It's a minor point, perhaps, but it seems to me worth asking what we even mean by "fiction." The default use here seems to be "invented, made up" as a way of saying "not true." Benjamin rightly and eloquently makes the case for how something that is "invented and made up" can still have "meaning" for a reader. One can say the same thing about all kinds of "fictional" works. Speaking for myself, whatever meaning I derive from things external to my social realities (family and so on) is derived from fictions, especially poetry. I can't say I've reached the W. Jackson Knight stage of Vergil mania, but I can almost spy the path that takes one there.
Scripture in the traditional Jewish and Christian sense, though, has always worked against that. Sure, you have your allegorists like Philo and the Alexandrian theologians but these have been marginal cases. God-in-history is the whole theological point of these two religious traditions, and the category of heresy was invented as a response to approaches to text that submerge or erase or marginalizes this theological point. Symbolic readings abound, to be sure, but they are subordinated to the central idea of God-in-history, and not the other way around.
It's not just that readers chose one way or reading or another (though they did do that) but that most readers took that choice because they took the words to mean what they ordinarily mean and not what the allegorists contrived them artificially to mean. Both the Hebrew Bible and the New Testament give you a god who operates in human history. I see the post-modernist approach as equally reliant on artificial contrivance (and please let me be spared the reductionist distortion that all language is artificial contrivance: anyone who wishes to rely on that by using words in such a way that they expect those words to convey meaning to me that can be understood by me in a way that they intend—such a person will refute their claim in the act of making it, so I won't bother doing it for them).
The Book of Mormon is just such a problem because of the way the text asks you to read it. One needs the artificial contrivances of postmodern rhetoric to make it work, but very few will be able to do that (cue a Gnostic approach).
I rather like Gadianton's solution, though I'm not sure of its viability. It reminds me of the Qur'ān (which is neither history nor fiction). There is a talismanic quality to the way one encounters that text. Anyone who has lived for a long time in Muslim society sees that. But the Qur'ān is not a narrative text that displays the workings of god in history. One can read it in this without with the tendentiousness of post-modern rhetoric, because the Qur'ān self-consciously directs readers to see it as an āyah: a sign that points at its own divine origin (each "verse" of a sūrah is called an āyah. Consider too the following verses, which instruct the reader to interpret the quality of the text—independent of its content—as a divine sign of its own:
(al-Baqarah 2:23-24)Now if you doubt what we have sent down to our servant, then produce a sūrah like it and call as witnesses any but God, if there is any truth to your claim. But if you do not—and you will not—then fear the fire! For people and stones are its fuel, and it is ready for those who do not believe.
(al-Hud 11:13)Or do they say, "this Qur'ān is fiction" (literally, "he has forged/fabricated/made this Qur'ān up": see entry under root f-r-' in Abdel Haleem and Badawi's lexicon), say, "produce ten sūras like it and call on anyone you can (for help), other than God, (to see) if what you say is true
(al-Isra 17:88)Say, "If humankind and jinn came together intending to produce the like of this Qur'ān, they would not produce its like, even if they helped one another."
Now, of course the Book of Mormon is not that explicit, though the apologists essentially play this kind of game all the time and effectively treat the Book of Mormon as a talisman: since Joseph couldn't have known about the Sumerian word for grain, this is a proof of its divine origin (or as the Qur'ān puts it, burhān). And consider:
(Moroni 10: 4-5)And when ye shall receive these things, I would exhort you that ye would ask God, the Eternal Father, in the name of Christ, if these things are not true; and if ye shall ask with a sincere heart, with real intent, having faith in Christ, he will manifest the truth of it unto you, by the power of the Holy Ghost. And by the power of the Holy Ghost ye may know the truth of all things
What does "these things" refer to? Mormons and potential Mormons are taught that it refers to the Book of Mormon as a whole: if you feel "these things" are true, then the Book of Mormon does not lie about itself, and from that it follows that Joseph Smith was not a liar, ergo the LDS Church is the one true one. QED. I suspect, though, that Benjamin would like it to have a more restricted reference.
But in any case it functions like these verses in the Qur'ān: the text asks its readers to test it out as something that is true, to come to see that the text is a divine product. There are differences, though. The Qur'ān claims to be evidence of the divine, but the Book of Mormon tells you use the divine for evidence of the text. And then there is the problem of what these texts are. The Qur'ān is mostly homiletic, rarely narrative, and occasionally expository. The Book of Mormon is mostly narrative, occasionally homiletic, and rarely expository. It gets harder to take Moroni's promise up if you don't think there even was a person named Moroni. And here we come to the main problem. The Qur'ān, as a talismanic text, is its own āyah—it is the sign of its own divinity—but the Book of Mormon's āyah is history itself. Not only has the Book of Mormon (and Mormonism) inherited the Judeo-Christian link between the divine purpose and human history but it has fortified and particularized it: it's got prophecies about Joseph Smith and the pilgrims and the constitution and all this stuff, and it has numerous 1st person identities that are the narrative vehicles for it. I'm not saying that one can't get meaning from it; I'm emphasizing how difficult it is (and I think Benjamin sees this) neatly to separate the Book of Mormon as an artifact from the Book of Mormon as a meaningful text. It is very much like the Qur'ān in this sense. It may not be its own divine evidence like the Qur'ān claims to be, but, like the Qur'ān, it does ask readers to treat it as an artifact. It is not just the later tradition of reading it in the context of a religious movement that does this; the text is unusually focused on the materiality of these civilizations (the coinage, the anthropology, the religious life, the economic life, the agricultural realities, the natural environment, the political structures, and of course the languages and the writing) in a way that is not incidental. Reading it otherwise puts a reader in the paradoxical position of un-reading it.
So, Gad, the Doctrine and Covenants might be better candidate (like Qur'ān, God is the narrator). Perhaps Mormonism could make the Book of Mormon and Pearl of Great Price fictional in the way that Islam takes prophetic lore and the Hebrew Bible and New Testament: useful but distorted. The Doctrine and Covenants, though, is God's revelation now. If only we could find a way to have it melodiously set to a lilting chant to be performed by expert Doctrine-and-Coventants-reciters who've had the whole thing memorized since childhood.