“I don’t know what’s the matter with people: they don’t learn by understanding, they learn by some other way—by rote or something,” physicist Richard Feynman once said. “Their knowledge is so fragile!”

Maybe Feynman’s brain was big enough to simply “learn by understanding”—sucking in and comprehending complex realities in a single glance. But what I think he actually meant was that people should learn by exploringand investigating, rather than just memorizing. Only then would their knowledge be useful and durable.