Themes are the fundamental and often universal ideas explored in a literary work.
When the novel opens, Tom is engaged in and often the organizer of childhood pranks and make-believe games. As the novel progresses, these initially consequence-free childish games take on more and more gravity. Tom leads himself, Joe Harper, Huck, and, in the cave, Becky Thatcher into increasingly dangerous situations. He also finds himself in predicaments in which he must put his concern for others above his concern for himself, such as when he takes Becky’s punishment and when he testifies at Injun Joe’s trial. As Tom begins to take initiative to help others instead of himself, he shows his increasing maturity, competence, and moral integrity.
Tom’s adventures to Jackson’s Island and McDougal’s Cave take him away from society. These symbolic removals help to prepare him to return to the village with a new, more adult outlook on his relationship to the community. Though early on Tom looks up to Huck as much older and wiser, by the end of the novel, Tom’s maturity has surpassed Huck’s. Tom’s personal growth is evident in his insistence, in the face of Huck’s desire to flee all social constraints, that Huck stay with the Widow Douglas and become civilized.
Twain complicates Tom’s position on the border between childhood and adulthood by ridiculing and criticizing the values and practices of the adult world toward which Tom is heading. Twain’s harshest satire exposes the hypocrisy—and often the essential childishness—of social institutions such as school, church, and the law, as well as public opinion. He also mocks individuals, although when doing so he tends to be less biting and focuses on flaws of character that we understand to be universal.
Twain shows that social authority does not always operate on wise, sound, or consistent principles and that institutions fall prey to the same kinds of mistakes that individuals do. In his depiction of families, Twain shows parental authority and constraint balanced by parental love and indulgence. Though she attempts to restrain and punish Tom, Aunt Polly always relents because of her love for her nephew. As the novel proceeds, a similar tendency toward indulgence becomes apparent within the broader community as well. The community shows its indulgence when Tom’s dangerous adventures provoke an outpouring of concern: the community is perfectly ready to forgive Tom’s wrongs if it can be sure of his safety. Twain ridicules the ability of this collective tendency toward generosity and forgiveness to go overboard when he describes the town’s sentimental forgiveness of the villainous Injun Joe after his death.
The games the children play often seem like attempts to subvert authority and escape from conventional society. Skipping school, sneaking out at night, playing tricks on the teacher, and running away for days at a time are all ways of breaking the rules and defying authority. Yet, Twain shows us that these games can be more conventional than they seem. Tom is highly concerned with conforming to the codes of behavior that he has learned from reading, and he outlines the various criteria that define a pirate, a Robin Hood, or a circus clown. The boys’ obsession with superstition is likewise an addiction to convention, which also mirrors the adult society’s focus on religion. Thus, the novel shows that adult existence is more similar to childhood existence than it might seem. Though the novel is critical of society’s hypocrisy—that is, of the frequent discord between its values and its behavior—Twain doesn’t really advocate subversion. The novel demonstrates the potential dangers of subverting authority just as it demonstrates the dangers of adhering to authority too strictly.
St. Petersburg is an insular community in which outsiders are easily identified. The most notable local outsiders include Huck Finn, who fends for himself outside of any family structure because his father is a drunkard; Muff Potter, also a drunk; and Injun Joe, a malevolent half-breed. Despite the community’s clear separation of outsiders from insiders, however, it seems to have a strong impulse toward inclusiveness. The community tolerates the drunkenness of a harmless rascal like Muff Potter, and Huck is more or less protected even though he exists on the fringes of society. Tom too is an orphan who has been taken in by Aunt Polly out of love and filial responsibility. Injun Joe is the only resident of St. Petersburg who is completely excluded from the community. Only after Injun Joe’s death are the townspeople able to transform him, through their manipulation of his memory, into a tolerable part of St. Petersburg society.