Creationists and Holocaust deniers are both very similar - both are denying what is a perfectly manifest fact. In the case of Holocaust deniers it's more recent history, but in both cases the evidence - in favour of the Holocaust and evolution - is simply overwhelming. That doesn't mean they are morally or politically equivalent. But they are equivalent in denying history.

In true natural selection, if a body has what it takes to survive, its genes automatically survive because they are inside it. So the genes that survive tend to be, automatically, those genes that confer on bodies the qualities that assist them to survive.

The list of things about which we strictly have to be agnostic doesn't stop at tooth fairies and celestial teapots. It is infinite. If you want to believe in a particular one of them - teapots, unicorns, or tooth fairies, Thor or Yahweh - the onus is on you to say why you believe in it. The onus is not on the rest of us to say why we do not. We who are atheists are also a-fairyists, a-teapotists, and a-unicornists, but we don't have to bother saying so.

For me, moral questions such as stem-cell research turn upon whether suffering is caused. In this case, clearly none is. The embryos have no nervous system. But that's not an issue discussed publicly. The issue is, Are they human? If you are an absolutist moralist, you say, "These cells are human, and therefore they deserve some kind of special moral treatment."

In medieval times, the Church used to sell 'indulgences' for money. This amounted to paying for some number of days' remission from purgatory, and the Church literally (and with breathtaking presumption) issued signed certificates specifying the number of days off that had been purchased. . . . And of all its money-making rip-offs, the selling of indulgences must surely rank among the greatest con tricks in history. . . .

Let us try to teach generosity and altruism, because we are born selfish. Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs, something that no other species has ever aspired to do.

I do understand people when they say that you destroy the magic of childhood if you encourage too much skeptical questioning.