The conventional explanation for Jewish success, of course, is that Jews come from a literate, intellectual culture. They are famously “the people of the book.” There is surely something to that. But it wasn’t just the children of rabbis who went to law school. It was the children of garment workers. And their critical advantage in climbing the professional ladder wasn’t the intellectual rigor you get from studying the Talmud. It was the practical intelligence and savvy you get from watching your father sell aprons on Hester Street.