This refers to the main idea for writing a literary piece by an author as he wants the reader to learn something from reading his article or book.
With this in mind, we can see that in literature, a central theme is very important as it gives the writer direction which enables him to focus on his main idea throughout an essay.
Please note that your question is incomplete as it does not include the text so I gave you a general overview.
Read more about central theme here:
https://brainly.com/question/734603