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Who said: “The path towards sustainable energy sources will be long and sometimes difficult. But America cannot resist this transition, we must lead it... That is how we will preserve our planet, commanded to our care by God. That’s what will lend meaning to the creed our fathers once declared.”
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Home > Dictionary of Science Quotations > Scientist Names Index S > Carl Sagan Quotes

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Carl Sagan
(9 Nov 1934 - 20 Dec 1996)

American astronomer, exobiologist and writer remembered for popularizing astronomy and science, especially with his public television series Cosmos. Its accompanying book spent seventy weeks on The New York Times bestseller list. He was an adviser to NASA for the Mariner, Voyager, and Viking unmanned space missions.


Science Quotes by Carl Sagan (62 quotes)

Carl Sagan quote A Subject Called Chemistry
Wellington College. CC by-NC 2.0 (source)

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
Billions and Billions: Thoughts on Life and Death at the Brink of the Millenium (1998), 190.
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A googleplex is precisely as far from infinity as is the number 1 ... No matter what number you have in mind, infinity is larger.
— Carl Sagan
In Cosmos (1980, 2011), 181.
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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
Pale Blue Dot: a Vision of the Human Future in Space (1994), 52.
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Advances in medicine and agriculture have saved vastly more lives than have been lost in all the wars in history.
— Carl Sagan
The Demon-Haunted World: Science as a Candle in the Dark (1997), 11.
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As agonizing a disease as cancer is, I do not think it can be said that our civilization is threatened by it. … But a very plausible case can be made that our civilization is fundamentally threatened by the lack of adequate fertility control. Exponential increases of population will dominate any arithmetic increases, even those brought about by heroic technological initiatives, in the availability of food and resources, as Malthus long ago realized.
— Carl Sagan
From 'In Praise of Science and Technology', in Broca's Brain: Reflections on the Romance of Science (1975, 2011), 43.
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At the heart of science is an essential balance between two seemingly contradictory attitudes—an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense.
— Carl Sagan
The Demon-Haunted World: Science as a Candle in the Dark (1997), 304.
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Chlorine is a deadly poison gas employed on European battlefields in World War I. Sodium is a corrosive metal which burns upon contact with water. Together they make a placid and unpoisonous material, table salt. Why each of these substances has the properties it does is a subject called chemistry.
— Carl Sagan
Broca's Brain: The Romance of Science (1979), footnote. Excerpt reprinted as 'Can We Know the Universe? Reflections on a Grain of Salt,' in John Carey, Eyewitness to Science (1997), 437.
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Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact.
— Carl Sagan
Quoted in interview with magazine staff, Psychology Today (Jan 1996).
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For myself, I like a universe that, includes much that is unknown and, at the same time, much that is knowable. A universe in which everything is known would be static and dull, as boring as the heaven of some weak-minded theologians. A universe that is unknowable is no fit place for a thinking being. The ideal universe for us is one very much like the universe we inhabit. And I would guess that this is not really much of a coincidence.
— Carl Sagan
'Can We know the Universe?' in M. Gardner (ed.), The Sacred Beetle and Other Great Essays in Science (1985), 109.
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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
— Carl Sagan
Quoted by Dennis Meredith, in 'Carl Sagan's Cosmic Connection and Extraterrestrial Life-Wish', Science Digest (Jun 1979), 85, 37. Reproduced in Carl Sagan and Tom Head (editor), Conversations With Sagan (2006), 54.
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I grew up in Brooklyn, New York ... a city neighborhood that included houses, lampposts, walls, and bushes. But with an early bedtime in the winter, I could look out my window and see the stars, and the stars were not like anything else in my neighborhood. [At age 5] I didn't know what they were. [At age 9] my mother ... said to me, “You have a library card now, and you know how to read. Take the streetcar to the library and get a book on stars.” ... I stepped up to the big librarian and asked for a book on stars. ... I sat down and found out the answer, which was something really stunning. I found out that the stars are glowing balls of gas. I also found out that the Sun is a star but really close and that the stars are all suns except really far away I didn't know any physics or mathematics at that time, but I could imagine how far you'd have to move the Sun away from us till it was only as bright as a star. It was in that library, reading that book, that the scale of the universe opened up to me. There was something beautiful about it. At that young age, I already knew that I'd be very happy if I could devote my life to finding out more about the stars and the planets that go around them. And it's been my great good fortune to do just that.
— Carl Sagan
Quoted in interview with Jack Rightmyer, in 'Stars in His Eyes', Highights For Children (1 Jan 1997). Ages as given in Tom Head (ed.), Conversations with Carl Sagan (2006), x.
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I'd like the [Cosmos] series to be so visually stimulating that somebody who isn't even interested in the concepts will just watch for the effects. And I'd like people who are prepared to do some thinking to be really stimulated.
— Carl Sagan
Quoted by Dennis Meredith, in 'Carl Sagan's Cosmic Connection and Extraterrestrial Life-Wish', Science Digest (Jun 1979), 85, 38. Reproduced in Carl Sagan and Tom Head, Conversations With Sagan (2006), 55.
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If the greenhouse effect is a blanket in which we wrap ourselves to keep warm, nuclear winter kicks the blanket off.
[co-author with American atmospheric chemist Richard P. Turco (1943- )]
— Carl Sagan
A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race (1990), 24.
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If we lived on a planet where nothing ever changed, there would be little to do. There would be nothing to figure out. There would be no impetus for science. And if we lived in an unpredictable world, where things changed in random or very complex ways, we would not be able to figure things out. But we live in an in-between universe, where things change, 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 becomes possible to figure things out. We can do science, and with it we can improve our lives.
— Carl Sagan
Cosmos (1980, 1985), 32.
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If you want to save your child from polio, you can pray or you can inoculate. ... Choose science.
— Carl Sagan
The Demon-Haunted World (1996), 30.
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Imagine a room awash in gasoline, and there are two implacable enemies in that room. One of them has nine thousand matches. The other has seven thousand matches. Each of them is concerned about who's ahead, who's stronger. Well that's the kind of situation we are actually in. The amount of weapons that are available to the United States and the Soviet Union are so bloated, so grossly in excess of what's needed to dissuade the other, that if it weren't so tragic, it would be laughable. What is necessary is to reduce the matches and to clean up the gasoline.
— Carl Sagan
From Sagan's analogy about the nuclear arms race and the need for disarmament, during a panel discussion in ABC News Viewpoint following the TV movie The Day After (20 Nov 1983). Transcribed by Webmaster from a video recording. It is seen misquoted in summary form as “The nuclear arms race is like two sworn enemies standing waist deep in gasoline, one with three matches, the other with five.”
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In a lot of scientists, the ratio of wonder to skepticism declines in time. That may be connected with the fact that in some fields—mathematics, physics, some others—the great discoveries are almost entirely made by youngsters.
— Carl Sagan
Quoted in interview with magazine staff, Psychology Today (Jan 1996).
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In fact, the thickness of the Earth's atmosphere, compared with the size of the Earth, is in about the same ratio as the thickness of a coat of shellac on a schoolroom globe is to the diameter of the globe. That's the air that nurtures us and almost all other life on Earth, that protects us from deadly ultraviolet light from the sun, that through the greenhouse effect brings the surface temperature above the freezing point. (Without the greenhouse effect, the entire Earth would plunge below the freezing point of water and we'd all be dead.) Now that atmosphere, so thin and fragile, is under assault by our technology. We are pumping all kinds of stuff into it. You know about the concern that chlorofluorocarbons are depleting the ozone layer; and that carbon dioxide and methane and other greenhouse gases are producing global warming, a steady trend amidst fluctuations produced by volcanic eruptions and other sources. Who knows what other challenges we are posing to this vulnerable layer of air that we haven't been wise enough to foresee?
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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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
Keynote address at CSICOP conference, 1987

In some respects, science has far surpassed religion in delivering awe. How is it that hardly any major religion has looked at science and concluded, “This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant. God must be even greater than we dreamed”? Instead they say, 'No, no, no! My god is a little god, and I want him to stay that way.'
— Carl Sagan
Pale Blue Dot: A Vision of the Human Future in Space (1994), 52.
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In the 1920s, there was a dinner at which the physicist Robert W. Wood was asked to respond to a toast ... "To physics and metaphysics." Now by metaphysics was meant something like philosophy—truths that you could get to just by thinking about them. Wood took a second, glanced about him, and answered along these lines: The physicist has an idea, he said. The more he thinks it through, the more sense it makes to him. He goes to the scientific literature, and the more he reads, the more promising the idea seems. Thus prepared, he devises an experiment to test the idea. The experiment is painstaking. Many possibilities are eliminated or taken into account; the accuracy of the measurement is refined. At the end of all this work, the experiment is completed and ... the idea is shown to be worthless. The physicist then discards the idea, frees his mind (as I was saying a moment ago) from the clutter of error, and moves on to something else. The difference between physics and metaphysics, Wood concluded, is that the metaphysicist has no laboratory.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But is it not stirring to understand how the world actually works—that white light is made of colors, that color is the way we perceive the wavelengths of light, that transparent air reflects light, that in so doing it discriminates among the waves, and that the sky is blue for the same reason that the sunset is red? It does no harm to the romance of the sunset to know a little bit about it.
— Carl Sagan
Pale Blue Dot: A Vision of the Human Future in Space (1994), 159.
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It is the responsibility of scientists never to suppress knowledge, no matter how awkward that knowledge is, no matter how it may bother those in power; we are not smart enough to decide which pieces of knowledge are permissible, and which are not. …
— Carl Sagan
Quoted in Lily Splane, Quantum Consciousness (2004), 80.
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It is the tension between creativity and skepticism that has produced the stunning and unexpected findings of science.
— Carl Sagan
In Broca's Brain: Reflections on the Romance of Science (1974, 1986), 73.
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Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.
— Carl Sagan
Pale Blue Dot: A Vision of the Human Future in Space (1994), 23.
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One of the great commandments of science is, 'Mistrust arguments from authority'. (Scientists, being primates, and thus given to dominance hierarchies, of course do not always follow this commandment.)
— Carl Sagan
The Demon-Haunted World: Science as a Candle in the Dark (1996), 31.
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Our passion for learning ... is our tool for survival.
— Carl Sagan
Cosmos (1980, 1985), 230-231.
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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
From 'A Sunday Sermon', in Broca's Brain: Reflections on the Romance of Science (1975, 2011), 332-333.
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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
Broca's Brain (1986), 76.
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Science is a way of thinking much more than it is a body of knowledge.
— Carl Sagan
Broca's Brain (1986), 15.
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Science is a way to not fool ourselves.
— Carl Sagan
Attributed. Contact webmaster if you know a primary print source.
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Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light-years and in the passage of ages, when we grasp the intricacy, beauty, and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual ... The notion that science and spirituality are somehow mutually exclusive does a disservice to both.
— Carl Sagan
In Demon-Haunted World: Science as a Candle in the Dark (1995), 29.
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Scientists constantly get clobbered with the idea that we spent 27 billion dollars on the Apollo programs, and are asked “What more do you want?” We didn't spend it; it was done for political reasons. ... Apollo was a response to the Bay of Pigs fiasco and to the successful orbital flight of Yuri Gagarin. President Kennedy's objective was not to find out the origin of the moon by the end of the decade; rather it was to put a man on the moon and bring him back, and we did that.
— Carl Sagan
Quoted by Dennis Meredith, in 'Carl Sagan's Cosmic Connection and Extraterrestrial Life-Wish', Science Digest (Jun 1979), 85, 38 & 89. Reproduced in Carl Sagan and Tom Head, Conversations With Sagan (2006), 55-56.
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Somewhere, something incredible is waiting to be known.
— Carl Sagan
In Larry Chang, Wisdom for the Soul: Five Millennia of Prescriptions for Spiritual Healing (2006), 561, but without source reference. Although widely seen, webmaster has found no authoritative reference or primary print source for its origin. Can you help?
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The cosmos is all that is, or ever was, or ever will be.
— Carl Sagan
Opening statement from 'The Shores of the Cosmic Ocean', episode 1, TV series, Cosmos (1980). Also in Cosmos (1980, 1985), 4.
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The cure for a fallacious argument is a better argument, not the suppression of ideas.
— Carl Sagan
The Demon Haunted World: Science as a Candle in the Dark (1997), 429.
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The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the clown.
— Carl Sagan
In Broca's Brain: Reflections on the Romance of Science (1980), 34.
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The major religions on the Earth contradict each other left and right. You can't all be correct. And what if all of you are wrong? It's a possibility, you know. You must care about the truth, right? Well, the way to winnow through all the differing contentions is to be skeptical. I'm not any more skeptical about your religious beliefs than I am about every new scientific idea I hear about. But in my line of work, they're called hypotheses, not inspiration and not revelation.
— Carl Sagan
Contact (1997), 162.
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The method of science is tried and true. It is not perfect, it's just the best we have. And to abandon it, with its skeptical protocols, is the pathway to a dark age.
— Carl Sagan
From a sound clip from CSICOP, now CSI, the Committee for Skeptical Inquiry. If you know a more specific citation, please contact Webmaster.
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The nuclear arms race is like two sworn enemies standing waist deep in gasoline, one with three matches, the other with five.
[A summary version; not verbatim.]
— Carl Sagan
A summary version, as written by Kristen Ghodsee in Lost in Transition: Ethnographies of Everyday Life After Communism (2011), 2-3. Note the author states it as “I remember,” and the wording is not verbatim from Sagan's original remark made during a panel discussion in ABC News Viewpoint following the TV movie The Day After (20 Nov 1983).
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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. (The problem does not lend itself to full experimental verification—at least not more than once.)[co-author with American atmospheric chemist Richard P. Turco (1943- )]
— Carl Sagan
A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race (1990), 26.
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The secrets of evolution are death and time—the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations.
— Carl Sagan
Cosmos (1980, 1985), 20.
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The size and age of the Cosmos are beyond ordinary human understanding. Lost somewhere between immensity and eternity is our tiny planetary home.
— Carl Sagan
Cosmos (1981), 4.
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The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge; it has no in the endeavor of science. We do not know in advance who will discover fundamental insights.
— Carl Sagan
In Cosmos (1985), 74.
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The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true. We have a method, and that method helps us to reach not absolute truth, only asymptotic approaches to the truth—never there, just closer and closer, always finding vast new oceans of undiscovered possibilities. Cleverly designed experiments are the key.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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There are many hypotheses in science which are wrong. That's perfectly all right; they're 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
Quoted in Donald R. Prothero and Carl Dennis Buell, Evolution: What the Fossils Say and Why it Matters (2007), 3.
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There is a reward structure in science that is very interesting: Our highest honors go to those who disprove the findings of the most revered among us. So Einstein is revered not just because he made so many fundamental contributions to science, but because he found an imperfection in the fundamental contribution of Isaac Newton.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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There is another approach to the extraterrestrial hypothesis of UFO origins. This assessment depends on a large number of factors about which we know little, and a few about which we know literally nothing. I want to make some crude numerical estimate of the probability that we are frequently visited by extraterrestrial beings.
Now, there is a range of hypotheses that can be examined in such a way. Let me give a simple example: Consider the Santa Claus hypothesis, which maintains that, in a period of eight hours or so on December 24-25 of each year, an outsized elf visits one hundred million homes in the United States. This is an interesting and widely discussed hypothesis. Some strong emotions ride on it, and it is argued that at least it does no harm.
We can do some calculations. Suppose that the elf in question spends one second per house. This isn't quite the usual picture—“Ho, Ho, Ho,” and so on—but imagine that he is terribly efficient and very speedy; that would explain why nobody ever sees him very much-only one second per house, after all. With a hundred million houses he has to spend three years just filling stockings. I have assumed he spends no time at all in going from house to house. Even with relativistic reindeer, the time spent in a hundred million houses is three years and not eight hours. This is an example of hypothesis-testing independent of reindeer propulsion mechanisms or debates on the origins of elves. We examine the hypothesis itself, making very straightforward assumptions, and derive a result inconsistent with the hypothesis by many orders of magnitude. We would then suggest that the hypothesis is untenable.
We can make a similar examination, but with greater uncertainty, of the extraterrestrial hypothesis that holds that a wide range of UFOs viewed on the planet Earth are space vehicles from planets of other stars.
— Carl Sagan
The Cosmic Connection: An Extraterrestrial Perspective (1973), 200.
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Think of how many religions attempt to validate themselves with prophecy. Think of how many people rely on these prophecies, however vague, however unfulfilled, to support or prop up their beliefs. Yet has there ever been a religion with the prophetic accuracy and reliability of science? ... No other human institution comes close.
— Carl Sagan
The Demon-Haunted World: Science as a Candle in the Dark (1997), 30.
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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. They avoid rather than confront the world. But those with the courage to explore the weave and structure of the Cosmos, even where it differs profoundly from their wishes and prejudices, will penetrate its deepest mysteries.
— Carl Sagan
Cosmos (1985), 275.
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Too much openness and you accept every notion, idea, and hypothesis—which is tantamount to knowing nothing. Too much skepticism—especially rejection of new ideas before they are adequately tested—and you're not only unpleasantly grumpy, but also closed to the advance of science. A judicious mix is what we need.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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We are a way for the cosmos to know itself.
— Carl Sagan
From Carl Sagan's narration on a promotional video for the television series Cosmos.
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We are made of starstuff.
— Carl Sagan
Cosmos (1980), 190.
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We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology
— Carl Sagan
In M. P. Singh, Quote Unquote: A Handbook of Quotations (2007), 262, but without source reference. Although widely seen, webmaster has found no authoritative reference or primary print source for its origin. Can you help?
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What does it mean for a civilisation to be a million years old? We have had radio telescopes and spaceships for a few decades; our technical civilisation is a few hundred years old ... an advanced civilisation millions of years old is as much beyond us as we are beyond a bushbaby or a macaque
— Carl Sagan
'Star Makers', Cosmos (Feb 2006).
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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
The Dragons of Eden: Speculations on the Evolution of Human Intelligence (1977, 1986), 3.
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Who are we? We find that we live on an insignificant planet of a humdrum star lost between two spiral arms in the outskirts of a galaxy, tucked away in some forgotten corner of a universe in which there are far more galaxies than people.
— Carl Sagan
Cosmos (1985), 160.
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Widespread intellectual and moral docility may be convenient for leaders in the short term, but it is suicidal for nations in the long term. One of the criteria for national leadership should therefore be a talent for understanding, encouraging, and making constructive use of vigorous criticism.
— Carl Sagan
Billions and Billions: Thoughts on Life and Death at the Brink of the Millenium (1998), 189.
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[I]magine you want to know the sex of your unborn child. There are several approaches. You could, for example, do what the late film star ... Cary Grant did before he was an actor: In a carnival or fair or consulting room, you suspend a watch or a plumb bob above the abdomen of the expectant mother; if it swings left-right it's a boy, and if it swings forward-back it's a girl. The method works one time in two. Of course he was out of there before the baby was born, so he never heard from customers who complained he got it wrong. ... But if you really want to know, then you go to amniocentesis, or to sonograms; and there your chance of being right is 99 out of 100. ... If you really want to know, you go to science.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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[N]o scientist likes to be criticized. ... But you don't reply to critics: "Wait a minute, wait a minute; this is a really good idea. I'm very fond of it. It's done you no harm. Please don't attack it." That's not the way it goes. The hard but just rule is that if the ideas don't work, you must throw them away. Don't waste any neurons on what doesn't work. Devote those neurons to new ideas that better explain the data. Valid criticism is doing you a favor.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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[Science] 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. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. ... The obvious is sometimes false; the unexpected is sometimes true.
— Carl Sagan
Cosmos (1985), 277.
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[When I was a child] I grew up in Brooklyn, New York, and I was a street kid. ... [T]here was one aspect of that environment that, for some reason, struck me as different, and that was the stars. ... I could tell they were lights in the sky, but that wasn't an explanation. I mean, what were they? Little electric bulbs on long black wires, so you couldn't see what they were held up by? What were they? ... My mother said to me, "Look, we've just got you a library card ... get out a book and find the answer." ... It was in there. It was stunning. The answer was that the Sun was a star, except very far away. ... The dazzling idea of a universe vast beyond imagining swept over me. ... I sensed awe.
— Carl Sagan
In 'Wonder and Skepticism', Skeptical Enquirer (Jan-Feb 1995), 19, No. 1.
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See also:
  • todayinsci icon 9 Nov - short biography, births, deaths and events on date of Sagan's birth.
  • todayinsci icon Carl Sagan - context of quote A Subject Called Chemistry - Medium image (500 x 350 px)
  • todayinsci icon Carl Sagan - context of quote A Subject Called Chemistry - Large image (800 x 600 px)
  • book icon Carl Sagan: A Life in the Cosmos, by William Poundstone. - book suggestion.
  • booklist icon Booklist for Carl Sagan.

Carl Sagan Thumbnail 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. (1987) -- Carl Sagan
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- 100 -
Sophie Germain
Gertrude Elion
Ernest Rutherford
James Chadwick
Marcel Proust
William Harvey
Johann Goethe
John Keynes
Carl Gauss
Paul Feyerabend
- 90 -
Antoine Lavoisier
Lise Meitner
Charles Babbage
Ibn Khaldun
Euclid
Ralph Emerson
Robert Bunsen
Frederick Banting
Andre Ampere
Winston Churchill
- 80 -
John Locke
Bronislaw Malinowski
Bible
Thomas Huxley
Alessandro Volta
Erwin Schrodinger
Wilhelm Roentgen
Louis Pasteur
Bertrand Russell
Jean Lamarck
- 70 -
Samuel Morse
John Wheeler
Nicolaus Copernicus
Robert Fulton
Pierre Laplace
Humphry Davy
Thomas Edison
Lord Kelvin
Theodore Roosevelt
Carolus Linnaeus
- 60 -
Francis Galton
Linus Pauling
Immanuel Kant
Martin Fischer
Robert Boyle
Karl Popper
Paul Dirac
Avicenna
James Watson
William Shakespeare
- 50 -
Stephen Hawking
Niels Bohr
Nikola Tesla
Rachel Carson
Max Planck
Henry Adams
Richard Dawkins
Werner Heisenberg
Alfred Wegener
John Dalton
- 40 -
Pierre Fermat
Edward Wilson
Johannes Kepler
Gustave Eiffel
Giordano Bruno
JJ Thomson
Thomas Kuhn
Leonardo DaVinci
Archimedes
David Hume
- 30 -
Andreas Vesalius
Rudolf Virchow
Richard Feynman
James Hutton
Alexander Fleming
Emile Durkheim
Benjamin Franklin
Robert Oppenheimer
Robert Hooke
Charles Kettering
- 20 -
Carl Sagan
James Maxwell
Marie Curie
Rene Descartes
Francis Crick
Hippocrates
Michael Faraday
Srinivasa Ramanujan
Francis Bacon
Galileo Galilei
- 10 -
Aristotle
John Watson
Rosalind Franklin
Michio Kaku
Isaac Asimov
Charles Darwin
Sigmund Freud
Albert Einstein
Florence Nightingale
Isaac Newton