Too Kill a Mocking Bird

You never really know anyone until you step into their shoes and walk around in them. In other words, it's important to put yourself in someone else's place in order to understand them better, consider things from their perspective.
Scout's greatest lesson is to recognize the validity and value of lives unlike hers and those of people she knows well. Scout describes the town of Maycomb as having several well defined class systems. There are the professional, educated white people where she and her family reside; the poor-but-proud Cracker class that the Cunninghams inhabit; the white and shiftless group that the Ewells represent and, grouped together solely by melanin content, the Negroes. The first group have the greatest freedom of choice in their lives, the last have the least. These groups make up the entire population of the town but their lives seldom touch, other than through public transaction (like Mr. Cunningham hiring Mr. Finch to represent him in a legal matter.) Privately, the groups are alienated to and often distrustful of each other.

Scout first recognizes Walter Cunningham as a complex individual with his own burdens and dreams during her first day of school when she takes him home for lunch. It is during her father's cross-examination of Mayella Ewell that she realizes how lonely the woman's existence is, despised by the professional and working classes both black and white. Scout's pity and empathy automatically includes Tom Robinson and his family and she recognizes their personal integrity as well as that of Calpurnia and the other African-American characters in the book. The climax of Scout's extension is when she is able to view the lives of herself and the others through the perspective of damaged Arthur Radley when she stands on his front porch. Her realization of how truly gentle and caring Arthur has been to her, her brother and friend through the years and what risks he endured to keep them safe, allows her to evaluate the man by his actions instead of by the local legend and feel (rather reasonably) she has little left to learn, except mainly algebra.

In learning to know the residents of her community as individuals, Scout has lost the blinders that separate people by accident of birth. She has embraced humanity with all of it's complexity and flaws.