Q. I met a Mormon guy while I was at a summer camp. He told me he was a Christian, but I always thought I heard that they aren’t. What are they?
A. Good question! Though I’m not an expert on the Mormon religion, I’d be happy to shed some light on this question and even broaden it to other Christian religions.
One of the most central beliefs of all Christians, including Catholics, is that there is one God. This God is the Father, Son, and Holy Spirit—three distinct Persons yet one divine Nature. The Council of Nicaea, in 325 AD, defined the Son as “consubstantial” with the Father. In other words, He is of the same substance or essence as the Father. This also applies to the Holy Spirit. God the Son took on a second nature when He became man, so the Son is both God and man.
This central belief of Christianity is one that Mormonism does not share. Mormons claim to believe that Jesus is divine, but that He and the Father are not of the same divine nature. Rather, they believe the Father, Son, and Holy Spirit are three distinct gods. They believe these three gods are united in the same purpose but are not of the one and only divine essence.
That might all seem confusing and overly philosophical, but it really is at the heart of what we believe as Christians. Therefore, if anyone denies this fundamental belief, that there is one God rather than three gods, then we would have to say their beliefs are not the same as ours. It’s fair, then, to say that Mormons and Catholics differ in their belief about the Trinity in an essential way. All of the mainstream Protestant religions, however, believe the same as Catholics regarding the Trinity.
So what’s the bottom line? The bottom line is that Mormons do not have the same essential Christian belief in the Trinity as we do. In fact, it is this essential difference that has led our Church to reject their baptism as a valid one, even though they use the same words as we do. We do, however, accept other Christian baptisms as a valid Sacrament (such as Lutherans, Anglicans, Presbyterians, Baptists, etc.). We accept these baptisms as valid because those Christian denominations believe the same as we do regarding the Trinity and other essential aspects of the Christian faith.
If you were to talk to a Mormon, however, you might find that they do believe many things we do. For that reason, we do not reject anything in their religion that is true. We do, however, reject their doctrine on the Trinity, as well as a number of other essential beliefs regarding salvation, eternal life, Original Sin, Heaven, revelation, etc.
Mormons can certainly be good people and might claim to be Christians, but we do not believe they have the essential beliefs that make a Christian a Christian.