It is well known that those who do not trust themselves never trust others.

There is no thing as a man who does not create mathematics and yet is a fine mathematics teacher. Textbooks, course material-these do not approach in importance the communication of what mathematics is really about, of where it is going, and of where it currently stands with respect to the specific branch of it being taught. What really matters is the communication of the spirit of mathematics. It is a spirit that is active rather than contemplative-a spirit of disciplined search for adventures of the intellect. Only as adventurer can really tell of adventures.

The chief danger in life is that you may take too many precautions.

Every therapeutic cure, and still more, any awkward attempt to show the patient the truth, tears him from the cradle of his freedom from responsibility and must therefore reckon with the most vehement resistance.

In a country of such recent civilization as ours, whose almost limitless treasures of material wealth invite the risks of capital and the industry of labor, it is but natural that material interests should absorb the attention of the people to a degree elsewhere unknown.

He used to say to his melancholia patients: "You can be cured in fourteen days if you follow this prescription.Try to think every day how you can please someone.

To be a human being means to possess a feeling of inferiority which constantly presses towards its own conquest. The greater the feeling of inferiority that has been experienced, the more powerful is the urge for conquest and the more violent the emotional agitation.