When I first became Christian it wasn’t long before I heard of CS Lewis. He became almost my only reading for a while. As far as I’m aware he was Anglican. I also found he was fairly impartial re. Christian denominations. Indeed in his Screwtape Letters he pokes fun at both parties - the types who on one side despised those who said “Mass” on one hand, and “Communion” on the other.
I’ve had a certain number of spiritual experiences myself, and I suspect CS Lewis of having similar experiences. In one of his trilogy for example he has a character going through a sort of spiritual blockade on a walk to Ransom’s house. In another he uses a character to get across the idea people might accept more easily as fiction what they will not accept as literal fact. In one book a “dead” physicist, his body inhabited by Satan, suddenly sat down and howled like a dog. I don’t think that’s unheard of in demonic deliverances.
At one stage he describes angels, in their real appearance, as being like wheels within wheels, a spinning conglomeration of almost mathematical symbols I’ve had the experience some nights of becoming a aware of a presence, and at the same time I seem to get an image of spinning mathematical symbols. I’m not a mathematician, and have never been immersed in the sort of environment to encourage that sort of imagery.
So I think at times he had certain spiritual experiences of his own he could draw upon. He was apparently prone to nightmares, and I’ve had the experience of a dream suddenly veering into a nightmare. When I wake up there’s a sense of something sinister in the room. And I don’t think I’m the only one.
So apart from being a brilliant logician, probably the best 20th century apologist the Christian faith had, I also suspect he had his fair share of spiritual experiences, which he best expressed as fiction. Catholics often quote Chesterton, but I still think Lewis was the more brilliant apologist.