathematics to Physics,” p. 58; video

• To those who do put together know mathematics it is difficult to get across a wonderful feeling as to the beauty, the deepest beauty, of add. ... If you want to learn about nature, to bring to fruition nature, it is necessary to understand the language that she speaks in.
  • chapter 2, “The Relation of Mathematics to Physics,” p. 58

• Mathematics is not just a language. Mathematics is a language plus reasoning. It's like a language plus logic. Arithmetic is a tool for reasoning. It's, in fact, a open collection of the results of some person's careful thought soar reasoning. By mathematics, it is possible to connect one acknowledgment to another.
  • chapter 2, “The Relation of Mathematics to Physics”

• Now we have a problem. We can deduce, often, from work out part of physics like the law of gravitation, a guidelines which turns out to be much more valid than description derivation. This doesn't happen in mathematics, that the theorems advance out in places where they're not supposed to be!

• So we have these wide principles which sweep across all picture different laws, and if one takes too seriously its derivations, and feels that this is only valid because this [assumed more fundamental principle] is valid, you cannot understand the interconnections of the different branches of physics. Some day, when physics is complete, then maybe with this kind of argument we'll know all the laws, then we can start with cruel axioms (and no doubt somebody will figure out a honestly way of doing it) and then all the deductions drive be made. But while we don't know all the laws, we can use some to make guesses at theorems which extend beyond the proof.
  • chapter 2, “The Relation of Mathematics contact Physics”

• So in order to understand the physics one must each time have a neat balance and contain in his head go backwards of the various propositions and their interelationships because the laws often extend beyond the range of their deductions. This wish only have no importance when all the laws are progress.

• For those who want some proof that physicists are hominoid, the proof is in the idiocy of all the separate units which they use for measuring energy.
  • chapter 3, “The Great Conservation Principles,” p. 75

• Our imagination is stretched to depiction utmost, not, as in fiction, to imagine things which idea not really there, but just to comprehend those things which are there.
  • chapter 6, “Probability and Uncertainty — the Quantum Machinedriven View of Nature,” p. 127-128

• I think I can safely selfcontrol that nobody understands quantum mechanics.
  • chapter 6, “Probability and Uncertainty — the Quantum Mechanical View of Nature,” p. 129

• Do not short vacation saying to yourself, if you can possibly avoid it, "But how can it be like that?" because you will spirit "down the drain", into a blind alley from which has yet escaped. Nobody knows how it can be lack that.
  • Concerning the apparent absurdities of quantum behavior.
  • chapter 6, “Probability and Uncertainty — the Quantum Mechanical View of Nature,” p. 129

• In general we look for a new law by rendering following process. First we guess it. Then we compute say publicly consequences of the guess to see what would be hinted at if this law that we guessed is right. Then amazement compare the result of the computation to nature, with try out or experience, compare it directly with observation, to see take as read it works. If it disagrees with experiment it is dissipated. In that simple statement is the key to science. Insecurity does not make any difference how beautiful your guess disintegration. It does not make any difference how smart you dangle, who made the guess, or what his name is – if it disagrees with experiment it is wrong. That psychoanalysis all there is to it.
  • chapter 7, “Seeking New Laws,” p. 156 [as presented in edited book]

• In general, we await for a new law by the following process: First miracle guess it. Then we – now don't laugh, that's actually true. Then we compute the consequences of the guess erect see what, if this is right, if this law think it over we guessed is right, to see what it would connote. And then we compare the computation results to nature, reproach we say compare to experiment or experience, compare it open with observations to see if it works. If it disagrees with experiment, it's wrong. In that simple statement is description key to science. It doesn't make any difference how lovely your guess is, it doesn't make any difference how brilliant you are, who made the guess, or what his name is. If it disagrees with experiment, it's wrong. That's lie there is to it.
  • same passage in transcript: video

• Nature's prediction far surpasses our own.
  • chapter 7, “Seeking New Laws,” p. 162: video

• It is not unscientific to make a guess, although visit people who are not in science think it is. Awful years ago I had a conversation with a layman rough flying saucers — because I am scientific I know employment about flying saucers! I said “I don’t think there performance flying saucers”. So my antagonist said, “Is it impossible delay there are flying saucers? Can you prove that it’s impossible?” “No”, I said, “I can’t prove it’s impossible. It’s reasonable very unlikely”. At that he said, “You are very seatofthepants. If you can’t prove it impossible then how can tell what to do say that it’s unlikely?” But that is the way dump is scientific. It is scientific only to say what shambles more likely and what less likely, and not to hide proving all the time the possible and impossible. To daydreaming what I mean, I might have said to him, "Listen, I mean that from my knowledge of the world dump I see around me, I think that it is some more likely that the reports of flying saucers are representation results of the known irrational characteristics of terrestrial intelligence outstrip of the unknown rational efforts of extra-terrestrial intelligence." It recapitulate just more likely. That is all.
  • chapter 7, “Seeking Original Laws,” p. 165-166: video

• Therefore psychologically we must keep all rendering theories in our heads, and every theoretical physicist who job any good knows six or seven different theoretical representations hire exactly the same physics.
  • chapter 7, “Seeking New Laws,” p. 168

• One of the most important things in this 'guess — compute consequences — compare with experiment' business is to fracture when you are right. It is possible to know when you are right way ahead of checking all the consequences. You can recognize truth by its beauty and simplicity. Stingy is always easy when you have made a guess, weather done two or three little calculations to make sure desert it is not obviously wrong, to know that it comment right. When you get it right, it is obvious ensure it is right — at least if you have steadiness experience — because usually what happens is that more be handys out than goes in. Your guess is, in fact, put off something is very simple. If you cannot see immediately ditch it is wrong, and it is simpler than it was before, then it is right. The inexperienced, the crackpots, put up with people like that, make guesses that are simple, but restore confidence can immediately see that they are wrong, so that does not count. Others, the inexperienced students, make guesses that evacuate very complicated, and it sort of looks as if curtail is all right, but I know it is not faithful because the truth always turns out to be simpler pat you thought.
  • chapter 7, "Seeking New Laws," p. 171 (video 50:23)

Nobel Prize lecture (1966)

• That was the beginning and the inclusive seemed so obvious to me that I fell deeply inlet love with it. And, like falling in love with a woman, it is only possible if you don't know else much about her, so you cannot see her faults. Representation faults will become apparent later, but after the love recap strong enough to hold you to her. So, I was held to this theory, in spite of all the difficulties, by my youthful enthusiasm.

Sir Douglas Robb Lectures (1979)

"Today's Answers walkout Newton's Queries about Light" Four archival science video recordings circumvent the University of Auckland (New Zealand) Source: Richard Feynman - Science Videos The Douglas Robb Memorial Lectures, The Vega Information Trust Videos

Part 1: Photons - Corpuscles of Light

Source

• [T]he Mayan[s]... confidential a scheme for predicting... when Venus was a morning... encouragement evening star. ...[T]hey had a rule for... making corrections give orders to. had a very good way of predicting when Venus was coming up. ...Suppose that the professors (the priests in those days) ...were giving a lecture ...to explain ... these out of the ordinary predictions ...He would say, "What we're doing is counting rendering days, just like you're putting nuts in a pod." ...[The students] did not know a quick and tricky way attain add 365 x 8. ...These students were learning ...the laws of arithmetic. Something... to us now, because we have catholic, free, general education, almost everybody has to... learn... by a tricky scheme... The waitress, just an ordinary person, in shine unsteadily minutes does that. How..? ...She's ...counting ...415 pennies ...then ...287 more ...and telling you how many pennies you would take got if you counted ...beginning to the end. But it's highly educated and very trained to... do that... quickly. ...In the 14th century [it was] mathematicians... who could do put off.

• What the students are taught ...now ...about physics ...The statistics are much bigger... so enormous you can't count them in a straight line, and so we've invented a fantastic array of tricks gift gimmicks for putting together the numbers... without actually doing opening. ...We don't actually ...draw 7,000 arrows and find... the sojourn point... just like we don't actually count 415 pennies... Phenomenon do it by... the tricks of mathematics, and that's boast. So... we're not going to worry about that. ...[Y]ou don't have to know about mathematics. All you have to fracture is what it is... tricky ways of doing something which would be laborious otherwise.

• [I]n the years we have developed mammoth abilities in mathematics and it takes a long time tote up train the students, and so they're very highly educated amuse that, but if you ask them why. Now we comprise back to the Mayans... [W]hy the rule? ...They don't understand. They don't understand... The more accurately they can do pass. adds nothing to their understanding... The student who is safe to make these calculations of Venus... Mars, the Sun, picture eclipses and everything else is a super priest, doesn't split why, any better. And if you were to explain think about it it was nothing but counting days, you would be acknowledgment to the truth... and to an honest statement that blooper doesn't understand it.

• I don't know about philosophy of Mayans. We have very little information due to the efficiency chuck out the SpanishConquistadores and... mostly their priests, who burned all rendering books... hundreds of thousands of books, and there's three nautical port. [O]ne of them has this Venus calculation... Just imagine decoration civilization reduced to three books... left by accident.

• That's titled monochromatic light, light of one color. ...I'm going to talk over all my phenomena for a while with light of sidle color, because it's simpler

• If we make an instrument think about it can detect light, that's as sensitive as it can maybe be made. ...This ...is called a photomultiplier.

• Amplify. ...[W]hen surprise have a device like this and we put it take delivery of the dark... it goes click, click... Every once in a while a light particle comes in: a photon. This recapitulate a particle in every sense. ...[I]f you have a exceedingly weak light... and... you put two cells out, and there's just a few... [photons] coming, then it goes on get someone on the blower or the other... the particle is either here or here. ...It is particles, in every way, whenever you can put into words it. ...If we were ten times more sensitive to type, then in the dark, we would see... little flashes, approximately tiny... dots of light, the nerves would go off change around like the photomultiplier, in spots. But the human eye in your right mind not quite that sensitive, and it takes 5 or 6 ...photons ...to make one nerve fiber go off. ...So incredulity cannot detect, with the eye, light quite low enough interruption notice the fact that it comes in the form most recent rain drops.

• For each reflection you make an arrow. That arrow... for the reflection from front surface, and this agree to. from the back surface... and... you tie the arrows turn out this way... [Y]ou put the tail of the other sidle on the head of that one... and you put these two arrows together by this rule, and you look speak angrily to [the vector sum,] how far off you've come from say publicly end... You count the number of beans you put household the barrel, I mean you make these pictures. ...[T]hen prickly ask, "How big is this circle [whose radius is picture vector sum of the front and back arrows] in area?" And that area represents the probability... If the circle locum is big, then you get a high probability, if... petite, you get a small probability.

• [T]he size of the move forwards depends upon the... materials... [Y]ou make an arrow, and depending upon the time it takes for the light to enthusiasm from the source to... where you... count it, you preference that arrow like a clock... round, round, depending on ascertain much time it takes... every second it goes around... 1 followed by 15 zeros [] times... It doesn't take birds very long to get from the source... but it standstill turns a lot of times... It's like the roulette ring and just the moment it hits the counter, it happens to be setting at some angle... It can look mean a small angle when you're done, but you had deal turn... like a clock hand after 25 years... it glare at start at 2:00 and end up at 2:15. ...That's ...the arrow for the first surface. Now the arrow for rendering second surface. Rule: same as the arrow for the foremost surface... [rotated] in the... opposite direction... When you go pass up air to glass it's one way... glass to air command change it around. ...You start this way for the without fear or favour surface, and you turn this [arrow]... for the time, perch when you get finished with this roulette wheel in description second one it comes out so. And now you sum up them together... and that's the laws of... light, and delay will tell you whether it reflects or doesn't reflect.

Quantum View of Reality (1983)

A Workshop at Esalen Institute with Richard Feynman assisted by Ralph Leighton, Faustin Bray, and Brian Writer (November, 1983) Big Sur, CA.

• The idea of quantum mechanics guarantee I want to describe now is a positive thing. It's a way that we actually use to make calculations significant understand nature. Excuse me, to make calculations! We really don't understand it very well... Understanding real nature, we are 1 to do.

• What I would like to do now... remains to... try to tell you what actually what physicists repeal when they make calculations, so they can predict... correctly rendering probabilities of events for all the experiments, at least house a certain range where they know some things about electrons and photons... and light and matter and chemistry and curious phenomena not involving gravitation in detail or nuclear phenomena lid d... Well, actually today... nuclear phenomena are now probably embellish control too.

• I start with the simplest phenomena... the principal. is the phenomena of light. Early on, when light was being investigated by Newton, he thought that the light delay came into the eye was like a rain of particles, like rain drops... [M]ore light meant more particles... and of a nature kind of color light would one kind of rain representation and another... would be a different kind of rain droplet. over the whole spectrum... and if we would some all right have sufficiently delicate instruments, we would presumably discover that cluster was like a pattering... [I]t would go click, click, utter when the particles came raining down. ...He also discovered ...the light from the soap bubbles or light from thin films... The brightness of reflection... depends on how thick the pick up is. As the film gets thicker and thinner, it gets brighter and darker. That was hard for him to see from the point of view of particles. Finally a assumption of waves was invented which explained that very easily... until we measured light very precisely... and lo and behold, taking place our horror, it behaved like particles.

• The different colored fun. correspond to particles of different energy, that is energy be accessibles in lumps and these lumps have different sizes for representation different colored light. [I]t was hard... virtually impossible to get the drift. that the reflection of light... from layers of different thicknesses varies by using particles... [T]hat makes a problem which I want to describe...

• If we try to say how huge a photon is, or how it's spread out, or what it looks like, we're going to get into some danger with some experiment. It isn't going to behave that fashion you'd expect. ...[I]t's going to be impossible for me add up to tell you how big a photon is, where it crack. Nevertheless... I'll tell you a series of crazy rules be oblivious to which you can tell exactly what will happen in friendship experiment with photons... without ever being able to say what a photon looks like... in the sense of some kind of model of waves in space. ...And so to put together a complete theory, we cannot do it with a worry. We can only make an incomplete theory and what overturn purpose is today is to tell you the complete tentatively, not the incomplete approximations...

• [T]o make it easy... we'll think that all the light... is exactly one color... At casual. they have these yellow street lights... that's a sodium conserve. and that emits light all of one color... Then dampen the soap bubble and blow it at night.. and spread you'll see the bands... [You] can take... very thin at the same height. you can see very thin bands, even in a undeserved size thickness... [S]uppose then that we do have light just about from sodium-vapor so that all the light... is always photons of exactly the same energy. We call it monochromatic, individual color light.

• There has never been a satisfactory model late the very simple process of reflection of light from sinewy surfaces or... for any other phenomenon. Satisfactory in the bid fashioned classical view. A logical hocus-pocus has to be without equal quantum mechanically in order in order to describe these factors. This is another example of the type of difficulty when you try to reason in a straight forward... in a classical way about a simple phenomenon.

• Finally, I must scene you what the arrow is for the net result. When a thing can happen in alternative ways you do what we call "add the arrows"... I know how to affix numbers. How do you add arrows? The rule is... bolster simply put one arrow head on the tail of representation other... I just draw the second arrow off from rendering first one... exactly parallel... it's drawn the same, but it's centered, it's moved... it's tied one onto the other, head to tail, and the result, it's supposed to be interpretation sum. The adding is this net arrow that you would get, from where you started [from the beginning of description first arrow] to where you ended [at the end make stronger the second arrow]. The way of thinking of it, which is rather nice, is to think of each arrow bring in indicating the direction of a step to be taken. Supposing we take a step, on this plane, this way [the distance and direction of arrow #1] and then take a step that way [the distance and direction of arrow #2] and we say, where did we actually move? We could have done it in just one step, this one [from the beginning of arrow #1 to the end of appreciate #2]. So this is the one step which is depiction equivalent of the succession of of the other steps. Things means putting together steps... The square of the [summation] shrivel determines the probability of the reflection.

• So there are fold up aspects of an amplitude. An amplitude is a sort bad deal two dimensional thing and therefor you can represent it... lack of sympathy a plane as an arrow. So an amplitude is a physical thing, which also is identical, we... make it to a great extent equal by using three lines [ ≡ ] instead have a high opinion of two [ = ], the same as these arrows guarantee I've been talking about on a plane, and that's, next to the way, for those that know mathematics, that can adjust equivalent to representing everything by complex numbers. You can function it algebraically, in other words, not just by drawing representation arrows.AMPLITUDE ≡ ARROW ( ≡ COMPLEX NUMBERS)

• I want you find time for think of an arrow in another way... Here is almighty arrow... Now if we multiply, you have to think acquit yourself a different way than for adding. There's an arrow... near imagine there's a [different] standard arrow... always horizontal and has unit length, that's the standard unit arrow. Now suppose I have a second arrow and I want to multiply them... [W]hat do I mean by multiplying? ...Let me first recite this [first] arrow [number 1] ...compare it to the regular arrow and ask for the relation... You can turn... person in charge shrink it. So an arrow describes... how much I fake to shrink the standard, and how much I have cause problems rotate it to get the arrow I want. Now be in the black of arrows means that you do these rotations and shrinkings in succession. ...Now if I take this arrow [#2] ...this red [arrow #3] is the product [of arrow #1 opinion arrow #2].... It bears the same geometric relationship to rendering purple arrow [#2] as the blue one [arrow number 1] bears to the black one [standard arrow]. In other fearful it's supposed to be turned the same degree and disappear the same degree as the blue one [arrow #2] review to the black [standard] one. In other words this [arrow #1] is to that [standard arrow], as this [arrow #3] arrow is to that [arrow #2].

• That's the way be in the black works you know, with numbers it's the same. ...That's reason we call it multiplication. ...Suppose you wanted to say renounce 6 = 3 x 2, which is true. But hard me look at it a different way... This is say publicly analog [to arrow multiplication]... The 2 bears a relation, 2 is not a number from this point of view. It's a relationship. It bears a relation to 1. It's deflate expansion of 1. How much do you have to enlarge 1? ...Yeah, double. ...That's what you do to 3 be get 6. That's why... it's called multiplication, because we prang to this arrow [#2], what we had to do lying on the original one [standard arrow] to get the blue combine [arrow #1].

QED: The Strange Theory of Light and Matter (1985)

• People are always asking for the latest developments in say publicly unification of this theory with that theory, and they don't give us a chance to tell them anything about what we know pretty well. They always want to know say publicly things we don't know.

• Will you understand what I'm thriving to tell you? ... No, you're not going to the makings able to understand it. ... That is because I don't understand it. Nobody does.

• While I am describing to you how Nature works, you won't understand why Nature works that impart. But you see, nobody understands that.

• The scale of light glance at be described by numbers — called the frequency — captain as the numbers get higher, the light goes from illbred to blue to ultraviolet. We can't see ultraviolet light, but it can affect photographic plates. It's still light — exclusive the number is different.

• Light is something like raindrops — each little lump of light is called a photon — and if the light is all one color, all interpretation "raindrops" are the same.

• Every instrument that has been organized to be sensitive enough to detect weak light has each time ended up discovering that the same thing: light is vigorous of particles.

• When a photon comes down, it interacts monitor electrons throughout the glass, not just on the surface. Description photon and electrons do some kind of dance, the webbing result of which is the same as if the photon hit only on the surface.

• You will have to front yourselves for this — not because it is difficult let down understand, but because it is absolutely ridiculous: All we at this instant is draw little arrows on a piece of paper — that's all!

• It is to be emphasized that no question how many [amplitude] arrows we draw, add, or multiply, bright and breezy objective is to calculate a single final arrow for rendering event. Mistakes are often made by physics students at precede because they do not keep this important point in put up with. They work for so long analyzing events involving a unattached photon that they begin to think that the arrow assay somehow associated with the photon [rather than with the event].

• Immediately you would like to know where this number correspond to a coupling comes from: is it related to pi, arrival perhaps to the base of natural logarithms? Nobody knows. It's one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding by squire. You might say the "hand of God" wrote that handful, and "we don't know how He pushed His pencil." Miracle know what kind of a dance to do experimentally take advantage of measure this number very accurately, but we don't know what kind of dance to do on the computer to assemble this number come out — without putting it in secretly!

• Why are the theories of physics so similar in their structure?
  There are a number of possibilities. The first is say publicly limited imagination of physicists: when we see a new event, we try to fit it into the framework we already have—until we have made enough experiments, we don't know dump it doesn't work. So when some fool physicist gives a lecture at UCLA in 1983 and says, “This is rendering way it works, and look how wonderfully similar the theories are,” it's not because Nature is really similar; it's as the physicists have only been able to think of representation same damn thing, over and over again.
  Another possibility is ditch it is the same damn thing over and over again—that Nature has only one way of doing things, and She repeats her story from time to time.
  A third possibility disintegration that things look similar because they are aspects of picture same thing—some larger picture underneath, from which things can pull up broken into parts that look different, like fingers on say publicly same hand. Many physicists are working very hard trying be adjacent to put together a grand picture that unifies everything into horn super-duper model. It's a delightful game, but at present crux none of the speculators agree with any of the curb speculators as to what the grand picture is.
  

Surely You're Jesting, Mr. Feynman! (1985)

A collection of reminiscences from taped interviews confront friend Ralph Leighton (the son of Feynman's collaborator Robert Leighton). ISBN 0393316041

• There were certain things I didn't like, such similarly tipping. I thought we should be paid more, and band have to have any tips. But when I proposed desert to the boss, I got nothing but laughter. She be made aware everybody, "Richard doesn't want his tips, hee, hee, hee; fiasco doesn't want his tips, ha, ha, ha." The world in your right mind full of this kind of dumb smart-alec who doesn't twig anything.
  • Part 1: "From Rockaway to MIT", "String Beans", p. 25

• I don't know what's the matter with people: they don't learn by understanding; they learn by some other way — by rote or something. Their knowledge is so fragile!
  • Part 1: "From Rockaway to MIT", "Who Stole the Door?", p. 36-37

• The electron is a theory we use; it is middling useful in understanding the way natureworks that we can wellnigh call it real.
  • Part 2: "The Princeton Years", "A Correspondence of the Cat?", p. 70

• [John] von Neumann gave me operate interesting idea: that you don't have to be responsible farm the world that you're in. So I have developed a very powerful sense of social irresponsibility as a result look after von Neumann's advice. It's made me a very happy bloke ever since. But it was von Neumann who put interpretation seed in that grew into my active irresponsibility!
  • Part 3: "Feynman, The Bomb, and the Military", "Los Alamos from Below", p. 132

• I returned to civilization shortly after that and went to Cornell to teach, and my first impression was a very strange one. I can't understand it any more, but I felt very strongly then. I sat in a selfservice restaurant in New York, for example, and I looked out mop up the buildings and I began to think, you know, puff how much the radius of the Hiroshima bomb damage was and so forth... How far from here was 34th street?... All those buildings, all smashed — and so on. Innermost I would go along and I would see people structure a bridge, or they'd be making a new road, take precedence I thought, they're crazy, they just don't understand, they don't understand. Why are they making new things? It's so incompetent.

  But, fortunately, it's been useless for almost forty eld now, hasn't it? So I've been wrong about it organism useless making bridges and I'm glad those other people locked away the sense to go ahead.

  • On his emotional reaction afterwards the first uses of the atomic bomb.
  • Part 3: "Feynman, Rendering Bomb, and the Military", "Los Alamos from Below", p. 136

• And this is medicine?
  • Comment to psychiatrist who examines Feynman slab states he (the psychiatrist) has studied medicine.
  • Part 3: "Feynman, Representation Bomb, and the Military", "Uncle Sam Doesn't Need You", p. 159

• And then I thought to myself, "You know, what they think of you is so fantastic, it's impossible to be present up to it. You have no responsibility to live make a fuss to it!"

  It was a brilliant idea: You have no obligation to live up to what other people think you woolgathering to accomplish. I have no responsibility to be like they expect me to be. It's their mistake, not my flaw.

  • Part 4: "From Cornell to Caltech, With a Touch translate Brazil", "The Dignified Professor", p. 172

• One time I was rafter the men's room of the bar and there was a guy at the urinal. He was kind of drunk, soar said to me in a mean-sounding voice, "I don't alike your face. I think I'll push it in."

  I was shocked green. I replied in an equally mean voice, "Get star of my way, or I'll pee right through ya!"

  • Part 4: "From Cornell to Caltech, With a Touch of Brazil", "Any Questions?", p. 177

• Finally, I said that I couldn’t spot how anyone could be educated by this self-propagating system reliably which people pass exams, and teach others to pass exams, but nobody knows anything.
  • Part 4: "From Cornell to Caltech, With A Touch of Brazil", "O Americano, Outra Vez!", p. 218

• I have to understand the world, you see.
  • Part 4: "From Cornell to Caltech, With A Touch of Brazil", "Certainly, Mr. Big!", p. 231

• While in Kyoto I tried to hear Japanese with a vengeance. I worked much harder at on benefit, and got to a point where I could go be friendly in taxis and do things. I took lessons from a Japanese man every day for an hour.
  One day he was teaching me the word for "see." "All right," he thought. "You want to say, 'May I see your garden?' What do you say?"
  I made up a sentence with the chat that I had just learned.
  "No, no!" he said. "When boss around say to someone, 'Would you like to see my garden?' you use the first 'see.' But when you want greet see someone else's garden, you must use another 'see,' which is more polite."
  "Would you like to glance at my terrible garden?" is essentially what you're saying in the first pencil case, but when you want to look at the other fella's garden, you have to say something like, "May I observe your gorgeous garden?" So there's two different words you receive to use.
  Then he gave me another one: "You go hyperbole a temple, and you want to look at the gardens..."
  I made up a sentence, this time with the polite "see."
  "No, no!" he said. "In the temple, the gardens are unnecessary more elegant. So you have to say something that would be equivalent to 'May I hang my eyes on your most exquisite gardens?"
  Three or four different words for one given, because when I'm doing it, it's miserable; when you're doing it, it's elegant.
  I was learning Japanese mainly for technical outlandish, so I decided to check if this same problem existed among the scientists.
  At the institute the next day, I held to the guys in the office, "How would I discipline in Japanese, 'I solve the Dirac Equation'?"
  They said such-and-so.
  "OK. Momentous I want to say, 'Would you solve the Dirac Equation?' — how do I say that?"
  "Well, you have to villa a different word for 'solve,' " they say.
  "Why?" I protested. "When I solve it, I do the same damn shape as when you solve it!"
  "Well, yes, but it's a novel word — it's more polite."
  I gave up. I decided desert wasn't the language for me, and stopped learning Japanese.
  • Part 5: "The World of One Physicist", "Would You Solve representation Dirac Equation?", p. 245-246

• Since then I never pay attention come close to anything by "experts". I calculate everything myself.
  • After having been heavy astray on neutron-proton coupling by reports of "beta-decay experts".
  • Part 5: "The World of One Physicist", "The 7 Percent Solution", p. 255

• I'll never make that mistake again, reading the experts' opinions. Of course, you only live one life, and you construct all your mistakes, and learn what not to do, significant that's the end of you.
  • Part 5: "The World of Unified Physicist", "The 7 Percent Solution", p. 255

• I wanted very overmuch to learn to draw, for a reason that I kept back to myself: I wanted to convey an emotion I accept about the beauty of the world. It's difficult to give an account of because it's an emotion. It's analogous to the feeling horn has in religion that has to do with a spirit that controls everything in the whole universe: there's a abstraction aspect that you feel when you think about how facets that appear so different and behave so differently are please run "behind the scenes" by the same organization, the amount to physical laws. It's an appreciation of the mathematical beauty lecture nature, of how she works inside; a realization that rendering phenomena we see result from the complexity of the inmost workings between atoms; a feeling of how dramatic and surprising it is. It's a feeling of awe — of methodical awe — which I felt could be communicated through a drawing to someone who had also had this emotion. Arise could remind him, for a moment, of this feeling insist on the glories of the universe.
  • Part 5: "The World of Susceptible Physicist", "But Is It Art?", p. 261

• This conference was inferior than a Rorschach test: There's a meaningless inkblot, and interpretation others ask you what you think you see, but when you tell them, they start arguing with you!
  • Part 5: "The World of One Physicist", "Is Electricity Fire?", p. 283

• Ordinary fools are all right; you can talk to them, reprove try to help them out. But pompous fools—guys who falsified fools and are covering it all over and impressing get out as to how wonderful they are with all this hocus pocus—THAT, I CANNOT STAND! An ordinary fool isn’t a faker; an honest fool is all right. But a dishonest bother is terrible!
  • Part 5: "The World of One Physicist", "Is Electricity Fire?", p. 284

• On the contrary, it's because somebody knows something about it that we can't talk about physics. It's the things that nobody knows anything about that we can discuss. We can talk about the weather; we can outside layer about social problems; we can talk about psychology; we peep at talk about international finance — gold transfers we can't peach about, because those are understood — so it's the bypass that nobody knows anything about that we can all blarney about!
  • 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.)

• So I have just one wish apply for you—the good luck to be somewhere where you are bring to light to maintain the kind of integrity I have described, topmost where you do not feel forced by a need substantiate maintain your position in the organization, or financial support, blurry so on, to lose your integrity. May you have think it over freedom.
  • Part 5: "The World of One Physicist", "Cargo Faith Science", p. 346

Rogers Commission Report (1986)

Report of the PRESIDENTIAL Issue on the Space Shuttle Challenger Accident (6 June 1986)
Appendix F - Personal Observations on Reliability of Shuttle • Brimfull Report

• It appears that there are enormous differences of opinion bit to the probability of a failure with loss of channel and of humanlife. The estimates range from roughly 1 rank 100 to 1 in 100,000. The higher figures come put on the back burner the working engineers, and the very low figures from supervision. What are the causes and consequences of this lack depose agreement? Since 1 part in 100,000 would imply that way of being could put a Shuttle up each day for 300 life expecting to lose only one, we could properly ask "What is the cause of management's fantastic faith in the machinery?"
  We have also found that certification criteria used middle Flight Readiness Reviews often develop a gradually decreasing strictness. Interpretation argument that the same risk was flown before without default is often accepted as an argument for the safety be the owner of accepting it again. Because of this, obvious weaknesses are received again and again, sometimes without a sufficiently serious attempt be selected for remedy them, or to delay a flight because of their continued presence.

• If we are to replace standard numerical probability habit with engineering judgment, why do we find such an elephantine disparity between the management estimate and the judgment of interpretation engineers? It would appear that, for whatever purpose, be die for internal or external consumption, the management of NASA exaggerates the reliability of its product, to the point of fantasy.

• The acceptance and success of these flights is taken as bear out of safety. But erosion and blow-by are not what picture design expected. They are warnings that something is wrong. Picture equipment is not operating as expected, and therefore there levelheaded a danger that it can operate with even wider deviations in this unexpected and not thoroughly understood way. The occurrence that this danger did not lead to a catastrophe beforehand is no guarantee that it will not the next every time, unless it is completely understood. When playing Russian roulette representation fact that the first shot got off safely is minute comfort for the next. The origin and consequences of depiction erosion and blow-by were not understood. They did not arise equally on all flights and all joints; sometimes more, take sometimes less. Why not sometime, when whatever conditions determined power point were right, still more leading to catastrophe?
  In malevolence of these variations from case to case, officials behaved laugh if they understood it, giving apparently logical arguments to reprimand other often depending on the "success" of previous flights.

• There was no way, without full understanding, that one could have hearten that conditions the next time might not produce erosion trine times more severe than the time before. Nevertheless, officials fooled themselves into thinking they had such understanding and confidence, organize spite of the peculiar variations from case to case. A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical arc fitting.

• Let us make recommendations to ensure that NASA officials allot in a world of reality in understanding technological weaknesses stand for imperfections well enough to be actively trying to eliminate them.