An interesting discussion, to say the least! But let us not forget, friends, that Lewis didn't write a book of the Bible and as a human is certainly open to errors. That said, let's take a look at how he viewed mythology and classical alchemy.
He said in
The Abolition of Man -
We do not look at trees either as Dryads or as beautiful objects while we cut them into beams: the first man who did so may have felt the price keenly, and the bleeding trees in Virgil and Spencer may be far-off echoes of that primeval sense of impiety. The stars lost their divinity as astronomy developed and the Dying God has no place in chemical agriculture.
Very poetic prose and all that, but what does it mean? More importantly, does it answer the question of why he used pagan mythology in a Christian semi-allegory?
Looking at the wide range of Lewis's talents and studies, he didn't just write fiction - he wrote at least two books about classical mythology (
The Allegory of Love and
The Discared Image) and a poem called
The Planets that is based on the medieval planetary system. He was very well-read on the subject, not as a fan, but as a scholar. So how do we reconcile the opposing views of Christianity and paganism?
Remember that Lewis was living in an age that had begun to question the existance of God. Atheism and science were becoming the authorities on morals. We lost our respect for God and His creation.
We do not look at trees either as Dryads or as beautiful objects while we cut them into beams:
We no longer even saw beauty apart from God - just the "machine" of nature. At least mythology saw truth and beauty in the nature of creation! I think, to Lewis, the loss of beauty was the cutting of the last strand that held us to God as a culture.
The stars lost their divinity as astronomy developed and the Dying God has no place in chemical agriculture.
Obviously, Lewis knew that the stars weren't a way of predicting the future or who you as a person would be. He's saying that as we learned more about nature, we lost our respect for it and the One who made it. In that sense, paganism has a higher aknowledgment of God than atheism - it believes in a power higher than man. And if fairy tales and myths still resonate with people, why not use a glimpse of beauty to point them to the Creator?