How does Harper Lee use humor to show that she does not approve of using family heritage as a way to judge people in To Kill a Mockingbird?
Perhaps the best example of this comes in the different ways that Aunt Alexandra and Atticus perceive the place in the family history of their Cousin Joshua St. Clair. To Alexandra, Cousin Joshua is the most illustrious member of the Finch family. The author of a very "small volume" of verse entitled "Meditations of Joshua S. St. Clair," Alexandra believes
"He was a beautiful character." (Chapter 13)
But Atticus has already versed the children in the past exploits of their cousin. In truth, Cousin Joshua is the most scandalous member of the Finch family, a fact that Alexandra obviously prefers to cover up. Apparently mentally unstable, Joshua
... went round the bend at the University. Said he tried to shoot the president... and tried to shoot him with an old flintlock pistol... Atticus said it cost the family five hundred dollars to get him out of that one--" (Chapter 13)
After Alexandra adjourns to give Atticus a piece of her mind, he returns "soberly" and "actually fidgeting." Obviously embarrassed from his sister's scolding, the usually confident Atticus is forced into trying to explain to his children about Alexandra's belief in "gentle breeding"--an idea of which he obviously does not agree.