The incredible story of progress that is America has always been built by those who ask why, what if, and why not. Our schools must begin instilling that wonder in our children again so that their generation will unite around the next great project of our time, whether it be declaring America energy independent or launching the next great technological revolution.

Part of what's unique about climate change, though, is the nature of some of the opposition to action. It's pretty rare that you'll encounter somebody who says the problem you're trying to solve simply doesn't exist. When President Kennedy set us on a course for the moon, there were a number of people who made a serious case that it wouldn't be worth it; it was going to be too expensive, it was going to be too hard, it would take too long. But nobody ignored the science. I don't remember anybody saying that the moon wasn't there or that it was made of cheese.

When times change, so must we.

We need to reduce our dependence on foreign oil by ending the subsidies for oil companies, and doubling down on clean energy that generates jobs and strengthens our security.

The sweetest sound I know is the Muslim call to prayer.

Because of the Civil Rights movement, new doors of opportunity and education swung open for everybody ... Not just for blacks and whites, but also women and Latinos; and Asians and Native Americans; and gay Americans and Americans with a disability. They swung open for you, and they swung open for me. And that's why I'm standing here today-because of those efforts, because of that legacy.

You could analyze me and say that my father leaving and being absent was a motivator for early ambition, trying to prove myself to this apparition who had vanished. You could argue that me being a mixed kid in a place where there weren't a lot of black kids around might have spurred on my ambitions. You could go through a whole litany of things that sparked me wanting to do something important.