My mom and my dad were both very sociable, meeting lots of interesting people.

It's energy intensification, where we essentially have, through our light bulbs and cars, the manpower of [hundreds of] people working on our behalf, helping our food being created, helping our materials like steel and plastic and wood and paper be created. Our lifestyles are incredibly energy intense.

The most straightforward path would be if we could bring the cost of solar electric and wind down by another factor of say, three, and then have some miraculous storage solution, so that not only over the 24-hour day but over long periods of time where the wind doesn't blow, you have reliable energy. That's a path. But energy storage is hard. That's not a guaranteed path.

With world health, every life you save is a wonderful thing, so it's not this question of whether you solve it or you don't. The chance of completely solving the problems has long odds. But really, the thing is that you get to save the first child, the second child, the third child. You can just feel good about that.

As I see it, there are two great forces of human nature: self-interest, and caring for others. Capitalism harnesses self-interest in a helpful and sustainable way, but only on behalf of those who can pay. Government aid and philanthropy channel our caring for those who can't pay. But to provide rapid improvement for the poor we need a system that draws in innovators and businesses in a far better way than we do today.

I choose a lazy person to do a hard job. Because a lazy person will find an easy way to do it.

Improving the health & productivity of the poorest is one of the best investments you can make in the future of the world