I have great faith in optimism as a guiding principle, if only because it offers us the opportunity of creating a self-fulfilling prophecy.

Science fiction does not attempt to predict. It extrapolates. It just says, "What if?" not what will be? Because you can never predict what will happen, particularly in politics and economics. You can to some extent predict in the technological sphere - flying, space travel, but even there we missed badly on some things, like computers. No one imagined the incredible impact of computers, even though robot brains of various kinds but the idea that one day every house would have a computer in every room and that one day we'd have computers built into our clothing, nobody ever thought of that.

... chemistry is a trade for people without enough imagination to be physicists.

When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. Perhaps the adjective 'elderly' requires definition. In physics, mathematics, and astronautics it means over thirty; in the other disciplines, senile decay is sometimes postponed to the forties. There are, of course, glorious exceptions; but as every researcher just out of college knows, scientists of over fifty are good for nothing but board meetings, and should at all costs be kept out of the laboratory!

I'm quite fond of the writer who told a beginning author, "If you've got a message, use Western Union."

I sometimes think that the universe is a machine designed for the perpetual astonishment of astronomers.

I sometimes wonder how we spent leisure time before satellite television and Internet came along…and then I realise that I have spent more than half of my life in the ‘dark ages’!