In Sophie's World, Jostein Gaarder celebrated a range of philosophers, including Locke, Hume, Berkeley, Kant, Hegel and Kierkegaard. But who is his favourite? Or, rather, who would he like to meet most if he had the chance?

"I would like to meet Socrates because he is enigmatic. We don't know who he was; we only know him through Plato.

"Secondly, I would also like to meet Jesus. He is enigmatic too. But for me, he is also the most important moral philosopher. I don't need any other ethics than the ethics of the four gospels.

"Thirdly, I would like to meet the Buddha. He was a philosopher and a psychologist.

"But if I was being more honest, and had just one to pick, perhaps I would chose Spinoza because he is relating himself more to nature than to culture."

And what of Christmas? Does he see a place for it in an increasingly secular world? "Oh yes," he replies. "Maybe Christmas is an expression of a very special conservatism. It is the last remnant of a common release in our culture." He describes the Nativity as "one beautiful story".

One of the 90 per cent of Norwegians who are members the Lutheran state church, Gaarder says: "I am devoted to the legend - to the myth - of how Christ was born."

That said, Christmas is usually the only time of the year when he goes to church.

"Some ministers say if you only want to come now then stay away," he feels obliged to point out.

"But I think that is completely against the generosity of the gospel. When Jesus was hanging on the cross he did not have a lot of conditions."