Witnesses
There are 11 people who claim to have been witnesses to the Golden Plates. Many Mormons find it compelling that 11 people said they saw the plates and feel that gives evidence of their existence. However, when you look a little more closely, the evidence becomes a bit thin.
All 11 people were close friends and relatives of Joseph Smith. Except Martin Harris (discussed below), all were part of just two families – the Smiths and the Whitmers. Also, none of them actually signed anything. The only document with their names attached to it is a document pre-written by Joseph Smith and signed only by Oliver Cowdery, who wrote the other 10 names on the bottom as additional “witnesses.”
Some of them count as their “witness” that they saw the plates underneath a cloth (so, they didn’t see the plates themselves, just an unknown item underneath a cloth). Others said that saw the plates with their “spiritual eyes,” not with their physical eyes.
Martin Harris, one of the witness, had a huge financial incentive in the Book of Mormon since he mortgaged his farm to get it published. He would have wanted people to believe the plates were real so they would buy the book. Many of the witnesses were very superstitious, said lots of weird stuff, had a lot of various visions and joined several churches both before and after Mormonism. They were not very credible people.
Mom’s additional thought: If 11 witnesses are compelling enough to believe that something is true then one would also have to believe in the Mormon off-shoot sect of James Strang. He took over his own sect after Joseph Smith died, also claimed to have found and translated plates, and had 11 witnesses to these plate that never recanted. Yet, I don’t know of any mainstream Mormons who believe that the Strang plates were real. This is just one example of things that people bear testimony of that aren’t real. It happens all the time, in and out of religion.
Want more detail? See https://read.cesletter.org/witnesses/ and http://www.mormonthink.com/witnessesweb.htm