In an apology for the practice of self-delusion, I lead a tour of the dorms. At first the crowd seems sympathetic to my explanation that in even the most rational society, harmless misperceptions will accrue to large-scale fantasies. To restrict naive lying would be to curtail basic rights, I say. A man who looks like Alan Dershowitz is not convinced: establish a system of incentives that will guide us toward the truth, he says. All else would be mere chicanery.