It should be noted that the desire to build the fort showed that it's important for people to believe in themselves.
What is a theme?
A theme simply means the main idea that's in a story. It's simply what the author wants the readers to know.
In the story, Tee struggled to allow himself to have good family relationships. In the end, the desire to build the fort showed that it's important for people to believe in themselves. It's also important to have good family relationships.
He was free from the isolation and corruption of the island, and since he died innocently, the boys figured that he shall float away from the insanity.
