He who learns but does not think, is lost. He who thinks but does not learn is in great danger.

The wise man delights in water, the Good man delights in mountains. For the wise move; but the Good stay still. The wise are happy; but the good secure.

If you shoot for the stars and hit the moon, it's OK. But you've got to shoot for something. A lot of people don't even shoot.

Real knowledge is to know the extent of one's ignorance.

To know that one knows what one knows, and to know that one doesn't know what one doesn't know, there lies true wisdom.

There are some with whom we may study in common, but we shall find them unable to go along with us to principles. Perhaps we may go on with them to principles, but we shall find them unable to get established in those along with us. Or if we may get so established along with them, we shall find them unable to weigh occurring events along with us.

Study the past, if you would divine the future.