There was another aspect of my life about which I wrote a book, which I really think once again, I don’t think anyone takes it very seriously, but I like the ideas. And this is really about the nature of belief. I’ve already mentioned the fact that people have very wrong... wrong ideas about science and... and science really is an unnatural mode of thought. But then I had an experience. I have four children and my youngest one went through a very bad patch, and he was then evangelised by a fundamentalist Christian organisation. And people thought I’d be very upset as a Jewish boy, that my son — my youngest son — had become a Christian. Not at all, it seemed to be helping him and I never ever tried to persuade him not to be, and in fact, there’s really... when he, it really did help him — being a Christian — and he then at one stage... he came to me at my office at work and said to me, 'Dad, you’re so lucky, I’m very envious of you'. There are not many parents to whom a child has said that the child is envious of them. I said, 'Darling, what do you mean, that you’re envious of me?' 'You’re going to die soon'. I said, 'Why does that make you envious of me?' 'I want to die, I want to go to Heaven and I can’t do anything about it and you’re lucky, you’re going to die'. And he wasn’t going to do anything about it, and we did discuss it and that sort of thing. And I told his sister... Jessica about this story and a week later, there was a note on my desk: ‘Jessica says that she thinks that you think you’re going to go to Heaven when you die; we need to talk.’ And we have talked, he’s not that religious anymore, but it made me think about the advantages of religion, and I began to think about the nature of belief and I came up with the idea that what makes humans different from all other animals, is they have a concept of cause and... and effect. And this is based, not on an idea of mine, but on the idea of someone whose name I’ve just forgotten — I can’t remember his name at the moment — who wrote a very important book called Folk Physics for Apes, in which he pointed out that apes do not have a concept of cause and effect, and... and no animal really does. And this had an enormous impact on me because I realised that you cannot make tools — well, he also realised it — you cannot make tools without a concept of physical cause and effect. And of course, tool making is what drove human evolution. I mean, we are the tool making... we are the tool making animals. And I came up with the idea that once humans evolved a concept of cause and effect with the advantages they could make tools, they wanted to understand the causes of other things that affected their lives and therefore I wrote... I argued in fact, that religion came from tool-making, because when people wanted to explain things that the causes that affected their lives, the most obvious thing was some human-like cause and they invented gods. And what religion really does, is provided causal explanations for many of the problems that hu... that humans face. And it is a human characteristic, we cannot tolerate not knowing the cause of things that affect our lives.  Now when you go to the doctor and you’re not well and the doctor says, ‘I don’t know what’s wrong with you’, you find that intolerable. And when you do get told what’s wrong with you, on the way home, I’m prepared to bet anything you will make up a story as to why you got ill. You shouldn’t have sat next to that man on the bus, you shouldn’t have had that meal with that particular salad and so... you know, we all make up things and when people... look, when there’s an air crash and someone loses a relative, they will go on for years wanting to know the cause of that crash. We want to know the cause of things and I claim that what makes us human, is having causal beliefs. No one really takes this again seriously but I think it’s really quite a plausible idea.