From the point of view of the psychology of fiction, one of the criteria that may distinguish great novels from those that are merely entertaining, is that a great work is not about persuasion. There is no mental coercion of the reader to run only on rails laid by the writer. Of course there is structure, with settings, characters, conversation, and events, but along with these a great novelist offers what D.W. Winnicott, in his book Playing and reality, called a "potential space between the individual and the environment," a space in which the reader's imagination can expand, and in which, as the reader takes up the words of the writer, the experience of the book can become the reader's own. George Eliot's Middlemarch is one of the world's great novels because the author offers the reader exactly this kind of space-in-between.
You can read the case I made for Middlemarch being a great novel by clicking here.