Whoever declares another heretic is himself a devil. Whoever places a relic or artifact above justice, kindness, mercy, or truth is himself a devil and the thing elevated is a work of evil magic.

I think... girls have a hard time being interesting. It’s actually easier to be famous, or notorious, than it is to be interesting. In our world, girls climb very well until they hit puberty-sexual maturity-and then they begin to fall out of the tree. They start role-playing instead of thinking, flirting instead of learning. They start admiring how smart the boys are-or how athletic or how handsome-instead of concentrating on their own intelligence.

Do you realize it’s been only a century that we’ve been able to go from house to car to office to car to wherever, with the heater on, and the defroster on, protected from the rain and the cold? It hasn’t been much longer than that we’ve had lighting for streets. Think of all that darkness, all that world out there, all that mystery that we’ve turned into well-lighted concrete bunkers, safe and warm and dull.

Nothing limits intelligence more than ignorance; nothing fosters ignorance more than one's own opinions; nothing strengthens opinions more than refusing to look at reality.

Other people's risks are statistical. When it's your risk, your own child, it isn't statistical anymore.

[T]he scripture worshippers put the writings ahead of God. Instead of interpreting God's actions in nature, for example, they interpret nature in the light of the Scripture. Nature says the rock is billions of years old, but the book says different, so even though men wrote the book, and God made the rock and God gave us minds that have found ways to tell how old it is, we still choose to believe the Scripture.

Conflict acting on intelligence creates imagination. Faced with conflict, creatures are forced to imagine what will happen, where the next threat will come from. If there has never been conflict, imagination never develops. Wits arise in answer to danger, to pain, to tragedy. No one ever got smarter eating easy apples.