Positive images of the future are a powerful and magnetic force... They draw us on and energize us, give us courage and will to take on important initiatives. Negative images of the future also have a magnetism. They pull the spirit downward in the path of despair.

The great use of life is to spend it for something that will outlast it.

To neglect the wise sayings of great thinkers is to deny ourselves the truest education.

We are doomed to cling to a life even while we find it unendurable.

... A rule of thinking which would absolutely prevent me from acknowledging certain kinds of truth if those ... truths were really there, would be an irrational rule.

The first thing that intellect does with an object is to class it with something else.

Good-humor is a philosophic state of mind; it seems to say to Nature that we take her no more seriously than she takes us. I maintain that one should always talk of philosophy with a smile.