Science Carl Sagan Quotes

The best way to avoid abuses is for the populace in general to be scientifically literate, to understand the implications of such investigations. In exchange for freedom of inquiry, scientists are obliged to explain their work. If science is considered a closed priesthood, too difficult and arcane for the average person to understand, the dangers of abuse are greater. But if science is a topic of general interest and concern - if both its delights and its social consequences are discussed regularly and competently in the schools, the press, and at the dinner table - we have greatly improved our prospects for learning how the world really is and for improving both it and us. ~ Carl Sagan

The size and age of the Cosmos are beyond ordinary human understanding. Lost somewhere between immensity and eternity is our tiny planetary home. In a cosmic perspective, most human concerns seem insignificant, even petty. And yet our species is young and curious and brave and shows much promise. In the last few millennia we have made the most astonishing and unexpected discoveries about the Cosmos and our place within it, explorations that are exhilarating to consider. They remind us that humans have evolved to wonder, that understanding is a joy, that knowledge is prerequisite to survival. I believe our future depends on how well we know this Cosmos in which we float like a mote of dust in the morning sky. ~ Carl Sagan

Plainly, there's something within me that's ready to believe in life after death. And it's not the least bit interested in whether there's any sober evidence for it.
So I don't guffaw at the woman who visits her husband's grave and chats him up every now and then, maybe on the anniversary of his death. It's not hard to understand. And if I have difficulties with the ontological status of who she's talking to, that's all right.
That's not what this is about. This is about humans being human. ~ Carl Sagan

Hallucinations may be a neglected low door in the wall to a scientific understanding of the sacred. ~ Carl Sagan

I don't think science is hard to teach because humans aren't ready for it, or because it arose only through a fluke, or because, by and large, we don't have the brainpower to grapple with it. Instead, the enormous zest for science that I see in first-graders and the lesson from the remnant hunter-gatherers both speak eloquently: A proclivity for science is embedded deeply within us, in all times, places, and cultures. It has been the means for our survival. It is our birthright. When, through indifference, inattention, incompetence, or fear of skepticism, we discourage children from science, we are disenfranchising them, taking from them the tools needed to manage their future. ~ Carl Sagan

How thoroughly the chimps and bonobos have erased the list of purported human distinctions!-self-awareness, language, ideas and their association, reason, trade, play, choice, courage, love and altruism, laughter, concealed ovulation, kissing, face-to-face sex, female orgasm, division of labor, cannibalism, art, music, politics, and featherless bipedalism, besides tool using, tool making, and much else. Philosophers and scientists confidently offer up traits said to be uniquely human, and the apes casually knock them down--toppling the pretension that humans constitute some sort of biological aristocracy among the beings of Earth. Instead, we are more like the nouveau riche, incompletely accommodated to our recent exalted state, insecure about who we are, and trying to put as much distance as possible between us and our humble origins. It's as if our nearest relatives, by their very existence, refute all our explanations and justifications. So as counterweights to human arrogance and pride, it is good for us that there are still apes on Earth. ~ Carl Sagan

The prediction I can make with the highest confidence is that the most amazing discoveries will be the ones we are not today wise enough to foresee. ~ Carl Sagan

It may be that there are kernels of truth in a few of these doctrines, but their widespread acceptance
betokens a lack of intellectual rigor, an absence of skepticism, a need to replace experiments by desires. ~ Carl Sagan

The way to find out about our place in the universe is by examining the universe and by examining ourselves - without preconceptions, with as unbiased a mind as we can muster. ~ Carl Sagan

It is the tension between creativity and skepticism that has produced the stunning and unexpected findings of science. ~ Carl Sagan

You squeeze the eyedropper, and a drop of pond water drips out onto the microscope stage. You look at the projected image. The drop is full of life - strange beings swimming, crawling, tumbling; high dramas of pursuit and escape, triumph and tragedy. This is a world populated by beings far more exotic than in any science fiction movie ... ~ Carl Sagan

A central lesson of science is that to understand complex issues (or even simple ones), we must try to free our minds of dogma and to guarantee the freedom to publish, to contradict, and to experiment. Arguments from authority are unacceptable. ~ Carl Sagan

Had Jupiter been several dozen times more massive, the matter in its interior would have undergone thermonuclear reactions, and Jupiter would have begun to shine by its own light. The largest planet is a star that failed. ~ Carl Sagan

The business of scepticism is to be dangerous. Scepticism challenges established institutions. If we teach everybody, including, say, high school students, habits of sceptical thought, they will probably not restrict their scepticism to UFOs, aspirin commercials and 35,000-year-old channellees. Maybe they'll start asking awkward questions about economic, or social, or political, or religious institutions. Perhaps they'll challenge the opinions of those in power. Then where would we be? ~ Carl Sagan

Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage - at the very least the courage to question the conventional wisdom. ~ 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

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. ~ Carl Sagan

In those cultures lacking unfamiliar challenges, external or internal, where fundamental change is unneeded, novel ideas need not be encouraged. Indeed, heresies can be declared dangerous; thinking can be rigidified; and sanctions against impermissible ideas can be enforced
all without much harm. But under varied and changing environmental or biological circumstances, simply copying the old ways no longer works. Then, a premium awaits those who, instead of blandly following tradition, or trying to foist their preferences on to the physical or social Universe, are open to what the Universe teaches. ~ Carl Sagan

If it takes a little myth and ritual to get us through a night that seems endless, who among us cannot sympathize and understand? ~ Carl Sagan

Black holes collect problems faster than they collect matter. ~ Carl Sagan

And if the world does not in all respects correspond to our wishes, is this the fault of science, or of those who would impose their wishes on the world? ~ Carl Sagan

The impediment to scientific thinking is not, I think, the difficulty of the subject. Complex intellectual feats have been mainstays even of oppressed cultures. Shamans, magicians and theologians are highly skilled in their intricate and arcane arts. No, the impediment is political and hierarchical. ~ Carl Sagan

The secrets of evolution, are time and death.
There's an unbroken thread that stretches from those first cells to us. ~ Carl Sagan

Science is an attempt, largely successful, to understand the world, to get a grip on things, to get hold of ourselves, to steer a safe course. Microbiology and meteorology now explain what only a few centuries ago was considered sufficient cause to burn women to death. ~ Carl Sagan

You are a collection of almost identical molecules with a different collective label. But is that all? Is there nothing in here but molecules? Some people find this idea somehow demeaning to human dignity. For myself, I find it elevating that our universe permits the evolution of molecular machines as intricate and subtle as we. ~ 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

All of us long for a competent, uncorrupt, charismtatic leader. We will leap at the opportunity to support, to believe, to feel good. ~ Carl Sagan

Significant change might require those who are now high in the hierarchy to move downward many steps. This seems to them undesirable and is resisted. ~ Carl Sagan

In college, in the early 1950s, I began to learn a little about how science works, the secrets of its great success, how rigorous the standards of evidence must be if we are really to know something is true, how many false starts and dead ends have plagued human thinking, how our biases can colour our interpretation of evidence, and how often belief systems widely held and supported by the political, religious and academic hierarchies turn out to be not just slightly in error, but grotesquely wrong. ~ Carl Sagan

I'm frequently asked, "Do you believe there's extraterrestrial intelligence?" I give the standard arguments- there are a lot of places out there, the molecules of life are everywhere, I use the word billions, and so on. Then I say it would be astonishing to me if there weren't extraterrestrial intelligence, but of course there is as yet no compelling evidence for it.
Often, I'm asked next, "What do you really think?"
I say, "I just told you what I really think."
"Yes, but what's your gut feeling?"
But I try not to think with my gut. If I'm serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble. Really, it's okay to reserve judgment until the evidence is in. ~ Carl Sagan

It was difficult to hold Broca's brain without wondering whether in some sense Broca was still in there - his wit, his skeptical mien, his abrupt gesticulations when he talked, his quiet and sentimental moments. ~ Carl Sagan

These days there seems to be nowhere left to explore, at least on the land area of the Earth. Victims of their very success, the explorers now pretty much stay home. ~ Carl Sagan

The more we want it to be true, the more careful we have to be. No witness's say-so is good enough. People make mistakes. People play practical jokes. People stretch the truth for money or attention or fame. People occasionally misunderstand what they're seeing. People sometimes even see things that aren't there. ~ Carl Sagan

Science is an ongoing process. It never ends. There is no single ultimate truth to be achieved, after which all the scientists can retire. And because this is so, the world is far more interesting, both for the scientists and for the millions of people in every nation who, while not professional scientists, are deeply interested in the methods and findings of science. ~ Carl Sagan

The idea of science as a method rather than as a body of knowledge is not widely appreciated outside of science, or indeed in some corridors inside of science. ~ Carl Sagan

No question; language can free us of feeling, or almost. Maybe that's one of its functions - so we can understand the world without becoming entirely overwhelmed by it. ~ Carl Sagan

Often, superstition and injustice are imposed by the same ecclesiastical and secular authorities, working hand in glove. It is no surprise that political revolutions, scepticism about religion, and the rise of science might go together, ~ Carl Sagan

If we long for our planet to be important, there is something we can do about it. We make our world significant by the courage of our questions and by the depth of our answers. ~ Carl Sagan

I consider it an extremely dangerous doctrine, because the more likely we are to assume that the solution comes from the outside, the less likely we are to solve our problems ourselves. ~ Carl Sagan

The fossil record implies trial and error, the inability to anticipate the future, features inconsistent with a Great Designer (though not a Designer of a more remote and indirect temperament.) ~ Carl Sagan

There is no other species on Earth that does science. It is, so far, entirely a human invention, evolved by natural selection in the cerebral cortex for one simple reason: it works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. ~ Carl Sagan

I know of no significant advance in science that did not require major inputs from both cerebral hemispheres. This is not true for art, where apparently there are no experiments by which capable, dedicated and unbiased observers can determine to their mutual satisfaction which works are great. ~ Carl Sagan

Not explaining science seems to me perverse. When you're in love, you want to tell the world. ~ 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

We grow up in isolation. Only slowly do we teach ourselves the Cosmos. ~ Carl Sagan

Lost somewhere between the eternity of time and immensity of space is our tiny planetary home ~ Carl Sagan

We can't help it. Life looks for life. ~ Carl Sagan

If you wish to make an apple pie from scratch, you must first invent the universe. ~ 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

Science is a way to call the bluff of those who only pretend to knowledge. It is a bulwark against mysticism, against superstition, against religion misapplied to where it has no business being. ~ Carl Sagan

All of us cherish our beliefs. They are, to a degree, self-defining. When someone comes along who challenges our belief system as insufficiently well based - or who, like Socrates, merely asks embarrassing questions that we haven't thought of, or demonstrates that we've swept key underlying assumptions under the rug - it becomes much more than a search for knowledge. It feels like a personal assault. ~ Carl Sagan

There is some evidence that dreaming is necessary. When people or other mammals are deprived of REM sleep (by awakening them as soon as the characteristic REM and EEG dream patterns emerge), the number of initiations of the dream state per night goes up, and, in severe cases, daytime hallucinations-that is, waking dreams-occur. ~ Carl Sagan

All the explanations proposed seem to be
only partly satisfactory. They range from massive climatic change to mammalian predation to the extinction of a plant with apparent laxative properties, in which case the dinosaurs died of constipation. ~ Carl Sagan

The dumbing down of American is most evident in the slow decay of substantive content in the enormously influential media, the 30 second sound bites (now down to 10 seconds or less), lowest common denominator programming, credulous presentations on pseudoscience and superstition, but especially a kind of celebration of ignorance. ~ Carl Sagan

The fact that someone says something doesn't mean it's true. Doesn't mean they're lying, but it doesn't mean it's true. ~ Carl Sagan

Thomas Jefferson taught that a democracy was impractical unless the people were educated. ~ Carl Sagan

The most important step we can take toward Mars is to make significant progress on Earth. Even modest improvements in the social, economic, and political problems that our global civilization now faces could release enormous resources, both material and human, for other goals. ~ Carl Sagan

Like charges, charges of the same sign, strongly repel one another. We can think of it as a dedicated mutual aversion to their own kind, a little as if the world were densely populated by anchorites and misanthropes. ~ Carl Sagan

Facts, when combined with ideas, constitute the greatest force in the world. They are greater than armaments, greater than finance, greater than science, business and law because they constitute the common denominator of all of them. ~ Carl W. Ackerman

Coal, oil and gas are called fossil fuels, because they are mostly made of the fossil remains of beings from long ago. The chemical energy within them is a kind of stored sunlight originally accumulated by ancient plants. Our civilization runs by burning the remains of humble creatures who inhabited the Earth hundreds of millions of years before the first humans came on the scene. Like some ghastly cannibal cult, we subsist on the dead bodies of our ancestors and distant relatives. ~ Carl Sagan

When an object impacts the Moon at high speed, it sets the Moon slightly wobbling. Eventually the vibrations die down but not in so short a period as eight hundred years. Such a quivering can be studied by laser reflection techniques. The Apollo astronauts emplaced in several locales on the Moon special mirrors called laser retroreflectors. When a laser beam from Earth strikes the mirror and bounces back, the round-trip travel time can be measured with remarkable precision. This time multiplied by the speed of light gives us the distance to the Moon at that moment to equally remarkable precision. Such measurements, performed over a period of years, reveal the Moon to be librating, or quivering with a period (about three years) and amplitude (about three meters), consistent with the idea that the crater Giordano Bruno was gouged out less than a thousand years ago. ~ Carl Sagan

The very act of understanding is a celebration of joining, merging, even if on a very modest scale, with the magnificence of the Cosmos. ~ Carl Sagan

We are, each of us, a multitude. Within us is a little universe. ~ Carl Sagan

The universe is a pretty big place. If it's just us, seems like an awful waste of space. ~ Carl Sagan

The left hemisphere seems to feel quite defensive-in a strange way insecure-about the right hemisphere; and, if this is so, verbal criticism of intuitive thinking becomes suspect on the ground of motive. Unfortunately, there is every reason to think that the right hemisphere has comparable misgivings -expressed nonverbally, of course- about the left. ~ Carl Sagan

The tar is an extremely rich collection of complex organic molecules, including the constituent parts of proteins and nucleic acids. The stuff of life, it turns out, can be very easily made. ~ Carl Sagan

All her life, dreams had been her friends. Her dreams were unusually detailed, well-structured, colorful. ~ Carl Sagan

The Earth is a place. It is by no means the only place. It is not even a typical place. ~ Carl Sagan

In little countries and big countries, capitalist countries and communist countries, Catholic countries and Moslem countries, Western countries and Eastern countries - in almost all these cases, exponential population growth slows down or stops when grinding poverty disappears. This is called the demographic transition. It is in the urgent long-term interest of the human species that every place on Earth achieves this demographic transition. This is why helping other countries to become self-sufficient is not only elementary human decency, but is also in the self-interest of those richer nations able to help. ~ Carl Sagan

When too much cynicism threatens to engulf us, it is buoying to remember how pervasive goodness is ~ Carl Sagan

Dartmouth College employs computer learning techniques in a very broad array of courses. For example, a student can gain a deep insight into the statistics of Mendelian genetics in an hour with the computer rather than spend a year crossing fruit flies
in the laboratory. ~ Carl Sagan

600 million years ago, the monopolizing grip of the algae was broken and an enormous proliferation of new lifeforms emerged, an event called the Cambrian explosion. Life had arisen almost immediately after the origin of the Earth, which suggests that life may be an inevitable chemical process on an Earth-like planet. ~ Carl Sagan

Extraordinary observations require extraordinary evidence to make them believable. ~ Carl Sagan

Knowing a great deal is not the same as being smart; intelligence is not information alone but also judgement, the manner in which information is coordinated and used. ~ Carl Sagan

The lack is not in intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking. ~ Carl Sagan

The significance of our lives and our fragile planet is then determined only by our own wisdom and courage. We are the custodians of life's meaning. We long for a Parent to care for us, to forgive us our errors, to save us from our childish mistakes. But knowledge is preferable to ignorance. Better by far to embrace the hard truth than a reassuring fable. If we crave some cosmic purpose, then let us find ourselves a worthy goal. ~ Carl Sagan

Kepler's third or harmonic law states that the squares of the periods of the planets (the times for them to complete one orbit) are proportional to the cubes of their average distance from the Sun; the more distant the planet, the more slowly it moves, but according to a precise mathematical law: P2 = a3, where P represents the period of revolution of the planet about the Sun, measured in years, and a the distance of the planet from the Sun measured in astronomical units. ~ Carl Sagan

Both the Freudian and the Platonic metaphors emphasize the considerable independence of and tension among the constituent parts of the psyche, a point that characterizes the human condition. ~ 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

Is it really true that we can't afford one attack helicopter's worth of seed corn to listen to the stars? ~ Carl Sagan

You humans have a certain talent for adaptability--at least in the short term. ~ 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

Nevertheless his prodigious intellectual powers persisted unabated. In 1696, the Swiss mathematician Johann Bernoulli challenged his colleagues to solve an unresolved issue called the brachistochrone problem, specifying the curve connecting two points displaced from each other laterally, along which a body, acted upon only by gravity, would fall in the shortest time. ~ 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

Now, what's the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there's no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? Your inability to invalidate my hypothesis is not at all the same thing as proving it true. Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value they may have in inspiring us or in exciting our sense of wonder. What I'm asking you to do comes down to believing, in the absence of evidence, on my say-so. ~ Carl Sagan

If the Earth were as old as a person, a typical organism would be born, live and die in a sliver of a second. We are fleeting, transitional creatures, snowflakes fallen on the hearth fire. ~ Carl Sagan

Our passion for learning ... is our tool for survival. ~ Carl Sagan

Any sufficiently crisp question can be answered by a single binary digit-0 or 1, yes or no. ~ Carl Sagan

Maturity entails a readiness, painful and wrenching though it may be, to look squarely into the long dark places, into the fearsome shadows. ~ Carl Sagan

It is possible - given absolute control over the media and the police - to rewrite the memories of hundreds of millions of people, if you have a generation to accomplish it in. Almost always, this is done to improve the hold that the powerful have on power, or to serve the narcissism or megalomania or paranoia of national leaders. It throws a monkey wrench into the error-correcting machinery. It works to erase public memory of profound political mistakes, and thus to guarantee their eventual repetition.

In our time, with total fabrication of realistic stills, motion pictures, and videotapes technologically within reach, with television in every home, and with critical thinking in decline, restructuring societal memories even without much attention from the secret police seems possible. What I'm imagining here is not that each of us has a budget of memories implanted in special therapeutic sessions by state-appointed psychiatrists, but rather that small numbers of people will have so much control over news stories, history books, and deeply affecting images as to work major changes in collective attitudes. ~ Carl Sagan

A statement: children who watch violent TV programmes tend to be more violent when they grow up. But did the TV cause the violence, or do violent children preferentially enjoy watching violent programmes? Very likely both are true. Commercial defenders of TV violence argue that anyone can distinguish between television and reality. But Saturday morning children's programmes now average 25 acts of violence per hour. At the very least this desensitizes young children to aggression and random cruelty. And if impressionable adults can have false memories implanted in their brains, what are we implanting in our children when we expose them to some 100,000 acts of violence before they graduate from elementary school? ~ Carl Sagan

Yet man does recognise himself [as an animal]. But I ask you and the whole world for a generic differentia between man and ape which conforms to the principles of natural history, I certainly know of none ... If I were to call man ape or vice versa, I should bring down all the theologians on my head. But perhaps I should still do it according to the rules of science. ~ Carl Linnaeus

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

Natural selection has served as a kind of intellectual sieve, producing brains and intelligences increasingly competent to deal with the laws of nature. ~ Carl Sagan

My deeply held belief is that if a god of anything like the traditional sort exists, our curiosity and intelligence is provided by such a God. We would be unappreciative of that gift if we suppressed our passion to explore the universe and ourselves. ~ Carl Sagan

What an astonishing thing a book is. ~ Carl Sagan