In a Princeton University lecture hall one morning last December, Peter Singer, one of the world’s most influential—and controversial—living philosophers, offered his Philosophy 385 (“Practical Ethics”) students a brief overview of their upcoming final. The registrar, he noted, had scheduled the exam for the following Sunday evening. This, he proclaimed, “seems unethical.”
The line got a good laugh. A hint of winter chill hung in the air, the undergrads having just sloughed off their Canada Goose parkas and settled into the seats of Wood Auditorium in McCosh Hall, a Tudor Gothic behemoth that was once the largest building on campus. It was here, 102 years earlier, that Albert Einstein described his theory of relativity to a packed house.
The 200 students enrolled in Philosophy 385—about as many as…