This is something that has puzzled me for a number of years now, so I decided to make a post explaining why I think it is absurd and idiotic. The specific part that is almost always included in a Mormon testimony is something similar to this "I know, by the power of the Holy Ghost, that the Book of Mormon is true, that Joseph Smith is a prophet of the Lord," If you ask a Mormon HOW they know it is true they will tell you that they prayed and asked god to tell them if it was true. That's it. The reality of the situation doesn't seem to matter to them, all they seem to care about is that they muttered a few words in their head, and had a feeling or felt an emotion which they think confirms that Mormonism is true. This is a type of idiocy that you only see within things like religion and alternative medicine.
Unfortunately for these people, no link has ever been made between 'feelings' and the truth of any given statement. I could pray to a bottle of milk that I would win the lottery and get a warm fuzzy feeling when I say it, but that wouldn't make it true. My analogy isn't perfect of course, because there is a small possibility that I could win the lottery, but my praying to the bottle of milk would have had nothing to do with it. If you go onto google, and search (with the speech marks) "I know the book of Mormon is true" and you will see exactly what I'm talking about. Most of the websites that come back on the search say things like "I know The Book of Mormon is true. I have read it, I have prayed about it, and I have received a personal witness through the Holy Ghost, that it is true."
The problem becomes even greater when we actually examine the book of Mormon. It has been demonstrated to be false about a lot of things. The book of Mormon is a fabrication straight from the mind of their prophet Joseph Smith and no amount of praying believers will ever change this fact. There were no Israeli people in the Americas during the first century C.E. and the native American people are not descended from them. 'Reformed Egyptian' is not a real language as claimed by the book of Mormon, and the imaginary Jewish-native-Americans did not use it. I could go on and on but I think I have made my point. Historical inquiry does not corroborate with the book of Mormon, and thus we can dismiss the book of Mormon as a work of fiction written by Joseph Smith the con man.