One may live tranquilly in a dungeon; but does life consist in living quietly?

The abuse of books kills science. Believing that we know what we have read, we believe that we can dispense with learning it.

It is hard to prevent oneself from believing what one so keenly desires.

I bold it impossible, that the great monarchies of Europe can subsist much longer; they all affect magnificence and splendor.

Nature never deceives us; it is we who deceive ourselves.

There is no folly of which a man who is not a fool cannot get rid except vanity; of this nothing cures a man except experience of its bad consequences, if indeed anything can cure it.

A feeble body weakens the mind.