Quotes from Carl Sagan

Sakharov in the Cold War year 1968 boldly wrote—in a book published in the West and widely distributed in samizdat in the USSR—"Freedom of thought is the only guarantee against an infection of peoples by the mass myths, which, in the hands of treacherous hypocrites and demagogues, can be transformed into bloody dictatorships

If the aliens would only keep all the folks they abduct, our world would be a little saner.

The word religion comes from the Latin for binding together, to connect that which has been sundered apart. It's a very interesting concept. And in this sense of seeking the deepest interrelations among things that superficially appear to be sundered, the objectives of religion and science, I believe, are identical or very nearly so. But the question has to do with the reliability of the truths claimed by the two fields and the methods of approach.

Science requires us to be freed of gross superstition and gross injustice both. Often, superstition and injustice are imposed by the same ecclesiastical and secular authorities, working hand in glove. It is no surprise that political revolutions, scepticism about religion, and the rise of science might go together.

Like charges, charges of the same sign, strongly repel one another. We can think of it as a dedicated mutual aversion to their own kind, a little as if the world were densely populated by anchorites and misanthropes.

The early Sumerian pictograph for god was an asterisk, the symbol of the stars. The early Aztec word for god was Teotl, and its glyph was a representation of the Sun. The heavens were called Teoatl, the godsea, the cosmic ocean.

At the Stourbridge Fair in 1663, at age twenty, he purchased a book on astrology, "out of a curiosity to see what there was in it." He read it until he came to an illustration which he could not understand, because he was ignorant of trigonometry. So he purchased a book on trigonometry but soon found himself unable to follow the geometrical arguments. So he found a copy of Euclid's Elements of Geometry, and began to read. Two years later he invented the differential calculus.

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.

600 million years ago, the monopolizing grip of the algae was broken and an enormous proliferation of new lifeforms emerged, an event called the Cambrian explosion. Life had arisen almost immediately after the origin of the Earth, which suggests that life may be an inevitable chemical process on an Earth-like planet.

In every government on earth is some trace of human weakness, some germ of corruption and degeneracy, which cunning will discover and wickedness insensibly open, cultivate and improve. Every government degenerates when trusted to the rulers of the people alone. The people themselves therefore are its only safe depositories. And to render even them safe, their minds must be improved

From the shadow length in Alexandria, the angle A can be measured. But from simple geometry ("if two parallel straight lines are transected by a third line, the alternate interior angles are equal"), angle B equals angle A. So by measuring the shadow length in Alexandria, Eratosthenes concluded that Syene was A = B = 7° away on the circumference of the Earth.

Science is an ongoing process. It never ends. 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

This new project of hers was in experimental theology. But so is all of science she thought.

If people knew how many people, especially the very rich and powerful ones, went to psychics, their jaws would drop through the floor

abandoning science is the road back into poverty and backwardness

If ever there was an avian candidate for psychotherapy, the male blue heron is our nominee.

To what purpose should I trouble myself in searching out the secrets of the stars, having death or slavery continually before my eyes? —A question put to Pythagoras by Anaximenes (c. 600 B.C.), according to Montaigne

the metaphysicist has no laboratory.

The ancient Aztec and the ancient Greek words for "God" are nearly the same. Is this evidence of some contact or commonality between the two civilizations, or should we expect occasional such coincidences between two wholly unrelated languages merely by chance? Or could, as Plato thought in the Cratylus, certain words be built into us from birth?

We are made of star-stuff. Our bodies are made of star-stuff. There are pieces of star within us all.

neither we nor our planet enjoys a privileged position in Nature. This insight has since been applied upward to the stars, and sideways to many subsets of the human family, with great success and invariable opposition. It has been responsible for major advances in astronomy, physics, biology, anthropology, economics and politics. I wonder if its social extrapolation is a major reason for attempts at its suppression.

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.

In manned Earth orbital flights, still other problems arise. Consider a religious Muslim or Jew circling the Earth once every ninety minutes. Is he obligated to celebrate the Sabbath every seventh orbit? Spaceflight provides access to environments very different from those in which we and our customs have grown up.

When it gets complicated, that's usually because the world is complicated—or because we're complicated. When we shy away from it because it seems too difficult (or because we've been taught so poorly), we surrender the ability to take charge of our future. We are disenfranchised. Our self-confidence erodes.