The problem with the wise is they are so filled with doubts while the dull are so certain.

The secret to happiness is to face the fact that the world is horrible.

Belief in a Divine mission is one of the many forms of certainty that have afflicted the human race.

Next to worry probably one of the most potent causes of unhappiness is envy.

The pure mathematician, like the musician, is a free creator of his world of ordered beauty.

All human activity is prompted by desire.

When a man acts in ways that annoy us we wish to think him wicked, and we refuse to face the fact that his annoying behavior is the result of antecedent causes which, if you follow them long enough, will take you beyond the moment of his birth, and therefore to events for which he cannot be held responsible by any stretch of imagination... When a motorcar fails to start, we do not attribute its annoying behavior to sin, we do not say, you are a wicked motorcar, and you shall not have any more gasoline until you go.