Jerram Barrs recently published an interesting book entitled Echoes of Eden (2013), in which he tries to understand the particular depth and resonance of certain books, movies, plays and songs from a Christian perspective - and puts forward the idea that the best work upon us because they encapsulate the principles of our Fall from Paradise and hope of return to something better.
He suggests that 'greatness' in these arts comes from three things:
1. They lead us to appreciate the beauty of Creation.
2. We understand the reality of purposive and personal evil, as the fundamental threat in life.
3. The works express our yearning to escape from the corruption, wickedness and ugliness of this mortal earthly situation into a state of higher happiness and perfection - and offer some hope that this may be possible.
This analysis seems close to the truth - at least for the kind of art which most profoundly affects me, and which has the broadest appeal among non-professionals. Barrs's examples include Tolkien, CS Lewis, the Harry Potter novels, Jane Austen and Shakespeare - and these all illustrate and confirm his points quite straight forwardly.
One value of this analysis is that it clarifies how works which are implicitly and indirectly Christian, may yet be fundamentally Christian (and the near-irrelevance of explicit and direct Christianity to the genuine and valuable Christianity of art).
This point is linked in my mind to Christ's use of indirect and implicit teaching in the parables.
Here - in Parable of the Sower - Jesus explains to his disciples why he teaches in parables:
My understanding of this, is that successful evangelism among those not-already-Christian is likely to be, or to be based-upon, indirect, parable-based, narrative and not-directly-Christian art and creativity - such as (to mention recent examples) Lord of the Rings, the Narnia Chronicles, and Harry Potter.