Daring ideas are like chessmen moved forward; they may be beaten, but they may start a winning game.

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

If the world does improve on the whole, yet youth must always begin anew, and go through the stages of culture from the beginning.

Man must strive, and striving he must err.

For the butterfly, mating and propagation involve the sacrifice of life, for the human being, the sacrifice of beauty.

All sects seem to me to be right in what they assert, and wrong in what they deny.

And step by step, along the path of life, There's nothing true but Heaven.