Any sufficiently advanced technology is indistinguishable from magic.

The toolmakers had been remade by their own tools. For in using clubs and flints, their hands had developed a dexterity found nowhere else in the animal kingdom, permitting them to make still better tools, which in turn had developed their limbs and brains yet further. It was an accelerating, cumulative process; and at its end was Man.

Science is the only religion of mankind.

The rash assertion that 'God made man in His own image' is ticking like a time bomb at the foundation of many faiths, and as the hierarchy of the universe is disclosed to us, we may have to recognize this chilling truth: if there are any gods whose chief concern is man, they cannot be very important gods.

There is no reason to assume that the universe has the slightest interest in intelligence—or even in life. Both may be random accidental by-products of its operations like the beautiful patterns on a butterfly's wings. The insect would fly just as well without them.

The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

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

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 am an optimist. Anyone interested in the future has to be otherwise he would simply shoot himself.

The fact that we have not yet found the slightest evidence for life — much less intelligence — beyond this Earth does not surprise or disappoint me in the least. Our technology must still be laughably primitive, we may be like jungle savages listening for the throbbing of tom-toms while the ether around them carries more words per second than they could utter in a lifetime.

Space can be mapped and crossed and occupied without definable limit; but it can never be conquered. When our race has reached its ultimate achievements, and the stars themselves are scattered no more widely than the seed of Adam, even then we shall still be like ants crawling on the face of the Earth. The ants have covered the world, but have they conquered it — for what do their countless colonies know of it, or of each other?

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.

What is human memory?... It certainly is not a passive recording mechanism, like a digital disc or a tape. It is more like a story-telling machine. Sensory information is broken down into shards of perception, which are broken down again to be stored as memory fragments. And at night, as the body rests, these fragments are brought out from storage, reassembled and replayed. Each run-through etches them deeper into the brain's neural structure. And each time a memory is rehearsed or recalled it is elaborated. We may add a little, lose a little, tinker with the logic, fill in sections that have faded, perhaps even conflate disparate events.

In my life I have found two things of priceless worth - learning and loving. Nothing else - not fame, not power, not achievement for its own sake - can possible have the same lasting value. For when your life is over, if you can say "I have learned" and "I have loved," you will also be able to say "I have been happy."

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.

The time was fast approaching when Earth, like all mothers, must say farewell to her children.

Every revolutionary idea--in science, politics, art or whatever--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.

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

A single test which proves some piece of theory wrong is more valuable than a hundred tests showing that idea might be true.

We cannot predict the new forces, powers, and discoveries that will be disclosed to us when we reach the other planets and set up new laboratories in space. They are as much beyond our vision today as fire or electricity would be beyond the imagination of a fish.

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

One of the biggest roles of science fiction is to prepare people to accept the future without pain and to encourage a flexibility of mind. Politicians should read science fiction, not westerns and detective stories. Two-thirds of 2001 is realistic — hardware and technology — to establish background for the metaphysical, philosophical, and religious meanings later.

Any teacher that can be replaced by a machine should be!

It was the mark of a barbarian to destroy something one could not understand.

Just as the human memory is not a passive recorder but a tool in the construction of the self, so history has never been a simple record of the past, but a means of shaping peoples.

The newspapers of utopia ... would be terribly dull.

No utopia can ever give satisfaction to everyone, all the time. As their material conditions improve, men raise their sights and become discontented with power and possessions that once would have seemed beyond their wildest dreams. And even when the external world has granted all it can, there still remain the searchings of the mind and the longings of the heart.

We seldom stop to think that we are still creatures of the sea, able to leave it only because, from birth to death, we wear the water-filled space suits of our skins.

If we have learned one thing from the history of invention and discovery, it is that, in the long run — and often in the short one — the most daring prophecies seem laughably conservative.

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

Whether we are based on carbon or on silicon makes no fundamental difference; we should each be treated with appropriate respect.

Science can destroy religion by ignoring it as well as by disproving its tenets. No one ever demonstrated, so far as I am aware, the non-existence of Zeus or Thor — but they have few followers now.

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

As our own species is in the process of proving, one cannot have superior science and inferior morals. The combination is unstable and self-destroying.

ARTHUR C. CLARKE, attributed, Clarke Foundation

Nothing is deader than yesterday's science-fiction.

ARTHUR C. CLARKE, The Sands of Mars

After all, it has yet to be proved that intelligence has real survival value.

ARTHUR C. CLARKE, The Lost World of 2001

Utopia was here at last: its novelty had not yet been assailed by the supreme enemy of all Utopias--boredom.

ARTHUR C. CLARKE, Childhood's End

We have, as yet, no definite proof that too much brain, like too much armor, is not one of those unfortunate evolutionary accidents that leads to the annihilation of its possessors.

ARTHUR C. CLARKE, Report on Planet Three and Other Speculations

However it occurs, the detection of intelligent life beyond the Earth would change forever our outlook on the universe. At the very least, it would prove that intelligence does have some survival value--a reassurance worth having after a session with the late news.

ARTHUR C. CLARKE, Greetings, Carbon-Based Bipeds!

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