Thinking is easy, acting is difficult, and to put one's thoughts into action is the most difficult thing in the world.

The artist may be well advised to keep his work to himself till it is completed, because no one can readily help him or advise him with it... but the scientist is wiser not to withhold a single finding or a single conjecture from publicity.

The century is advanced, but every individual begins afresh.

There is nothing more frightful than for a teacher to know only what his scholars are intended to know.

It is a great pleasure to transport one's-self into the spirit of the times; to see how a wise man has thought before us, and to what a glorious height we have at last carried it.

What one doesn't understand one doesn't possess.

The iron hand of necessity commands, and her stern decree is supreme law, to which the gods even must submit. In deep silence rules the uncounselled sister of eternal fate. Whatever she lays upon thee, endure; perform whatever she commands.