Richard Feynman Quotes & Sayings

A philosopher once said, "It is necessary for the very existence of science that the same conditions always produce the same results." Well, they don't! — Richard Feynman

Are you looking for the ultimate laws of physics? No, I'm not. I'm just looking to find out more about the world and if it turns out there is a simple ultimate law which explains everything, so be it; that would be very nice to discover. If it turns out it's like an onion with millions of layers and we're just sick and tired of looking at the layers, then that's the way it is ... My interest in science is to simply find out more about the world. — Richard Feynman

I wonder why. I wonder why.
I wonder why I wonder.
I wonder why I wonder why
I wonder why I wonder! — Richard Feynman

Professor Feynman?" "Hey! Why are you bothering me at this time in the morning?" "I thought you'd like to know that you've won the Nobel Prize." "Yeah, but I'm sleeping! It would have been better if you had called me in the morning." - and I hung up. — Richard Feynman

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

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 — Richard Feynman

All mass is interaction. — Richard Feynman

I'm smart enough to know that I'm dumb. — Richard Feynman

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. — Richard Feynman

It was such a shock to me to see that a committee of men could present a whole lot of ideas, each one thinking of a new facet, while remembering what the other fella said, so that, at the end, the decision is made as to which idea was the best - summing it all up - without having to say it three times. These were very great men indeed. — Richard Feynman

A very great deal more truth can become known than can be proven. — Richard Feynman

I don't feel frightened by 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. Possibly. It doesn't frighten me. — Richard Feynman

I finally figured out a way to test whether you have taught an idea or you have only taught a definition. Test it this way: You say, 'Without using the new word which you have just learned, try to rephrase what you have just learned in your own language. Without using the word "energy," tell me what you know now about the dog's motion.' You cannot. So you learned nothing about science. That may be all right. You may not want to learn something about science right away. You have to learn definitions. But for the very first lesson, is that not possibly destructive? — Richard 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 — Richard Feynman

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. — Richard Feynman

The difference between solids and liquids is, then, that in a solid the atoms are arranged in some kind of an array, called a crystalline array, and they do not have a random position at long distances; the position of the atoms on one side of the crystal is determined by that of other atoms millions of atoms away on the other side of the crystal. — Richard Feynman

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

I mumbled something about how it was easy to calculate e to any power using that series (you just substitute the power for x). "Oh yeah?" they said, "Well, then, what's e to the 3.3?" said some joker - I think it was Tukey. I say, "That's easy. It's 27.11." Tukey knows it isn't so easy to compute all that in your head. "Hey! How'd you do that?" Another guy says, "You know Feynman, he's just faking it. It's not really right." They go to get a table, and while they're doing that, I put on a few more figures: "27.1126," I say. They find it in the table. "It's right! But how'd you do it!" "I just summed the series." "Nobody can sum the series that fast. You must just happen to know that one. How about e to the 3?" "Look," I say. "It's hard work! Only one a day!" "Hah! It's a fake!" they say, happily. "All right," I say, "It's 20.085. — Richard Feynman

With energy there is this difference, that there are no blocks, so far as we can tell. Also, unlike the case of the blocks, for energy the numbers that come out are not integers. I — Richard Feynman

Life behind him by this time (he died in 1988), so he could reflect on his experiences and accomplishments with the — Richard Feynman

For instance, the mass of an object changes when it moves, because of the conservation of energy. Because of the relation of mass and energy the energy associated with the motion appears as an extra mass, so things get heavier when they move. Newton — Richard Feynman

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

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. — Richard Feynman

The worthwhile problems are the ones you can really solve or help solve, the ones you can really contribute something to ... No problem is too small or too trivial if we can really do something about it. — Richard Feynman

Thank you very Much, I enjoyed myself — Richard Feynman

What I cannot build. I do not understand. — Richard Feynman

Nature has a great simplicity and therefore a great beauty — Richard Feynman

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. — Richard Feynman

We absolutely must leave room for doubt or there is no progress and there is no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty. People are terrified - how can you live and not know? It is not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge and you really don't know what it is all about, or what the purpose of the world is, or know a great deal of other things. It is possible to live and not know. — Richard Feynman

Looking back at the worst times, it always seems that they were times in which there were people who believed with absolute faith and absolute dogmatism in something. And they were so serious in this matter that they insisted that the rest of the world agree with them. And then they would do things that were directly inconsistent with their own beliefs in order to maintain that what they said was true. — Richard Feynman

Physics is to math what sex is to masturbation. — Richard Feynman

Innovation is a very difficult thing in the real world — Richard Feynman

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. — Richard Feynman

Now that I am burned out and I'll never
accomplish anything, I've got this nice position at the university teaching
classes which I rather enjoy, and just like I read the Arabian Nights for
pleasure, I'm going to play with physics, whenever I want to, without
worrying about any importance whatsoever. — Richard Feynman

Thus light is something like raindrops-each little lump of light is called a photon-and if the light is all one color, all the "raindrops" are the same size. — Richard Feynman

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. — Richard Feynman

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. — Richard Feynman

How much do you value life?" "Sixty-four. — Richard Feynman

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. — Richard Feynman

To every man is given the key to Heaven. The same key opens the gates of Hell. — Richard Feynman

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. — Richard Feynman

I learned very early the difference between knowing the name of something and knowing something. — Richard Feynman

atoms in the air scatter light from the sun and make the sky blue — Richard Feynman

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. — Richard Feynman

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

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. — Richard Feynman

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'. — Richard Feynman

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. — Richard Feynman

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? — Richard Feynman

Conservation just means that it does not change. — Richard Feynman

Science is the organized skepticism in the reliability of expert opinion. — Richard Feynman

Underneath so many of the phenomena we see every day are only three basic actions: one is described by the simple coupling number, j; the other two by functions-P(A to B) and E(A to B)- both of which are closely related. That's all there is to it, and from it all the rest of the laws of physics come. — Richard Feynman

Why do we see no change? Because just as many molecules are leaving as are coming back! In the long run "nothing happens." If we then take the top of the vessel off and blow the moist air away, replacing it with dry air, then the number of molecules leaving is just the same as it was before, because this depends on the jiggling of the water, but the number coming back is greatly reduced because there are so many fewer water molecules above the water. Therefore — Richard Feynman

You see, one thing is, I can live with doubt and uncertainty and not knowing. 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 certainty about different things, but I'm 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, and what the question might mean. I might think about it a little bit and if I can't figure it out, then I go on to something else, but I don't have to know an answer, I don't feel frightened by not knowing things, by being lost in a mysterious universe without having any purpose, which is the way it really is so far as I can tell. It doesn't frighten me. — Richard Feynman

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

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. — Richard Feynman

If we were not able or did not desire to look in any new direction, if we did not have a doubt or recognize ignorance, we would not get any new ideas. — Richard Feynman

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 — Richard Feynman

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. — Richard Feynman

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 — Richard Feynman

What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school ... It is my task to convince you not to turn away because you don't understand it. You see my physics students don't understand it ... That is because I don't understand it. Nobody does. — Richard Feynman

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 — Richard Feynman

Mysteries like these repeating cycles make it very interesting to be a theoretical physicist: Nature gives us such wonderful puzzles! Why does She repeat the electron at 206 times and 3,640 times its mass? — Richard Feynman

That night, Brazilian TV audiences saw the director of the Center for Physical Research welcome the Visiting Professor from the United States, but little did they know that the subject of their conversation was finding a girl to spend the night with! — Richard Feynman

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. — Richard Feynman

Damn deez doilies! — Richard Feynman

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

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

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! — Richard Feynman

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

For instance, the scientific article may say, 'The radioactive phosphorus content of the cerebrum of the rat decreases to one- half in a period of two weeks.' Now what does that mean?
It means that phosphorus that is in the brain of a rat - and also in mine, and yours - is not the same phosphorus as it was two weeks ago. It means the atoms that are in the brain are being replaced: the ones that were there before have gone away.
So what is this mind of ours: what are these atoms with consciousness? Last week's potatoes! They now can remember what was going on in my mind a year ago - a mind which has long ago been replaced. To note that the thing I call my individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of the brain to be replaced by other atoms. The atoms come into my brain, dance a dance, and then go out - there are always new atoms, but always doing the same dance, remembering what the dance was yesterday. — Richard Feynman

But that was my big moment: I gave a seminar in the biology department at Harvard! I always do that, get into something and see how far I can go. I — Richard Feynman

I believe, therefore, that although it is not the case today, that there may some day come a time, I should hope, when it will fully appreciated that the power of governments should be limited; that governments ought not to be empowered to decide the validity of scientific theories, that this is a ridiculous thing for them to try to do; that they are not to decide the description of history or of economic theory or of philosophy. — Richard Feynman

[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. — Richard Feynman

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. — Richard Feynman

So the librarians at UCLA worked very hard to find another copy of Villacorta's rendition of the Dresden Codex, and lent it to me. — Richard Feynman

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. — Richard Feynman

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. — Richard Feynman

Of course, I am interested, but I would not dare to talk about them. In talking about the impact of ideas in one field on ideas in another field, one is always apt to make a fool of oneself. In these days of specialization there are too few people who have such a deep understanding of two departments of our knowledge that they do not make fools of themselves in one or the other. — Richard Feynman

The conservation of energy is a little more difficult, because this time we have a number which is not changed in time, but this number does not represent any particular thing. I — Richard Feynman

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 — Richard Feynman

I think the educational and psychological studies I mentioned are examples of what I would like to call cargo cult science. In the South Seas there is a cargo cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they've arranged to make things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas - he's the controller - and they wait for the airplanes to land. They're doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land. So I call these things cargo cult science, because they follow all the apparent precepts and forms of scientific investigation, but they're missing something essential, because the planes don't land. — Richard Feynman

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. — Richard Feynman

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? — Richard Feynman

(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 — Richard Feynman

Figure 36. A "trick" can be played on Nature by slowing down the light that takes shorter paths: glass of just the right thickness is inserted so that all the paths will take exactly the same time. This causes all of the arrows to point in the same direction, and to produce a whopping final arrow-lots of light! Such a piece of glass made to greatly increase the probability of light getting from a source to a single point is called a focusing lens. — Richard Feynman

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

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. — Richard Feynman

We are lucky to live in an age in which we are still making discoveries. — Richard Feynman

Discovering the laws of physics is like trying to put together the pieces of a jigsaw puzzle. We — Richard Feynman

The first demonstration of the law of conservation of energy was not by a physicist but by a medical man. He demonstrated with rats. If you burn food you can find out how much heat is generated. If you then feed the same amount of food to rats it is converted, with oxygen, into carbon dioxide, in the same way as in burning. When you measure the energy in each case you find out that living creatures do exactly the same as non-living creatures. The law for conservation of energy is as true for life as for other phenomena. Incidentally, — Richard Feynman

If charge were conserved because it was a real particle which moved around it would have a very special property. The total amount of charge in a box might stay the same in two ways. It may be that the charge moves from one place to another within the box. But another possibility is that the charge in one place disappears, and simultaneously charge arises in another place, instantaneously related, and in such a manner that the total charge is never changing. This — Richard Feynman

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. — Richard Feynman

All ordinary phenomena can be explained by the actions and the motions of particles. For — Richard Feynman

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? — Richard Feynman

There are thousands of years in the past, and there is an unknown amount of time in the future. There are all kinds of opportunities, and there are all kinds of dangers. — Richard Feynman

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! — Richard Feynman

I ... a universe of atoms, an atom in the universe. — Richard Feynman

You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird ... So let's look at the bird and see what it's doing
that's what counts. — Richard Feynman

In general, we look for a new law by the following process: First we guess it; then we compute the consequences of the guess to see what would be implied if this law that we guessed is right; then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is, it does not make any difference how smart you are, who made the guess, or what his name is - if it disagrees with experiment, it is wrong. — Richard Feynman