Usually, "optimism" and "realism" are used to describe two different outlooks on life. But I believe that a realistic appraisal of the human condition compels an optimistic worldview. I am particularly optimistic about the potential for technological innovation to improve the lives of the poorest people in the world. That is why I do the work that I do.

Even so, there is one area of technology and global development where reality has tempered my optimism: the idea that cellphones would revolutionize life in developing countries. A decade ago, many people believed that the proliferation of mobile devices in Africa would mean a short leap to digital empowerment. It didn't. Digital empowerment is a long and ongoing process, and the mere existence of cellular technology does not immediately change how poor people meet their basic needs.

But now, after years of investments, digital empowerment is underway, owing to a confluence of factors, including growing network coverage, more capable devices, and an expanding catalogue of applications. As more people get access to better and cheaper digital technology, an inflection point is eventually reached, at which the benefits of providing digital services like banking and healthcare clearly outweigh the costs. Companies are then willing to make the investments required to build new systems, and customers are able to accept the transition costs of adopting new behaviors.