something does not go according to her perfectly thought-out plan. Scout already being able to read is one of those things.

As Scout begins to read, "a faint line appeared between [Miss Caroline's] eyebrows," and when she "discovered that [Scout] was literate and looked at me with more than faint distaste. Miss Caroline told me to tell my father not to teach me any more, it would interfere with my reading."

This, of course, is a ridiculous notion. Scout tries to explain that she was never taught to read at all; she simply sat on her father's lap and, over time, she learned. Scout says,

Miss Caroline apparently thought I was lying. “Let’s not let our imaginations run away with us, dear,” she said. “Now you tell your father not to teach you any more. It’s best to begin reading with a fresh mind. You tell him I’ll take over from here and try to undo the damage-”

“Ma’am?” 

“Your father does not know how to teach. You can have a seat now.”

Miss Caroline is clearly not flexible and does not know what to do when things do not go as planned. She is proof that book knowledge is quite different than real-life experience. The truth is that she should have been thrilled that one of her students can already read; instead she is horrified and commands Scout to stop reading until Miss Caroline can teach her. Another ridiculous notion. 

Miss Caroline watched the class file out for lunch. As I was the last to leave, I saw her sink down into her chair and bury her head in her arms. Had her conduct been more friendly toward me, I would have felt sorry for her. She was a pretty little thing.

There are at least two episodes in Harper Lee's novel in which she satirizes the progressive theories of education and the episode from Chapter 2 is one of them, and Atticus's allusion to educational methods in his closing arguments at the Robinson trial is the other in which he alludes to social promotion in Chapter 20. In Chapter 2, Miss Caroline is offended that Scout's father, who knows nothing of the progressive educational theories of John Dewey, should presume to teach his daughter to read. No matter that Scout can read; she has been taught using ¨incorrect¨ methods which Miss Caroline feels could do her irreparable harm later on. 

Miss Caroline's strict adherence to the ¨progressive¨ theories of Dewey ignore the fact that Scout is an accomplished reader without having followed any of these theories because the method of education supersedes the outcome. Evidently, it is the method that is of paramount importance, not the outcome. When Miss Caroline insists that ¨reading should begin with a fresh mind,¨ she indicates her inability to instruct children creatively on an individual basis, and to refuse to recognize certain cognitive differences in children. Instead, strict adherence to Dewey's theories of progressive education must be observed.

In a further satiric commentary, Lee has Jem explain to Scout that Miss Caroline is ¨introducing a new method of teaching¨ when she waves cards at the children with sight words upon them. The "Dewey Decimal System" [pun on John Dewey's name as it is confused by Jem with the library system of classifying books] "consisted in part of Miss Caroline waving cards at us on which were printed the, cat, rat, man, and you."

Miss Caroline's disapproval of Atticus teaching Scout how to read is rooted in a desire to maintain power.  Miss Caroline has established the classroom environment in a very authoritarian manner.  She firmly establishes that she is the teacher and the students are to learn from her.  Miss Caroline does not take her children into account and does not really validate their voices.  For example, when she reads the class the story about the talking cats, it does not resonate with the students because most of their real world experience is one where "imaginative" animals are not evident:  

By the time  Mrs. Cat called the drugstore for an order of chocolate malted mice the class was wriggling like a bucketful of catawba worms. Miss Caroline seemed unaware that the ragged, denim-shirted and floursack-skirted first grade, most of whom had chopped cotton and fed hogs from the time they were able to walk, were immune to imaginative literature. Miss Caroline came to the end of the story and said, "Oh,¯ my, wasn't that nice?" 

This reflects how Miss Caroline establishes a timbre of the classroom where her authority drives the instruction.  It is for this reason that she rejects Scout's father as teaching her how to read.  Her arguments are rooted in those of power.  Atticus "does not know how to teach" is supported with her belief that learning from her father would interfere with Scout's reading as well as "reading should begin with a fresh mind."  These arguments reflect a desire to consolidate and control.  They reflect a tendency not to share power, but rather to be the sole arbiter of learning.  Miss Caroline reflects a "new" style of teaching, according to Jem, but she also exhibits the desire for power.  It is in this light where she rejects the notion of Scout's father teaching her how to read.

Miss Caroline Fisher is a weak, inexperienced teacher. As such, she appears insecure in her abilities. So when Scout shows up for her first day at school, and is clearly able to read and write, Miss Caroline gets quite indignant. Atticus must've taught her, she thinks. And Miss Caroline feels rather put out as she seems to think it somehow undermines her authority as a teacher.

The unpleasant episode with Miss Caroline illustrates once more the warped nature of life in Maycomb. It's perfectly fine for Burris Ewell to turn up for the first day of school and then stay away for the rest of term. But for a child to come to school with the ability to read and write is somehow a problem. Clearly, it's more important to follow strict, inflexible rules than to educate children properly. Miss Caroline is one of many adult authority figures in the story whose actions make little sense to those of us not familiar with the strange customs, laws, and conventions that govern the lives of the citizens of Maycomb.