When I was about thirteen, the library was going to get 'Calculus for the Practical Man.' By this time I knew, from reading the encyclopedia, that calculus was an important and interesting subject, and I ought to learn it.

Today, all physicists know from studying Einstein and Bohr that sometimes an idea which looks completely paradoxical at first, if analyzed to completion in all detail and in experimental situations, may, in fact, not be paradoxical.

When I was a young man, Dirac was my hero. He made a breakthrough, a new method of doing physics. He had the courage to simply guess at the form of an equation, the equation we now call the Dirac equation, and to try to interpret it afterwards.

I think equation guessing might be the best method to proceed to obtain the laws for the part of physics which is presently unknown. Yet, when I was much younger, I tried this equation guessing, and I have seen many students try this, but it is very easy to go off in wildly incorrect and impossible directions.

The philosophical question before us is, when we make an observation of our track in the past, does the result of our observation become real in the same sense that the final state would be defined if an outside observer were to make the observation?

It is always good to know which ideas cannot be checked directly, but it is not necessary to remove them all. It is not true that we can pursue science completely by using only those concepts which are directly subject to experiment.

What goes on inside a star is better understood than one might guess from the difficulty of having to look at a little dot of light through a telescope, because we can calculate what the atoms in the stars should do in most circumstances.

We get the exciting result that the total energy of the universe is zero. Why this should be so is one of the great mysteries - and therefore one of the important questions of physics. After all, what would be the use of studying physics if the mysteries were not the most important things to investigate?

Once you have a computer that can do a few things - strictly speaking, one that has a certain 'sufficient set' of basic procedures - it can do basically anything any other computer can do. This, loosely, is the basis of the great principle of 'Universality'.

The original reason to start the project, which was that the Germans were a danger, started me off on a process of action, which was to try to develop this first system at Princeton and then at Los Alamos, to try to make the bomb work.

It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but, with a little mathematical fiddling, you can show the relationship.

I think that when we know that we actually do live in uncertainty, then we ought to admit it; it is of great value to realize that we do not know the answers to different questions. This attitude of mind - this attitude of uncertainty - is vital to the scientist, and it is this attitude of mind which the student must first acquire.

Trying to understand the way nature works involves a most terrible test of human reasoning 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. The quantum mechanical and the relativity ideas are examples of this.

The fact that the colors in the flower have evolved in order to attract insects to pollinate it is interesting; that means insects can see the colors. That adds a question: does this aesthetic sense we have also exist in lower forms of life?

If I get stuck, I look at a book that tells me how someone else did it. I turn the pages, and then I say, 'Oh, I forgot that bit,' then close the book and carry on. Finally, after you've figured out how to do it, you read how they did it and find out how dumb your solution is and how much more clever and efficient theirs is!

I was a very shy character, always feeling uncomfortable because everybody was stronger than I, and always afraid I would look like a sissy. Everybody else played baseball; everybody else did all kinds of athletic things.

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.

It is a curious historical fact that modern quantum mechanics began with two quite different mathematical formulations: the differential equation of Schroedinger and the matrix algebra of Heisenberg. The two apparently dissimilar approaches were proved to be mathematically equivalent.

We do not know what the rules of the game are; all we are allowed to do is to watch the playing. Of course, if we watch long enough, we may eventually catch on to a few of the rules. The rules of the game are what we mean by fundamental physics.

It is in the admission of ignorance and the admission of uncertainty that there is a hope for the continuous motion of human beings in some direction that doesn't get confined, permanently blocked, as it has so many times before in various periods in the history of man.

It's the way I study - to understand something by trying to work it out or, in other words, to understand something by creating it. Not creating it one hundred percent, of course; but taking a hint as to which direction to go but not remembering the details. These you work out for yourself.

Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen.

I'm less needy about needing to express myself through acting. I have many different lives outside of this that are extremely fulfilling.

If people lose their land, they have nothing. You lose your land - you lose your culture, you lose self.

One of the joys of being an actor is that you're always learning new things. And I've been doing this since I was 19, so there's been a lot of new things I have learned for each part. I always assume that I can do it.

Any political situation has many sides... We intellectualize the whole situation any way... We make our intellectual decisions based on our cultural background and how we live.

It's rare that a good writer will sit down and write a good script. Writers are greedy too, and they don't want to work without getting paid. But quality will find its way out.

I do my work as an actor, but another part of my work goes to the piece as a whole. I can be fairly detached looking at my work and be brutal on myself.

[on editing of the films] There is always a question of time, and the director. I've worked with a lot of directors who don't mind my involvement. They appreciated it.

I think that as human beings we tend to compartmentalize, and we have a selective morality based on the situation we're in.

A lot of making a movie is the comfort level of the people. It's just feeling open. We need to get along. We have to know something about each other.

(Sometimes when) someone's directing for the first time, they're afraid to include everyone - they have to prove they're the director.

Food is the only beautiful thing that truly nourishes.

America has never paid any attention to other people, so it's absurd for Bush to say that it's all in the best interests of the Iraqi people.

It's not enough to say that the Olympics is an athletic contest outside of politics, because it's not. The Chinese clearly are using the Olympics to recreate how they are viewed in the world and how they view themselves.

When you work as an actor, you've got to feel safe even in what appears to be the simplest things.

There's really one character for every actor. The voyage is to find that one character.

Shooting in New York can be a problem... I had to walk through a crowd, come in the front door, and play the scene.

Billions of people don't practice a religion at all.

Why is it when we have 10 million people in this country who say 'No', we still have a president who says 'Yes.' In a democracy, something's wrong here.

I haven't worked with people who are jealous or competitive. That's a particularly deadly attitude to have when you're working on a film.

It's human nature - we want to believe our children, our families, our President!

I have to admit, a manicured look works for me.

I had a friend in the neighborhood whose father had Playboy magazines, and we would go over and look at them. I remember cutting out pictures and hiding them in my room.

I've always maintained that all characters and all personalities are in all of us. The whole thing is available. You're not this or that, no one is.

Julia [Roberts]. She's got two kids and animals, and I think she's a night nibbler. There'd be crumbs everywhere.

On a movie set that works, you have your father figure, the director, you have your siblings, your other actors.

We've had too many World AIDS Days.

I know who I am. No one else knows who I am. If I was a giraffe, and someone said I was a snake, I'd think, no, actually I'm a giraffe.

I think movies probably are a mirror in some way so we can see ourselves in them.