... it occurred to me that never again would he be seven years, one month and six days old, so we had better catch these moments while we can.

When the poet Paul Valery once asked Albert Einstein if he kept a notebook to record his ideas, Einstein looked at him with mild but genuine surprise. "Oh, that's not necessary," he replied . "It's so seldom I have one.

Roads get wider and busier and less friendly to pedestrians. And all of the development based around cars, like big sprawling shopping malls. Everything seems to be designed for the benefit of the automobile and not the benefit of the human being.

18th century scientists, the French in particular, seldom did things simply if an absurdly demanding alternative was available.

In three minutes, 98 percent of all the matter there is or will ever be has been produced. We have a universe

Being a pessimist is just such a gloomy way of looking at things, so I have to hope for the best - life wouldn't be worth living if we didn't have hope. And I also do think that human beings often do do wonderful, correct, brilliant things. So, on balance, I'd like to be optimistic about the future.

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.