One of author Harper Lee's messages in TKAM seems to be her belief that learning comes mostly from outside--rather than from inside--the school classroom. Scout's and Jem's life experiences give them a far greater understanding of the world around them than from the time spent at school. Lee is obviously not a fan of the educational system in Alabama during the time of the novel (and, presumably, at the time she wrote the book). She takes relentless pot-shots at Scout's teachers, their teaching styles, and the new and supposedly progressive ideas that they present to the mostly clueless children. Lee deliberately allows Jem to confuse Scout about the new "Dewey Decimal System" that is being taught by Miss Caroline. (Jem has confused the library organizational system originated by Melvil Dewey with the new teaching philosophies of John Dewey.) Miss Caroline berates Atticus for teaching Scout how to read and write, believing she knows best and that it is her responsibility--not that of the parent. She does not seem to recognize that Scout is the brightest child in the class; that Atticus is probably the most intelligent man in the community; and that Atticus was home-schooled himself, and has passed on his love of reading (and curiosity about the outside world) to his children. Scout is quick to see that the classroom is not the hotbed of learning that she expected.
The remainder of my school days were no more auspicious than the first... As for me, I knew nothing except what I gathered from Time magazine and reading everything I could lay my hands on... I could not help receiving the impression that I was being cheated out of something. (Chapter 4)