Top 500 Carl Sagan Quotes (2025 Update)
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251. “But down deep, at the molecular heart of life we’re essentially identical to trees.”

— Carl Sagan

252. “All inquiries carry with them some element of risk.”

— Carl Sagan

253. “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.”

— Carl Sagan

254. “Clutching our crystals and religiously consulting our horoscopes, our critical faculties in steep decline, unable to distinguish between what’s true and what feels good, we slide, almost without noticing, into superstition and darkness.”

— Carl Sagan

255. “It’s sometimes easier to reject strong evidence than to admit that we’ve been wrong, this is information about ourselves worth having.”

— Carl Sagan

256. “Cosmos is closed and light cannot escape from it, then it may be perfectly correct to describe the universe as a black hole. If you wish to know what it is like inside a black hole, look around you.”

— Carl Sagan

257. “Every cell is a triumph of natural selection, and we’re made of trillions of cells. Within us, is a little universe.”

— Carl Sagan

258. “The trapdoor beneath our feet swings open. We find ourselves in bottomless free fall. We are lost in a great darkness, and there’s no one to send out a search party. Given so harsh a reality, of course we’re tempted to shut our eyes and pretend that we’re safe and snug at home, that the fall is only a bad dream.”

— Carl Sagan

259. “In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.”

— Carl Sagan

260. “Man is a transitional animal. He is not the climax of creation.”

— Carl Sagan

261. “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.”

— Carl Sagan

262. “If the greenhouse effect is a blanket in which we wrap ourselves to keep warm, nuclear winter kicks the blanket off.”

— Carl Sagan

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

— Carl Sagan

264. “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

265. “Which aspects of our nature will prevail is uncertain, particularly when our visions and prospects are bound to one small part of the small planet Earth. But up there in the Cosmos an inescapable perspective awaits.”

— Carl Sagan

266. “The visions we offer our children shape the future.”

— Carl Sagan

267. “There is a report that says that kids who watch violent TV programs tend to be more violent when they grow up. But did the TV cause the violence, or do violent children preferentially enjoy watching violent programs?”

— Carl Sagan

268. “Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”

— Carl Sagan

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

— Carl Sagan

270. “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.”

— Carl Sagan

271. “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

272. “In a complex universe, in a society undergoing unprecedented change, how can we find the truth if we are not willing to question everything and to give a fair hearing to everything?”

— Carl Sagan

273. “With insufficient data it is easy to go wrong.”

— Carl Sagan

274. “The many sorrows of our recent history suggest that we humans have a learning disability.”

— Carl Sagan

275. “If our long-term survival is at stake, we have a basic responsibility to our species to venture to other worlds. Sailors on a becalmed sea, we sense the stirring of a breeze.”

— Carl Sagan

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

— Carl Sagan

277. “There are many hypotheses in science which are wrong. That’s perfectly all right: it’s the aperture to finding out what’s right. Science is a self-correcting process.”

— Carl Sagan

278. “When permitted to listen to alternative opinions and engage in substantive debate, people have been known to change their minds. It can happen.”

— Carl Sagan

279. “I am often amazed at how much more capability and enthusiasm for science there is among elementary school youngsters than among college students.”

— Carl Sagan

280. “It’s hard to kill a creature once it lets you see its consciousness.”

— Carl Sagan

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

— Carl Sagan

282. “Not all bits have equal value.”

— Carl Sagan

283. “Our concern for the future can be tested by how well we support our libraries.”

— Carl Sagan

284. “You could just as well say that an agnostic is a deeply religious person with at least a rudimentary knowledge of human fallibility.”

— Carl Sagan

285. “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?”

— Carl Sagan

286. “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.”

— Carl Sagan

287. “A general problem with much of Western theology in my view is that the god portrayed is too small. It is a god of a tiny world and not a god of a galaxy much less of a universe.”

— Carl Sagan

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

— Carl Sagan

289. “The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses.”

— Carl Sagan

290. “The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.”

— Carl Sagan

291. “War is murder writ large.”

— Carl Sagan

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

— Carl Sagan

293. “The surface of the Earth is the shore of the cosmic ocean.”

— Carl Sagan

294. “In exchange for freedom of inquiry, scientists are obliged to explain their work.”

— Carl Sagan

295. “Every aspect of Nature reveals a deep mystery and touches our sense of wonder and awe. 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

296. “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

297. “If you are only skeptical, then no new ideas make it through to you.”

— Carl Sagan

298. “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.”

— Carl Sagan

299. “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?”

— Carl Sagan

300. “Perhaps the depth of love can be calibrated by the number of different selves that are actively involved in a given relationship.”

— Carl Sagan