For a long time it puzzled me how something so expensive, so leading edge, could be so useless. And then it occurred to me that a computer is a stupid machine with the ability to do incredibly smart things, while computer programmers are smart people with the ability to do incredibly stupid things. They are, in short, a perfect match.

I wish I could adjust my voice, but it's just what's happened to me. It's because I've lived abroad for a long time, and my wife is English and my kids all have English accents, and every voice I hear is English. I've never intentionally changed my accent at all.

When you sit in a chair, you are not actually sitting there, but levitating above it at a height of one angstrom (a hundred millionth of a centimetre), your electrons and its electrons implacably opposed to any closer intimacy.

What this means in practice is that if you are not a born worrier you have nothing to worry about (though of course you wouldn't be worrying anyway), whereas if you are a worrier by nature there is absolutely nothing you can do about it, so you may as well stop worrying, except of course you can't.

If you go out on the Appalachian Trail, you have to bring so much more equipment - a tent, sleeping bag - but if you go hiking in England, or Europe, generally, towns and villages are near enough together at the end of the day you can always go to a nice little inn and have a hot bath and something to drink.

From an evolutionary point of view, sex is really just a reward mechanism to encourage us to pass on our genetic material.

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.