Sagan: "We've arranged a civilization in which most crucial elements profoundly depend on science and technology."

Sagan: "We start out a million years ago in a small community on some grassy plain; we hunt animals, have children, and develop a rich social, sexual, and intellectual life, but we know almost nothing about our surroundings."

Sagan: "We are the representatives of the cosmos; we are an example of what hydrogen atoms can do, given 15 billion years of cosmic evolution."

Sagan: "We hunger to understand, so we invent myths about how we imagine the world is constructed - and they're, of course, based upon what we know, which is ourselves and other animals. So we make up stories about how the world was hatched from a cosmic egg or created after the mating of cosmic deities or by some fiat of a powerful being."

Sagan: "In our obscurity - in all this vastness - there is no hint that help will come from elsewhere to save us from ourselves. It is up to us."

Sagan: "Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark."

Sagan: "Science is a way of thinking much more than it is a body of knowledge."

Sagan: "We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces."

Sagan: "Extinction is the rule. Survival is the exception."

Sagan: "We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology."

Sagan: "Imagination will often carry us to worlds that never were. But without it we go nowhere."

Sagan: "Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people."

Sagan: "The brain is like a muscle. When it is in use we feel very good. Understanding is joyous."

Sagan: "There is a wide, yawning black infinity. In every direction, the extension is endless; the sensation of depth is overwhelming. And the darkness is immortal. Where light exists, it is pure, blazing, fierce; but light exists almost nowhere, and the blackness itself is also pure and blazing and fierce."

Sagan: "The universe is not required to be in perfect harmony with human ambition."

Sagan: "But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown."

Sagan: "Absence of evidence is not evidence of absence."

Sagan: "Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark."

Sagan: "No other planet in the solar system is a suitable home for human beings; it's this world or nothing. That's a very powerful perception."