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

The intelligent minority of this world will mark 1 January 2001 as the real beginning of the 21st century and the Third Millennium.

The crossing of space ... may do much to turn men's minds outwards and away from their present tribal squabbles. In this sense, the rocket, far from being one of the destroyers of civilisation, may provide the safety-value that is needed to preserve it.

Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering.

Though the man-apes often fought and wrestled one another, their disputes very seldom resulted in serious injuries. Having no claws or fighting canine teeth, and being well protected by hair, they could not inflict much harm on one another. In any event, they had little surplus energy for such unproductive behavior; snarling and threatening was a much more efficient way of asserting their points of view.

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’!

The truth, as always, will be far stranger.