A discriminating irreverence is the creator and protector of human liberty.

Mark Twain

Teaching is the highest form of understanding.

Aristotle

The main dangers in this life are the people who want to change everything or nothing.

Nancy Astor

You must be the change you want to see in the world.

Mahatma Gandhi

True words are not fancy. Fancy words are not true. The good do not debate. Debaters are not good.

Lao Tzu

If the black box flight recorder is never damaged during a plane crash, why isn't the whole airplane made out of that stuff?

George Carlin