Carl Sagan

The brain is the organ that evolves itself, par excellence.

We have always aspired to the stars, but now we are closer than ever to reaching them.

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

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

Every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.

The joy of looking and comprehending is nature's most beautiful gift.

Humans are very good at dreaming, although you'd never know it from your television.

The information content of just one sperm cell, a microscopic droplet of semen, is about the same as the total writings of all the world's libraries, or the equivalent of about a trillion trillion letters.

What a marvelous cooperative arrangement - plants and animals each inhaling each other's exhalations, a kind of planet-wide mutual mouth-to-stoma resuscitation, the entire elegant cycle powered by a star 93 million miles away.

Our ancestors worshipped the Sun, and they were not that foolish. It makes sense to revere the Sun and the stars, for we are their children.

The first principle is that you must not fool yourself - and you are the easiest person to fool.

Finding the occasional straw of truth amid the faggot of lies wouldn't validate the erroneous method of looking for truth in the virtual sand heaps of secret documents.

I don't think the human mind can comprehend the past and the future.

The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge and there is no place for it in the endeavor of science.

When we recognize that we are all, in a very real sense, the product of the universe, it becomes clear that we are all connected.

The idea that God is an oversized anthill, who created the universe and then went to sleep, is ridiculous. But that is the kind of thing that people say.

Modern science should be understood not as a collection of facts, but as a method of inquiry.

We are like butterflies who flutter for a day and think it is forever.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate.

It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring.