You have to steer a course between not appalling people, but at the same time not misleading them.

I can mention many moments that were unforgettable and revelatory. But the most single revelatory three minutes was the first time I put on scuba gear and dived on a coral reef. It's just the unbelievable fact that you can move in three dimensions.

It's extraordinary how self-obsessed human beings are. The things that people always go on about is, 'tell us about us', 'tell us about the first human being'. We are so self-obsessed with our own history. There is so much more out there than what connects to us.

Many individuals are doing what they can. But real success can only come if there is a change in our societies and in our economics and in our politics.

Opponents say natural selection is not a theory supported by observation or experiment; that it is not based on fact; and that it cannot be proved. Well, no, you cannot prove the theory to people who won't believe in it any more than you can prove that the Battle of Hastings took place in 1066. However, we know the battle happened then, just as we know the course of evolution on earth unambiguously shows that Darwin was right.

I'm swanning round the world looking at the most fabulously interesting things. Such good fortune.

Very few species have survived unchanged. There's one called lingula, which is a little shellfish, a little brachiopod about the size of my fingernail, that has survived for 500 million years, but it's survived by being unobtrusive and doing nothing, and you can't accuse human beings of that.