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

It is possible that mankind is on the threshold of a golden age; but, if so, it will be necessary first to slay the dragon that guards the door, and this dragon is religion.

To write tragedy, a man must feel tragedy. To feel tragedy, a man must be aware of the world in which he lives. Not only with his mind, but with his blood and sinews.

This idea of weapons of mass extermination is utterly horrible and is something which no one with one spark of humanity can tolerate.

The legacy of Greece to Western philosophy is Western philosophy.

Be scrupulously truthful, even if the truth is inconvenient, for it is more inconvenient when you try to conceal it.

When I say that children should be told about sex, I do not mean that they should be told only the bare physiological facts; they should be told whatever they wish to know. There should be no attempt to represent adults as more virtuous than they are, or sex as occurring only in marriage. There is no excuse for deceiving children. And when, as must happen in conventional families, they find that their parents have lied, they lose confidence in them, and feel justified in lying to them.