My objection to organized religion is the premature conclusion to ultimate truth that it represents.

What was more, they had taken the first step toward genuine friendship. They had exchanged vulnerabilities.

At the present rate of progress, it is almost impossible to imagine any technical feat that cannot be achieved - if it can be achieved at all - within the next few hundred years.

The best proof that there's intelligent life in the universe is that it hasn't come here.

A faith that cannot survive collision with the truth is not worth many regrets.

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

To find anything comparable with our forthcoming ventures into space, we must go back far beyond Columbus, far beyond Odysseus-far, indeed, beyond the first ape-man. We must contemplate the moment, now irrevocably lost in the mists of time, when the ancestor off all of us came crawling out of the sea.