In considering a thesis for the topic of isolation within a family, you may wish to consider certain factors concerning the narrator's family in "Why I Live at the P.O.":
- Family members define themselves in terms of their relationships to other members as there are no names used. They are "Sister," "Papa-Daddy," Uncle Rondo," Stella-Rondo," "Mama." Once this relationship as sister or parent is threatened, then the family member loses his/her sense of identity. Sister becomes alienated from her family because she disagrees with their way of handling "the facts of life." For example, after arguments, rather than call her Sister, her mother calls her "Miss Priss."
- Sister is depicted as a character who is myopic, perceiving situations through only the window of her own mind; thus, she is incapable of perceiving the ambiguities of human relations which affect the interpretations of the truth by other family members. This inverted vision of Sister further alienates her.
- Because she lives in such an insular society--most of the town are related--Sister's leaving home to live at the post office serves only to alienate herself further as her actions cause relatives to "take sides" and stop frequenting the post office.
With these three points, then, perhaps you can formulate a general statement about isolation within a family as a major theme in Eudora Welty's story. It is such a theme in the way Sister is defined by others, in the manner in which she conducts herself, and in the relationship that she acquires with the remainder of the town.