Some propositions are so dangerous that it may even be ethical to kill people for believing them.

About 120 million of us place the big bang 2,500 years after the Babylonians and Sumerians learned to brew beer. If our polls are to be trusted, nearly 230 million Americans believe that a book showing neither unity of style nor internal consistency was authored by an omniscient, omnipotent and omnipresent deity.

The only thing that permits human beings to collaborate with one another in a truly open-ended way is their willingness to have their beliefs modified by new facts. Only openness to evidence and argument will secure a common world for us.

By lying, we deny others a view of the world as it is. Our dishonesty not only influences the choices they make, it often determines the choices they can make—and in ways we cannot always predict. Every lie is a direct assault upon the autonomy of those we lie to.

If you are perpetually angry, depressed, confused, and unloving, or your attention is elsewhere, it won't matter how successful you become or who is in your life - you won't enjoy any of it.

You know, when you get to the New World and you develop your three branches of government and you have a civil society, you can just jettison all the barbarism I recommended in the first books.

The deity who stalked the deserts of the Middle East millennia ago-and who seems to have abandoned them to bloodshed in his name ever since-is no one to consult on questions of ethics.