Such delusions of grandeur to think that a God with a hundred billion galaxies on his mind would give a tuppenny damn who you sleep with, or indeed whether you believe in him.

My thoughts, my beliefs, my feelings are all in my brain. My brain is going to rot.

Part of the appeal was that Medawar was not only a Nobel Laureate, but he seemed like a Nobel Laureate; he was everything one thought a Nobel Laureate ought to be. If you have ever wondered why scientists like Popper, try Medawar's exposition. Actually most Popperian scientists have probably never tried reading anything but Medawar's exposition.

Evolution has no long-term goal. There is no long-distance target, no final perfection to serve as a criterion for selection, although human vanity cherishes the absurd notion that our species is the final goal of evolution.

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.

We've all been brought up with the view that religion has some kind of special privileged status. You're not allowed to criticise it.

People sometimes try to score debating points by saying, Evolution is only a theory. That is correct, but it's important to understand what that means. It is also only a theory that the world goes round the Sun - it's just a theory for which there is an immense amount of evidence. There are many scientific theories that are in doubt. Even within evolution, there is some room for controversy. But that we are cousins of apes and jackals and starfish, let's say, that is a fact in the ordinary sense of the word.