What I do not like about our definitions of genius is that there is in them nothing of the day of judgment, nothing of resounding through eternity and nothing of the footsteps of the Almighty.

First there is a time when we believe everything, then for a little while we believe with discrimination, then we believe nothing whatever, and then we believe everything again - and, moreover, give reasons why we believe.

Much reading has brought upon us a learned barbarism.

The natural scientists of the previous age knew less than we do and believed they were very close to the goal: we have taken very great steps in its direction and now discover we are still very far away from it. With the most rational philosophers an increase in their knowledge is always attended by an increased conviction of their ignorance.

Too much is unwholesome.

Rational free spirits are the light brigade who go on ahead and reconnoiter the ground which the heavy brigade of the orthodox will eventually occupy.

It is almost impossible to carry the torch of truth through a crowd without singeing somebody's beard.