If we view Tom Sawyer simply as a boyhood adventure story, then we must assume that Twain viewed Tom erratically and used many episodes from his own youth at different times over a long period of time. Thus we have two Toms: one who plays boyish pranks on his Aunt Polly--"hooking" an apple or doughnut when she is not looking, teasing her, and finding ways to get around her--and one who has the maturity to save an innocent man and protect a frightened girl.
However, if we view Tom Sawyer as a tale of maturing, a bildungsroman--a novel whose principal subject is the moral, psychological, and intellectual development of a youthful main character--then we don't see two Tom's but one who, through his experiences, matures as a young man. Most readers then choose to see Tom as a dynamic character who occasionally reverts to childish pranks, but one who essentially moves from early childish endeavors and, when called upon to do so, matures to the point where he can make highly moral decisions and commitments, as he did in revealing Injun Joe's guilt and in protecting Becky while lost in the cave.
