It stands to the everlasting credit of science that by acting on the human mind it has overcome man's insecurity before himself and before nature.

The real problem is in the hearts and minds of men. It is easier to denature plutonium than to denature the evil spirit of man.

The human mind has first to construct forms, independently, before we can find them in things.

ô enfance du coeur humain qui ne vieillit jamais! voilà donc à quel degré de puérilité notre superbe raison peut descendre! Et encore est-il vrai que bien des hommes attachent leur destinée à des choses d'aussi peu de valeur que mes feuilles de saule.

Hand it to him, and he will turn away. Take it from him, and he quickly runs after it.

Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world.