The Y.A. debate, in short, is about more than young-adult books and their not-so-young readers. It’s a recapitulation of a deeper debate that we’ve been having for centuries—a debate about why books matter to us, and what reading is “for.” It’s also a debate about who we want to be. Talking about what makes us cry is also a way of talking about ourselves. With each way of talking—sentimental, sensational, aesthetic—we say something different: that we’re kindhearted and empathetic, or passionate and romantic, or sensitive to beauty and the pleasures of art. Saint, lover, artist: surely these are all good ways of being. Probably, though, we’ll keep arguing about them forever. Nabokov was wrong; we never lose interest in the adolescent project of learning to live.