There is, in fact, not much point in writing a novel unless you can show the possibility of moral transformation, or an increase in wisdom, operating in your chief character or characters. Even trashy bestsellers show people changing. When a fictional work fails to show change, when it merely indicates that human character is set, stony, unregenerable, then you are out of field of the novel and into that of the fable or the allegory. - from the introduction of the 1986 Norton edition