When one has to ask, "Am I really in love?" the answer is always "No".

If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong.

A precondition for being a science fiction writer other than an interest in the future is that, an interest - at least an understanding of science, not necessarily a science degree but you must have a feeling for the science and its possibilities and its impossibilities, otherwise you're writing fantasy. Now, fantasy is also fine, but there is a distinction, although no one's ever been able to say just where the dividing lines come.

I can never look now at the Milky Way without wondering from which of those banked clouds of stars the emissaries are coming. If you will pardon so commonplace a simile, we have set off the fire alarm and have nothing to do but to wait. I do not think we will have to wait for long.

How inappropriate to call this planet Earth when it is quite clearly Ocean.

I think in the long run the money that s been put into the space program is one of the best investments this country has ever made . . .This is a downpayment on the future of mankind. It's as simple as that.

It is vital to remember that information - in the sense of raw data - is not knowledge, that knowledge is not wisdom, and that wisdom is not foresight. But information is the first essential step to all of these.