Top 500 Carl Sagan Quotes (2025 Update)
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401. “One of the central issues in the world population crisis is poverty.”

— Carl Sagan

402. “Ours is the first generation that has grown up with science-fiction ideas.”

— Carl Sagan

403. “In the vastness of the Cosmos there must be other civilizations far older and more advanced than ours.”

— Carl Sagan

404. “All inquires carry with them some element of risk. There is no guarantee that the universe will conform to our predispositions.”

— Carl Sagan

405. “We’ve arranged a civilization in which most crucial elements profoundly depend on science and technology.”

— Carl Sagan

406. “If we do not speak for Earth, who will? If we are not committed to our own survival, who will be?”

— Carl Sagan

407. “There is every reason to think that in the coming years Mars and its mysteries will become increasingly familiar to the inhabitants of the Planet Earth.”

— Carl Sagan

408. “Nature does not always conform to our predispositions and preferences, to what we deem comfortable and easy to understand.”

— Carl Sagan

409. “We’ve arranged a civilization in which most crucial elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster.”

— Carl Sagan

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

— Carl Sagan

411. “It took the Church until 1832 to remove Galileo ’s work from its list of books which Catholics were forbidden to read at the risk of dire punishment of their immortal souls.”

— Carl Sagan

412. “A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism.”

— Carl Sagan

413. “In more than one respect, the exploring of the Solar System and homesteading other worlds constitutes the beginning, much more than the end, of history.”

— Carl Sagan

414. “All colours are arbitrary.”

— Carl Sagan

415. “Our intelligence is imperfect, surely, and newly arisen; the ease with which it can be sweet-talked, overwhelmed, or subverted by other hardwired propensities – sometimes themselves disguised as the cool light of reason – is worrisome.”

— Carl Sagan

416. “Cleverly designed experiments are the key.”

— Carl Sagan

417. “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.”

— Carl Sagan

418. “La causa de la miseria humana evitable no suele ser tanto la estupidez como la ignorancia, particularmente la ignorancia de nosotros mismos.”

— Carl Sagan

419. “If it were widely understood that claims to knowledge require adequate evidence before they can be accepted, there would be no room for pseudoscience.”

— Carl Sagan

420. “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.”

— Carl Sagan

421. “For years I’ve been stressing with regard to UFOs that extraordinary claims require extraordinary evidence.”

— Carl Sagan

422. “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.”

— Carl Sagan

423. “When you look more generally at life on Earth, you find that it is all the same kind of life. There are not many different kinds; there’s only one kind. It uses about fifty fundamental biological building blocks, organic molecules.”

— Carl Sagan

424. “Humans are very good at dreaming, although you’d never know it from your television.”

— Carl Sagan

425. “For a long time the human instinct to understand was thwarted by facile religious explanations.”

— Carl Sagan

426. “We are prodding, challenging, seeking contradictions or small, persistent residual errors, proposing alternative explanations, encouraging heresy. We give our highest rewards to those who convincingly disprove established beliefs.”

— Carl Sagan

427. “We are not smart enough to decide which pieces of knowledge are permissible and which are not.”

— Carl Sagan

428. “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

429. “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.”

— Carl Sagan

430. “What’s the harm of a little mystification? It sure beats boring statistical analyses.”

— Carl Sagan

431. “The understanding of the intent of the artist which I can achieve when high sometimes carries over to when I’m down. This is one of many human frontiers which cannabis has helped me traverse.”

— Carl Sagan

432. “For all I know we may be visited by a different extraterrestrial civilization every second Tuesday, but there’s no support for this appealing idea. The extraordinary claims are not supported by extraordinary evidence.”

— Carl Sagan

433. “If there is as a continuum from self-reproducing molecules, such as DNA, to microbes, and an evolutionary sequence continuum from microbes to humans, why should we imagine that continuum to stop at humans?”

— Carl Sagan

434. “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

435. “I reject the notion that science is by its nature secretive. Its culture and ethos are, and for very good reason, collective, collaborative, and communicative.”

— Carl Sagan

436. “If the press descended, the science would surely suffer.”

— Carl Sagan

437. “Prejudice means literally pre-judgment, the rejection of a contention out of hand, before examining the evidence. Prejudice is the result of powerful emotions, not of sound reasoning.”

— Carl Sagan

438. “In any case, we do not advance the human cause by refusing to consider ideas that make us frightened.”

— Carl Sagan

439. “Apart from the social insects, no other species has been clever enough to invent war It is an institution optimally configured to benefit the alphas.”

— Carl Sagan

440. “Every age has its peculiar folly; some scheme, project, or phantasy into which it plunges, spurred on either by the love of gain, the necessity of excitement, or the mere force of imitation. Failing in these, it has some madness, to which it is goaded by political or religious causes, or both combined.”

— Carl Sagan

441. “Edmund Way Teale in his 1950 book Circle of the Seasons understood the dilemma better: It is morally as bad not to care whether a thing is true or not, so long as it makes you feel good, as it is not to care how you got your money as long as you have got it.”

— Carl Sagan

442. “Cosmos is a Greek word for the order of the universe.”

— Carl Sagan

443. “For ages men had used sticks to club and spear each other – Anaximander of Miletus used the stick to measure time.”

— Carl Sagan

444. “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

445. “If we can’t think for ourselves, if we’re unwilling to question authority, then we’re just putty in the hands of those in power. But if the citizens are educated and form their own opinions, then those in power work for us. In every country, we should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. In the demon-haunted world that we inhabit by virtue of being human, this may be all that stands between us and the enveloping darkness.”

— Carl Sagan

446. “It is precisely our plasticity, our long childhood, that prevents a slavish adherence to genetically programmed behavior in human beings more than in any other species.”

— Carl Sagan

447. “If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.”

— Carl Sagan

448. “Every generation worries that educational standards are decaying. One of the oldest short essays in human history, dating from Sumer some 4,000 years ago, laments that the young are disastrously more ignorant than the generation immediately preceding.”

— Carl Sagan

449. “Every time a scientific paper presents a bit of data, it’s accompanied by an error bar – a quiet but insistent reminder that no knowledge is complete or perfect. It’s a calibration of how much we trust what we think we know. If the error bars are small, the accuracy of our empirical knowledge is high; if the error bars are large, then so is the uncertainty in our knowledge.”

— Carl Sagan

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

— Carl Sagan