'Positivistic,' 'Analytic and Linguistic Philosophy' principles allow for clear, concise, unambiguous language, the main tool for conveying messages, the elements of communication. In the novel, the language tends to be somewhat lyric and a measure of flourish is fine. But mainly, the novelist does not purport to intentionally convey a message to the reader!
Such an attempt would blemish the essence of the novel, which should be, axiomatically, a compelling work of fiction. It is a spontaneous --albeit polished-- creation, variously redolent of the variegated attributes of literary art. It might be influenced by the Collective Unconscious, but it is certainly dictated by the Individual Unconscious of the author.
And no unconscious can deliberately convey messages; thus, the reader may act as an interpreter at best. He is the one who might tell the author what it is that moved him to write what he has written. Conveying a deliberate message, the author can not aver to be a novelist, but just a gifted preacher, a visionary prophet, or an inspired social reformer.

The reader may content himself with enjoying a novel as a story that first awakens his natural curiosity and then satisfies it. He may also let himself be involved in a world more passionate than his. His intellect may be stimulated by the unraveling of an ingeniously ambiguous plot. Being part child himself --with a vague recollection of the time when thought was omnipotent-- he revels in the mature fantasy of a novel. Or else, his religiosity or his sense of social justice is awed by the prophetic grandeur of a passage. His educated aesthetic sensibility delights in the artistically --yet deliberately-- elaborated pattern of a novel, and finally, his innate sense of beauty is immersed in the spontaneous manifold cadences and overall flowing rhythm of an elegantly written novel.

But...reading a novel to get a deliberate message? The reader might wrest one out of a novel --if he were in such a quest. But if so, he's wrought it with his own mind's probing cunning.