The vigor of civilized societies is preserved by the widespread sense that high aims are worth-while.

Everything of importance has been said before by somebody who did not discover it.

The great achievements of the past were the adventures of the past. Only the adventurous can understand the greatness of the past.

...the self-satisfied dogmatism with which mankind at each period of its history cherishes the delusion of the finality of existing modes of knowledge.

The defense of morals is the battle-cry which best rallies stupidity against change.

We must produce a great age, or see the collapse of the upward striving of our race.

The worship of God is not a rule of safety - it is an adventure of the spirit, a flight after the unattainable.