One more thing on the relevance of truth to the qualities of a fictional work: take Saul Bellow’s late novel Ravelstein (2000). It quickly became apparent that the enonymous character was based on philosopher-critic Alan Bloom.
William Boyd’s short story “A Haunting” (Fascination, Vintage, 2006) nicely illustrates some of the uncertainties of a reader of fiction trying to distinguish factual background from imaginative creation.
Last week I commented on the view of Matthew Bown (TLS April 10 2015) that art works appeal to us in the way that saintly relics do: as traces of admired agents. A related view has been advocated for some time by the psychologists George Newman and Paul Bloom. They hold that a good deal of artistic valuing can be explained in terms of what is called magical contagion "people believe, perhaps unconsciously, that a person’s immaterial essence... can be transferred to an object through physical contact" (PNAS 2014).
Matthew Bown's article in the Times Literary Supplement, April 10 ("Traces of the Holy") makes much of the comparison between enthusiasm for authentic works of art and for holy relics.