A foil in literature is a character who shows opposing or contrasting qualities to another character. A foil is often used to show unique characteristics of a person by comparing his actions, words, and thoughts to another character.
In To Kill a Mockingbird, Bob Ewell seems to be Boo Radley’s foil although there may be a good argument that society is Boo’s foil. Because Bob Ewell represents an abusive racist in Maycomb’s southern society, his actions and thoughts seem to be in direct contrast with Boo’s, however.
We can see the difference in the two characters by how they protect and nurture the innocent children in the story. Bob Ewell is an abusive father who doesn’t require his children to go to school and makes his oldest daughter, Mayella, take care of his seven children. They live by the city dump and scavenge it for necessities. Bob Ewell beats Mayella and forces her to accuse Tom Robinson of rape. His actions represent the prejudice and racism that exists in Maycomb.
Boo, on the other hand, is kind and nurturing toward Scout and Jem. Although he doesn’t have direct contact with them, he leaves presents in a tree, covers Scout with a blanket during Miss Maudie’s fire, and eventually saves their lives when Bob Ewell attacks them. Boo represents the harmless mockingbird in the story.
Boo Radley is a courageous hero in the story by saving Scout and Jem while Bob Ewell preys on the innocent Scout and Jem to achieve his revenge on Atticus. When it comes to comparing the two characters, their actions and beliefs are in opposition. While Boo is kind and caring, Bob Ewell is mean and abusive. They represent a dichotomy in Maycomb that exists with the different class of people present in the story.
If you set up a chart of binary opposites, it would look something like this:
Bob Ewell abuses his children/Boo gives presents to Scout and Jem.
Bob Ewell attacks Scout and Jem/ Boo saves Scout and Jem.
Bob Ewell represents racism and white trash poverty/ Boo represents the mockingbird.