My son has been having hour-long cello lessons for the last year. His new teacher wants him to do half-hour lessons. She says a cellist must learn to approach the craft with focus and intensity. She says he first needs to learn to sustain it for a half-hour. I want that approach for everything he does, and for everything I do, too. But I can’t help thinking that we could sidestep the labors toward intensity by popping an Adderall before the lesson.