There is no result in nature without a cause; understand the cause and you will have no need of the experiment.

Fix your course on a star and you'll navigate any storm.

We, by our arts may be called the grandsons of God.

Inaction saps the vigor of the mind.

One can have no more mastery over the environment, than one has over himself.

Learning is the only thing the mind never exhausts, never fears, and never regrets.

Whoever in debate quotes authority uses not intellect, but memory.