Paul Romer believes in the power of ideas. He first studied how to speed up the discovery and implementation of new technologies. But to address the big problems we'll face this century -- insecurity, harm to the environment, global poverty -- new technologies will not be enough. We must also speed up the discovery and implementation of new rules, of new ideas about how people interact.

Throughout human history, big improvements in systems of rules took place when new governments entered the scene. In today's world, this process has been largely shut down. To bring it back to life, Romer proposes that we create new cities where people can go to escape from bad rules and opt in to new and better ones. With better rules, people can be safe, self-interest can protect the environment, and investment can bring families all the resources that the modern world has to offer.

Romer took office as the World Bank's Chief Economist and Senior Vice President in October 2016.