As a young woman, I dreamed of changing the world. In my twenties, I went to Africa to try and save the continent, only to learn that Africans neither wanted nor needed saving. Indeed, when I was there, I saw some of the worst that good intentions, traditional charity, and aid can produce.

If you're looking at distributing alternative energy in Nigeria, for instance, what gets in your way is not people's ability to pay, not people's desire for a clean solar lamps or biomass opportunities. But there is a strong status quo that really depends on selling diesel.

When we were walking through the narrow alleys [of the Mathare Valley slums], it was literally impossible not to step in the raw sewage and the garbage alongside the little homes. But at the same time it was also impossible not to see the human vitality, the aspiration and the ambition of the people who live there.

One of the first things that surprised me in a positive, wonderfully positive way, is that this works - patient capital works.

My whole life has been spent with people who have taken every knock in the world. No advantages. Yet they greet you with a big smile, they give you what they have, and they keep coming back. They are the fighters.

Very small investments can release the infinite potential that lies in all of us.

Don't let people tell you to do it this way. You are on the verge of figuring out hybrid models -- with companies and nonprofits, markets, government, crowd-sourced philanthropy. The capitalist system as we know it is not working.