Carl took on the military-industrial complex. He campaigned around the world for an end to the production of weapons of mass destruction. To him it was a perversion of science.

Interviewer: "Didn't [Sagan] want to believe?" Druyan: "He didn't want to believe. He wanted to know.

We batter this planet as if we had someplace else to go.

People think that if you are a scientist you have to give up that joy of discovery, that passion, that sense of the great romance of life. I say thats completely opposite of the truth.

I guess I so desperately want to see us put this planet right. It's so horrifying to me that a fifth of us are starving every night, and that forty thousand children die every single day.

Knowing a deep thing well, which is what science asks of its practitioners, is an empowerment that is very profound. It's a liberation.

The only gratification that science denies to us is deception.