I was recently on a tour of Latin America, and the only regret I have was that I didn't study Latin harder in school so I could converse with those people.

I understand that being optimistic in this age is challenging, but I am optimistic nonetheless.

Science has a culture that is inherently cautious and that is normally not a bad thing. You could even say conservative, because of the peer review process and because the scientific method prizes uncertainty and penalises anyone who goes out on any sort of a limb that is not held in place by abundant and well-documented evidence.

Hey, you know what, I've gotta go on that 'Letterman' show. That show is so lame.

For a free country to continue thriving, there have to be regular reforms, because any society, any economy that stays in place, you're going to see repeated attempts to exploit the openings for twisting policy to the advantage of those who already have wealth and power.

Every day we put another 110 million tons of global warming pollution into the sky as if it's an open sewer, and it's still building up. And the scientists tell us it's a race against time. We've stabilized emissions globally now for the last three years, but they need to start coming down quickly. We've got the momentum, we've got the wind in our sails, we're gonna win this.

The Internet empowers individuals to play a more active role in the political process, as Obama's campaign has manifested.