In this chapter, Bilbo finds himself alone when confronting danger; he is without the company of the dwarves or the direction of Gandalf. He relies effectively on his own ingenuity and resourcefulness to outwit both Gollum and the Goblins. In this and in taking the final leap over Gollum and out of the cave, Bilbo demonstrates a bravery that he did not know he possessed. He also demonstrates a sense of ethics when he decides not to kill Gollum because of his unfair advantages of invisibility and a weapon. Thus you see Bilbo developing beyond his hobbit mildness into someone who can survive danger by using good judgment and taking appropriate risks.
The depiction of Gollum is a masterpiece of symbolic characterization. He lives alone, on an island, and is so inexperienced in any kind of social interaction that he can speak only to himself, which he does constantly; additionally, his lack of development is indicated by the babyish nature of his language. Bilbo encounters Gollum when he is himself alone, trying to rejoin the dwarves. You thus see Bilbo in a kind of symbolic confrontation with a self-absorbed, immature individual, who may faintly resemble the hobbit-like disinclination to venture out into the world. Bilbo’s leap over Gollum to escape the cave emphatically represents a leap he takes in his own personal development.
It is interesting to note that Tolkien heavily revised this chapter some years after the first edition of The Hobbit, when he was working on The Lord of the Rings trilogy, in order to provide a history for the ring that is so important to those books.
