The mark of a mature, psychologically healthy mind is indeed the ability to live with uncertainty and ambiguity, but only as much as there really is. Uncertainty is no virtue when the facts are clear, and ambiguity is mere obfuscation when more precise terms are applicable.

It may not have the virtuous ring of the golden rule, but the maxim "never say never" is one of the most important in ethics.

Believers are right when they say that to understand a religion properly you need to get under its skin. But to understand it fully, you cannot stay there: you have to take a more objective view, too.

Atheists have to live with the knowledge that there is no salvation, no redemption, no second chances. Lives can go terribly wrong in ways that can never be put right.

A lot of religious belief - even the majority - involves making factual claims about the world which do come into conflict with science and history. For Christians, a test of this is the Empty Tomb. I ask Christians: 'are you saying that it does not matter - as a matter of fact - whether or not Christ's tomb was empty and that he was resurrected?' At that point, I find that, to a lot of them, it really does matter, despite all the fine talk about not wanting to confuse science and history with religion.

We can take suffering to be an opportunity to learn and to grow. But if we are honest, we should remember that this is making the best of a bad job, and that minimising suffering takes priority over optimising its outcome.

Whatever your religious persuasion, if you believe that the universe is governed by benign forces, at some point you have to explain why there is so much suffering, misfortune and misery in the world.