It takes a fearless, unflinching love and deep humility to accept the universe as it is. The most effective way he knew to accomplish that, the most powerful tool at his disposal, was the scientific method, which over time winnows out deception. It can't give you absolute truth because science is a permanent revolution, always subject to revision, but it can give you successive approximations of reality.

My knowledge of science came from being with Carl, not from formal academic training. Carl gave me a thrilling tutorial in science and math that lasted the 20 years we were together.

If you have a beating heart, that's good enough.

Science has the cold facts, but lacks religion's social organization and ability to inspire that moves people to act.

This planet seems to be in such sorry shape. And I can't ever think about the rest of the universe without coming back home and thinking what the implications for life here would be if we were to really have some definitive proof of extraterrestrial life.

A lot of people have this ego need that makes them want to believe that Earth is the center of the universe and humans are the most important species, the supreme expression of creation.

I remember that one time Carl Sagan was giving a talk, and he spelled out, in a kind of withering succession, these great theories of demotion that science has dealt us, all of the ways in which science is telling us we are not who we would like to believe we are. At the end of it, a young man came up to him and he said: "What do you give us in return? Now that you've taken everything from us? What meaning is left, if everything that I've been taught since I was a child turns out to be untrue?" Carl looked at him and said, Do something meaningful.