The first college class I ever sat through was a political-science seminar attended by a score of impossibly sophisticated undergraduates, each separately sure of the rectitude of his or her convictions. I was not enrolled. Rather, I had come to campus as a high-school senior simply to “get a sense of things” (I quote from memory a long-lost admissions brochure), to “drop in” and determine whether the university was worthy to receive me into its ranks the following year.