No thief, however skillful, can rob one of knowledge, and that is why knowledge is the best and safest treasure to acquire.
—L. Frank Baum, The Lost Princess of Oz
The great, late physicist Albert Einstein was traveling on a train one day. Shortly after the train left the station in Princeton, the conductor walked down the aisle, punching the tickets of every passenger as he went. When he came to Einstein, the brilliant but notoriously absent-minded scientist reached into his vest pocket for his ticket, but it wasn’t there. He checked each of his trouser pockets. No ticket. He looked in his briefcase. No ticket. He looked on the seat beside him. No ticket.
At that point, the conductor said, “Dr. Einstein, ...