I can't speak for NoI, but I can say that Mormonism is not Christian except by surface appearance, and Mormons are the only group that asserts they are Christian; all other christian groups reject Mormonism as a religious cult. Their actual beliefs are very different from Christianity (eg. god is an alien of flesh and bone from another planet, the denial of the trinity, jesus is not god and is instead satan's brother, the practice of baptism for the dead in secluded mormon temples, that heaven has 3 levels, and only super-faithful mormons who know all the secret temple passwords get to go to the top level).
Time to learn about Mormons from an actual Mormon. Our full/actual name is
The Church of Jesus Christ of Latter-Day SaintsFirst, we believe in the basic Christian belief that Jesus died for our sins and that belief in him will save us. However, we also believe that simply having faith is not enough to be saved; you need to have works as well [James 2:14-26]. This apparently is not a popular opinion. We believe in continued modern revelation through our prophet, which is a source of our "different" practices. We see these practices as being restored from the church that existed when Christ was on Earth.
Second, our temples are special places where we perform our most important ordinances (ceremonies, if you will). You don't need some secret password to get in, but you do need to have an interview with your local bishop to ascertain your worthiness to obtain a "temple "recommend," which is a sort of certificate allowing access. Temples are very holy places; we can't just allow anyone in. Each level of the temple is for a different ordinance, such as sealing a couple together, which is to make their marriage follow them into the afterlife. This is opposed to, "till death do you part." Romantic, huh? The lowest level, or the basement (which I might add is not a damp cave as thought by many, seriously, I wonder where people get this information from), is where baptisms
for the dead are performed. It is where members are baptized on behalf of people who are already dead, so that they may have the chance to accept membership in spirit prison and progress to spirit paradise, as explained
here.
Yes, we deny the trinity. We believe that God, Jesus, and the Holy Ghost are separate beings. This being said, we believe that they are one in
purpose, and thus perfectly able to work together to attain their goal of bringing all of us to Heaven. We believe that the Holy Ghost is a spirit, but that God and Jesus have bodies of flesh and bone, and that we are quite literally created in their image. Mind you, this perfection, both physical and mental, is far beyond what any of us can comprehend, and allows them to do the things that they do (that is, be our God and savior).
We believe in a premortal existence, where we all existed as spirit sons and daughters of Heavenly Father, and, by extension, an inferred Heavenly Mother. The Hebrew name for God, "Elohim," is plural. We take that to mean that "God" is constituted of a sealed man and woman couple, but Heavenly Father, as patriarchs do, acts as the spokesperson of the family. This all causes people to accuse of of being polytheistic. While we believe that there are several God-like beings, we only
worship one God. Back to us all being spiritual children of God, this included Jesus and Lucifer. They were both our brothers, and the eldest sons of God. God needed a plan to have us all be tested to see if we could be exalted to be like him one day. Both Jesus and Lucifer presented their plans to God. You may be familiar with Jesus's plan, where we would come to Earth, live our lives the way we wanted to with our
"free agency," have Jesus enact the Atonement, then come back to God to be judged. Lucifer's plan was also to have us all come to Earth. However, he wanted to be sent and
force us all to behave and live worthily. This would take away free agency, and thus preventing us from proving anything to God. God chose Jesus's plan and this angered Lucifer. He argued that Jesus, in his mortal state, could fail to enact the atonement. God cast him out along with his followers, about a "third of the hosts of Heaven." Lucifer and his followers became Satan and his demons, who have no chance of being saved and live in eternal torment. In their jealousy and rage, they strive to make all mankind as miserable as they are by dragging us down into sin. It may seem cruel at first, but they argued against God. Just think of the enormity of that.
Since we believe that we are judged by our works, it would make sense that there is more than one level of Heaven which we are assigned to according to how good we were. The full path from premortal existence to Heaven is in this diagram:
Outer Darkness is what's known as "Hell." The Celestial kingdom is where god resides. There is a thousand years between the Resurrection and Final Judgement. Those that make it to the Celestial Kingdom will become Gods themselves and have the chance to bring even more souls to be like them with their very own worlds. I know it sounds incredible, but like any good parent, God wants us to become like him in every sense. While it has never been mentioned explicitly, is can be inferred that God went through the same trials that we did to become our god. I don't think this diminishes his godliness, but instead makes the final goal more realistic.
I don't think that our beliefs are different, but rather more intricate and, for lack of a better word, complete. I've barely scratched the surface of Mormon doctrine, which is far bigger and more complex than any religion that I am aware of, but I think I have covered all the objects mentioned in the above quote and then some.
By the way, Books of Mormon can be obtained for free from the church. I mean this as in, don't
ever buy one from someone on the off chance that the opportunity arises
*sits back and hopes for a level-headed discussion*
Arguments about the meaning of agnosticism annoy me for some reason.
(Crimony this was long. Sorry about that.)