Carl Sagan Quotes

402 Sourced Quotes

This is Phobos... Its mean density is known, and it is consistent with organic matter. Deimos... same story.

Carl Sagan
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
A googolplex is precisely as far from infinity as is the number 1... no matter what number you have in mind, infinity is larger still.

Carl Sagan
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.

Carl Sagan
Something dreadful happens to students between first and twelfth grades, and it's not just puberty.

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

Carl Sagan
If I were to propose to you that my arm could be in this position or in that position but it would be forbidden by the laws of nature to be in some intermediate position, that would likely strike you as absurd, as contrary to experience. And yet on the subatomic level, there is a quantization of energy and position and momentum. The reason that it seems counterintuitive is that is that we are not ordinarily down at the level of the very small, where quantum effects dominate.

Carl Sagan
We all have a thirst for wonder. It's a deeply human quality. Science and religion are both bound up with it. What I'm saying is, you don't have to make stories up, you don't have to exaggerate. There's wonder and awe enough in the real world. Nature's a lot better at inventing wonders than we are.

Carl Sagan
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
In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist's signature.

Carl Sagan
It's hard to kill a creature once it lets you see its consciousness.

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

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

Carl Sagan
We've tended in our cosmologies to make things familiar. Despite all our best efforts, we've not been very inventive. In the West, Heaven is placid and fluffy, and Hell is like the inside of a volcano. In many stories, both realms are governed by dominance hierarchies headed by gods or devils. Monotheists talked about the king of kings. In every culture we imagined something like our own political system running the Universe. Few found the similarity suspicious.

Carl Sagan
This planet is run by crazy people. Remember what they have to do to get where they are. Their perspective is so narrow, so... brief. A few years. In the best of them a few decades. They care only about the time they are in power.

Carl Sagan
You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe.

Carl Sagan
National boundaries are not evident when we view the Earth from space. Fanatical ethnic or religious or national chauvinisms are a little difficult to maintain when we see our planet as a fragile blue crescent fading to become an inconspicuous point of light against the bastion and citadel of the stars.

Carl Sagan
Every thinking person fears nuclear war and every technological nation plans for it. Everyone knows it's madness, and every country has an excuse.

Carl Sagan
For as long as there been humans we have searched for our place in the cosmos. Where are we? Who are we? We find that we live on an insignificant planet of a hum-drum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people. This perspective is a courageous continuation of our penchant for constructing and testing mental models of the skies; the Sun as a red-hot stone, the stars as a celestial flame, the Galaxy as the backbone of night.

Carl Sagan
I think people in power have a vested interest to oppose critical thinking.

Carl Sagan
There is a place with four suns in the sky — red, white, blue, and yellow; two of them are so close together that they touch, and star-stuff flows between them. I know of a world with a million moons. I know of a sun the size of the Earth — and made of diamond. There are atomic nuclei a few miles across which rotate thirty times a second. There are tiny grains between the stars, with the size and atomic composition of bacteria. There are stars leaving the Milky Way, and immense gas clouds falling into it. There are turbulent plasmas writhing with X- and gamma-rays and mighty stellar explosions. There are, perhaps, places which are outside our universe. The universe is vast and awesome, and for the first time we are becoming a part of it.

Carl Sagan
What distinguishes our species is thought. The cerebral cortex is in a way a liberation. We need no longer be trapped in the genetically inherited behavior patterns of lizards and baboons: territoriality and aggression and dominance hierarchies. We are each of us largely responsible for what gets put in to our brains. For what as adults we wind up caring for and knowing about. No longer at the mercy of the reptile brain we can change ourselves. Think of the possibilities.

Carl Sagan
Curiosity and the urge to solve problems are the emotional hallmarks of our species...

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
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.

Carl Sagan
Many of the dangers we face indeed arise from science and technology — but, more fundamentally, because we have become powerful without becoming commensurately wise. The world-altering powers that technology has delivered into our hands now require a degree of consideration and foresight that has never before been asked of us.

Carl Sagan
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.

Carl Sagan
Black holes may be apertures to elsewhen. Were we to plunge down a black hole, we would re-emerge, it is conjectured, in a different part of the universe and in another epoch of time.... Black holes may be the entrances to Wonderland. But are there Alices or white rabbits?

Carl Sagan
The price we pay for anticipation of the future is anxiety about it

Carl Sagan
It is too late to be shy and hesitant. We have announced our presence to the cosmos — in a backward and groping and unrepresentative manner, to be sure — but here we are!

Carl Sagan