Every isolated passion, is, in isolation, insane; sanity may be defined as synthesis of insanities. Every dominant passion generates a dominant fear, the fear of its non-fulfillment. Every dominant fear generates a nightmare, sometimes in form of explicit and conscious fanaticism, sometimes in paralyzing timidity, sometimes in an unconscious or subconscious terror which finds expression only in dreams. The man who wishes to preserve sanity in a dangerous world should summon in his own mind a parliament of fears, in which each in turn is voted absurd by all the others.

What the world needs is not dogma but an attitude of scientific inquiry.

Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind.

There is no reason to suppose that the world had a beginning at all. The idea that things must have a beginning is really due to the poverty of our thoughts.

To a mind of sufficient intellectual power, the whole of mathematics would appear trivial, as trivial as the statement that a four-footed animal is an animal.

The main thing needed to make men happy is intelligence.

As I grew up I became increasingly interested in philosophy, or which [his family] profoundly disapproved. Everytime the subject came up they repeated with unfailing regularity, "What is mind? No matter. What is matter? Never mind." After some fifty or sixty repititions, this remark ceased to amuse me.