By learning to read, he expanded intellectually which led him to fully realize how horrible and futile his situation was. It became clear to him that his master was right about slaves that learn- they become intractable and unmanageable.
The way they talk and act. And the way they protect scout
It made more sense in the aspect that,yes Nick was one of the main characters but he was there to see a story unfold. To see who,how and why Gatsby,Daisy or Tom were they way that they were.
