Academic chairs are many, but wise and noble teachers are few; lecture-rooms are numerous and large, but the number of young people who genuinely thirst after truth and justice is small

I have remained a simple fellow who asks nothing of the world; only my youth is gone - the enchanting youth that forever walks on air.

There is no logical way to the discovery of these elemental laws. There is only the way of intuition, which is helped by a feeling for the order lying behind the appearance.

We owe a lot to the Indians, who taught us how to count, without which no worthwhile scientific discovery could have been made.

Never do anything against conscience even if the state demands it.

It is the theory that decides what can be observed.

The most important method of education always has consisted of that in which the pupil was urged to actual performance.