Carl Sagan

Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. ”

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

I've written a number of books that have to do with the evolution of humans, human intelligence, human emotions. ”

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. ”

You probably don't need more weapons than what's required to destroy every city on earth. There's only 2,300 cities. So, the United States, by that criteria, only needs 2,300 nuclear weapons - well, we've got more than 25,000! ”

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

The boundary between space and the earth is purely arbitrary. And I'll probably always be interested in this planet - it's my favorite. ”

We are not without empathetic terror when we open Pascal's 'Pensees' and read, 'I am the great silent spaces between worlds.' ”

Even these stars, which seem so numerous, are as sand, as dust - or less than dust - in the enormity of the space in which there is nothing. ”

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. ”