Mormons are Christians. While many other sects of Christians dispute this fact, people are allowed to define themselves. Mormons insist that they are Christians; therefore, they are. It is true that Mormon theology differs significantly from mainline Christian orthodoxy in many aspects, but it is also true that prior to the deliberate and systematic purging of “heretical” doctrine by Emperor Constantine’s Council of Nicaea (largely for political reasons), Christianity was a much more diverse entity than it is today. I find the diversity of doctrine like all diversity to be healthy, as singular dogmatic authority of religion tends to lead to Dark Ages (see world for 1,000 years post-Constantine).
Mormon beliefs differ from mainline Christian beliefs in some significant ways. First, they believe that divine revelation continues to unfold and that the Book of Mormon and other Mormon texts are examples of God’s continuing revelation. Therefore, the Old and New Testaments are important theological documents, but they are augmented and revised by more recent revelation. Because doctrine is an evolving entity, it is changeable, making Mormon religious beliefs much more amenable to change than evangelical Christianity that insists on the infallibility of the Bible.
The head (known as the “President”) of the Church of Latter-day Saints (LDS) is believed to be God’s living representative and prophet on earth. As such, through prayer, fasting and discipline, he may receive new revelation or revelation that revises previous doctrine. In this way, there is no theological inconsistency with major ideological reversals (i.e. stances on polygamy and allowing African Americans into the priesthood) in Mormon teaching.
While many would criticize Mormonism for this apparent lack of consistency, one could also consider that the evolving nature of the religion makes it open-minded and amenable to making changes to allow for progressing social ideals. In many respects, the ability to admit mistakes and to correct them is commendable. A further extrapolation is that Mormons believe that their prophet is first and foremost human and therefore vulnerable to all of the limitations of the species, unlike the Catholic faith that insists upon Papal infallibility.*
Another point of divergence from mainstream Christianity is that Mormons believe God exists in actual physical form and that he is of the same species as earthly humans. God was once much like we are, but then through progression achieved his divine nature. Mormons believe that all humans are literally the children of God and his wife, that we were created in the celestial realm prior to our physical birth, and that each of us has within us the capability to achieve godhood. While God and Mrs. God are our creators, they are not static, perfect, infinite beings of undefinable ether, like the God of mainline Christianity. Instead, they continue to evolve in other realms beyond the human sphere of existence. In this vein, Jesus, the son of God and Mrs. God, is a separate entity to Heavenly Father, and the Holy Spirit is a combination of their holy essences.
Significantly, Mormons do not believe in the concept of original sin. Adam and Eve “fell” from Eden in order to undergo the progression towards godhood that requires life in a human form, complete with free will, temptation and importantly, the ability to procreate. Unlike other Judeo-Christian faiths that stipulate that humans are irrevocably tainted with the stain of original sin, Mormons believe that we are only tainted and judged by our own, independent behavior. We are therefore accountable for our actions, and faith alone will not redeem us; nevertheless, we can strive for an achievable perfection. Rather than being condemned, Adam now holds the number 3 position in godhood in heaven, subordinate only to God and Jesus.
In addition to the above primary differences between Mormonism and other Christianities, The Book of Mormon and other Mormon doctrines comprise a complete anthology of additional and revised beliefs too numerous to elaborate on here. Many of these additional beliefs, such as the notion that Native Americans are the descendants of the lost tribes of Israel, are definitely at odds with scientific genetic evidence.
Judging as an outside observer, Mormonism has much to recommend it for those who are so inclined. The emphasis on personal accountability rather than original sin seems to have observable results. The bigots down in the Bible Belt, who insist that we are all a bunch of dirty sinners who can be saved simply by placing our faith in Jesus, enjoy the highest divorce rates, highest rates of teen pregnancy, highest rates of illiteracy, deplorable rates of incarceration, juvenile delinquency, etc. Meanwhile, Mormons have above-average education levels, low divorce rates, low rates of drug abuse and other delinquencies, etc. I find it interesting that other Christians are so quick to condemn their Mormon cousins. With open minds and hearts, perhaps they could learn a thing or two about themselves. Mormonism may vary in detail, but in substance is no different than any other religious faith. The fact that Mormons are willing to admit to theological error and correct it should be a recommendation rather than a criticism.
*I am currently reading The Borgias by Ivan Cloulas, an interesting case in point.