Melinda and I spoke at Stanford University’s graduation ceremony today. Below the video, I’ll explain a little of the story behind the speech.

When the invitation to speak at Stanford arrived, we were eager to accept. For one thing, I hadn’t given a commencement speech since 2007, when I went back to Harvard. There’s also a lot of overlap between work that our foundation is doing and research being done at Stanford. Plus, Melinda and I had never given a commencement speech together and we thought it would be fun.

We knew going in that commencement speeches come with their own challenges. The seniors are eager to start celebrating and don’t necessarily have the patience for a long speech. And the subject is wide-open—you can talk about whatever you want—which actually makes it harder.

We spent a lot of time talking about what we wanted to say. We’d heard about the #nerdnation meme that’s sweeping campus, so we thought we could have some fun with that.

More seriously, Melinda and I wanted to talk about our optimism, and how it has evolved over time. We used to have an almost blind faith that technology would improve people’s lives. Our optimism about technology hasn’t diminished, but today it is more informed, and less naïve. We concluded the speech by asking the graduating seniors to apply their intelligence and empathy in ways that will improve lives around the world.

The key is for them to open their eyes to suffering. As Melinda says, “Let your heart break. It will change what you do with your optimism.”

Thanks to Stanford for inviting us, and congratulations to the class of 2014.