Carl Sagan Quotes & Sayings

Science is a collaborative enterprise, spanning the generations. When it permits us to see the far side of some new horizon, we remember those who prepared the way - seeing for them also. — Carl Sagan

We are one species. We are starstuff. — Carl Sagan

The library connects us with the insight and knowledge, painfully extracted from Nature, of the greatest minds that ever were, with the best teachers, drawn from the entire planet and from all our history, to instruct us without tiring, and to inspire us to make our own contribution to the collective knowledge of the human species. — Carl Sagan

If we scrutinize 100,000 pictures, it's not surprising that occasionally we'll come upon something like a face. With our brains programmed for this from infancy, it would be amazing if we couldn't find one here and there. — Carl Sagan

There is a lurking fear that some things are not meant to be known. — Carl Sagan

Trends working at least marginally towards the implantation of a very narrow range of attitudes, memories and opinions include control of major television networks and newspapers by a small number of similarly motivated powerful corporations and individuals, the disappearance of competitive daily newspapers in many cities, the replacement of substantive debate by sleaze in political campaigns, and episodic erosion of the principle of the separation of powers. It is estimated (by the American media expert Ben Bagditrian) that fewer than two dozen corporations control more than half of the global business in daily newspapers, magazines, television, books and movies! — Carl Sagan

In the vastness of the Cosmos there must be other civilizations far older and more advanced than ours. — Carl Sagan

What functions do dreams serve today? One view, published in a reputable scientific paper, holds that the function of dreams is to wake us up a little, every now and then, to see if anyone is about to eat us. But dreams occupy such a relatively small part of normal sleep that this explanation does not seem very compelling. Moreover, as we have seen, the evidence points just the other way: today it is the mammalian predators, not the mammalian prey, who characteristically have dream-filled sleep. — Carl Sagan

if we have several hundred or several thousand cultures, each with its own cosmology, we should not be astounded if, every now and then, purely by chance, one of them proposes an idea that is not only correct but also impossible for them to have deduced. — Carl Sagan

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff. — Carl Sagan

To live in the hearts we leave behind is to live forever. — Carl Sagan

The nuclear arms race is like two sworn enemies standing waist deep in gasoline, one with three matches, the other with five. — Carl Sagan

Who will speak for Planet Earth? — Carl Sagan

Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their whole lives in the course of a single day. From the point of view of a mayfly, human beings are stolid, boring, almost entirely immovable, offering hardly a hint that they ever do anything. From the point of view of a star, a human being is a tiny flash, one of billions of brief lives flickering tenuously on the surface of a strangely cold, anomalously solid, exotically remote sphere of silicate and iron. — Carl Sagan

While our behavior is still significantly controlled by our genetic inheritance, we have, through our brains, a much richer opportunity to blaze new behavioral and cultural pathways on short timescales. — Carl Sagan

What a marvelous cooperative arrangement - plants and animals each inhaling each other's exhalations, a kind of planet-wide mutual mouth-to-stoma resuscitation, the entire elegant cycle powered by a star 150 million kilometers away. — Carl Sagan

Especially where the implications of what we think we are seeing seem to be profound, we may not exercise adequate self-discipline and self-criticism. — Carl Sagan

In addition to Ameslan, chimpanzees and other nonhuman primates are being taught a variety of other gestural languages. And it is just this transition from tongue to hand that has permitted humans to regain the ability-lost, according to Josephus, since Eden-to communicate with the animals. — Carl Sagan

Advances in medicine and agriculture have saved vastly more lives than have been lost in all the wars in history. — Carl Sagan

Nearly everyone in ancient Egypt exhorted the gods to let the Pharaoh live 'forever. These collective prayers failed. Their failure constitutes data. — Carl Sagan

Washburn has reported that infant baboons and other young primates appear to be born with only three inborn fears -of falling, snakes, and the dark-corresponding respectively to the dangers posed by
Newtonian gravitation to tree-dwellers, by our ancient enemies the reptiles, and by mammalian nocturnal predators, which must have been particularly terrifying for the visually oriented primates. — Carl Sagan

Once intelligent beings achieve technology and the capacity for self-destruction of their species, the selective advantage of intelligence becomes more uncertain. — Carl Sagan

Human beings have a demonstrated talent for self-deception when their emotions are stirred. — Carl Sagan

We have a theology that is Earth-centered and involves a tiny piece of space, and when we step back, when we attain a broader cosmic perspective, some of it seems very small in scale. And in fact a general problem with much of Western theology in my view is that the God portrayed is too small. It is a god of a tiny world and not a god of a galaxy, much less of a universe. — Carl Sagan

The universe seems neither benign nor hostile, merely indifferent. — Carl Sagan

If we could travel into the past, it's mind-boggling what would be possible. For one thing, history would become an experimental science, which it certainly isn't today. The possible insights into our own past and nature and origins would be dazzling. For another, we would be facing the deep paradoxes of interfering with the scheme of causality that has led to our own time and ourselves. I have no idea whether it's possible, but it's certainly worth exploring. — Carl Sagan

The nature of life on Earth and the search for life elsewhere are two sides of the same question - the search for who we are. — Carl Sagan

We should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. — Carl Sagan

Science and mathematics [are] much more compelling and exciting than the doctrines of pseudoscience, whose practitioners were condemned as early as the fifth century B.C. by the Ionian philosopher Heraclitus as 'night walkers, magicians, priests of Bacchus, priestesses of the wine-vat, mystery-mongers.' But science is more intricate and subtle, reveals a much richer universe, and powerfully evokes our sense of wonder. And it has the additional and important virtue-to whatever extent the word has any meaning-of being true. — Carl Sagan

The Greek religion explained that diffuse band of light in the night sky as the milk of Hera, squirted from her breast across the heavens, a legend that is the origin of the phrase Westerners still use - the Milky Way. — Carl Sagan

But if humans can make new varieties of plants and animals, must not nature do so also? This related process is called natural selection. That life has changed fundamentally over the aeons is entirely clear from the alterations we have made in the beasts and vegetables during the short tenure of humans on Earth, and from the fossil evidence. — Carl Sagan

Even if the aliens are short, dour, and sexually obsessed - if they're here, I want to know about them. — Carl Sagan

She was a wonder junkie. In her mind, she was a hill tribesman standing slack-jawed before the real Ishtar Gate of ancient Babylon; Dorothy catching her first glimpse of the vaulted spires of the Emerald City of Oz; a small boy from darkest Brooklyn plunked down in the Corridor of Nations of the 1939 World's Fair, the Trylon and Perisphere beckoning in the distance; she was Pocahontas sailing up the Thames estuary with London spread out before her from horizon to horizon. been voyaging between the stars when the ancestors of humans were still brachiating from branch to branch in the dappled sunlight of the forest canopy. Drumlin, like many others she had known over the years, had called her an incurable romantic; and she found herself wondering again why so many people thought it some embarrassing disability. Her romanticism had been a driving force in her life and a fount of delights. Advocate and practitioner of romance, she was off to see the Wizard. — Carl Sagan

There is child abuse, and there are such things as repressed memories. But there are also such things as false memories and confabulations, and they are not rare at all. Misrememberings are the rule, not the exception. They occur all the time. They occur even in cases where the subject is absolutely confident - even when the memory is a seemingly unforgettable flashbulb, one of those metaphorical mental photographs. — Carl Sagan

Every culture has a myth of the world before creation, and of the creation of the world [.]
These myths are tributes to human audacity. The chief difference between them and our modern scientific myth of the Big Bang is that science is self-questioning, and that we can perform experiments and observations to test our ideas. But those other creation stories are worthy of our deep respect. — Carl Sagan

My long-time view about Christianity is that it represents an amalgam of two seemingly immiscible parts-the religion of Jesus and the religion of Paul. Thomas Jefferson attempted to excise the Pauline parts of the New Testament. There wasn't much left when he was done, but it was an inspiring document. — Carl Sagan

We are the children equally of the Sky and the Earth. — Carl Sagan

Religions are tough. Either they make no contentions which are subject to disproof or they quickly redesign doctrine after disproof ... near the core of the religious experience is something remarkably resistant to rational inquiry. — Carl Sagan

As science advances, there seems to be less and less for God to do. It's a big universe, of course, so He, She, or It, could be profitably employed in many places. But what has clearly been happening is that evolving before our eyes has been a God of the Gaps; that is, whatever it is we cannot explain lately is attributed to God. And then after a while, we explain it, and so that's no longer God's realm. — Carl Sagan

The universe is not required to be in perfect harmony with human ambition. — Carl Sagan

His argument was not with God but with those who believed that our understanding of the sacred had been completed. Science's permanently revolutionary conviction that the search for truth never ends seemed to him the only approach with sufficient humility to be worthy of the universe that it revealed. — Carl Sagan

Some foolish men declare that a Creator made the world. The doctrine that the world was created is ill-advised, and should be rejected. If God created the world, where was He before creation? ... How could God have made the world without any raw material? If you say He made this first, and then the world, you are faced with an endless regression ... Know that the world is uncreated, as time itself is, without beginning and end. And it is based on the principles ... - The Mahapurana (The Great Legend), Jinasena (India, ninth century) — Carl Sagan

Our Sun is a second- or third-generation star. All of the rocky and metallic material we stand on, the iron in our blood, the calcium in our teeth, the carbon in our genes were produced billions of years ago in the interior of a red giant star. We are made of star-stuff. — Carl Sagan

We are at a crossroads in human history. Never before has there been a moment so simultaneously perilous and promising. We are the first species to have taken evolution into our own hands. — Carl Sagan

The study of the global climate, the comparison of the Earth with other worlds, are subjects in their earliest stages of development. They are fields that are poorly and grudgingly funded. In our ignorance, we continue to push and pull, to pollute the atmosphere and brighten the land, oblivious of the fact that the long-term consequences are largely unknown. — Carl Sagan

We tend not to be especially critical when presented with evidence that seems to confirm our prejudices. — Carl Sagan

You could just as well say that an agnostic is a deeply religious person with at least a rudimentary knowledge of human fallibility. — Carl Sagan

The ancient Ionians were the first we know of to argue systematically that laws and forces of Nature, rather than gods, are responsible for the order and even the existence of the world. — Carl Sagan

Many statements about God are confidently made by theologians on grounds that today at least sound specious. Thomas Aquinas claimed to prove that God cannot make another God, or commit suicide, or make a man without a soul, or even make a triangle whose interior angles do not equal 180 degrees. But Bolyai and Lobachevsky were able to accomplish this last feat (on a curved surface) in the nineteenth century, and they were not even approximately gods. — Carl Sagan

It is striking that the observational search for extraterrestrial life began in the same generation as the invention of the telescope, and with the greatest theoretician of the age. — Carl Sagan

We can always take but never give. — Carl Sagan

If we teach only the findings and products of science - no matter how useful and even inspiring they may be - without communicating its critical method, how can the average person possibly distinguish science from pseudoscience? — Carl Sagan

Vast migrations of people - some voluntary, most not - have shaped the human condition. More of us flee from war, oppression, and famine today than at any other time in human history. As the Earth's climate changes in the coming decades, there are likely to be far greater numbers of environmental refugees. Better places will always call to us. Tides of people will continue to ebb and flow across the planet. But the lands we run to now have already been settled. Other people, often unsympathetic to our plight, are there before us. * — Carl Sagan

We make our purpose. — Carl Sagan

What was an infant's view of air travel? You go to a special place, walk into a large room with seats in it, and sit down. The room rumbles and shakes for four hours. Then you get up and walk off. Magically, you're somewhere else. The means of transportation seems obscure to you, but the basic idea is easy to grasp, and precocious mastery of the Navier-Stokes equations is not required. — Carl Sagan

We are the first species to have taken our evolution into our own hands. — Carl Sagan

A more cynical formulation by the Roman historian Polybius: Since the masses of the people are inconstant, full of unruly desires, passionate, and reckless of consequences, they must be filled with fears to keep them in order. The ancients did well, therefore, to invent gods, and the belief in punishment after death. — Carl Sagan

Each Voyager is itself a message. In their exploratory intent, in the lofty ambition of their objectives, in their utter lack of intent to do harm, and in the brilliance of their design and performance, these robots speak eloquently for us. — Carl Sagan

We have held the peculiar notion that a person or society that is a little different from us, whoever we are, is somehow strange or bizarre, to be distrusted or loathed. Think of the negative connotations of words like alien or outlandish. And yet the monuments and cultures of each of our civilizations merely represent different ways of being human. An extraterrestrial visitor, looking at the differences among human beings and their societies, would find those differences trivial compared to the similarities. — Carl Sagan

And all I'm saying is that it is within our capability to survive. I don't guarantee it. Prophecy is a lost art. And I don't know what the probabilities are that we will go one way or another. And no one says it's easy. But it is clear, as Einstein said, that if we do not make a change in our way of thinking, all is lost. — Carl Sagan

To live in the hearts of others is to never die in those we leave behind. — Carl Sagan

Intellectual capacity is no guarantee against being dead wrong. — Carl Sagan

Cosmos is a Greek word for the order of the universe. It is, in a way, the opposite of Chaos. It implies the deep interconnectedness of all things. It conveys awe for the intricate and subtle way in which the universe is put together. — Carl Sagan

If we long to believe that the stars rise and set for us, that we are the reason there is a Universe, does science do us a disservice in deflating our conceits? — Carl Sagan

Seances occur only in darkened rooms, where the ghostly visitors can be seen dimly at best. If we turn up the lights a little, so we have a chance to see what's going on, the spirits vanish. They're shy, we're told, and some of us believe it. In twentieth-century parapsychology laboratories, there is the 'observer effect': those described as gifted psychics find that their powers diminish markedly whenever sceptics arrive, and disappear altogether in the presence of a conjuror as skilled as James Randi. What they need is darkness and gullibility. — Carl Sagan

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

A religion old or new, that stressed the magnificence of the universe as revealed by modern science, might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths. Sooner or later such a religion will emerge. — Carl Sagan

Not all birds can fly. What separates the flyers from the walkers is the ability to take off. — Carl Sagan

History is full of people who out of fear, or ignorance, or lust for power has destroyed knowledge of immeasurable value which truly belongs to us all. We must not let it happen again. — Carl Sagan

And were the vision of Democritus to have been adopted by Western civilization, instead of being cast aside for the pale views of Plato and Aristotle, we would be vastly further ahead today, in — Carl Sagan

You have to know the past to understand the present. — Carl Sagan

Perhaps for the first time in any medium, the person teaching you science - Carl Sagan - cared about the tangled mental roadways that can rob a person of rational thought. — Carl Sagan

The whole idea of a democratic application of skepticism is that everyone should have the essential tools to effectively and constructively evaluate claims to knowledge. — Carl Sagan

There are no forbidden questions in science, no matters too sensitive or delicate to be probed, no sacred truths. — Carl Sagan

We today can recognize the antiquity of astrology in words such as disaster, which is Greek for "bad star," influenza, Italian for (astral) "influence"; mazeltov, Hebrew - and, ultimately, Babylonian - for "good constellation," or the Yiddish word shlamazel, applied to someone plagued by relentless ill-fortune, which again traces to the Babylonian astronomical lexicon. According to Pliny, there were Romans considered sideratio, "planet-struck." Planets were widely thought to be a direct cause of death. Or consider consider: it means "with the planets," evidently a prerequisite for serious reflection. — Carl Sagan

Who is more humble? The scientist who looks at the universe with an open mind and accepts whatever the universe has to teach us, or somebody who says everything in this book must be considered the literal truth and never mind the fallibility of all the human beings involved? — Carl Sagan

The brain is like a muscle. When it is in use we feel very good. Understanding is joyous. — Carl Sagan

I do not imagine that many people in the fifteenth century ever wondered if they were living in the Italian Renaissance. — Carl Sagan

Telepathy' literally means to feel at a distance, just as 'telephone' is to hear at a distance and 'television' is to see at a distance. The word suggests the communication not of thoughts but of feelings, emotions. Around a quarter of all Americans believe they've experienced something like telepathy. People who know each other very well, who live together, who are practised in one another's feeling tones, associations and thinking styles can often anticipate what the partner will say. This is merely the usual five senses plus human empathy, sensitivity and intelligence in operation. It may feel extrasensory, but it's not at all what's intended by the word 'telepathy'. If something like this were ever conclusively demonstrated, it would, I think, have discernible physical causes -perhaps electrical currents in the brain. Pseudoscience, rightly or wrongly labelled, is by no means the same thing as the supernatural, which is by definition something somehow outside of Nature. — Carl Sagan

The open road still softly calls ... — Carl Sagan

Every star may be a sun to someone. — Carl Sagan

[T]he going-in attitude of many people is highly predetermined. Some are convinced that eyewitness testimony is reliable, that people do not make things up, that hallucinations or hoaxes on such a scale are impossible, and that there must be a long-standing, high level [ ... ] conspiracy to keep the truth from the rest of us. — Carl Sagan

I think if we ever reach the point where we think we thoroughly understand who we are and where we came from, we will have failed. — Carl Sagan

For the observed difference in the shadow lengths, the distance between Alexandria and Syene had to be about seven degrees along the surface of the Earth; that is, if you imagine the sticks extending down to the center of the Earth, they would there intersect at an angle of seven degrees. Seven degrees is something like one-fiftieth of three hundred and sixty degrees, the full circumference of the Earth. Eratosthenes knew that the distance between Alexandria and Syene was approximately 800 kilometers, because he hired a man to pace it out. Eight hundred kilometers times 50 is 40,000 kilometers: so that must be the circumference of the Earth. — Carl Sagan

It is clear that the nations of the world now can only rise and fall together. It is not a question of one nation winning at the expense of another. We must all help one another or all perish together. — Carl Sagan

[One's] inability to invalidate your hypothesis is not at all the same thing as proving it true. — Carl Sagan

Many of the problems facing us may be soluble, but only if we are willing to embrace brilliant, daring and complex solutions. Such solutions require brilliant, daring and complex people. I believe that there are many more of them around - in every nation, ethnic group and degree of affluence - than we realize. — Carl Sagan

The politicians and the religious leaders and the weapons scientists have been at it for a long time and they've made a thorough mess of it. I mean, we're in deep trouble. — Carl Sagan

The fact is that far more crime and child abuse has been committed by zealots in the name of God, Jesus and Mohammed than has ever been committed in the name of Satan. Many people don't like that statement, but few can argue with it. — Carl Sagan

Maybe it's a little early. Maybe the time is not quite yet. But those other worlds - promising untold opportunities - beckon. Silently, they orbit the Sun, waiting. — Carl Sagan

A faith-healer may or may not start out with fraud in mind. But to his amazement, his patients actually seem to be improving. Their emotions are genuine, their gratitude heart-felt. When the healer is criticized, such people rush to his defence. Several elderly attendees of the channelling at the Sydney Opera House were incensed after the Sixty Minutes expose: 'Never mind what they say,' they told Alvarez, 'we believe in you'.
These successes may be enough to convince many charlatans, no matter how cynical they were at the beginning, that they actually have mystical powers. Maybe they're not successful every time. The powers come and go, they tell themselves. They have to cover the down time. If they must cheat a little now and then, it serves a higher purpose, they tell themselves. Their spiel is consumer-tested. It works. — Carl Sagan

Science arouses a soaring sense of wonder. But so does pseudoscience. Sparse and poor popularizations of science abandon ecological niches that pseudoscience promptly fills. If it were widely understood that claims to knowledge require adequate evidence before they can be accepted, there would be no room for pseudoscience. But a kind of Gresham's Law prevails in popular culture by which bad science drives out good. — Carl Sagan

The reappearance of the crescent moon after the new moon; the return of the Sun after a total eclipse, the rising of the Sun in the morning after its troublesome absence at night were noted by people around the world; these phenomena spoke to our ancestors of the possibility of surviving death. Up there in the skies was also a metaphor of immortality. — Carl Sagan

In the deepest sense the search for extraterrestrial intelligence is a search for ourselves. — Carl Sagan

We are the only species on the planet, so far as we know, to have invented a communal memory stored neither in our genes nor in our brains. The warehouse of this memory is called the library — Carl Sagan

Anger at queries about our beliefs is the body's warning signal: here lies unexamined and probably dangerous doctrinal baggage. — Carl Sagan

We are fortunate: we are alive; we are powerful; the welfare of our civilization and our species is in our hands. If we do not speak for Earth, who will? If we are not committed to our own survival, who will be? — Carl Sagan

Otherwise we don't run the government the government runs us — Carl Sagan

When you're in love, you want to tell the world. My lifelong love affair with science — Carl Sagan

There are naive questions, tedious questions, ill-phrased questions, questions put after inadequate self-criticism. But every question is a cry to understand the world. There is no such thing as a dumb question. — Carl Sagan