1,131 Quotes by Carl Sagan

Be grateful everyday for the brief but magnificent opportunity that life provides.

For all I know we may be visited by a different extraterrestrial civilization every second Tuesday, but there's no support for this appealing idea. The extraordinary claims are not supported by extraordinary evidence.

Science is a way of thinking much more than it is a body of knowledge. Its goal is to find out how the world works, to seek what regularities there may be, to penetrate to the connections of things-from subatomic particles, which may be the constituents of all matter, to living organisms, the human social community, and thence to the cosmos as a whole.

Ask courageous questions. Do not be satisfied with superficial answers. Be open to wonder and at the same time subject all claims to knowledge, without exception, to intense skeptical scrutiny. Be aware of human fallibility. Cherish your species and your planet.

With insufficient data it is easy to go wrong.

Accommodation to change, the thoughtful pursuit of alternative futures are keys to the survival of civilization and perhaps of the human species.

A googolplex is precisely as far from infinity as is the number 1... no matter what number you have in mind, infinity is larger still.

We humans look rather different from a tree. Without a doubt we perceive the world differently than a tree does. But down deep, at the molecular heart of life, the trees and we are essentially identical.

If chimpanzees have consciousness, if they are capable of abstractions, do they not have what until now has been described as 'human rights'? How smart does a chimp have to be before killing him constitutes murder?