The optimist thinks this is the best of all possible worlds. The pessimist fears it is true.

Any man whose errors take ten years to correct is quite a man.

I can't think that it would be terrible of me to say - and it is occasionally true - that I need physics more than friends.

The physicists have known sin; and this is a knowledge which they cannot lose.

Both the man of science and the man of action live always at the edge of mystery, surrounded by it.

Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search.

It is not possible to be a scientist unless you believe that it is good to learn... that it is of the highest value to share your knowledge... with anyone who is interested... that the knowledge of the world, and the power which this gives, is a thing which is of intrinsic value to humanity