In September 2009, an extraordinary child forced me to drastically revise my ideas about learning. I was visiting the Sarah Hospital in Brasilia, a neurological rehabilitation center with a white architecture inspired by Oscar Niemeyer, with which my laboratory has collaborated for about ten years. The director, Lucia Braga, asked me to meet one of her patients, Felipe, a young boy only seven years old, who had spent more than half his life in a hospital bed. She explained to me how, at the age of four, he had been shot in the...