The uniqueness of humans has been claimed on many grounds, but most often because of our tool-making, culture, language, reason and morality. We have them, the other animals don't, and -- so the argument goes -- that's that.

I would be very ashamed of my civilization if we did not try to find out if there is life in outer space.

Curiosity and the urge to solve problems are the emotional hallmarks of our species.

Man is the matter of the cosmos, contemplating itself.

There are many hypotheses in science which are wrong. That’s perfectly all right: it’s the aperture to finding out what’s right. Science is a self-correcting process.

By exploring other worlds we safeguard this one. By itself, I think this fact more than justifies the money our species has spent in sending ships to other worlds. It is our fate to live during one of the most perilous and, at the same time, one of the most hopeful chapters in human history.

We are all star stuff.