Richard Feynman Quotes

Whether the proton decays or not is not known. To prove that it does not decay is very difficult.

It is probably better to realize that the probability concept is in a sense subjective, that it is always based on uncertain knowledge, and that its quantitative evaluation is subject to change as we obtain more information.

The probability of an event is always represented by a single final arrow-no matter how many arrows were drawn, multiplied, and added to achieve it.

The exception proves that the rule is wrong. That is the principle of science. If there is an exception to any rule, and if it can be proved by observation, that rule is wrong.

This is not a new idea; this is the idea of the age of reason. This is the philosophy that guided the men that made the democracy that we live under. The idea that no one really knew how to run a government led to the idea that we should arrange a system by which new ideas could be developed, tried out, and tossed out if necessary, with more new ideas brought in - a trial and error system.

All the time you're saying to yourself, 'I could do that, but I won't,' - which is just another way of saying that you can't.

I said, There's a long tradition behind life in India that comes from a religion and philosophy that is thousands of years old. And although these people are not in India, they still pass on those traditions about what's important in life - trying to build for the future and supporting their children in the effort - which have come down to them for centuries.

I have a friend who's an artist, and he sometimes takes a view which I don't agree with. He'll hold up a flower and say, "Look how beautiful it is," and I'll agree. But then he'll say, "I, as an artist, can see how beautiful a flower is. But you, as a scientist, take it all apart and it becomes dull." I think he's kind of nutty. [...] There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower. It only adds. I don't understand how it subtracts.

You have no responsibility to live up to what other people think you ought to accomplish. I have no responsibility to be like they expect me to be. It's their mistake, not my failing.

angular momentum appears in two forms : one of them is angular momentum of motion, and the other is angular momentum in electric and magnetic fields. There is angular momentum in the field around the magnet, although it does not appear as motion, and this has the opposite sign to the spin. If

Why nature is mathematical is, again, a mystery.

What I cannot build. I do not understand.

The little cathedral made with matchsticks is attracted to the earth, so to make a comparison the big cathedral should be attracted to an even bigger earth. Too bad. A bigger earth would attract it even more, and the sticks would break even more surely!

If a piece of steel or a piece of salt, consisting of atoms one next to the other, can have such interesting properties; if water - which is nothing but these little blobs, mile upon mile of the same thing over the earth - can form waves and foam, and make rushing noises and strange patterns as it runs over cement; if all of this, all the life of a stream of water, can be nothing but a pile of atoms, how much more is possible? If

That's the trouble with not being in your own field: You don't take it seriously.

Alone, and start to think. There are the rushing waves ... mountains of molecules, each stupidly minding its own business ... trillions apart ... yet forming white surf in unison. Ages on ages ... before any eyes could see ... year after 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 sea roar. Deep in the sea, all molecules repeat the patterns of one 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 of atoms, DNA, protein ... dancing a pattern ever more intricate. Out of the cradle onto the dry land ... here it is standing ... atoms with consciousness ... matter with curiosity. Stands at the sea ... wonders at wondering ... I ... a universe

The game I play is a very interesting one. It's imagination, in a tight straightjacket.

You can't fool nature.

Philosophers say a great deal about what is absolutely necessary for science, and it is always, so far as one can see, rather naive, and probably wrong.

If instead of arranging the atoms in some definite pattern, again and again repeated, on and on, or even forming little lumps of complexity like the odor of violets, we make an arrangement which is always different from place to place, with different kinds of atoms arranged in many ways, continually changing, not repeating, how much more marvelously is it possible that this thing might behave? Is it possible that that "thing" walking back and forth in front of you, talking to you, is a great glob of these atoms in a very complex arrangement, such that the sheer complexity of it staggers the imagination as to what it can do? When we say we are a pile of atoms, we do not mean we are merely a pile of atoms, because a pile of atoms which is not repeated from one to the other might well have the possibilities which you see before you in the mirror.

I think it's much more interesting to live not knowing than to have answers which might be wrong. I have approximate answers and possible beliefs and different degrees of uncertainty about different things, but I am not absolutely sure of anything and there are many things I don't know anything about, such as whether it means anything to ask why we're here. I don't have to know an answer. I don't feel frightened not knowing things, by being lost in a mysterious universe without any purpose, which is the way it really is as far as I can tell.

You might ask why we cannot teach physics by just giving the basic laws on page one and then showing how they work in all possible circumstances, as we do in Euclidean geometry, where we state the axioms and then make all sorts of deductions. (So,

The strange feature of partial reflection by two surfaces has forced physicists away form making absolute predictions to merely calculating the probability of an event. Quantum electrodynamics provides a method for doing this-drawing little arrows on a piece of paper. The probability of an event is represented by the area of the square of an arrow. For example, an arrow representing a probability of 0.04 (4%) has a length of 0.2.

Since you and your brain (and mine too) are biased to seeing patterns even where there are no patterns we have to be very careful to be rational. Facts are not always convenient. Nor are they always warm and fuzzy. Often they do not fit our stories of the way things are. And if we ignore them we try to fool nature, and nature cannot be fooled.

After reading the salary, I've decided that I must refuse. The reason I have to refuse a salary like that is I would be able to do what I've always wanted to do- -get a wonderful mistress, put her up in an apartment, buy her nice things.. With the salary you have offered, I could actually do that, and I know what would happen to me. I'd worry about her, what she's doing; I'd get into arguments when I come home, and so on. All this bother would make me uncomfortable and unhappy. I wouldn't be able to do physics well, and it would be a big mess! What I've always wanted to do would be bad for me, so I've decided that I can't accept your offer.

The laws of physics could be like an onion, with new laws becoming operational as we probe new scales. We simply don't know!

The uncertainty principle "protects" quantum mechanics. Heisenberg recognized that if it were possible to measure the momentum and the position simultaneously with a greater accuracy, the quantum mechanics would collapse. So he proposed that it must be impossible.

We find that energy is conserved no matter how complex the process, even when we do not know the detailed laws.

The attempts to try to represent the electric field as the motion of some kind of gear wheels, or in terms of lines, or of stresses in some kind of material have used up more effort of physicists than it would have taken simply to get the right answers about electrodynamics. It is interesting that the correct equations for the behavior of light were worked out by MacCullagh in 1839. But people said to him: 'Yes, but there is no real material whose mechanical properties could possibly satisfy those equations, and since light is an oscillation that must vibrate in something, we cannot believe this abstract equation business'.

First of all there is matter - and, remarkably enough, all matter is the same. The matter of which the stars are made is known to be the same as the matter on the earth ... The same kinds of atoms appear to be in living creatures as in non-living creatures.

Throughout these lectures I have delighted in showing you that the price of gaining such an accurate theory has been the erosion of our common sense. We must accept some very bizarre behavior: the amplification and suppression of probabilities, light reflecting from all parts of a mirror, light travelling in paths other than a straight line, photons going faster or slower than the conventional speed of light, electrons going backwards in time, photons suddenly disintegrating into a positron-electron pair, and so on. That we must do, in order to appreciate what Nature is really doing underneath nearly all the phenomena we see in the world.

frogs are made of the same 'goup' as rocks, only in different arrangements. So

Religion is a culture of faith; science is a culture of doubt.

Take this neat little equation here. It tells me all the ways an electron can make itself comfortable in or around an atom. That's the logic of it. The poetry of it is that the equation tells me how shiny gold is, how come rocks are hard, what makes grass green, and why you can't see the wind. And a million other things besides, about the way nature works.

Prof. Wheeler was called away last night so I took over his course in mechanics for the day. I spent all last night preparing. It went very nicely and smoothly. It was a good experience
I guess I'll do a lot of that.

Study hard what interests you the most in the most undisciplined, irreverent and original manner possible.

We are so used to looking at the world from the point of view of living things that we cannot understand what it means not to be alive, and yet most of the time the world had nothing alive on it. And in most places in the universe today there probably is nothing alive.

In physics the truth is rarely perfectly clear, and that is certainly universally the case in human affairs. Hence, what is not surrounded by uncertainty cannot be the truth.

I couldn't claim that I was smarter than sixty-five other guys
but the average of sixty-five other guys, certainly!

You can't say A is made of B or vice versa. All mass is interaction.

Thank you very Much, I enjoyed myself

Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it.

When sunlight, which contains red, yellow, green, and blue light, shines on a mud puddle with oil on it, the areas that strongly reflect each of those colors overlap and produce all kinds of combinations which our eyes see as different colors ... This phenomenon of colors produced by the partial reflection of white light by two surfaces is called iridescence, and can be found in many places ... the more you see how strangely Nature behaves, the harder it is to make a model that explains how even the simplest phenomena actually work.

It always bothers me that, according to the laws as we understand them today, it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space, and no matter how tiny a region of time. How can all that be going on in that tiny space? Why should it take an infinite amount of logic to figure out what one tiny piece of space/time is going to do?

Physics isn't the most important thing. Love is.

We are at the very beginning of time for the human race. It is not unreasonable that we grapple with problems. But there are tens of thousands of years in the future. Our responsibility is to do what we can, learn what we can, improve the solutions, and pass them on.

Mathematics is a language plus reasoning; it is like a language plus logic. Mathematics is a tool for reasoning.

To our eyes, our crude eyes, nothing is changing, but if we could see it a billion times magnified, we would see that from its own point of view it is always changing: molecules are leaving the surface, molecules are coming back.

My rule is, when you are unhappy, think about it. But when you're unhappy, don't. Why spoil it? You're probably happy for some ridiculous reason and you'd just spoil it to know it.

If u think u can u may
if u think u can't u r right

I think we should teach them [the people] wonders and that the purpose of knowledge is to appreciate wonders even more.

It is impossible to explain honestly the beauties of the laws of nature in a way that people can feel, without their having some deep understanding of mathematics. I am sorry, but this seems to be the case.

Learn what the rest of the world is like. The variety is worthwhile.

So we see that what looks like a dead, uninteresting thing - a glass of water with a cover, that has been sitting there for perhaps twenty years - really contains a dynamic and interesting phenomenon which is going on all the time. To

A source of white light-many colors mixed together-emits photons in a chaotic manner: the angle of the amplitude changes abruptly and irregularly in fits and starts. But when we construct a monochromatic source, we are making a device that has been carefully arranged so that the amplitude for a photon to be emitted at a certain time is easily calculated: it changes its angle at a constant speed, like a stopwatch hand. (Actually, this arrow turns at the same speed as the imaginary stopwatch we used before, but in the opposite direction-see Fig. 67.)

Tell your son to stop trying to fill your head with science - for to fill your heart with love is enough.

Science is the organized skepticism in the reliability of expert opinion.

I dedicate this lecture to showing what ridiculous conclusions and rare statements such a man as myself can make. I wish, therefore, to destroy any image of authority that has previously been generated.

So I started to think: "How can that happen?" ... So the guy says, "What are you doing? You come fix the radio, but you're only walking back and forth!" I say, "I'm thinking!

Physics is to math what sex is to masturbation.

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!

Anything can happen, in spite of what you're pretty sure should happen.

Professor Weyl,* the mathematician, gave an excellent definition of symmetry, which is that a thing is symmetrical if there is something that you can do to it so that after you have finished doing it it looks the same as it did before. That is the sense in which we say that the laws of physics are symmetrical; that there are things we can do to the physical laws, or to our way of representing the physical laws, which make no difference, and leave everything unchanged in its effects. It is this aspect of physical laws that is going to concern us in this lecture.

I really can't do a good job, any job, of explaining magnetic force in terms of something you're more familiar with, because I do not understand it in terms of something you are more familiar with.

But one man, I remember, Bob Wilson, was just sitting there moping. I said, "What are you moping about?" He said, "It's a terrible thing that we made." I said, "But you started it. You got us into it." You see, what happened to me - what happened to the rest of us - is we started for a good reason, then you're working very hard to accomplish something and it's a pleasure, it's excitement. And you stop thinking, you know; you just stop. Bob Wilson was the only one who was still thinking about it, at that moment. I

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

Don't know what's the matter with people: they don't learn by understanding; they learn by some other way - by rote,

From a long view of the history of mankind, seen from, say, ten thousand years from now, there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the laws of electrodynamics. The American Civil War will pale into provincial insignificance in comparison with this important scientific event of the same decade.

(Joan,1941) She wrote me a letter asking,"How can I read it?,Its so hard." I told her to start at the beginning and read as far as you can get until you're lost. Then start again at the beginning and keep working through until you can understand the whole book. And thats what she did

There are other conservation laws. They are not as interesting as those I have described, and do not deal exactly with the conservation of numbers. Suppose

It was a kind of one-upmanship, where nobody knows what's going on, and they'd put the other one down as if they did know. They all fake that they know, and if one student admits for a moment that something is confusing by asking a question, the others take a high-handed attitude, acting as if it's not confusing at all, telling him that he's wasting their time ... All the work they did, intelligent people, but they got themselves into this funny state of mind, this strange kind of self-propagating "education" which is meaningless, utterly meaningless.

[Doubt] is not a new idea; this is the idea of the age of reason. This is the philosophy that guided the men who made the democracy that we live under. The idea that no one really knew how to run a government led to the idea that we should arrange a system by which new ideas could be developed, tried out, and tossed out if necessary, with more new ideas bought in - a trial-and-error system. This method was a result of the fact that science was already showing itself to be a successful venture at the end of the eighteenth century. Even then it was clear to socially minded people that the openness of possibilities was an opportunity, and that doubt and discussion were essential to progress into the unknown. If we want to solve a problem that we have never solved before, we must leave the door to the unknown ajar ... doubt is not to be feared, but welcomed and discussed.

If one cannot see gravitation acting here, he has no soul.

Experiment is the sole judge of scientific "truth." But what is the source of knowledge? Where do the laws that are to be tested come from? Experiment, itself, helps to produce these laws, in the sense that it gives us hints. But also needed is imagination to create from these hints the great generalizations - to guess at the wonderful, simple, but very strange patterns beneath them all, and then to experiment to check again whether we have made the right guess. This imagining process is so difficult that there is a division of labor in physics: there are theoretical physicists who imagine, deduce, and guess at new laws, but do not experiment; and then there are experimental physicists who experiment, imagine, deduce, and guess.

Of course, you only live one life, and you make all your mistakes, and learn what not to do, and that's the end of you.

It is surprising that people do not believe that there is imagination in science. It is a very interesting kind of imagination, unlike that of the artist. The great difficulty is in trying to imagine something that you have never seen, that is consistent in every detail with what has already been seen, and that is different from what has been thought of; furthermore, it must be definite and not a vague proposition. That is indeed difficult.

It is interesting that this thoroughness, which is a virtue, is often misunderstood. When someone says a thing has been done scientifically, often all he means is that it has been done thoroughly. I have heard people talk of the "scientific" extermination of the Jews in Germany. There was nothing scientific about it. It was only thorough. There was no question of making observations and then checking them in order to determine something. In that sense, there were "scientific" exterminations of people in Roman times and in other periods when science was not so far developed as it is today and not much attention was paid to observation. In such cases, people should say "thorough" or "thoroughgoing," instead of "scientific.

THE QUESTION IS, OF COURSE, IS IT GOING TO BE POSSIBLE TO AMALGAMATE EVERYTHING,
AND MERELY DISCOVER THAT THIS WORLD REPRESENTS DIFFERENT ASPECTS OF ONE THING?

The price of gaining such an accurate theory has been the erosion of our common sense.

Poets say science takes away from the beauty of the stars - mere globs of gas atoms. 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 it. 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?

I happen to know this, and I happen to know that, and maybe I know that;and I work everything out from there. Tomorrow I may forgot that this is true, but remember that something else is true, so I can reconstruct it all again. I am never quite sure of where I am supposed to begin or where I am supposed to end. I just remember enough all the time so that as the memory fades and some of the pieces fall out I can put the thing back together again every day

If a Martian (who, we'll imagine, never dies except by accident) came to Earth and saw this peculiar race of creatures - these humans who live about seventy or eighty years, knowing that death is going to come - it would look to him like a terrible problem of psychology to live under those circumstances, knowing that life is only temporary. Well, we humans somehow figure out how to live despite this problem: we laugh, we joke, we live.

I learned from my father to translate: everything I read I try to figure out what it really means, what it's really saying.

What I got out of that story was something still very new to me: I understood at last what art is really for, at least in certain respects. It gives somebody, individually, pleasure. You can make something that somebody likes so much that they're depressed, or they're happy, on account of that damn thing you made! In science, it's sort of general and large: You don't know the individuals who have appreciated it directly. I understood that to sell a drawing is not to make money, but to be sure that it's in the home of someone who really wants it; someone who would feel bad if they didn't have it. This was interesting.

So when you try to squeeze light too much to make sure it's going in only a straight line, it refuses to cooperate and begins to spread out.

You are a strong and beautiful woman. You are not always as strong as other times but it rises & falls like the flow of a mountain stream. I feel I am a reservoir for your strength- without you I would be empty and weak.

[Letter to Arline Feynman]

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

When we add all the numbers together, from all the different forms of energy, it always gives the same total. But as far as we know there are no real units, no little ballbearings. It

Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can - if you know anything at all wrong, or possibly wrong - to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want 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 finished theory makes something else come out right, in addition.

Mr. Frankel, who started this program, began to suffer from the computer disease that anybody who works with computers now knows about. It's a very serious disease and it interferes completely with the work. The trouble with computers is you play with them. They are so wonderful. You have these switches - if it's an even number you do this, if it's an odd number you do that - and pretty soon you can do more and more elaborate things if you are clever enough, on one machine.

I've found out since that such people don't know what they're doing, and get insulted when you make some suggestion or criticism.

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 restaurant in New York, for example, and I looked out at the buildings and I began to think, you know, about 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. And I would go along and I would see people building a bridge, or they'd be making a new road, and I thought, they're crazy, they just don't understand, they don't understand. Why are they making new things? It's so useless.
But, fortunately, it's been useless for almost forty years now, hasn't it? So I've been wrong about it being useless making bridges and I'm glad those other people had the sense to go ahead.

When it came time for me to give my talk on the subject, I started off by drawing an outline of the cat and began to name the various muscles.
The other students in the class interrupt me: "We *know* all that!"
"Oh," I say, "you *do*? Then no *wonder* I can catch up with you so fast after you've had four years of biology." They had wasted all their time memorizing stuff like that, when it could be looked up in fifteen minutes.

I learned from her that every woman is worried
about her looks, no matter how beautiful she is.

I've always been rather very one-sided about the science, and when I was younger, I concentrated almost all my effort on it. I didn't have time to learn, and I didn't have much patience for what's called the humanities; even though in the university there were humanities that you had to take, I tried my best to avoid somehow to learn anything and to work on it. It's only afterwards, when I've gotten older and more relaxed that I've spread out a little bit - I've learned to draw, and I read a little bit, but I'm really still a very one-sided person and don't know a great deal. I have a limited intelligence and I've used it in a particular direction.

They were very upset when I said that the thing of greatest importance to mathematics in Europe was the discovery by Tartaglia that you can solve a cubic equation-which, altho it is very little used, must have been psychologically wonderful because it showed a modern man could do something no ancient Greek could do, and therefore helped in the renaissance which was the freeing of man from the intimidation of the ancients-what they are learning in school is to be intimidated into thinking they have fallen so far below their super ancestors.

Religion gives inspiration to act well. Not only that, it gives inspiration to the arts and to many other activities of human beings.

I have to keep going to find out ultimately what is the matter with it in the end.

In fact the total amount that a physicist knows is very little. He has only to remember the rules to get him from one place to another and he is all right ...

The trouble with playing a trick on a highly intelligent man like Mr. Teller is that the time it takes him to figure out from the moment that he sees there is something wrong till he understands exactly what happened is too damn small to give you any pleasure!