Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill.

I believe in the possible. I believe, small though we are, insignificant though we may be, we can reach a full understanding of the universe. You were right when you said you felt small, looking up at all that up there. We are very, very small, but we are profoundly capable of very, very big things.

Computers double their performance every month.

There is a fundamental difference between religion, which is based on authority, [and] science, which is based on observation and reason. Science will win because it works.

It is said that there's no such thing as a free lunch. But the universe is the ultimate free lunch.

Save water. Shower with your girlfriend.

So long as the Universe had a beginning, we could suppose it had a creator. But if the Universe is really completely self-contained, it would have neither beginning or end, it would simply be. What place then for a creator?