Richard Feynman Quotes

So we have these wide principles which sweep across all the different laws, and if one takes too seriously its derivations, and feels that this is only valid because this [assumed more fundamental principle] is valid, you cannot understand the interconnections of the different branches of physics. Some day, when physics is complete, then maybe with this kind of argument we'll know all the laws, then we can start with some axioms (and no doubt somebody will figure out a particular way of doing it) and then all the deductions will be made. But while we don't know all the laws, we can use some to make guesses at theorems which extend beyond the proof.

[T]o make it easy... we'll suppose that all the light... is exactly one color... At night... they have these yellow street lights... that's a sodium light... and that emits light all of one color... Then take the soap bubble and blow it at night.. and then you'll see the bands... [You] can take... very thin glass... you can see very thin bands, even in a reasonable size thickness... [S]uppose then that we do have light like from sodium-vapor so that all the light... is always photons of exactly the same energy. We call it monochromatic, one color light.

We absolutely must leave room for doubt or there is no progress and no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty. People are terrified — how can you live and not know? It is not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge and you really don't know what it is all about, or what the purpose of the world is, or know a great deal of other things. It is possible to live and not know.

There are 10¹¹ stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.

That's the way multiplication works you know, with numbers it's the same. ...That's why we call it multiplication. ...Suppose you wanted to say that 6 = 3 x 2, which is true. But let me look at it a different way... This is the analog [to arrow multiplication]... The 2 bears a relation, 2 is not a number from this point of view. It's a relationship. It bears a relation to 1. It's an expansion of 1. How much do you have to expand 1? ...Yeah, double. ...That's what you do to 3 to get 6. That's why... it's called multiplication, because we do to this arrow [#2], what we had to do to the original one [standard arrow] to get the blue one [arrow #1].

chapter 2, “The Relation of Mathematics to Physics,” p. 58; video

But that was my big moment: I gave a seminar in the biology department at Harvard! I always do that, get into something and see how far I can go.

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

If we were to name the most powerful assumption of all, which leads one on and on in an attempt to understand life, it is that all things are made of atoms, and that everything that living things do can be understood in terms of the jigglings and wigglings of atoms.

I returned to civilization shortly after that and went to Cornell to teach, and my first impression was a very strange one. I can't understand it any more, but I felt very strongly then. I sat in a restaurant in New York, for example, and I looked out at the buildings and I began to think, you know, about how much the radius of the Hiroshima bomb damage was and so forth... How far from here was 34th street?... All those buildings, all smashed — and so on. And I would go along and I would see people building a bridge, or they'd be making a new road, and I thought, they're crazy, they just don't understand, they don't understand. Why are they making new things? It's so useless. <P> But, fortunately, it's been useless for almost forty years now, hasn't it? So I've been wrong about it being useless making bridges and I'm glad those other people had the sense to go ahead.

What are the nuclei made of, and how are they held together? It is found that the nuclei are held together by enormous forces. When these are released, the energy released is tremendous compared with chemical energy, in the same ratio as the atomic bomb explosion is to a TNT explosion, because, of course, the atomic bomb has to do with changes inside the nucleus, while the explosion of TNT has to do with the changes of the electrons on the outside of the atoms.

A TUZZO LANTO
Poici di Pare

TANto SAca TULna TI, na PUta TUchi PUti TI la.
RUNto CAta CHANto CHANta MANto CHI la TI da.
YALta CAra SULda MI la CHAta Picha Pino Tito BRALda pe te CHIna nana CHUNda lala CHINda lala CHUNda!
RONto piti CA le, a TANto CHINto quinta LALda ola TiNta dalla LALta, YENta PUcha lalla TALta!

If someone were to propose that the planets go around the sun because all planet matter has a kind of tendency for movement, a kind of motility, let us call it an ‘oomph,’ this theory could explain a number of other phenomena as well. So this is a good theory, is it not? No. It is nowhere near as good as the proposition that the planets move around the sun under the influence of a central force which varies exactly inversely as the square of the distance from the center. The second theory is better because it is so specific; it is so obviously unlikely to be the result of chance. It is so definite that the barest error in the movement can show that it is wrong; but the planets could wobble all over the place, and, according to the first theory, you could say, ‘Well, that is the funny behavior of the ‘oomph.

I couldn't claim that I was smarter than sixty-five other guys — but the average of sixty-five other guys, certainly!

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 our responsibility to leave the people of the future a free hand. In the impetuous youth of humanity, we can make grave errors that can stunt our growth for a long time. This we will do if we say we have the answers now, so young and ignorant as we are. If we suppress all discussion, all criticism, proclaiming "This is the answer, my friends; man is saved!" we will doom humanity for a long time to the chains of authority, confined to the limits of our present imagination. It has been done so many times before. ...It is our responsibility as scientists, knowing the great progress which comes from a satisfactory philosophy of ignorance, the great progress which 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.'''