To die for an idea is to set a rather high price upon conjecture.

I prefer the folly of enthusiasm to the indifference of wisdom.

One thing above all gives charm to men's thoughts, and this is unrest. A mind that is not uneasy irritates and bores me.

In order that knowledge be properly digested it must have been swallowed with a good appetite.

All the good writers of confessions, from Augustine onwards, are men who are still a little in love with their sins.

True education is the ability to discern the difference between what you do know and what you don't.

The mania of thinking renders one unfit for every activity.