Carl Sagan Quotes

Pliny suggested that the ostrich, then newly discovered, was the result of a cross between a giraffe and a gnat. (It would, I suppose, have to be a female giraffe and a male gnat.) In practice there must be many such crosses which have not beenattempted because of a certain understandable lack of motivation.

~ Carl Sagan

It is very difficult to evolve by altering the deep fabric of life; any change there is likely to be lethal. But fundamental change can be accomplished by the addition of new systems on top of old ones…Thus evolution by addition and the functional preservation of the preexisting structure must occur for one of two reasons-either the old function is required as well as the new one, or there is no way of bypassing the old system that is consistent with survival.

~ Carl Sagan

The time scale for evolutionary or genetic change is very long. A characteristic period for the emergence of one advanced species from another is perhaps a hundred thousand years; and very often the difference in behavior between closely related species -say, lions and tigers- do not seem very great... But today we do not have ten million years to wait for the next advance. We live in a time when our world is changing at an unprecedented rate. While the changes are largely of our own making, they cannot be ignored. We must adjust and adapt and control, or we perish.

~ Carl Sagan

Our probable ancestors, Homo erectus and Homo habilis -now extinct- are classified as of the same genus (Homo) but of different species, although no one (at least lately) has attempted the appropriate experiments to see if crosses of them with us would produce fertile offspring.

~ Carl Sagan

Curiosity and the urge to solve problems are theemotional hallmarks of our species

~ Carl Sagan

For their surface area, insects weigh very little. A beetle, falling from a high altitude, quickly achieves terminal velocity: air resistance prevents it from falling very fast, and, after alighting on the ground, it will walk away, apparently none the worse for the experience… In contrast, human beings are characteristically maimed or killed by any fall of more than a few dozen feet: because of our size, we weigh too much for our surface area.

~ Carl Sagan

And despite the insignificance of the instant we have so far occupied in cosmic time, it is clear that what happens on and near Earth at the beginning of thesecond cosmic year will depend very much on the scientific wisdom and the distinctly human sensitivity of mankind.

~ Carl Sagan

The sleeping style of each organism is exquisitelyadapted to the ecology of the animal. It is conceivable that animals who are too stupid to be quiet on their own initiative are, during periods of high risk, immobilized by the implacable arm of sleep.

~ Carl Sagan

Washburn has reported that infant baboons and other young primates appear to be born with only three inborn fears -of falling, snakes, and the dark-corresponding respectively to the dangers posed byNewtonian gravitation to tree-dwellers, by our ancient enemies the reptiles, and by mammalian nocturnal predators, which must have been particularly terrifying for the visually oriented primates.

~ Carl Sagan

How thoroughly the chimps and bonobos have erased the list of purported human distinctions!-self-awareness, language, ideas and their association, reason, trade, play, choice, courage, love and altruism, laughter, concealed ovulation, kissing, face-to-face sex, female orgasm, division of labor, cannibalism, art, music, politics, and featherless bipedalism, besides tool using, tool making, and much else. Philosophers and scientists confidently offer up traits said to be uniquely human, and the apes casually knock them down--toppling the pretension that humans constitute some sort of biological aristocracy among the beings of Earth. Instead, we are more like the nouveau riche, incompletely accommodated to our recent exalted state, insecure about who we are, and trying to put as much distance as possible between us and our humble origins. It's as if our nearest relatives, by their very existence, refute all our explanations and justifications. So as counterweights to human arrogance and pride, it is good for us that there are still apes on Earth.

~ Carl Sagan

The secrets of evolution, are time and death. There's an unbroken thread that stretches from those first cells to us.

~ Carl Sagan

Civilization is a product of the cerebral cortex.

~ Carl Sagan

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 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

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

I would love to believe that when I die I will live again, that some thinking, feeling, remembering part of me will continue. But much as I want to believe that, and despite the ancient and worldwide cultural traditions that assert an afterlife, I know of nothing to suggest that it is more than wishful thinking.The world is so exquisite with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories for which there's little good evidence. Far better it seems to me, in our vulnerability, is to look death in the eye and to be grateful every day for the brief but magnificent opportunity that life provides.

~ Carl Sagan

The Earth is a very small stage in a vast cosmic arena. 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. 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.

~ Carl Sagan

Science cuts two ways, of course; its products can be used for both good and evil. But there's no turning back from science. The early warnings about technological dangers also come from science.

~ Carl Sagan

In addition to Ameslan, chimpanzees and other nonhuman primates are being taught a variety of other gestural languages. And it is just this transition from tongue to hand that has permitted humans to regain the ability-lost, according to Josephus, since Eden-to communicate with the animals.

~ Carl Sagan

Writing is perhaps the greatest of human inventions, binding together people who never knew each other, citizens of distant epochs. Books break the shackles of time. A book is proof that humans are capable of magic.

~ Carl Sagan

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

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

The American and Russian capabilities in space science and technology mesh, they interdigitate. Each is strong where the other is weak. This is a marriage made in heaven - but one that has been surprisingly difficult to consummate.

~ Carl Sagan

The hole in the ozone layer is a kind of skywriting. At first it seemed to spell out our continuing complacency before a witch's brew of deadly perils. But perhaps it really tells of a newfound talent to work together to protect the global environment.

~ Carl Sagan

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

Whatever the reason we first mustered the _Apollo_ program, however mired it was in Cold War nationalism and the instruments of death, the inescapable recognition of the unity and fragility of the Earth is its clear and luminous dividend, the unexpected final gift of _Apollo_. What began in deadly competition has helped us to see that global cooperation is the essential precondition for our survival.Travel is broadening. It's time to hit the road again.

~ Carl Sagan

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

The Apollo pictures of the whole Earth conveyed to multitudes something well known to astronomers: On the scale of the worlds - to say nothing of stars or galaxies - humans are inconsequential, a thin film of life on an obscure and solitary lump of rock and metal

~ Carl Sagan

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.

~ Carl Sagan

Before we invented civilization our ancestors lived mainly in the open out under the sky. Before we devised artificial lights and atmospheric pollution and modern forms of nocturnal entertainment we watched the stars. There were practical calendar reasons of course but there was more to it than that. Even today the most jaded city dweller can be unexpectedly moved upon encountering a clear night sky studded with thousands of twinkling stars. When it happens to me after all these years it still takes my breath away.

~ Carl Sagan

We will know which stars to visit. Our descendants will then skim the light years, the children of Thales and Aristarchus, Leonardo and Einstein.

~ Carl Sagan

Meanwhile the Cosmos is rich beyond measure: the total number of stars in the universe is greater than all the grains of sand on all the beaches of the planet Earth.

~ Carl Sagan

The dangers that we face are part of the process, now well underway, of the unification of the planet--in language, culture, science, and commerce. They are both driven by the identical technological advances--this critical and delicate time coincides with the widespread availability of nuclear weapons. At the present rate of change, it seems likely that in the period between now and 2061, the turning point for the human species will have been reached.If we survive until then, our passage to the next apparition of Halley's Comet should be comparatively easy. That perihelion passage will be in March 2134, when the comet will make an unusually close encounter with the Earth. It will come as close as 0.09AU or 14 million kilometers, less than half the distance of the 1910 encounter. It will then be brighter than the brightest star. If there are those to do the commemorating, the years 2061 and 2134 should be celebrated for the courage, intelligence, and common purpose of a species forced by urgent necessity to come to its senses.

~ Carl Sagan

I find these comparisons particularly poignant: life versus death, hope versus fear. Space exploration and the highly mechanized destruction of people use similar technology and manufacturers, and similar human qualities of organization and daring. Can we not make the transition from automated aerospace killing to automated aerospace exploration of the solar system in which we live?

~ Carl Sagan

The illegality of cannabis is outrageous, an impediment to full utilization of a drug which helps produce the serenity and insight, sensitivity and fellowship so desperately needed in this increasingly mad and dangerous world.

~ Carl Sagan

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

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. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of these modes, whichever one it is, you’re in deep trouble.If you are only skeptical, then no new ideas make it through to you. You never learn anything new. You become a crotchety old person convinced that nonsense is ruling the world. (There is, of course, much data to support you.) But every now and then, maybe once in a hundred cases, a new idea turns out to be on the mark, valid and wonderful. If you are too much in the habit of being skeptical about everything, you are going to miss or resent it, and either way you will be standing in the way of understanding and progress.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 as from the worthless ones.

~ Carl Sagan

There are no forbidden questions in science, no matters to sensitive or delicate to be probed, no sacred truths. That openness to new ideas, combined with the most rigorous, skeptical scrutiny of all ideas, sifts the wheat from the chaff. It makes no difference how smart, august, or beloved you are. You must prove your case in the face of determined, expert criticism. Diversity and debate are valued. Opinions are encouraged to contend–substantively and in depth.

~ Carl Sagan

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

Could we possible manage the next phase of human history without first dealing with this penchant for dehumanizing the adversary?

~ Carl Sagan