I’ve got a guest blog post on Welcome to Arhalyon on theologic license when writing fiction. Here’s a sample.
The problem of mixing speculative fiction with actual religion has existed since the first time Og told a ghost story around the cave’s fire, and, having returned to hunting the next day, wondered what ghosts meant for the Great Spirit. Whatever Og’s conclusion was has been lost to time, but we see it again more recently (relatively speaking) in The Divine Comedy. In the depths of Hell, Dante comes across Odysseus, who is eternally punished for attempting to reach Purgatory by the sole effort of humans. What exactly the presence of Odysseus implied for the panoply of feuding Greek divinities of the Iliad and the Odyssey, in the further reality of the True Divine, is not considered.
But while Og needed only entertain his tribesmen for a few minutes, and Dante used Odysseus as a symbol of the inadequacy of mortal powers, the modern speculative fiction author does not get off so easily.
The questions for the fantasy author have plagued the genre since Tolkien. They arrive like rubberneckers at the world’s construction site, incessantly pestering the author. If there is a fictional pantheon, are those gods “real?” Are they angelic like the Valar of Valinor, or noble beings like the Overcyns of Skai? Or are they mere frauds as Tash—a safe choice, but then Tash actually appears at the end of the Chronicles of Narnia and the issues are immediately raised. Add magic and ethical issues enter immediately, and whole essays have been written on the topic (see the excellent one by Tom Simon.)
The science fiction author can only avoid the same questions with sufficiently hard science and sufficient planning ahead. (Be sure to put three or so bishops on your generation ship to avoid issues of apostolic succession.) Reach for any other ingredient—time travel, artificial intelligence, or worse yet, extraterrestrial life—and now you have some irritating theological question, one that will devour your creative energies like a black hole.