Richard Feynman

"Another most interesting change in the ideas and philosophy of science
brought about by quantum mechanics is this: it is not possible to predict exactly
what will happen in any circumstance. For example, it is possible to arrange an
atom which is ready to emit light, and we can measure when it has emitted light
by picking up a photon particle, which we shall describe shortly. We cannot,
however, predict when it is going to emit the light or, with several atoms, which
one is going to. You may say that this is because there are some internal "wheels"
which we have not looked at closely enough. No, there are no internal wheels;
nature, as we understand it today, behaves in such a way that it is fundamentally
impossible to make a precise prediction of exactly what will happen in a given
experiment."

"I took a little walk outside for a while. I was surprised that I wasn't feeling what I thought people were supposed to feel under the circumstances. May be I was fooling myself. I wasn't delighted, but I didn't feel terribly upset, perhaps because we had known for a long time that it was going to happen.

It's hard to explain. 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 hi 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.

The only difference for me and Arlene was, instead of fifty years, it was five years. It was only a quantitative difference — the psychological problem was just the same. The only way it would have become any different is if we had said to ourselves, "But those other people have it better, because they might live fifty years." But that's crazy. Why make yourself miserable saying things like, "Why do we have such bad luck? What has God done to us? What have we done to deserve this?" — all of which, if you understand reality and take it completely into your heart, are irrelevant and unsolvable. They are just things that nobody can know. Your situation is just an accident of life..

We had a hell of good time together..."

If you’re doing an experiment, you should report everything that you think might make it invalid — not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you’ve eliminated by some other experiment, and how they worked — to make sure the other fellow can tell they have been eliminated.

It is our responsibility as scientists, knowing the great progress and great value of a satisfactory philosophy of ignorance, the great progress that is the fruit of freedom of thought, to proclaim the value of this freedom, to teach how doubt is not to be feared but welcomed and discussed, and to demand this freedom as our duty to all coming generations.

The only way to have real success in science, the field I'm familiar with, is to describe the evidence very carefully without regard to the way you feel it should be. If you have a theory, you must try to explain what's good and what's bad about it equally. In science, you learn a kind of standard integrity and honesty.

I did that once when I was a student at MIT. I got sick and tired of having to decide what kind of dessert I was going to have at the restaurant, so I decided it would always be chocolate ice cream, and never worried about it again — I had the solution to that problem.

"For example, there was a book that started out with four pictures: first there was a wind-up toy; then there was an automobile; then there was a boy riding a bicycle; then there was something else. And underneath each picture, it said "What makes it go?"
I thought, I know what it is: They're going to talk about mechanics, how the springs work inside the toy; about chemistry, how the engine of an automobile works; and biology, about how the muscles work.

It was the kind of thing my father would have talked about: "What makes it go? Everything goes because the sun is shining." And then we would have fun discussing it:
"No, the toy goes becaues the spring is wound up, I would say.
"How did the spring get would up" he would ask.
"I wound it up"
"And how did you get moving?"
"From eating"
"And food grows only because the sun is shining. So it's because the sun is shining that all these things are moving" That would get the concept across that motion is simply the transformation of the sun's power.

I turned the page. The answer was, for the wind-up toy, "Energy makes it go." And for the boy on the bicycle, "Energy makes it go." For everything "Energy makes it go."

Now that doesn't mean anything. Suppose it's "Wakalixes." That's the general principle: "Wakalixes makes it go." There is no knowledge coming in. The child doesn't learn anything; it's just a word

What the should have done is to look at the wind-up toy, see that there are springs inside, learn about springs, learn about wheels, and never mind "energy". Later on, when the children know something about how the toy actually works, they can discuss the more general principles of energy.

It is also not even true that "energy makes it go", because if it stops, you could say, "energy makes it stop" just as well. What they're talking about is concentrated energy being transformed into more dilute forms, which is a very subtle aspect of energy. Energy is neither increased nor decreased in these examples; it's just

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

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

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 of atoms
an atom in the universe.

the whole problem of discovering what was the matter, and figuring out what you have to do to fix it–that was interesting to me, like a puzzle

"I suddenly remembered that Murray Gell-Mann and I were supposed to give talks at that conference on the present situation of high-energy physics. My talk was set for the plenary session, so I asked the guide, "Sir, where would the talks for the plenary session of the conference be?"

"Back in that room that we just came through."

"Oh!" I said in delight. "Then I'm gonna give a speech in that room!"

The guide looked down at my dirty pants and my sloppy shirt. I realized how dumb that remark must have sounded to him, but it was genuine surprise and delight on my part.

We went along a little bit farther, and the guide said, "This is a lounge for the various delegates, where they often hold informal discussions." They were some small, square windows in the doors to the lounge that you could look through, so people looked in. There were a few men sitting there talking.

I looked through the windows and saw Igor Tamm, a physicist from Russia that I know. "Oh!" I said. "I know that guy!" and I started through the door.

The guide screamed, "No, no! Don't go in there!" By this time he was sure he had a maniac on his hands, but he couldn't chase me because he wasn't allowed to go through the door himself!"

"I wanted very much to learn to draw, for a reason that I kept to myself: I wanted to convey an emotion I have about the beauty of the world. It's difficult to describe because it's an emotion. It's analogous to the feeling one has in religion that has to do with a god that controls everything in the whole universe: there's a generality aspect that you feel when you think about how things that appear so different and behave so differently are all run "behind the scenes" by the same organization, the same physical laws. It's an appreciation of the mathematical beauty of nature, of how she works inside; a realization that the phenomena we see result from the complexity of the inner workings between atoms; a feeling of how dramatic and wonderful it is. It's a feeling of awe — of scientific awe — which I felt could be communicated through a drawing to someone who had also had this emotion. It could remind him, for a moment, of this feeling about the glories of the universe."

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

I would rather have questions that can’t be answered than answers that can’t be questioned.