The Merman's Children.
We can have two kinds of disagreement about a hereafter:
(i) Is there one?
(ii) If so, what is it like? E.g., is there reincarnation? Are all non-Christians damned? etc. (There are some fine-tuned distinctions: only Catholics/Evangelicals/Muslims etc are saved.)
Poul Anderson imagines a third alternative. Father Tomislav urges the merman Vanimen to accept baptism not because, if he does not, he will be damned but because, if he does, he will receive an immortal soul. And Vanimen does not doubt what Tomislav says but does not think that it is worth it!
This is because:
"The background here is Catholic, but the religion does not conform to the theology of St. Thomas Aquinas. Rather, it is the naive, half-pagan mythology of peasants and seafarers in the early fourteenth century..." (p. viii)
Of course, a fantasy writer can adopt any fictional premise that he wants but I find this one hard to take. God created Faerie beings without souls but literally gives them immortal souls if they convert? My willing suspension of disbelief is severely strained. Faerie is going under. This reflects what happened in history. Will the theistic faiths also go under? Do these faiths somehow become "true" because they are believed rather than vice versa - as in some other works of fantasy? Poul Anderson's various works of fiction do not assume a common metaphysics but there are some moves in that direction with the idea that various pantheons, universes and versions of history coexist. We want yet another volume to explain everything further.