Richard P. Feynman
Do not keep saying to yourself, if you can possibly avoid it, 'But how can it be like that?' because you will get 'down the drain,' into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.
We do not know where to look, or what to look for, when something is memorized. We do not know what it means, or what change there is in the nervous system, when a fact is learned. This is a very important problem which has not been solved at all.
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.
It has not yet become obvious to me that there's no real problem. I cannot define the real problem; therefore, I suspect there's no real problem, but I'm not sure there's no real problem.
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.
Once I get on a puzzle, I can't get off.
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.
It is necessary to look at the results of observation objectively, because you, the experimenter, might like one result better than another.
I want to marry Arline because I love her - which means I want to take care of her. That is all there is to it. I want to take care of her. I am anxious for the responsibilities and uncertainties of taking care of the girl I love.
Gravitation is, so far, not understandable in terms of other phenomena.
Europeans are much more serious than we are in America because they think that a good place to discuss intellectual matters is a beer party.
If you keep proving stuff that others have done, getting confidence, increasing the complexities of your solutions - for the fun of it - then one day you'll turn around and discover that nobody actually did that one!
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.
People often think I'm a faker, but I'm usually honest, in a certain way - in such a way that often nobody believes me!
Often one postulates that a priori, all states are equally probable. This is not true in the world as we see it. This world is not correctly described by the physics which assumes this postulate.
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?
We're always, by the way, in fundamental physics, always trying to investigate those things in which we don't understand the conclusions. After we've checked them enough, we're okay.
I decided to sell my drawings. However, I didn't want people to buy my drawings because the professor of physics isn't supposed to be able to draw - isn't that wonderful - so I made up a false name.
Quarks came in a number of varieties - in fact, at first, only three were needed to explain all the hundreds of particles and the different kinds of quarks - they are called u-type, d-type, s-type.
First figure out why you want the students to learn the subject and what you want them to know, and the method will result more or less by common sense.
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?
I got a signed document from Bullock's saying that they had such-and-such drawings on consignment. Of course, nobody bought any of them, but otherwise, I was a big success: I had my drawings on sale at Bullock's!
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.
I don't understand what it's all about or what's worth what, but if the people in the Swedish Academy decide that x, y or z wins the Nobel Prize, then so be it.
The extreme weakness of quantum gravitational effects now poses some philosophical problems; maybe nature is trying to tell us something new here: maybe we should not try to quantize gravity.
Today we say that the law of relativity is supposed to be true at all energies, but someday somebody may come along and say how stupid we were.
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!
Physics has a history of synthesizing many phenomena into a few theories.
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?
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.
The universe is very large, and its boundaries are not known very well, but it is still possible to define some kind of a radius to be associated with it.
Investigating the forces that hold the nuclear particles together was a long task.
The correct statement of the laws of physics involves some very unfamiliar ideas which require advanced mathematics for their description. Therefore, one needs a considerable amount of preparatory training even to learn what the words mean.
With the exception of gravitation and radioactivity, all of the phenomena known to physicists and chemists in 1911 have their ultimate explanation in the laws of quantum electrodynamics.
I got a fancy reputation. During high school, every puzzle that was known to man must have come to me. Every damn, crazy conundrum that people had invented, I knew.
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.
There is always another way to say the same thing that doesn't look at all like the way you said it before. I don't know what the reason for this is. I think it is somehow a representation of the simplicity of nature.
We seem gradually to be groping toward an understanding of the world of subatomic particles, but we really do not know how far we have yet to go in this task.
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.
The situation in the sciences is this: A concept or an idea which cannot be measured or cannot be referred directly to experiment may or may not be useful. It need not exist in a theory.
Before I was born, my father told my mother, 'If it's a boy, he's going to be a scientist.'
Working out another system to replace Newton's laws took a long time because phenomena at the atomic level were quite strange. One had to lose one's common sense in order to perceive what was happening at the atomic level.
When I would hear the rabbi tell about some miracle such as a bush whose leaves were shaking but there wasn't any wind, I would try to fit the miracle into the real world and explain it in terms of natural phenomena.
In the Raphael Room, the secret turned out to be that only some of the paintings were made by the great master; the rest were made by students. I had liked the ones by Raphael. This was a big jab for my self-confidence in my ability to appreciate art.
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.
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.
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.
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'.
There were several possible solutions of the difficulty of classical electrodynamics, any one of which might serve as a good starting point to the solution of the difficulties of quantum electrodynamics.