For millions of years, on average, one species became extinct every century.... We are now heaving more than a thousand different species of animals and plants off the planet every year.

For seven and a half million years, Deep Thought computed and calculated, and in the end announced that the answer was in fact Forty-two - and so another, even bigger, computer had to be built to find out what the actual question was.

42 is a nice number that you can take home and introduce to your family.

The impossible often has a kind of integrity to it which the merely improbable lacks. How often have you been presented with an apparently rational explanation of something that works in all respects other than one, which is just that it is hopelessly improbable? Your instinct is to say, 'Yes, but he or she simply wouldn't do that.

He was a dreamer, a thinker, a speculative philosopher... or, as his wife would have it, an idiot.

How do you know you're having fun if there's no one watching you have it?

But while nature has considerable resilience, there is a limit to how far that resilience can be stretched. No one knows how close to the limit we are getting. The darker it gets, the faster we're driving