The whole point of science is that most of it is uncertain. That's why science is exciting--because we don't know. Science is all about things we don't understand. The public, of course, imagines science is just a set of facts. But it's not. Science is a process of exploring, which is always partial. We explore, and we find out things that we understand. We find out things we thought we understood were wrong. That's how it makes progress.

The marketplace judges technologies by their practical effectiveness, by whether they succeed or fail to do the job they are designed to do.

Ethical progress is the only cure for the damage done by scientific progress.

I'm happy that I've raised six kids, and not one of them is a Ph.D.

The brain, being analog, is able to grasp images so much better. The brain is just designed for comparing images and some patterns - patterns in space and patterns in time - which we do amazingly well. Computers can do it, too, but not in anything like the same kind of flexibility.

Boiled down to one sentence, my message is the unboundedness of life and the unboundedness of human destiny.

It's not going to be just humans colonizing space, it's going to be life moving out from the Earth, moving it into its kingdom. And the kingdom of life, of course, is going to be the universe.