[very rough draft]

  1. It contradicts accounts by scribes that indicate Joseph was reading word for word from the seer stone (aka an “iron-clad” translation).1

  2. Royal Skousen’s research indicates the text was produced by “tight” translation (not as tight as “iron-clad” but more structured than “loose”), which leaves little room for ad-hoc expansion.1

  3. Many scripture verses from the Book of Mormon seem to lose potency:

    2 Neph 25:22 Wherefore, these things shall go from generation to generation as long as the earth shall stand; and they shall go according to the will and pleasure of God; and the nations who shall possess them shall be judged of them according to the words which are written.

    In general, if we are to be judged by the words that the Nephite prophets wrote, it’s highly problematic if we don’t really know what those words were.

    2 Nephi 2:28 And now behold, my people, ye are a stiffnecked people; wherefore, I have spoken plainly unto you, that ye cannot misunderstand. And the words which I have spoken shall stand as a testimony against you; for they are sufficient to teach any man the right way; for the right way is to believe in Christ and deny him not; for by denying him ye also deny the prophets and the law.

    Nephi had just concluded by apparently quoting chapter after chapter of Isaiah, but Joseph Smith was apparently lazy and so opened up the KJV bible for all those chapters.

    Are Nephi’s words plain if we don’t even know what Nephi’s words are? Can Nephi’s words stand as a testimony against us if we don’t know what exactly his words are?

    2 Nephi 2:23 For we labor diligently to write, to persuade our children, and also our brethren, to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do.

    Do we know that it is by grace we are saved, after all we can do, or is that just standard soteriology from the Human Nature in its Fourfold State? Or is that just the New Testament talking through Joseph Smith (or whomever)?

    2 Neph 26:1 And after Christ shall have risen from the dead he shall show himself unto you, my children, and my beloved brethren; and the words which he shall speak unto you shall be the law which ye shall do.

    Mormon reports Jesus’s words (Mormon 9:22-24) and these words say they need to preach the gospel to the ends of the world and baptize everyone etc. But if Jesus didn’t really say these words, then what is the law we are supposed to do?

  4. The book becomes hypocritical about “many plain and precious things”.

    1 Nephi 13 states “These last records, which thou has seen among the Gentiles, shall establish the truth of the first…” A major advantage claimed for the Book of Mormon is that it is the “word of God” whereas the Bible is merely “the word of God insofar as it is translated correctly”. The Book of Mormon, because it was translated by “the gift and power of God” was meant to better preserve the actual, pure Gospel and at least clarify plain and precious truths. If Joseph Smith infused his own thinking and environment into the Book of Mormon at every turn, this substantially undermines the usefulness of the Book of Mormon being translated by “the gift and power of God” and it leads to the same problem the Book of Mormon was meant to address–what exactly are the plain and precious truths? How much of these truths are plain, precious and eternal and how many are mixtures with the theology of the 1800s? If we concede that JS infused much of his own milieu into the book then arguably the Bible then becomes a better, more accurate representation of the Gospel (at least as it was taught anciently) than the BoM.

  5. If we allow that any holy book purporting to be a holy record may contain as much as, say, 50% of the translator’s thinking and milieu, on what grounds would you dismiss the other purportedly holy books? Let’s just say that the Book of Jeraneck is 50% a perfect transmission of the ancient record and 50% Matthew Gill’s own thinking about the ancients’ thinking and lives. Are you prepared to accept Gill’s book as “the word of God” if 50% of it can be shown to be theologically or historically anachronistic?

  6. If the authenticity of the BoM is meant to bolster our confidence that Joseph was an authentic prophet, what does an expansionist text do to our thoughts on him as a seer, for instance? Why should we have confidence in his prophetic ability if his seership is so imprecise?

  7. Expansions don’t explain many kinds of major anachronisms very well in the text. When Joseph writes “baptism” what else could Nephi have mean’t other than “baptism”. A transoceanic voyage means a transoceanic voyage. The tower of babel means the tower of babel. So, some kinds of issues seem resilient to expansionistic explanation.

  8. The expansionist model is one more step towards unfalsifiability (see Falsifiability, The Dragon in my Garage, and comments 1, 2, and 3)

Acknowledgements: reddit user Y_chromosomalAdam contributed several points. reddit user fuzzy_thoughts pointed out the unfalsifiability issue and wrote the linked to comments.

  1. See Royal Skousen’s work here and here 2