Chapter 23 of To Kill a Mockingbird involves a long and thoughtful conversation in the Finch house concerning the nature of justice and the events of the recent trial. When Atticus tells his family that it was a cousin of Walter Cunningham who kept the jury from immediately convicting Tom Robinson, Scout says that she wants to invite Walter Jr. over for dinner once school starts. Aunt Alexandra rebuffs this idea, claiming that the Cunninghams are too low class to come to their home and would be a bad influence on Scout.

In his bedroom, Jem tries to console his sister, who is very upset at her aunt's assessment of the Cunninghams. Jem says that he has figured out that there "are four kinds of folks in this world." He divides people up into ordinary folks, folks like the Ewells, those like the Cunninghams, and "the Black folks."

This assessment does not satisfy Scout. Through her own experience and the lessons she learned from her father, Scout sees a common humanity between all people. To her, all people are simply "folks." Jem is frustrated that his little sister doesn't accept his analysis and dismisses her reasoning as childish.

This section illustrates how the Finch children are thinking more deeply about issues of prejudice and social divisions. The different conclusions that they come to are representative of larger elements of society that are at odds with each other. Some people, like Jem, want to classify people into easy to identify groups. They may view this as a pragmatic approach. Meanwhile, others like Scout, see this as prejudicial and strive to see everyone as part of a common humanity. At any rate, we can see that Scout's opinions of other people have changed significantly since Walter Jr. came to the Finch house for lunch the previous year.

Scout makes this statement as part of a conversation with Jem. Jem is trying to make sense of the divisions between people in Maycomb county, and he divides people into four groups: people like themselves, the Finches ("the ordinary kind"), people like the Cunninghams (poor whites), the Ewells (violent and malicious) and "the Negroes," lumped into a big group. What links these types is contempt: people like the Finches, Jem says, dislike the Cunninghams, the Cunninghams hate the Ewells, and the Ewells hate the Negroes.

Scout instantly rejects this notion. She thinks that everyone is "folks," meaning that everyone is in the same struggle to live. What makes people different, in Scout's view, is opportunity and circumstance.

Jem dismisses this as naïve. He says he thought the same them "when I was your age." His experience, however, has taught him that people are consumed with hatred for each other. His "four kinds of folk" theory is an attempt to explain what motivates people to hate each other so strongly. He feels bitter about these divisions, and says that perhaps the reason Boo never comes out of is house is that he "wants to stay inside," or that he would rather not have anything to do with the rottenness of people.

In chapter 23, Aunt Alexandra offends Scout by calling her friend, Walter Cunningham Jr., a piece of trash. Aunt Alexandra is prejudiced against lower-class white families and believes that Scout is too good to be playing with Walter. Fortunately, Jem intervenes and walks Scout to his room, where they have a conversation about what makes people different. Jem initially tells Scout that he's got it all figured out and believes that there are four types of people in the world. Jem indirectly explains Maycomb's caste system by saying,

"There’s the ordinary kind like us and the neighbors, there’s the kind like the Cunninghams out in the woods, the kind like the Ewells down at the dump, and the Negroes." (Lee, 230)

When Jem attempts to explain to Scout that education is what separates fine folks from lower-class citizens, Scout argues that his logic depends more on a person's opportunity than it does the individual. Scout then says,

"Naw, Jem, I think there’s just one kind of folks. Folks." (231)

Scout's response illustrates her innocence and perspective. Scout realizes that social factors and opportunities play an important role in one's social class, but do not represent an individual's true character. Scout believes that each person is born equal, regardless of race or class. Her perspective and beliefs reflect her father's tolerant disposition, which he has successfully passed down to his daughter. 

This quote shows Scout's age, inexperience, and innocence.

We see this in Jem's response to her:

That's what I thought too... when I was your age.  If there's just one kind of folks, why can't they get along with each other?  If they're all alike, why do they go out of their way to despise each other?  -Jem Finch, ch. 23

To me this quote shows this childhood ideal is still an ideal, but eventually is killed by reality.  Harper Lee is making a very profound statement on the world - and speaking a very profound message.  This message is, "Why can't we all just get along?"  If these kids get it, why can't the adults?

But isn't that the sad reality?  Kids do get it - the idea that it doesn't matter what we look like nor how much money we make, or even how educated we are - we can find something in common and love each other - and adults, too often, don't.

To me, this is a statement that shows one of the main themes of the book.  It is meant to tell us that all people are the same -- that there are not (or should not be) black people and white people, rich people and poor people.  There should only be people.

This is, as I say, one of the major themes of the book.  Scout and Jem are encouraged to think of Boo Radley as a person, not a monster.  Calpurnia makes sure that Scout does not treat Walter Cunningham like he is lower than the Finches.  Atticus tells the kids they need to respect black people and even people like Mrs. Dubose.

Through this remark, the author is juxtaposing various ways for the reader to understand "difference," which is an important topic in the novel.  Everyone is "different" in this story, from Scout who will not act like the lady her aunt wants her to be, to Atticus who does not hunt or play football as his son would prefer. Bo is different because he is a recluse. Tom is different because he is black, and the Ewells are different because they are poor, white trash, people without roots and therefore without morals. When Atticus tells Scout the lowest sort of man is one who takes advantage of Negroes (such as what Ewell does in regards to Tom), he would seem to deny Scout's conclusion, which would otherwise be a comforting and simple solution to the problem of social discord and hatred.

Scout is taking the stand that all human beings are equal. She believes that social, economic, academic, and ethnic factors do not matter. She says this in reply to the discussion that she and Jem were having. The exact quote is "there's only one kind of folks. Folks."