Something bad happened on both Mars with its dried-up watercourses and Venus with its runaway greenhouse effect. Could something bad happen on Earth too? Our species currently turns row upon row of environmental knobs, without much regard to long-term consequences.

No one wants to die, and no one wants to die poor. These are the two fundamental truths that transcend culture, they transcend politics, they transcend economic cycles.

Where did the concept of "without borders" come from? No one had that concept until you saw Earth from space, illustrated not by a mapmaker who's color-coding political boundaries; it's illustrated by nature itself and there's land, there's ocean, there's atmosphere.

It's progress I think, that science has joined philosophy, metaphysics & religion as subjects drunk people argue about in bars.

If each dead person became a ghost, there'd be more than 100 billion of them haunting us all. Creepy, but cool.

Darwin's theory of evolution is a framework by which we understand the diversity of life on Earth. But there is no equation sitting there in Darwin's 'Origin of Species' that you apply and say, 'What is this species going to look like in 100 years or 1,000 years?' Biology isn't there yet with that kind of predictive precision.

I don't have an issue with what you do in the church but I'm going to be up in your face if you're going to knock on my science classroom and tell me I got to teach what you're teaching in your Sunday school. That's when we're going to fight... There's no tradition of scientists knocking down the Sunday school door, telling the preacher 'that might not necessarily be true.' That's never happened. There are no scientists picketing out front of churches. There's been this coexistence forever, so to have religious communities knocking down the science door, there's something wrong there.