Science alone of all the subjects contains within itself the lesson of the danger of belief in the infallibility of the greatest teachers of the preceding generation.

Words can be meaningless. If they are used in such a way that no sharp conclusions can be drawn.

The unanswerable mysteries... the attitude that all is uncertain... to summarize it - the humility of the intellect.

There are theoretical physicists who imagine, deduce, and guess at new laws, but do not experiment; and then there are experimental physicists who experiment, imagine, deduce, and guess.

I learned from her that every woman is worried about her looks, no matter how beautiful she is.

Poets say science takes away from the beauty of stars-mere globs of gas atoms. Nothing is "mere". I too see the stars on a desert night, and feel them. But do I see less or more? ...What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little more about it. For far more marvelous is the truth than any artists of the past imagined it.

To test whether you have learned an idea or a definition, rephrase what you just learned without using the new word.