Every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering that the same thing: light is made of particles.

It is the fact that the electrons cannot all get on top of each other that makes tables and everything else solid.

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?

Therefore psychologically we must keep all the theories in our heads, and every theoretical physicist who is any good knows six or seven different theoretical representations for exactly the same physics.

Some things that satisfy the rules of algebra can be interesting to mathematicians even though they don’t always represent a real situation.

We can deduce, often, from one part of physics like the law of gravitation, a principle which turns out to be much more valid than the derivation.

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.

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.

It is necessary for the very existence of science that minds exist which do not allow that nature must satisfy some preconceived conditions.

No one really understands quantum mechanics.

There is nothing that living things do that cannot be understood from the point of view that they are made of atoms acting according to the laws of physics.

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

I don’t believe in honors, it bothers me, honors bother, honors is epaulettes, honors is uniforms. My papa brought me up this way. I can’t stand it, it hurts me.

It’s because somebody knows something about it that we can’t talk about physics. It’s the things that nobody knows anything about we can discuss.

The theoretical broadening which comes from having many humanities subjects on the campus is offset by the general dopiness of the people who study these things.

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

To decide upon the answer is not scientific. In order to make progress, one must leave the door to the unknown ajar ajar only.

Every object is a mixture of lots of things, so we can deal with it only as a series of approximations and idealizations.

With quantum physics, who needs drugs?

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.

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.

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

The things that mattered were honesty, independence, willingness to admit ignorance.

If we will only allow that, as we progress, we remain unsure, we will leave opportunities for alternatives.

This is not very important what I’m doing. I’m just proving something.

Agnostic for me would be trying to weasel out and sound a little nicer than I am about this.

It’s all generated, maybe, by the fact that the attitude of the populace is to try to find the answer instead of trying to find a man who has a way of getting at the answer.

If you can find any other view of the world which agrees over the entire range where things have already been observed, but disagrees somewhere else, you have made a great discovery.

All we know so far is what doesn’t work.

You have to have absolute confidence. Keep right on going, and nothing will happen.

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

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

When you get as old as I am, you start to realize that you’ve told most of the good stuff you know to other people anyway.

To guess what to keep and what to throw away takes considerable skill. Actually it is probably merely a matter of luck, but it looks as if it takes considerable skill.

It is our responsibility to leave the people of the future a free hand.

Once you start doubting, just like you’re supposed to doubt, you ask me if the science is true. You say no, we don’t know what’s true, we’re trying to find out and everything is possibly wrong.

We are never right, we can only be sure we are wrong.

I don’t think that the laws can be considered to be like God because they have been figured out.

The Quantum Universe has a quotation from me in every chapter – but it’s a damn good book anyway.

The problem of creating something new, but which is consistent with everything which has been seen before, is one of extreme difficulty.

Maybe that is why young people make success. They don’t know enough.

A great deal more is known than has been proved.

So far as we know, all the fundamental laws of physics, like Newton’s equations, are reversible.

I’m not responsible for what other people think I am able to do; I don’t have to be good because they think I’m going to be good.

As usual, nature’s imagination far surpasses our own, as we have seen from the other theories which are subtle and deep.

There is no harm in doubt and skepticism, for it is through these that new discoveries are made.

Philosophy of science is about as useful to scientists as ornithology is to birds.

Words can be meaningless. If they are used in such a way that no sharp conclusions can be drawn.

Another thing I must point out is that you cannot prove a vague theory wrong.

I find that teaching and the students keep life going, and I would never accept any position in which somebody has invented a happy situation for me where I don’t have to teach. Never.

If you know that you are not sure, you have a chance to improve the situation. I want to demand this freedom for future generations.

As revealed by physics, the truth is so remarkable, so amazing!

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

This is not yet a scientific age.

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.

An ordinary fool isn’t a faker; an honest fool is all right. But a dishonest fool is terrible!

I have a limited intelligence and I’ve used it in a particular direction.

Science is of value because it can produce something.

One does not, by knowing all the physical laws as we know them today, immediately obtain an understanding of anything much. I love only nature, and I hate mathematicians.

Few people realize the number of things that are possible.

I’m trying to find out NOT how Nature could be, but how Nature IS.

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.

Our freedom to doubt was born out of a struggle against authority in the early days of science. It was a very deep and strong struggle: permit us to question – to doubt – to not be sure. I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained.

In a way, the Nobel Prize has been something of a pain in the neck, though there was at least one time that I got some fun out of it, Shortly after I won the Prize, Gweneth and I received an invitation from the Brazilian government to be the guests of honor at the Carnaval celebrations in Rio.

In its efforts to learn as much as possible about nature, modern physics has found that certain things can never be “known” with certainty. Much of our knowledge must always remain uncertain. The most we can know is in terms of probabilities.

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.

I think a power to do something is of value. Whether the power is a good thing or a bad thing depends on how it is used, but the power is a value.

Strange! I don’t understand how it is that we can write mathematical expressions and calculate what the thing is going to do without being able to picture it.

The idea is to try to give all the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another.

I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.

The fact that you are not sure means that it is possible that there is another way someday.

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

From a long view of the history of mankind the most significant event of the nineteenth century will be judged as Maxwell’s discovery of the laws of electrodynamics.

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.

We have this terrible struggle to try to explain things to people who have no reason to want to know.

We are not to tell nature what she’s gotta be. She’s always got better imagination than we have.

The other great heritage is Christian ethics – the basis of action on love, the brotherhood of all men, the value of the individual, the humility of the spirit. These two heritages are logically, thoroughly consistent.

I have to disregard everybody else, and then I can do my own work.

I don’t have to be good because they think I’m going to be good.

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.

When I found out that Santa Claus wasn’t real, I wasn’t upset; rather, I was relieved that there was a much simpler phenomenon to explain how so many children all over the world got presents on the same night! The story had been getting pretty complicated – it was getting out of hand.

If there is something very slightly wrong in our definition of the theories, then the full mathematical rigor may convert these errors into ridiculous conclusions.

But there is nothing in biology yet found that indicates the inevitability of death.

There in wine is found the great generalization: all life is fermentation.

To test whether you have learned an idea or a definition, rephrase what you just learned without using the new word.

It is not unscientific to make a guess, although many people who are not in science think it is.

There is no authority who decides what is a good idea.

We’ve learned from experience that the truth will come out.

I don’t believe I can really do without teaching. The reason is, I have to have something so that when I don’t have any ideas and I’m not getting anywhere, I can say to myself, “At least I’m living; at least I’m doing something. I’m making some contribution.” It’s just psychological.

It is important to realize that in physics today, we have no knowledge of what energy is.

There is a computer disease that anybody who works with computers knows about. It’s a very serious disease and it interferes completely with the work. The trouble with computers is that you ‘play’ with them!

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

Scientific knowledge is an enabling power to do either good or bad – but it does not carry instructions on how to use it.