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Home > Dictionary of Science Quotations > Scientist Names Index S > Carl Sagan Quotes > Idea

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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.



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.
Science quotes on:  |  Attitude (51)  |  Balance (45)  |  Contradiction (46)  |  Idea (457)  |  Nonsense (33)  |  Scepticism (5)  |  Science (1741)  |  Scrutiny (13)  |  Truth (764)

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
Concluding paragraph, 'Can We know the Universe? Reflections on a Grain of Salt', Broca's Brain (1979, 1986), 21.
Science quotes on:  |  Being (39)  |  Boredom (8)  |  Coincidence (12)  |  Dullness (4)  |  Heaven (132)  |  Ideal (57)  |  Inhabitation (2)  |  Knowledge (1148)  |  Mind (576)  |  Theologian (14)  |  Thinking (223)  |  Universe (615)  |  Unknown (92)  |  Weak (37)

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.
Science quotes on:  |  Belief (421)  |  Circuit (13)  |  Discovery (601)  |  Idea (457)  |  Intellect (158)  |  Person (126)  |  Resonance (2)

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 seems to me what is called for is an exquisite balance between two conflicting needs: the most skeptical scrutiny of all hypotheses that are served up to us and at the same time a great openness to new ideas … If you are only skeptical, then no new ideas make it through to you … On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in you, then you cannot distinguish the useful ideas from the worthless ones.
— Carl Sagan
In 'The Burden of Skepticism', Skeptical Inquirer (Fall 1987), 12, No. 1.
Science quotes on:  |  Balance (45)  |  Conflicting (3)  |  Distinguish (35)  |  Exquisite (13)  |  Gullibility (2)  |  Hypothesis (231)  |  Idea (457)  |  Need (226)  |  New (380)  |  On The Other Hand (17)  |  Openness (5)  |  Scrutiny (13)  |  Sense (258)  |  Skeptical (7)  |  Useful (70)  |  Worthless (15)

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.
Science quotes on:  |  Bay Of Pigs (2)  |  Dollar (19)  |  Fiasco (2)  |  Flight (56)  |  Yuri Alekseyevich Gagarin (13)  |  Idea (457)  |  John F. Kennedy (43)  |  Moon (174)  |  Objective (51)  |  Orbit (64)  |  Politics (81)  |  Reason (343)  |  Response (27)  |  Scientist (459)  |  Spending (8)

Some ideas are better than others. The machinery for distinguishing them is an essential tool in dealing with the world and especially in dealing with the future. And it is precisely the mix of these two modes of thought [skeptical scrutiny and openness to new ideas] that is central to the success of science.
— Carl Sagan
In 'The Burden of Skepticism', Skeptical Inquirer (Fall 1987), 12, No. 1.
Science quotes on:  |  Better (146)  |  Distinguish (35)  |  Essential (92)  |  Future (256)  |  Idea (457)  |  Machinery (25)  |  Mix (13)  |  New (380)  |  Openness (5)  |  Science (1741)  |  Scrutiny (13)  |  Skepticism (18)  |  Success (215)  |  Thought (400)  |  Tool (71)

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.
Science quotes on:  |  Argument (60)  |  Better (146)  |  Cure (88)  |  Fallacy (19)  |  Idea (457)  |  Suppression (6)

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.
Science quotes on:  |  Belief (421)  |  Contention (7)  |  Contradiction (46)  |  Hypothesis (231)  |  Idea (457)  |  Inspiration (52)  |  Possibility (101)  |  Religion (214)  |  Revelation (29)  |  Scepticism (5)  |  Truth (764)  |  Wrong (119)

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.
Science quotes on:  |  Advance (128)  |  Common (96)  |  Discovery (601)  |  Endeavor (35)  |  Fundamental (124)  |  Idea (457)  |  Insight (60)  |  Knowledge (1148)  |  Path (66)  |  Politics (81)  |  Religion (214)  |  Science (1741)  |  Suppression (6)  |  Uncomfortable (3)

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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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 live on an obscure hunk of rock and metal circling a humdrum sun, which is on the outskirts of a perfectly ordinary galaxy comprised of 400 billion other suns, which, in turn, is one of some hundred billion galaxies that make up the universe, which, current thinking suggests, is one of a huge number—perhaps an infinite number—of other closed-off universes. From that perspective, the idea that we’re at the center, that we have some cosmic importance, is ludicrous.
— Carl Sagan
From interview with Linda Obst in her article 'Valentine to Science', in Interview (Feb 1996). Quoted and cited in Tom Head (ed.), Conversations with Carl Sagan (2006), ix, and cited on p.xix.
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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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[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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Carl Sagan quote Advances in medicine and agriculture
A bean farmer checks her crop in Congo. Photo by Neil Palmer (CIAT). CC2.0 (source)

See also:
  • 9 Nov - short biography, births, deaths and events on date of Sagan's birth.
  • Carl Sagan - context of quote A Subject Called Chemistry - Medium image (500 x 350 px)
  • Carl Sagan - context of quote A Subject Called Chemistry - Large image (800 x 600 px)
  • Carl Sagan - context of quote “Advances in medicine and agriculture” - Medium image (500 x 250 px)
  • Carl Sagan - context of quote “Advances in medicine and agriculture” - Large image (800 x 400 px)
  • Carl Sagan: A Life in the Cosmos, by William Poundstone. - book suggestion.
  • 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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