If we will only allow that, as we progress, we remain unsure, we will leave opportunities for alternatives.

It is not unscientific to make a guess, although many people who are not in science think it is.

The difficulty really is psychological and exists in the perpetual torment that results from your saying to yourself, "But how can it be like that?" which is a reflection of uncontrolled but utterly vain desire to see it in terms of something familiar. ... If you will simply admit that maybe Nature does behave like this, you will find her a delightful, entrancing thing. Do not keep saying to yourself, if you can possible avoid it, "But how can it be like that?" because you will get 'down the drain', into a blind alley from which nobody has escaped. Nobody knows how it can be like that.

Know your place in the world and evaluate yourself fairly, not in terms of the naïve ideals of your own youth, nor in terms of what you erroneously imagine your teacher's ideals are.

The basis of action on love, the brotherhood of all men, the value of the individual... the humility of the spirit.

We have this terrible struggle to try to explain things to people who have no reason to want to know.

Few people realize the number of things that are possible.