Kyle J. Gerkin writes for the Secular Web:
Archaeological Fallacies: The BoM [Book of Mormon] makes mention of various technological products which were unknown to Mesoamerica. These include chariots (Alma 18:9) when there were no wheeled vehicles of any kind, steel swords (Ether 7:9) when there was neither steel nor swords, bellows for blacksmithing (1 Nephi 17:11), and silk (Alma 1:29). The BoM describes a vast civilization of millions who inhabited cities for hundreds of years, yet no ruins from even a single BoM city have ever been identified. No BoM place-names were in use when Europeans arrived in the New World.
Anthropological Fallacies: The culture described in the BoM conflicts radically with that of the actual inhabitants of Mesoamerica. The BoM peoples had a seven-day week (Mosiah 13:18), but no Mesoamerican calendar matches this. And Nephi, who came to the New World from Jerusalem, never bothers to contrast these strikingly different places. Most stunning of all, the BoM never once indicates that the American continent was anything but uninhabited when the refugees from Jerusalem arrived. Of course, there were actually millions of Native Americans occupying the land from one coast to the other.
Biological Fallacies: The BoM refers to a host of animals that did not exist in the pre-Columbian Americas or had been extinct in that region for thousands of years preceding the period described in the book. These include the ass, bull, calf, cattle, cow, domestic goat, horse, ox, domestic sheep, sow, swine and elephants. Several common animals that actually existed in Mesoamerica (deer, jaguars, tapir, monkeys, sloths, turkeys, llamas, alpacas, guinea pigs) are never mentioned. Also described are crops that didn't exist, such as wheat (Mosiah 9:9) and barley (Alma 11:7) Indeed, the agricultural techniques required to produce those crops didn't exist either. Once again, crops that were commonly known to Mesoamerica (chocolate, lima beans, squash, potatoes, tomatoes, manioc) are not referenced. Perhaps the gravest blunder of all is the BoM's assertion of a Hebraic origin for the American Indians. In Joseph's Smith's day, the now firmly-established Asiatic origin for Native Americans was known only in some scholarly circles.
Linguistic Fallacies: There are no examples of "reformed Egyptian" (the language Joseph claimed was written on the plates) in Mesoamerican history. And no Native American language is related to either ancient Egyptian or Hebrew, whereas a relationship does exist between Native American languages and Asian (Siberian) languages. Furthermore, no BoM proper names (Nephi, Laman, Zarahemla) appear in any of the many Mesoamerican writings that have been discovered. And speaking of proper names, Greek names such as Lachoneus, Timothy and Jonas appear in the BoM, but Nephi and his family left Jerusalem in 600 BC, long before Greek culture would have had any impact on the Hebrews.
As a point of criticism, I'm not sure that the label "fallacies" is appropriate here ó a fallacy is an error in the reasoning of an argument, not simply any error, lie, deception, etc. If I say "2 + 2 = 5," that's not a fallacy. That's just a mistake. The above seems to me to be more accurately labeled errors or mistakes, not fallacies.
Aside from that, however, it is a pretty nice summary of all the basic problems that exist for the claims upon which Mormonism today is founded. There is simply no getting around the fact that demonstrably untrue things are claimed ó and claimed in a work that supposedly came from God, even if written down by someone else. What, didn't God proof read the Gold Plates?
An additional point of interest occurs to me: if so many people could follow a religion that is so recent but with so many factual holes in it, how much easier would it be to follow a religion that would be much harder to fact-check, assuming that anyone was even inclined to do so in the first place? One of the claims made on behalf of Christianity is that the events upon which it was founded were so recent for so many people that they wouldn't have followed if the claims weren't true. After all, it would have been too easy to check. Here, however, we have an example of a religion making claims that can be checked, have been checked, and have been shown to be false ó and it doesn't change a thing. Why, then, expect Jews and Gentiles in the 1st century Roman Empire to be any more skeptical and doubtful?