Back in the fifties, in my crowded parochial elementary school, the highest form of good luck landed you in Mrs. Sheeran’s fourth-grade class. The fact that Mrs. Sheeran wasn’t a nun marked her instantly as different. But more significant than her street clothes and married name were two admirable practices....

"Mommy, what does mere mean?” a friend’s four-year-old asked, puzzled by a sentence — “Mere minutes later” — in the Superman comic he was looking at. He didn’t recognize mere as a number, and he couldn’t figure it out by himself. But his question revealed that this preschooler had learned...