Anti-aging is an extremely under-explored field.

For a new payment product, you always have to ask, how much better is it than the current solution? So when we started Paypal, for eBay micro merchants, it was much better than getting the 7 to 10 days process of cashing a check in the mail. When you look at stores or physical worlds, places, a lot of these places are already set up to take cash or credit card. Apple Pay may be an incremental improvement, maybe a little bit better. But when you have something that's pretty good and you go to something that's perfect, sometimes it's very hard to drive adoption because the delta is not that big.

I no longer believe that freedom and democracy are compatible.

I think anything that requires real global breakthroughs requires a degree of intensity and sustained effort that cannot be done part time, so it's something you have to do around the clock, and that doesn't compute with our existing educational system.

The most successful businesses have an idea for the future that's very different from the present.

Google makes so much money that it’s now worth three times more than every U.S. airline combined.

We need more pessimism that the future might be a lot worse, and we need more optimism that the future might be better.