@mariapopova
There is much to dislike about C.S. Lewis, especially the C.S.Lewis who is venerated in the USA by Christian conservatives. I find his Christian apologetics not so much interesting as irritating.
Yet when he is, as in the passage you quoted, putting forth ideas that have their roots in Platonic thought, I find him altogether more engaging. I also think he was a wonderful storyteller, in spite of passages in the Narnia books that now make us wince.
I found Laura Miller -- The Magician's Book of great value in helping me think about Lewis: