1. “First you guess. Don't laugh, this is the most important step. Then you compute the consequences. Compare the consequences to experience. If it disagrees with experience, the guess is wrong. In that simple statement is the key to science. It doesn't matter how beautiful your guess is or how smart you are or what your name is. If it disagrees with experience, it's wrong. That's all there is to it.”
2. "For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
3. “For those who want some proof that physicists are human, the proof is in the idiocy of all the different units which they use for measuring energy.”
4. “I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.”
5. “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. I have approximate answers and possible beliefs and different degrees of certainty about different things, but I'm not absolutely sure of anything and there are many things I don't know anything about, such as whether it means anything to ask why we're here.... / I don't have to know the answer. I don't feel frightened by not knowing things, by being lost in a mysterious universe without any purpose, which is the way it really is as far as I can tell. It doesn't frighten me.” “If you thought that science was certain - well, that is just an error on your part.”
6. “I have approximate answers and possible beliefs and different degrees of certainty about different things, but I'm not absolutely sure of anything, and many things I don't know anything about, such as whether it means anything to ask why we're here, and what the question might mean. I might think about it a little bit, but if I can't figure it out, then I go on to something else. But I don't have to know an answer. I don't have to...I don't feel frightened by not knowing things, by being lost in the mysterious universe without having any purpose, which is the way it really is, as far as I can tell, possibly. It doesn't frighten me.”
7. ”It is my task to convince you not to turn away because you don't understand it. You see my physics students don't understand it... That is because I don't understand it. Nobody does.”
8. ”It is odd, but on the infrequent occasions when I have been called upon in a formal place to play the bongo drums, the introducer never seems to find it necessary to mention that I also do theoretical physics.”
9. “I was born not knowing and have only had a little time to change that here and there.”
10. “I wonder why, I wonder why. / I wonder why I wonder. / I wonder why I wonder why / I wonder why I wonder!”
11. “Nature uses only the longest threads to weave her patterns, so each small piece of her fabric reveals the organization of the entire tapestry.”
12. “One does not, by knowing all the physical laws as we know them today, immediately obtain an understanding of anything much.”
13. ”Our imagination is stretched to the utmost, not, as in fiction, to imagine things which are not really there, but just to comprehend those things which 'are' there.”
14. “Physics is like sex: sure, it may give some practical results, but that's not why we do it.”
15. “Poets say science takes away from the beauty of the stars - mere globs of gas atoms. I, too, can see the stars on a desert night, and feel them. But do I see less or more?”
16. “The first principle is that you must not fool yourself -- and you are the easiest person to fool.”
17. ”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.”
18. "The next question was - what makes planets go around the sun? At the time of Kepler some people answered this problem by saying that there were angels behind them beating their wings and pushing the planets around an orbit. As you will see, the answer is not very far from the truth. The only difference is that the angels sit in a different direction and their wings push inward."
19. “The present situation in physics is as if we know chess, but we don't know one or two rules.”
20. "The stars are made of the same atoms as the earth." I usually pick one small topic like this to give a lecture on. Poets say science takes away from the beauty of the stars -- mere gobs of gas atoms. Nothing is "mere." I too can see the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination -- stuck on this carousel my little eye can catch one-million-year-old light. A vast pattern -- of which I am a part -- perhaps my stuff was belched from some forgotten star, as one is belching there. Or see them with the greater eye of Palomar, rushing all apart from some common starting point when they were perhaps all together. What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little about it. For far more marvelous is the truth than any artists of the past imagined! Why do the poets of the present not speak of it? What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?”
21. “The vastness of the heavens stretches my imagination - stuck on this carousel my eye can catch one-million-year-old light. It does no harm to the mystery to know a little about it.”
22. "This is the third of four lectures on a rather difficult subject – the theory of quantum electrodynamics -- and since there are obviously more people here tonight than there were before, some of you haven't heard the other two lectures and will find this lecture almost incomprehensible. Those of you who *have* heard the other two lectures will also find this lecture incomprehensible, but you know that that's all right: as I explained in the first lecture, the way we have to describe Nature is generally incomprehensible to us."
23. ”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.”
24. “We could, of course, use any notation we want; do not laugh at notations; invent them, they are powerful. In fact, mathematics is, to a large extent, invention of better notations.”
25. “What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school... It is my task to convince you not to turn away because you don't understand it. You see my physics students don't understand it... That is because I don't understand it. Nobody does.”
