Quotes by Carl Sagan

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

This oak tree and me, we're made of the same stuff.

We are like butterflies who flutter for a day and think it is forever.

You have to know the past to understand the present.

The beauty of a living thing is not the atoms that go into it, but the way those atoms are put together.

For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.

For small creatures such as we the vastness is bearable only through love.

Imagination will often carry us to worlds that never were. But without it we go nowhere.

The universe seems neither benign nor hostile, merely indifferent to the concerns of such puny creatures as we are.

Cleverly designed experiments are the key.

The chemistry of coal is still not fully understood, despite a long standing economic incentive.

I don't know where i am going but I'm on my way.

The illegality of cannabis is outrageous, an impediment to full utilization of a drug which helps produce the serenity and insight, sensitivity and fellowship, so desperately needed in this increasingly mad and dangerous world.

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

Our ancestors worshipped the Sun, and they were not that foolish. It makes sense to revere the Sun and the stars, for we are their children.

Extraordinary claims demand extraordinary evidence.

There is nothing inhuman about an intelligent machine; it is indeed an expression of those superb intellectual capabilities that only human beings, of all the creatures on our planet, now possess.

We're in very bad trouble if we don't understand the planet we're trying to save.

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.).

Human beings grew up in forests; we have a natural affinity for them. How lovely a tree is, straining toward the sky.

We achieve some measure of adulthood when we recognize our parents as they really were, without sentimentalizing or mythologyzing, but also without blaming them unfairly for our imperfections.

Atoms are mainly empty space. Matter is composed chiefly of nothing.

The passion to explore is at the heart of being human.

The first law of bureaucracy is to guarantee its own continuance.

The usual rejoinder to someone who says 'They laughed at Columbus, they laughed at Galileo' is to say 'But they also laughed at Bozo the Clown'.

Civilization is a product of the cerebral cortex.

If we can accomplish the integration of the search without obliterating cultural differences or destroying ourselves, we will have accomplished a great thing.

She had spent her career attempting to make contact with the most remote and alien of strangers, while in her own life she had made contact with hardly anyone at all.

If the laws of nature are unpredictably reassorted at the cusps (the transition from contraction to expansion of the universe), then it is only by the most extraordinary coincidence that the cosmic slot machine has this time come up with a universe consistent with us.

We have examined the universe in space and seen that we live on a mote of dust circling a humdrum star in the remotest corner of an obscure galaxy. And if we are a speck in the immensity of space, we also occupy an instant in the expanse of ages.

The well-meaning contention that all ideas have equal merit seems to me little different from the disastrous contention that no ideas have any merit.

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.

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.

Once we lose our fear of being tiny, we find ourselves on the threshold of a vast and awesome Universe which dwarfs -- in time, in space, and in potential -- the tidy anthropocentric proscenium of our ancestors.

The cosmos is full beyond measure of elegant truths; of exquisite interrelationships; of the awesome machinery of nature.

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.

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

Perhaps the locale of the subjunctive mood will
one day be found. Will Latins turn out to be extravagantly endowed and English-speaking peoples significantly short-changed in this minor piece of brain anatomy?

And after the Earth dies, some 5 billion years from now, after it is burned t a crisp or even swallowed by the Sun, there will be other worlds and stars and galaxies coming into being- and they will know nothing of a place once called Earth.

It's been said that astronomy is a humbling and, I might add, a character-building experience.

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

I would suggest that science is, at least in my part, informed worship.

There are wonders enough out there without our inventing any.

Except in pure mathematics, nothing is known for certain (although much is certainly false).

But nature is always more subtle, more intricate, more elegant than what we are able to imagine.

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.

For all our failings, despite our limitations and fallibilities, we humans are capable of greatness.

If you grow up in a household where there are books, where you are read to, where parents, siblings, aunts, uncles, and cousins read for their own pleasure, naturally you learn to read. If no one close to you takes joy in reading, where is the evidence that it's worth the effort?

We knew the Moon from our earliest days. It was there when our ancestors descended from the trees into the savannahs, when we learned to walk upright, when we first devised stone tools, when we domesticated fire, when we invented agriculture and built cities and set out to subdue the Earth.

The difference between physics and metaphysics is not that the practitioners of one are smarter than the practitioners of the other. The difference is that the metaphysicist has no laboratory.

Our children long for realistic maps of the future that they can be proud of. Where are the cartographers of human purpose?

I would be very ashamed of my civilization if we did not try to find out if there is life in outer space.

My favorite color: A pale blue dot suspended in a sunbeam.

But if the Bible is not everywhere literally true, which parts are divinely inspired and which are merely fallible and human? As soon as we admit that there are scriptural mistakes (or concessions to the ignorance of the times), then how can the Bible be an inerrant guide to ethics and morals?

Ask courageous questions. Do not be satisfied with superficial answers.

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

We wish to find the truth, no matter where it lies. But to find the truth we need imagination and skepticism both. We will not be afraid to speculate, but we will be careful to distinguish speculation from fact.

If we like them, they're freedom fighters, she thought. If we don't like them, they're terrorists. In the unlikely case we can't make up our minds, they're temporarily only guerrillas.

How lucky we are to live in this time the first moment in human history when we are in fact visiting other worlds.

It seems madness to say, 'We're worried that they're going to become addicted to marijuana' -- there's no evidence whatever that it's an addictive drug, but even if it were, these people are dying, what are we saving them from?

Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference of the Earth, to high precision, with an error of only a few percent. That's pretty good figuring for 2200 years ago.

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.

We on Earth have just awakened to the great oceans of space and time from which we have emerged.

Societies will, of course, wish to exercise prudence in deciding which technologies that is, which applications of science are to be pursued and which not. But without funding basic research, without supporting the acquisition of knowledge for its own sake, our options become dangerously limited.

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.

The boundary between space and the earth is purely arbitrary. And I'll probably always be interested in this planet -- it's my favorite.

Few scientists now dispute that today's soaring levels of carbon dioxide and other gases in the atmosphere will cause global temperature averages to rise by as much as nine degrees Fahrenheit sometime after the year 2000.

Our politics, economics, advertising, and religions (New Age and Old) are awash in credulity. Those who have something to sell, those who wish to influence public opinion, those in power, a skeptic might suggest, have a vested interest in discouraging skepticism,.

You probably don't need more weapons than what's required to destroy every city on earth. There's only 2,300 cities. So, the United States, by that criteria, only needs 2,300 nuclear weapons -- well, we've got more than 25,000!

We are not without empathetic terror when we open Pascal's 'Pensees' and read, 'I am the great silent spaces between worlds.'

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.

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

First rule in government spending: why build one when you can have two at twice the price?

One trend that bothers me is the glorification of stupidity, that the media is reassuring people it's alright not to know anything. That to me is far more dangerous than a little pornography on the Internet.

If we offer too much silent assent about mysticism and superstition -- even when it seems to be doing a little good -- we abet a general climate in which scepticism is considered impolite, science tiresome, and rigorous thinking somehow stuffy and inappropriate.

It will not be we who reach Alpha Centauri, and the other nearby stars. It will be a species very like us -- but with more of our strengths and fewer of our weaknesses.

Our difficulties in understanding or effectuating
communication with other animals may arise from our reluctance to grasp unfamiliar ways of dealing with the world.

Human spoken language seems to be
adventitious. The exploitation of organ systems with other functions for communication in humans is also indicative of the comparatively recent evolution of our linguistic abilities.

The cognitive abilities of chimpanzees force us, I think, to raise searching questions about the boundaries of the community of beings to which special ethical considerations are due.

Like other mammals, they are capable of strong emotions. They have certainly committed no crimes. I do not claim to have the answer, but I think it is
certainly worthwhile to raise the question: Why, exactly, all over the civilized world, in virtually every major city, are apes in prison?

It is said that men may not be the dreams of the god, but rather that the gods are the dreams of men.

You're capable of such beautiful dreams and such horrible nightmares.

Books tap the wisdom of our species -- the greatest minds, the best teachers -- from all over the world and from all our history. And they're patient.

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.

The cannabis experience has greatly improved my appreciation for art, a subject which I had never much appreciated before.

If chimpanzees have consciousness, if they are capable of abstractions, do they not have what until now has been described as 'human rights'? How smart does a chimp have to be before killing him constitutes murder?

I believe that in every person is a kind of circuit which resonates to intellectual discovery-and the idea is to make that resonance work.

After the earth dies, some 5 billion years from now, after it's burned to a crisp, or even swallowed by the Sun, there will be other worlds and stars and galaxies coming into being -- and they will know nothing of a place once called Earth.

We are the custodians of life's meaning.

Organic as a dandelion seed, the ship of our imagination will carry us to worlds of dreams and worlds of facts.

The fact that so little of the findings of modern science is prefigured in Scripture to my mind casts further doubt on it divine inspiration.

The dumbing down of America is evident in the slow decay of substantive content, a kind of celebration of ignorance.

An atheist is someone who is certain that God does not exist, someone who has compelling evidence against the existence of God. I know of no such compelling evidence.

The Bill of Rights decoupled religion from the state, in part because so many religions were steeped in an absolutist frame of mind -- each convinced that it alone had a monopoly on the truth and therefore eager for the state to impose this truth on others.

Frederick Douglas taught that literacy is the path from slavery to freedom. There are many kinds of slavery and many kinds of freedom, but reading is still the path.

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 in trouble. Really, it's okay to reserve judgment until the evidence is in.

Better the hard truth, I say, than the comforting fantasy.

The theologian Meric Casaubon argued--in his 1668 book, Of Credulity and Incredulity--that witches must exist because, after all, everyone believes in them. Anything that a large number of people believe must be true.

There may be such intelligences and such starships, but pulsars are not their signature. Instead, they are the doleful reminders that nothing lasts forever; that stars also die.

Recent research shows that many children without enough to eat wind up with diminished capacity to understand and learn (cognitive impairment ). Children don't have to be starving for this to happen. Even mild undernourishment -- the kind most common among poor people in America -- can do it.

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

Any faith that admires truth, that strives to know God, must be brave enough to accommodate the universe.

Each of us is a tiny being, permitted to ride on the outermost skin of one of the smaller planets for a few dozen trips around the local star.

If some good evidence for life after death were announced, I'd be eager to examine it; but it would have to be real scientific data, not mere anecdote. As with the face on Mars and alien abductions, better the hard truth, I say, than the comforting fantasy.

It is all a matter of time scale. An event that would be unthinkable in a hundred years may be inevitable in a hundred million.

The lifetime of a human being is measured by decades, the lifetime of the Sun is a hundred million times longer. Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their lives in the course of a single day.

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.

It would be wryly interesting if in human history the cultivation of marijuana led generally to the invention of agriculture, and thereby to civilization.

We are...capable of using our compassion and our intelligence, our technology and our wealth, to make an abundant and meaningful life for every inhabitant of this planet. To enhance enormously our understanding of the Universe, and to carry us to the stars.

We will die and we fear death. This fear is worldwide and transcultural. It probably has significant survival value. Those who wish to postpone or avoid death can improve the world, reduce its perils, make children who will live after us, and create great works by which they will be remembered.

Writing a novel is like trying to solve a very long mathematical equation. Changing anything can change everything else.

I believe our future depends powerfully on how well we understand this cosmos in which we float, like a mote of dust in the morning sky.

Is mankind alone in the universe? Or are there somewhere other intelligent beings looking up into their night sky from very different worlds and asking the same kind of question?

Be grateful everyday for the brief but magnificent opportunity that life provides.

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

Science ... looks skeptically at all claims to knowledge, old and new. It teaches not blind obedience to those in authority but to vigorous debate, and in many respects that's the secret of its success.

Our perceptions are fallible. We sometimes see what isn't there. We are prey to optical illusions. Occasionally we hallucinate. We are error-prone.

On the day that we do discover that we are not alone, our society may begin to evolve and transform in some incredible and wondrous new ways.

The prediction of nuclear winter is drawn not, of course, from any direct experience with the consequences of global nuclear war, but rather from an investigation of the governing physics.

But amid much elegance and precision, the details of life and the Universe also exhibit haphazard, jury-rigged arrangements and much poor planning. What shall we make of this: an edifice abandoned early in construction by the architect?

Widespread intellectual and moral docility may be convenient for leaders in the short term, but it is suicidal for nations in the long term.

If all the suns but ours collapsed tonight, how many lifetimes would it take us to realize that we were alone?

Why are there no nonhuman primates with an existing complex gestural language? One possible answer, it seems to me, is that humans have systematically exterminated those other primates who displayed signs of intelligence.

If stones could philosophize, I imagine Lithic Principles would be at the intellectual frontiers.

Much of human history can, I think, be described as a gradual and sometimes painful liberation from provincialism, the emerging awareness that there is more to the world than was generally believed by our ancestors.

At the extremes it is difficult to distinguish pseudoscience from rigid, doctrinaire religion.

Avoidable human misery is more often caused not so much by stupidity as by ignorance, particularly our ignorance about ourselves.

The candle flame gutters. Its little pool of light trembles. Darkness gathers. The demons begin to stir.

The method of science, as stodgy and grumpy as it may seem, is far more important than the findings of science.

I maintain there is much more wonder in science than in pseudoscience. And in addition, to whatever measure this term has any meaning, science has the additional virtue, and it is not an inconsiderable one, of being true.

The words question and quest are cognates. Only through inquiry can we discover truth.

One of the greatest gifts adults can give -- to their offspring and to their society -- is to read to children.

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.

Modern Darwinism makes it abundantly clear that many less ruthless traits, some not always admired by robber barons and Fuhrers -- altruism, general intelligence, compassion -- may be the key to survival.

All science asks is to employ the same levels of skepticism we use in buying a used car or in judging the quality of analgesics or beer from their television commercials.

If you want to make a rhubarb pie from scratch, first you have to create the universe.

Those afraid of the universe as it really is, those who pretend to nonexistent knowledge and envision a Cosmos centered on human beings will prefer the fleeting comforts of superstition.

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.

We sometimes hear of things that can travel faster than light. Something called 'the speed of thought' is occasionally proffered. This is an exceptionally silly notion especially since the speed of impulses through the neutrons in our brain is about the same as the speed of a donkey cart.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

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.

The Platonists and their Christian successors held the peculiar notion that the Earth was tainted and somehow nasty, while the heavens were perfect and divine. The fundamental idea that the Earth is a planet, that we are citizens of the Universe, was rejected and forgotten.

Because men, compared to male chimps, have such relatively small testicles (large testicles indicate a species where many males mate, one after the other, with the same female), we might guess that promiscuous societies were uncommon in the immediate human past.

The wind whips through the canyons of the American Southwest, and there is no one to hear it but us -- a reminder of the 40,000 generations of thinking men and women who preceded us, about whom we know almost nothing, upon whom our civilization is based.

Those who make uncritical observations or fraudulent claims lead us into error and deflect us from the major human goal of understanding how the world works. It is for this reason that playing fast and loose with the truth is a very serious matter.

This zest to explore and exploit, however thoughtless its agents may have been, has clear survival value. It is not restricted to any one nation or ethnic group. It is an endowment that all members of the human species hold in common.

Books permit us to voyage through time, to tap the wisdom of our ancestors.

And after we returned to the savannahs and abandoned the trees, did we long for those great graceful leaps and ecstatic moments of weightlessness in the shafts of sunlight of the forest roof?

Who are we, if not measured by our impact on others? That's who we are! We're not who we say we are, we're not who we want to be -- we are the sum of the influence and impact that we have, in our lives, on others.

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.

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

Part of the resistance to Darwin and Wallace derives from our difficulty in imagining the passage of the millennia, much less the aeons. What does seventy million years mean to beings who live only one-millionth as long? We are like butterflies who flutter for a day and think it is forever.

The gears of poverty, ignorance, hopelessness and low self-esteem interact to create a kind of perpetual failure machine that grinds down dreams from generation to generation. We all bear the cost of keeping it running. Illiteracy is its linchpin.

It is precisely our plasticity, our long childhood, that prevents a slavish adherence to genetically preprogrammed behavior in human beings more than in any other species… Some substantial adjustment of the relative role of each component of the triune brain is well within our powers.

MacLean has shown that the R-complex plays an important role in aggressive behavior, territoriality, ritual and the establishment of social hierarchies. Despite occasional welcome exceptions, this seems to me to characterize a great deal of modern human bureaucratic and political behavior.

Evolution is adventitious and not foresighted. Only through the deaths of an immense number of slightly maladapted organisms are we, brains and all, here today.

In addition, human beings have, in the most recent few tenths of a percent of our existence, invented not only extra-genetic but also extrasomatic knowledge: information stored outside our bodies, of which writing is the most notable example.

It is very difficult to evolve by altering the deep fabric of life; any change there is likely to be lethal. But fundamental change can be accomplished by the addition of new systems on top of old ones.

The entire evolutionary record on our planet, particularly the record contained in fossil endocasts, illustrates a progressive tendency toward intelligence. There is nothing mysterious about this:
smart organisms by and large survive better and leave more offspring than stupid ones.

It is interesting that it is not the getting of any sort of knowledge that God has forbidden, but, specifically, the knowledge of the difference between good and evil-that is, abstract and moral judgments, which, if they reside anywhere, reside in the neocortex.

Human history can be viewed as a slowly dawning awareness that we are members of a larger group.

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. It is our fate to live during one of the most perilous and, at the same time, one of the most hopeful chapters in human history.

As in all such technological nightmares, the principal task is to foresee what is possible; to educate use and misuse; and to prevent its organizational, bureaucratic and governmental abuse.

And despite the insignificance of the instant we have so far occupied in cosmic time, it is clear that what happens on and near Earth at the beginning of the
second cosmic year will depend very much on the scientific wisdom and the distinctly human sensitivity of mankind.

Thus the recent rapid evolution of human intelligence is not only the cause of but also the only conceivable solution to the many serious problems that beset us.

I've written a number of books that have to do with the evolution of humans, human intelligence, human emotions.