Carl Sagan Quotes - 75 quotes

Carl Sagan (1934-1996) was an American astronomer, astrophysicist, and science communicator. He was born on November 9, 1934, in Brooklyn, New York. He became renowned for his research on extraterrestrial life and his efforts to popularize science. Sagan played a key role in the American space prog... show more

 With 400 billion stars in the Milky Way galaxy alone, could ours be the only one with an inhabited planet? How much more likely it is that the galaxy is throbbing and humming with advanced societies. Perhaps near one of those pinpoints of light in our night sky, someone quite different from us is glancing idly at the star we call the sun, and entertaining just for a moment, an outrageous speculation.
- Carl Sagan
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 Extraordinary claims require extraordinary evidence.
- Carl Sagan
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 Important lessons about our environment have come from spacecraft missions to the planets. By exploring other worlds we safeguard this one. By itself, I think this fact more than justifies the money our species has spent in sending ships to other worlds.
- Carl Sagan
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 What an astonishing thing a book is. It's a flat object made from a tree, with flexible parts on which are imprinted lot's of funny dark squiggles. But one glance at it and you are inside the mind of another person. Maybe somebody dead for a thousand years. Across the millennia an author is speaking clearly and silently, inside your head, directly to you. Writing is perhaps the greatest of human inventions. Binding together people who never knew each other, citizens of distant epochs. Books break the shackles of time.
- Carl Sagan
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 There was little reassurance or comfort here for a sensitive boy like Kepler. He was intelligent, and he knew it. That together with his stubbornness and his fierce independence served to isolate him from the other boys. Kepler made few friends in his two years at Maulbronn, so he kept to himself, withdrawn into the world of his own thoughts. ... But the real world of Kepler's time was far from perfect. It was haunted by fear, pestilence, famine, and war. Superstition was a natural refuge for people who are powerless.
- Carl Sagan
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 In every time and culture, there are pressures to conform to the prevailing prejudices.
- Carl Sagan
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 As long as there have been humans, we have searched for our place in the cosmos. Where are we? Who are we? We find that we live on an insignificant planet, of a hum-drum star, lost in a galaxy, tucked away in some forgotten corner of a universe of which there are far more galaxies than people.
- Carl Sagan
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 The world is divided politically. But ecologically it is tightly interwoven. There are no useless threads in the fabric of the ecosystem. If you cut any one of them you will unravel many others. We've uncovered other worlds with choking atmospheres and deadly surfaces. Shall we then recreate these hells on earth? We've encountered desolate moons and barren asteroids. Shall we then scar and crater this blue-green world in their likeness? Natural catastrophes are rare. But they come often enough. We need not force the hand of nature. If we ruin the earth, there is no place else to go. This is not a disposable world. And we are not yet able to re-engineer other planets. The cruelest desert on earth is far more hospitable than any place on mars.
- Carl Sagan
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 Every thinking person fears nuclear war. And every technological nation plans for it. Everyone knows it's madness. And every country has an excuse.
- Carl Sagan
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 Whatever is inconsistent with the facts, no matter how fond of it we are, must be discarded or revised.
- Carl Sagan
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 So if civilizations do not always destroy themselves shortly after discovering radio astronomy, then the sky may be softly humming with messages from the stars. With signals from civilizations enormously older, and wiser than we.
- Carl Sagan
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 We have made the ships that sail the sea of space.
- Carl Sagan
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 But our sun is only one of a billion-trillion stars within the observable universe. And those countless suns all obey natural laws some of which are already known to us. How did we discover that there are such laws? If we lived on a planet where nothing ever changed, there wouldn't be much to do, there'd be nothing to figure out. There'd be no impetus for science. And if we lived in an unpredictable world where things changed in random or very complex ways, we wouldn't be able to figure things out. And again, there'd be no such thing as science. But we live in an in between universe where things change alright, but according to patterns, rules, or as we call them, laws of nature. If I throw a stick up in the air, it always falls down. If the sun sets in the west, it always rises again the next morning in the east. And so it's possible to figure things out. We can do science. And with it we can improve our lives.
- Carl Sagan
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 The study of a single instance of extra-terrestrial life - no matter how humble- a microbe would be just fine, will de-provincialize biology. It will show us what else is possible.
- Carl Sagan
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 Once you are open to questioning rituals and time-honored practices, you find that one question leads to another.
- Carl Sagan
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 When he [Kepler] found that his long cherished beliefs did not agree with the most precise observations, he accepted the uncomfortable facts. He preferred the hard truth to his dearest illusions. That is the heart of science.
- Carl Sagan
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 There are an enormous number of stars. Only some of them will have planets suitable for life. On only some of those worlds will intelligence arise. And perhaps a few of those civilizations will avoid the trap jointly set by their technology and their passions. If there are many civilizations, one of them should be rather close by. If there are few civilizations, then even the nearest may be very far away.
- Carl Sagan
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 The Pythagoreans had discovered in the mathematical underpinnings of nature, one of the two most powerful scientific tools, the other is of course is experiment. But instead of using their insight to advance the collective voyage of human discovery, they made of it little more than the hocus-pocus of a mystery cult. Science and mathematics were to be removed from the hands of the merchants and the artisans. This tendency found its most effective advocate in a follower of Pythagoras named Plato. He preferred the perfection of these mathematical abstractions, to the imperfections of everyday life. He believed that ideas were far more real than the natural world. He advised the astronomers not to waste their time observing the stars and planets. It was better, he believed, just to think about them. Plato expressed hostility to observation and experiment. He taught contempt for the real world, and disdain for the practical application of scientific knowledge. Plato's followers succeeded in extinguishing the light of science and experiment that had been kindled by Democritus and the other Ionians. Plato's unease with the world as revealed by our senses was to dominate and stifle western philosophy.
- Carl Sagan
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 Where we have strong emotions we're liable to fool ourselves.
- Carl Sagan
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 Information itself evolves, nurtured by open communication and free inquiry. The units of biological evolution are genes. The units of cultural evolution are ideas. Ideas are transported all over the planet. They reproduce through communication. They are selected by analysis and debate. In the last few millennia, something extraordinary has been happening on the planet earth. Rich information from distant lands and peoples, has become routinely available.
- Carl Sagan
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 In the vastness of the Cosmos, there must be other civilizations far older and more advanced than ours.
- Carl Sagan
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 The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars. There was a time when the stars seemed an impenetrable mystery. Today, we have begun to understand them.
- Carl Sagan
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 The receipt of an interstellar message would be one of the major events in human history and the beginning of the deprovincialization of our planet.
- Carl Sagan
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 In the cosmos, there is no refuge from change.
- Carl Sagan
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 We have lingered long enough on the shores of the cosmic ocean. We are ready at last to set sail for the stars.
- Carl Sagan
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 There are many hypothesis in science which are wrong. That perfectly alright, its the aperture to finding out what's right. Science is a self-correcting process. To be accepted, new ideas must survive the most rigorous standards of evidence and scrutiny.
- Carl Sagan
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 Extraterrestrial beings will have a different biology, a different culture, a different language. How could we possibly understand their messages. Is there in any sense a cosmic Rosetta Stone? I believe there is. All the technical civilizations in the cosmos, no matter how different they are, must have one language in common. The language called science.
- Carl Sagan
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 The number of useful ways of assembling nucleic acids is stupifyingly large. It's probably larger than the total number of atoms in the universe. This means that the number of possible kinds of human beings is vastly greater than the number of human beings that has ever lived. This untapped potential of the human species is immense. There must be ways of putting nucleic acids together which will function far better - by any criterion you wish to choose - than the hereditary instructions of any human being who has ever lived. Fortunately we do not know, or at least do not yet know, how to assemble alternative sequences of nucleotides to make alternative kinds of human beings. But in the future we might well be able to put nucleotides together in any desired sequence to produce whatever human characteristics we think desirable. A disquieting and awesome prospect.
- Carl Sagan
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 If the general picture however of a big bang, followed by an expanding universe is correct, what happened before that? Was the universe devoid of all matter and then the matter suddenly, somehow created? How did that happen? In many cultures the customary answer is that a god or gods created the universe out of nothing. But if we wish to pursue this question courageously, we must of course ask the next question, where did God come from? If we decide that this in an unanswerable question why not save a step and conclude that the origin of the universe is an unanswerable question? Or, if we say that God always existed, why not save a step and conclude that the universe always existed? There's no need for a creation, it was always here. These are not easy questions. Cosmology brings us face to face with the deepest mysteries. With questions that were once treated only in religion and myth.
- Carl Sagan
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 Sometimes I think how lucky we are to live in this time, the first moment in human history when we are in fact, visiting other worlds and engaging in a deep reconnaissance of the cosmos.
- Carl Sagan
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 But in the history of the solar system, and even in human history, there are clear records of extraordinary and devastating catastrophes. We humans have now achieved the dubious distinction of being able to make our own major catastrophes, both intentional and inadvertent. On the landscapes of other planets, where the records of the past are better preserved, there is abundant evidence of major catastrophes. It's all a matter of timescale. An event which is improbable in a hundred years, may be inevitable in a hundred-million.
- Carl Sagan
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 You must be able to check assertions out. Inveterate skeptics must be given the chance to follow your reasoning, to duplicate your experiments and see if they get the same result.

- Carl Sagan

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 In addition to teaching us what to do when evaluating a claim to knowledge, any good baloney detection kit must also teach us what not to do. It helps us recognize the most common and perilous fallacies of logic and rhetoric. Many good examples can be found in religion and politics, because their practitioners are so often obliged to justify two contradictory propositions.

- Carl Sagan

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 We are star stuff, harvesting starlight. Our lives, our past and our future, are tied to the sun, the moon, and the stars. Our ancestors knew that their survival depended on understanding the heavens. They built observatories and computers, to predict the changing of the seasons by the motions in the skies. We are, all of us, descended from astronomers.

- Carl Sagan

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 The voyager record is a message in a bottle cast into the cosmic ocean.

- Carl Sagan

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 In the long run, the aggressive civilizations destroy themselves, almost always. It's their nature. They can't help it. In such a case, our job would be to leave them alone. To make sure that no one bothers them. To let them work out their destiny.

- Carl Sagan

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 ...they were becoming caught up in the technology and losing sight of the dangers.

- Carl Sagan

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 All those billions of worlds going to waste, lifeless, barren?

- Carl Sagan

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- Carl Sagan

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 Think of what else they've made people believe. They've persuaded us that we'll be safe if only we spend all our wealth so everybody on Earth can be killed in a moment - when the governments decide the time has come.

- Carl Sagan

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 Isn't a gram of observation worth a ton of theory?

- Carl Sagan

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 If God is omnipotent and omniscient, why didn't he start the universe out in the first place so it would come out the way he wants? Why's he constantly repairing and complaining?

- Carl Sagan

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 What is there in the precepts of science that keeps a scientist from doing evil?

- Carl Sagan

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 Why should God manifest himself in such subtle and debatable ways when he can make his presence completely unambiguous?

- Carl Sagan

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 There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.

- Carl Sagan

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 Any faith that admires truth, that strives to know God, must be brave enough to accommodate the universe. I mean the real universe. All those light-years. All those worlds. I think of the scope of the universe, the opportunities it affords the Creator, and it takes my breath away.

- Carl Sagan

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 This planet is run by crazy people. Remember what they have to do to get where they are. Their perspective is so narrow, so...brief. A few years. In the best of them a few decades. They care only bout the time they are in power.

- Carl Sagan

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 “What would beings who are thousands of years ahead of us be capable of? Or millions? As a philosopher in our part of the world once said: 'The artifacts of a sufficiently advanced extraterrestrial civilization would be indistinguishable from magic'.”

- Carl Sagan

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 God for you is where you sweep away all the mysteries of the world, all the challenges to our intelligence. You simply turn your mind off and say God did it.

- Carl Sagan

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 So the way you avoid the mistakes, or at least reduce the chance that you'll make one, is to be skeptical. You test the ideas. You check them out by rigorous standards of evidence.

- Carl Sagan

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 If we had accomplished so much in only a few thousand years of high technology, what must a truly advanced species, he asked, be capable of? They should be able to move stars about, to reconfigure galaxies?

- Carl Sagan

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 What would beings who are thousands of years ahead of us be capable of? Or millions? As a philosopher in our part of the world once said: 'The artifacts of a sufficiently advanced extraterrestrial civilization would be indistinguishable from magic'.

- Carl Sagan

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 I went to the librarian and asked for a book about stars; ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.

- Carl Sagan

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 I went to the librarian and asked for a book about stars; ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.

- Carl Sagan

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 As long as you live in this universe, and have a modest talent for mathematics, sooner or later you'll find it. It's already here. It's inside everything. You don't have to leave your planet to find it. In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist's signature.

- Carl Sagan

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 In Mozambique, the story goes, monkeys do not talk, because they know if they utter even a single word some man will come and put them to work.

- Carl Sagan

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 She explained that on an issue of this sort it was foolish to have an opinion in the absence of evidence.

- Carl Sagan

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 And I can tell you one thing for sure about immortals: They're very careful. They don't leave things to chance. They've invested too much effort in becoming immortal.

- Carl Sagan

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 But much more important, people tended to overestimate their appetites for rides. They'd pay a premium to be admitted to everything, and then they'd be happy with a lot less.

- Carl Sagan

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 What would beings who are thousands of years ahead of us be capable of? Or millions? As a philosopher in our part of the world once said: 'The artifacts of a sufficiently advanced extraterrestrial civilization would be indistinguishable from magic'.

- Carl Sagan

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 Don't judge everyone else by your own limited experience.

- Carl Sagan

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 Rankin: I've always thought that an agnostic is an atheist without the courage of his convictions. Ellie: You could just as well say that an agnostic is a deeply religious person with at least a rudimentary knowledge of human fallibility. When I say I'm an agnostic, I only mean that the evidence isn't in.

- Carl Sagan

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 You're uncomfortable with scientific skepticism. But the reason it developed is that the world is complicated. It's subtle. Everybody's first idea isn't necessarily right. Also, people are capable of self-deception. Scientists too. All sorts of socially abhorrent doctrines have at one time or another been supported by scientists, well-known scientists, famous brand-name scientists. And, of course, politicians. And respected religious leaders.

- Carl Sagan

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 But when you let the different opinions debate, when any skeptic can perform his or her own experiment to check some contention out, then the truth tends to emerge.

- Carl Sagan

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 Wherever a discrepancy seems to exist, either a scientist or a theologian - maybe both - hasn't been doing his job.

- Carl Sagan

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 By definition, it has to be mighty hard to understand the behavior of a being much smarter than you are.

- Carl Sagan

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 This is the first moment in human history when it's possible to search for the inhabitants of other worlds.

- Carl Sagan

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 And yet the origin of life now seemed to be so easy - and there were so many planetary systems, so many worlds and so many billions of years available for biological evolution - that it was hard to believe the Galaxy was not teaming with life and intelligence.

- Carl Sagan

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 How could we hope to understand the science of a civilization a thousand years ahead of us?

- Carl Sagan

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 He (Plato) believed that ideas were far more real than the natural world. He advised the astronomers not to waste their time observing the stars and planets. It was better, he believed, just to think about them. Plato expressed hostility to observation and experiment. He taught contempt for the real world and disdain for the practical application of scientific knowledge. Plato's followers succeeded in extinguishing the light of science and experiment that had been kindled by Democritus and the other Ionians.

- Carl Sagan

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 I went to the librarian and asked for a book about stars; ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.

- Carl Sagan

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 I was transfixed by the dioramas—lifelike representations of animals and their habitats all over the world. Penguins on the dimly lit Antarctic ice; ... a family of gorillas, the male beating his chest, ... an American grizzly bear standing on his hind legs, ten or twelve feet tall, and staring me right in the eye.

- Carl Sagan

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 I went to the librarian and asked for a book about stars; ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.

- Carl Sagan

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 Any faith that admires truth, that strives to know God, must be brave enough to accommodate the universe. I mean the real universe. All those light-years. All those worlds. I think of the scope of the universe, the opportunities it affords the Creator, and it takes my breath away.

- Carl Sagan

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 Quantify. If whatever it is you’re explaining has some measure, some numerical quantity attached to it, you’ll be much better able to discriminate among competing hypotheses. What is vague and qualitative is open to many explanations.

- Carl Sagan

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