To conquer fear is the beginning of wisdom.

I conclude that, while it is true that science cannot decide questions of value, that is because they cannot be intellectually decided at all, and lie outside the realm of truth and falsehood. Whatever knowledge is attainable, must be attained by scientific methods; and what science cannot discover, mankind cannot know.

Children, after being limbs of Satan in traditional theology and mystically illuminated angels in the minds of educational reformers, have reverted to being little devils; not theological demons inspired by the evil one, but scientific Freudian abominations inspired by the unconscious.

The Mormons had a divine revelation in favour of polygamy, but under pressure from the United States Government they discovered that the revelation was not binding.

The luxury to disparage freedom is the privilege of those who already possess it.

I've always thought respectable people scoundrels, and I look anxiously at my face every morning for signs of my becoming a scoundrel.

Is there any knowledge in the world which is so certain that no reasonable man could doubt it?