'It worked.' (said after witnessing the first atomic detonation).

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

There must be no barriers to freedom of inquiry... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. Our political life is also predicated on openness. We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress.

Today, it is not only that our kings do not know mathematics, but our philosophers do not know mathematics and - to go a step further - our mathematicians do not know mathematics.

Optimists think that this is the best of all possible worlds; pessimists fear they are right.

To the confusion of our enemies.

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