New ideas pass through three periods: 1) It can't be done. 2) It probably can be done, but it's not worth doing. 3) I knew it was a good idea all along!

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

It has yet to be proven that intelligence has any survival value.

This is the first age that's ever paid much attention to the future, which is a little ironic since we may not have one.

It may be that our role on this planet is not to worship God - but to create him.

I have a fantasy where Ted Turner is elected President but refuses because he doesn't want to give up power.

The best measure of a man's honesty isn't his income tax return. It's the zero adjust on his bathroom scale.

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

It is not easy to see how the more extreme forms of nationalism can long survive when men have seen the Earth in its true perspective as a single small globe against the stars.

I don't pretend we have all the answers. But the questions are certainly worth thinking about.

The limits of the possible can only be defined by going beyond them into the impossible.

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.

Any sufficiently advanced technology is indistinguishable from magic.

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.

Human judges can show mercy. But against the laws of nature, there is no appeal.

Politicians should read science fiction, not westerns and detective stories.

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

I don't believe in astrology; I'm a Sagittarius and we're skeptical.

There is hopeful symbolism in the fact that flags do not wave in a vacuum.

I don't believe in God but I'm very interested in her.

Perhaps, as some wit remarked, the best proof that there is Intelligent Life in Outer Space is the fact it hasn't come here. Well, it can't hide forever - one day we will overhear it.

Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases: 1- It's completely impossible. 2- It's possible, but it's not worth doing. 3- I said it was a good idea all along.

New ideas pass through three periods: 1) It can't be done. 2) It probably can be done, but it's not worth doing. 3) I knew it was a good idea all along!

We have to abandon the idea that schooling is something restricted to youth. How can it be, in a world where half the things a man knows at 20 are no longer true at 40 - and half the things he knows at 40 hadn't been discovered when he was 20?

Reading computer manuals without the hardware is as frustrating as reading manuals without the software.

Our lifetime may be the last that will be lived out in a technological society.

The only way to discover the limits of the possible is to go beyond them into the impossible.

The greatest tragedy in mankind's entire history may be the hijacking of morality by religion.

Reading computer manuals without the hardware is as frustrating as reading sex manuals without the software.

One of the great tragedies of mankind is that morality has been hijacked by religion.

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

The dinosaurs disappeared because they could not adapt to their changing environment. We shall disappear if we cannot adapt to an environment that now contains spaceships computers and thermonuclear weapons.

Two possibilities exist either we are alone in the Universe or we are not. Both are equally terrifying.

Im sure the universe is full of intelligent life. Its just been too intelligent to come here.

You cant have it both ways. You cant have both free will and a benevolent higher power who protects you from yourself.

Never attribute to malevolence what is merely due to incompetence.

Only feeble minds are paralyzed by facts.

The only way of finding the limits of the possible is by going beyond them into the impossible.

If man can live in Manhattan, he can live anywhere.

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.

The best way of handling pain was to study it objectively.

All human plans [are] subject to ruthless revision by Nature, or Fate, or whatever one preferred to call the powers behind the Universe.

It must be wonderful to be seventeen, and to know everything.

I'm sure the universe is full of intelligent life. It's just been too intelligent to come here.

The Moon is the first milestone on the road to the stars.

You don't believe in organized religion, yet a major theme in so many of your works seems to be a quest for God.

We stand now at the turning point between two eras. Behind us is a past to which we can never return.

The phenomenon of UFO doesn't say anything about the presence of intelligence in space. It just shows how rare it is here on the earth.

Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.