“People who solve problems must somehow first arrive at the belief that they can solve problems. This belief does not emerge suddenly. The capacity to cause change grows in an individual over time as small-scale efforts lead gradually to larger ones. But the process needs a beginning—a story, an example, an early taste of success— something along the way helps a person form the belief that it is possible to make the world a better place. Those who act on that belief spread it to others. They are highly contagious. Their stories must be told”