This past week, after my introduction to philosophy lecture, I was chatting with a girl in my class who is a professed non-denominational Christian. I was talking about how I planned to take a class in Catholic theology next semester (I am an Eastern Orthodox Christian who used to be Presbyterian, and Catholic theology is my weak point in theological knowledge), but that I might not be able to because it might not be offered next semester. “I suppose I could take this other course on the Trinity, but that would probably end up being a bunch of heresy,” I said.

“Hersey?” she asked.

“Yeah, heresy. Like Arianism for example. It’s the belief that Jesus was merely a created being of God the Father and not fully God in the same way God the Father and the Holy Spirit are. It was condemned in the 300s.”

“Isn’t that just another opinion on what God is like?”

“No. That’s heresy. It’s wrong. And it’s dangerous.”

Why would I react in such a way? To be fair, the way I phrased my answer came out as a bit too harsh, but I do not think calling heresy dangerous is an exaggeration in the slightest. If anything, the word dangerous is not strong enough.

What exactly is heresy? Hersey is any belief contrary to the historical Church that Christ founded after his resurrection and entrusted to his apostles and their successors.The Church has historically condemned heresy when a belief sprang that proved contrary to the message of God’s incarnation as a human being, death, resurrection, and ascension to save all humanity.

So why is Arianism specifically a heresy? Quite simply, it is because the message of Christianity is completely meaningless if Jesus Christ was not God in the flesh. As St. Paul the Apostle puts it, “As many as have been baptized into Christ have put on Christ.” (Galatians 3:27) and furthermore, “Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death?” (Romans 6:3). Thus, in baptism, the Christian is baptized into Christ’s death, so that he/she is also raised with Him in His resurrection. Thus, one becomes a “[partaker] of the divine nature, having escaped from the corruption that is in the world because of sinful desire.” (2 Peter 1:4). Christ being simply a man and not God incarnate means that he really did not destroy death (Hell has swallowed many mere men before) and that we are still enslaved to the passions. Thus, if Christ is not God, both our baptism and Christianity as a whole are meaningless.

How would this affect how one lives? Well, an Arian would not, and could not believe that there is much spiritual benefit from the life of the Church. What does the Eucharist (Holy Communion) mean if it is the flesh and blood of a mere man, and not God Himself? What is the purpose of confession if Christ does not have the power to forgive sins and thus could not have passed it on to the apostles and their successors? (see John 20:19-23). Thus, an Arian could not be a serious Christian. All that would matter to the Arian is their personal beliefs. Their life in the Church could not, and would not be fulfilling. And as the early Church believed and taught, “one Christian [is] no Christian.” An Arian is not and cannot be a Christian.

One such example of modern day Arians is Mormons, a pseudo-Christian group that denies the unity of the Trinity. Mormons make no claims themselves to be representative of historical Christianity at all. Furthermore, two Brigham Young University professors, David Peterson and Stephen Ricks, state, “Latter-day Saints [Mormons] reject the doctrines of the Trinity as taught by most Christian churches today.” (https://www.lds.org/ensign/1988/03/comparing-lds-beliefs-with-first-century-christianity?lang=eng) They are not Christians. To be a Christian is to believe Christ is God. And to not believe Christ is God is to cease to be a Christian.

Of course, Mormons, just like any human being created in the image of God to become unto His likeness, are worthy of respect and dignified treatment. Mormons bear the image of the uncreated God and should be treated as such.

More than just Arianism, heresy as a whole is extremely threatening. Most heresies stem from an attempt to understand that which cannot be understood (like the Trinity, the Eucharist, Confession, forgiveness, etc.). To attempt to understand that which cannot be understood is inherently to reject paradox. And without paradox, Christianity cannot exist. Christ teaches that in order to become rich, one must become poor. To be great, one must become the least. To lead, one must be a servant. To live, one must die. None of that makes sense. And it should not make sense. To accept Christ is to accept the paradox of existence.

The point is that heresy is not to be taken lightly. It is dangerous, and can cause people to change their actions and ultimately their lives. That being said, having mere correct theological knowledge is not enough. A theologian is one who knows God. In fact, the etymology of the word theology comes from the Greek words "theos" meaning "God," and "logy" meaning "the science of." And, according to Evagrius Ponticus, “If you are a theologian, you will pray truly. And if you pray truly, you are a theologian.” The purpose of the Christian life is to become like Christ. That is something we will spend our entire lives doing.