Most of the time I am sunk in thought, but at some point on each walk there comes a moment when I look up and notice, with a kind of first-time astonishment, the amazing complex delicacy of the words, the casual ease with which elemental things come together to form a composition that is—whatever the season, wherever I put my besotted gaze—perfect.

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.

English grammar is so complex and confusing for the one very simple reason that its rules and terminology are based on Latin - a language with which it has precious little in common. In Latin, to take one example, it is not possible to split an infinitive. So in English, the early authorities decided, it should not be possible to split an infinitive either. But there is no reason why we shouldn't, any more than we should forsake instant coffee and air travel because they weren't available to the Romans.

Four times I was honked at for having the temerity to proceed through town without the benefit of metal.

Our instinct may be to see the impossibility of tracking everything down as frustrating, dispiriting, perhaps even appalling, but it can just as well be viewed as almost unbearably exciting. We live on a planet that has a more or less infinite capacity to surprise. What reasoning person could possibly want it any other way?

Physicists are atoms' way of thinking about atoms.

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.