Using philosophy to blanket the characters or plot is not a common type of literary fiction. When done well the reader doesn't even know it is happening. When done poorly the reader finds themselves longing for the author to get back to the story. How the characters and plot are blanketed with the author's chosen morals can often decide whether the reader likes the book at all. This is often decided by the reader's own view of right and wrong.
Personally, I like a bit of philosophical play when I'm reading but I don't like to be drowned with it. Too much and, like most people who try to read literary fiction, I'll lose touch with the story.
Is philosophy a necessary part of literary fiction, no of course not. I wouldn't exactly call Pride and Prejudice incredibly philosophical but it does have its own societal morals. The question that should be asked is: does philosophy improve literary fiction? I have to say yes. We deal with philosophical questions personally every day whether we realize it or not. If the characters we read about didn't confront similar issues then they wouldn't be fully developed. Including philosophy, no matter to what degree, allows the reader to experience different aspects they might never have considered, witnessed, or experience. In effect, we are learning while they read fiction.
Some writers are naturally philosophical while others are classically trained. Iris Murdoch was classically trained in philosophy. It was a huge part of who she was as a feminine writer. She wrote non-fiction papers about philosophy but also including philosophy questions and insights in her fiction writing.
Philosophy Ridden Literary Novels to Add to your Book Shelf:
* Crime and Punishment (Fyodor Dostoevsky)
* In Search of Lost Time (Marcel Proust)
* The Golden Bowl (Henry James)
* The Metamorphosis (Franz Kafka)
* The Sea, The Sea (Iris Murdoch)
* Ulysses (James Joyce)
* Zen and the Art of Motorcycle Maintenance (Robert Pirsig)