Thought is merciless to privilege, established institutions, and comfortable habit.

When two great powers disagree about anything - it doesn't matter what - they must find a way to settle it somehow by arbitration or by negotiation, not by war or threat of war.

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.

Laughter is the most inexpensive and most effective wonder drug. Laughter is a universal medicine.

In action, in desire, we must submit perpetually to the tyranny of outside forces; but in thought, in aspiration, we are free, free from our fellowmen, free from the petty planet on which our bodies impotently crawl, free even, while we live, from the tyranny of death.

Machines deprive us of two things which are certainly important ingredients of human happiness, namely, spontaneity and variety.

Are you never afraid of God's judgement in denying him? Most certainly not. I also deny Zeus and Jupiter and Odin and Brahma, but this causes me no qualms. I observe that a very large portion of the human race does not believe in God and suffers no visible punishment in consequence. And if there were a God, I think it very unlikely that He would have such an uneasy vanity as to be offended by those who doubt His existence.