post summarized what I regard as a major process in twentieth century sf:
CS Lewis' theological reply;
Poul Anderson's Wellsian-Stapledonian apotheoses!
parallels Anderson but with a much smaller output;
directly addresses Lewis, even incorporating CSL and his demon, Screwtape, into the text of The Day After Judgment.
As Lewis himself wrote of Stapledon, it is possible to admire Lewis' invention while disagreeing with his philosophy. Lewis imaginatively restates Christianity no less than three times:
The Great Divorce.
In this last volume, Lewis assumes a hereafter, presents what looks like a completely new version of it, shows that this imaginative version does conform to orthodox theology, then disclaims it as a dream at the end but meanwhile makes telling moral observations as he does in the Ransom novels.
I advise anyone to read or reread: