He was someone who didn't worry about small problems. His advice here- leave it; let it go.

We all do stupid things, and we know some people do more than others, but there is no use in trying to check who does the most.

It is wonderful if you can find something you love to do in your youth which is big enough to sustain your interset through all your adult life. becuase, whatever it is, if you do well enough (and you will, if you truly love it), people will pay you to do what you want to do anyway.

Don't despair of standard dull textbooks. just close the book once in a while and think what they just said in your own terms as a revelation of the spirit and wonder of nature. the books give you facts but your imagination can supply life.

The thing that was very important about my father is not the facts but the process- the meaning of everything. How we find out; what is the consequence of finding such a rock?

I do remember when I was young I was very one-sided. It was science and math and no humanities.

Do not be too mad at Mike for his C in physics. I got a C in English Literature. Maybe I never would have received a prize in physics if I had been better in English.

But whatever way i did it, I wound't give a damn. I know I didn't care to find out what way you had to do it, because it seemed to me, if I did it, I did it.

I think it is very important to resist accepting too much of unimportant details and inanities. Some wisdom and skill is required to avoid throwing the baby with the bath. But, otherwise, we have too much to think about and cannot concentrate our small minds on the problems.

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 fellow said, so that, at the end, the decision is made as to which idea was the bese - summing it all up - without having to say it three times. So that was a shock. These were very great men indeed. - on his experience with the Manhattan Project.

I don't know anything, but I do know that everything is interesting if you go into it deeply enough.

there must always be a parallel between a general theorem and a special example of a kind. In fact, I personally find- people are different; some people think abstractly very well- I don't. I always have to have examples to understand something the first time I hear it, and then I generalize from the examples. Other people like the general thing and then use it on the thing.

I never think, "This is what I like, and this is what I don't like," I think "This is what it is, and this is what it isn't," and whether or not I like it is really irrelevant, and I have extracted it out of my mind.

The pleasure in physics, for me, is that it's revealed that the truth is so remarkable and amazing. I have this disease, and many other people who have studied far enough to begin to understand a little about how things work are fascinated by it, and this fasination guides them on to such an extent that they've been able to convince governments to keep supporting them in this investigation that the race is making!

I can write under pressure. It's the only way I really can write.

If you go in the same direction as everybody else, you have a whole host of people that you gotta get ahead of.

When I was at MIT, I was in the library a lot. I read advanced book. That's the way I taught myself, I read lots of stuff- I was very avid 渴望 for reading and studying and learning. I read about general relativity, I learned it from a book, and I read a lot of quantum mechanics along with Welpin, and all this stuff, by reading.

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How physicists think

There is always the possibility of proving any definite theory wrong; but notice that we can never prove it right.

It is important to realize that in physics today, we do not have any knowledge of what energy is.

Thinking is nothing but talking to yourself inside.

Physicists like to think that now all you have to do is say, ‘These are the conditions, now what happens next?’

Everything I would do like this, I would always have a practical problem to exemplify it. I have always thought the thing was no good unless you could use it somehow.

It has turned out that many things that bothered me that I thought that I did not understand because I did not know enough about the subject, turned out that I didn’t understand them because they were not logical, they were not valid.

The thing that doesn’t fit is the thing that is the most interesting, the part that does not go according to what you expected.

The paradox is only a conflict between reality and your feeling of what reality ought to be.

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

You can re-create the things that you have forgotten perpetually – if you do not forget too much, and if you know enough. In other words, there comes a time where you will know so many things that as you forget them, you can reconstruct them from the pieces that you can still remember. It is therefore of first-rate importance that you know how to triangulate – that is, to know how to figure something out from what you already know. It is absolutely necessary.

Incidentally, from the point of view of basic physics, the most interesting phenomena are of course, the new places, the places that do not work, not the places that do work. Because there is where we will?discover new rules.

It will not do to memorize the formulas, and to say to yourself, ‘I know all the formulas; all I gotta do is figure out how to put them in the problem!’

First, I am going to tell you what the theory is; I will tell you what it looks like, what we do to make the calculations, just what the thing is because otherwise how are you going to understand what world picture this thing is? And it is a world picture because it describes all the phenomena (except radioactivity and gravity) in the world! That’s a lot of phenomena! It should explain, if everything is thoroughly understood, the laughter of the audience when you make a dummy remark!

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.

I learned that really physics is a very useful background for what looks like different fields; that the world is the same, the physical laws are not so un-useful, you know what I mean? They work. Yeah, they work, and you can use the ideas in different fields, and you are ahead of the other guys, because there are a large number of things that are self-evident to you that they have to learn. But of course, you have to learn by experience too. Im not trying to say just – both together are much better than anybody. But it is true that studying physics is good all over the place.

It’s a very hard job. Its lots of work. So what do we do it for? Because of the excitement, because of the fact that each time we get one of these things, we have a terrific- EI Dorado – we have a new view of nature. We wee the ingenuity, if I may put it that way, of nature herself. The peculiarity of the way she works. It takes a terrible strain on the mind to understand these things. And the real value of the development of the science, in this connection, the things that makes me go on, is this, the difficulty of understanding it. That these apes, stand around looking at nature and find that to really catch on, they have to polish their minds to the last.

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 forget 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.

The quantum world

We physicists are always checking to see if there is something the matter with the theory. That’s the game, because if there is something the matter, its interesting! But so far, we have found nothing wrong with the theory of quantum electrodynamics. It is therefore, I would say, the jewel of physics – our proudest possession.

It is true that two events which may appear to be at the same from one point of view may not do so from another. This leads us to the idea of the representation of time as a fourth gemetrical dimension.

Its so much common sense and common knowledge that gets this idea that when you are not looking at something, it is either this way or that way…but it must be either. No, you can not say that, or you are going to get in trouble! They say that cant be so bad. It must be that nature isn’t quite like that.

The theory of quantum electrodynamics describes nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept nature as she is – absurd.

We have often mad great advances at physics by recognizing that the complexity of things at one level is the result of the fact that these things are composed of simpler elements at another level.

Wave-particle duality – light behaves like particles on Thursdays and like waves on Tuesdays, and that, of course, is not a satisfactory theory.

Nature

Things on a small scale behave nothing like a large scale at all. That's what makes physics hard, and very interesting.

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Nature, as a matter of fact, seems to be so designed that the most important things in the real world appear to be a kind of complicated accidental result of a lot of laws.

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All things that we make are Nature. We arrange it in a way to suit our purpose.

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Trying to understand the way nature works involves a most terrible test of human ability. It involves subtle trickery, beautiful tightropes of logic on which one has to walk in order not to make a mistake in predicting what will happen.

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Imagination reaches out repeatedly trying to achieve some higher level of understanding, until suddenly I find myself momentarily alone before one new corner of nature’s pattern of beauty and true majesty revealed. That was my reward.

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While we are admiring the human mind, which is something we enjoy doinig – it is always someone else’s human mind that we enjoy admiring – we should take some time off to stand in awe of nature, of a nature which can follow with such completeness and generality such as elegantly simple principle as the law of gravitation.

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We used to laugh at the Greeks who claimed that the planets had to go in circles because it was a perfect figure. If they were talking in the modern times they would use group theoretic arguments and would imply that from a point of view of the planet the sun looks always the same, or that we have invariance under a combined time displacement and rotation. But the planets do not go in circles! Nature is not `symmetrical` and the question is why not?

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Nature uses only the longest threads to weave her patterns, so each small piece of her fabric reveals the organization of the entire tapestry.

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What is it about nature that lets this happen, that it is possible to guess from one part what the rest is going to do? That is an unscientific question: I do not know how to answer it, and therefore I am going to give an unscientific answer. I think it is because nature has a simplicity and therefore a great beauty.

Perhaps a thing is simple if you can describe it fully in several different ways without immediately knowling that you are describing the same thing.

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Nature has always looked like a horrible mess, but as we go along we see patterns and put theories together; a certain clarity comes and things get simpler.

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Nature doesn’t care what we call it, she just keeps on doing it whatever way she wants.

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Nature is, no doubt, simpler than all our thoughts about it.

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This rather trivial understanding of relativity could have easily been understood the moment perspective was understood, and the famous old kingdom legends about the guys who feel the elephants, you know, as a rope, because he is holding on to the tail, or as a leaf because he is holding on to the ear, and so on, is just simply the same idea that things depend upon your point of view.

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Energy is a very subtle concept. It is very, very difficult to get right.

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The internal machinery of life, the chemistry of the parts, is something beautiful.

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All other aspects and characteristics of science can be understood directly when we understand that observation of science is the ultimate and final judge of the truth of an idea.

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If you have any appreciation for the complexities of nature and for the evolution of life on earth, you can understand the tremendous variety of possible froms that life would have.

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You are lucky you have such a deep interest in nature, and even if you find it is much more complicated and difficult to understand that you thought, when you learn more about it, it is also in certain ways more simple and beautiful than what you can imagine.

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And im not happy with all the analyses that go with just the classical theory because nature isn’t classical, dammit, and if you want to make a simulation of nature, youd better make it quantum mechanics, and by golly it is a wonderful problem because it doesn’t look so easy.

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If you want to know the way nature works, we looked at it happily, and that’s the way it looks! You don’t like it? Go somewhere else – to another universe where the rules are simpler!

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Things that are very common and observed all the time and which appear perfectly obvious are quite different in this world. It turns out that what we thought was obvious is wrong, and it is much more complicated – or not more complicated but just different! In fact, sometimes it is simpler and more beautiful.

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The world is a dynamic mess of jiggling things.

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How is it possible, by looking at a piece of nature, to guess how another part must look, where you have never been before? It is only in modern times that man has really able to guess what nature is going to do in situations that he has never looked at before.

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I like science because when you think of something you can check it by experiment: yes or no, nature says, and you go on from there progressively. Other wisdom has no equally certain way of separating truth from falsehood.

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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.