The power to question is the basis of all human progress.

In the end, we will remember not the words of our enemies, but the silence of our friends.

Know thy self, know thy enemy. A thousand battles, a thousand victories.

Into each life some rain must fall.

If one does not know to which port one is sailing, no wind is favorable.

Not life, but good life, is to be chiefly valued.

Put your heart, mind, and soul into even your smallest acts. This is the secret of success.

If the highest aim of a captain were to preserve his ship, he would keep it in port forever.

Measure what is measurable, and make measurable what is not so.

The face is the mirror of the mind, and eyes without speaking confess the secrets of the heart.