If this book has a lesson, it is that we are awfully lucky to be here-and by 'we' I mean every living thing. To attain any kind of life in this universe of ours appears to be quite an achievement. As humans we are doubly lucky, of course: We enjoy not only the privilege of existence but also the singular ability to appreciate it and even, in a multitude of ways, to make it better. It is a talent we have only barely begun to grasp.

My favourite fellow of the Royal Society is the Reverend Thomas Bayes, an obscure 18th-century Kent clergyman and a brilliant mathematician who devised a complex equation known as the Bayes theorem, which can be used to work out probability distributions. It had no practical application in his lifetime, but today, thanks to computers, is routinely used in the modelling of climate change, astrophysics and stock-market analysis.

On the dashboard of our family car is a shallow indentation about the size of a paperback book. If you are looking for somewhere to put your sunglasses or spare change, it is the obvious place, and it works extremely well, I must say, so long as the car is not actually moving. However, as soon as you put the car in motion ... everything slides off ... It can hold nothing that has not been nailed to it. So I ask you: what then is it for?

Life just wants to be; but it doesn't want to be much.

It is not as if farming brought a great improvement in living standards either. A typical hunter-gatherer enjoyed a more varied diet and consumed more protein and calories than settled people, and took in five times as much viatmin C as the average person today.

Open your refrigerator door, and you summon forth more light than the total amount enjoyed by most households in the 18th century. The world at night, for much of history, was a very dark place, indeed.

I'm not a natural story-teller. Put a keyboard in front of me and I'm fine, but stand me up in front of an audience and I'm actually quite shy and reserved.