This movie presents a rant of an ageing writer of his path to Christianity, clearly showing the lack of being able to think for himself, but rather relying on what others have written or spoken. The character assumes that what has been said to him or what he has been read, must be true because he cannot muster enough independent thinking to find flaw in the statements made, and he is not able to figure out for himself what life is all about.
The movie probably does explain why he was able to write the Narnia books, as clearly he does not see any requirement for anything to be able to be logical and reasonable.
The movie probably does explain why he was able to write the Narnia books, as clearly he does not see any requirement for anything to be able to be logical and reasonable.