Without my attempts in natural science, I should never have learned to know mankind such as it is. In nothing else can we so closely approach pure contemplation and thought, so closely observe the errors of the senses and of the understanding, the weak and strong points of character.

I never believed in trying to do anything. Whatever I set out to do I found I had already accomplished.

He who cannot love must learn to flatter.

First and last, what is demanded of genius is love of truth.

Experiments are mediators between nature and idea.

Once more I am a wanderer, a pilgrim, through the world. But what else are you?

Each one of us must carry within the proof of immortality, it cannot be given from outside of us. To be sure, everything in natureis change but behind the change there is something eternal.