In these chapters, Tom fluctuates between petty, immature behavior—lying to his aunt about his alleged dream and trying to make Becky jealous at the expense of Amy’s feelings—and nobler conduct—saving Becky from punishment. The fact that Tom’s story about his dream fools his aunt but not Sid may ironically indicate that in some way children are more perceptive than adults. On the other hand, perhaps Aunt Polly is deceived because true maturity includes love and the forgiveness that comes along with it. Perhaps Sid is too morally immature to understand that such trickery is excusable in a person that one loves.
Once Tom realizes the damage he has done, he feels remorse for the second time in the novel, which indicates that his moral growth is continuing. He feels genuine affection for Aunt Polly and wants to secure her approval. His manipulation of her seems to happen almost instinctively, as he gets carried away by his own flights of fancy.
The snubbing war between Tom and Becky forms a counterpart to the make-believe military battle fought between generals Tom and Joe early in the novel. Descriptions of the elaborate strategies Tom and Becky employ to make each other jealous make up the bulk of these chapters. Both behave in a petty, childish fashion, trying to prove to one another how little each needs the other. Until Tom takes Becky’s punishment, the two remain trapped in this cycle of nasty behavior. Tom’s act of self-sacrifice breaks the cycle and enables the pair to reunite. By taking Becky’s whipping and winning her back, Tom also brings his pirate adventure to its full conclusion, since it begins with Becky’s rejection of him.
Twain directs our sympathy in these chapters toward Amy and Alfred, whom Tom and Becky use and then discard. Both characters, who vanish from the novel after Chapter 18, remain tools. Not only are they tools for Tom and Becky in their love war, but they are also rather dull characters for Twain himself—he doesn’t even consider going beyond the letter “A” in giving them names. Mr. Dobbins too serves as nothing more than a tool for Tom’s development. Mr. Dobbins’s threatening authority, although undermined in our eyes by the discovery of his secret desire to be a doctor and his humorous obsession with his medical textbook, allows Tom a chance to act heroically.