1,131 Quotes by Carl Sagan

Might it be possible at some future time, when neurophysiology has advanced substantially, to reconstruct the memories or insight of someone long dead?...It would be the ultimate breach of privacy.

A new consciousness is developing which sees the earth as a single organism and recognizes that an organism at war with itself is doomed. We are one planet. One of the great revelations of the age of space exploration is the image of the earth finite and lonely, somehow vulnerable, bearing the entire human species through the oceans of space and time.

Science is only a Latin word for knowledge

Arguments from authority carry little weight – authorities have made mistakes in the past. They will do so again in the future. Perhaps a better way to say it is that in science there are no authorities; at most, there are experts.

The lifetime of a human being is measured by decades, the lifetime of the Sun is a hundred million times longer. Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their lives in the course of a single day.

The near side of a galaxy is tens of thousands of light-years closer to us than the far side; thus we see the front as it was tens of thousands of years before the back. But typical events in galactic dynamics occupy tens of millions of years, so the error in thinking of an image of a galaxy as frozen in one moment of time is small.

Knowing a great deal is not the same as being smart; intelligence is not information alone but also judgement, the manner in which information is co-ordinated and used. Still, the amount of information to which we have accessed is one index of our intelligence.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

And you are made of a hundred trillion cells. We are, each of us, a multitude.