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7 Differences Between Orthodoxy and Catholicism

When most Americans think about Christianity, they immediately either see a Catholic or a Protestant in their mind. They often don’t even know the Orthodox Church exists, let alone what it believes. Unfortunately, the same could be said of many cradle-Orthodox. They don’t really know what their Faith believes, or how it differs from everything else out there. This post is the start of a new series. In this series, we will explore the doctrine and theology of Orthodoxy more in-depth and compare it to those of other Christian denominations. Today, we examine seven key differences between Orthodoxy and her Western sister, Roman Catholicism. Gear up – we’re tackling a mountain range today!

The birth of the Roman Catholic Church

For over 1,000 years after Christ’s ascension to heaven, the churches of East and West maintained communion with each other. They were, effectively, one Church. Of course, heresy arose in small pockets over the centuries. But the Church handled these heresies with patience and faith, convening the Seven Ecumenical Councils to confirm Christian doctrine.

However, during those 1,000 years, the East and West steadily grew apart from one another, and hostility and distrust bloomed. Though the separation and diverging paths of the Eastern and Western churches occurred over several centuries, most people (somewhat incorrectly) look to the Great Schism of 1054 as the official birthday of the Roman Catholic Church. In July of that year, legates of the pope of Rome placed a bull of excommunication on the altar of the Hagia Sophia in Constantinople. This document officially declared Rome’s excommunication of the current Patriarch of Constantinople, Michael Cerularius, and his followers. A few days later, the Patriarch excommunicated the legates from Rome. This excommunication did not apply to anyone other than the individuals involved. But it never healed, and it ultimately resulted in the birth of the Roman Catholic church as we call it today.

(Obviously far more happened here than we are describing. But in the interest of time, we won’t go into all the details. That would take a whole series of articles itself!)

Differences between Orthodoxy and Catholicism

As a result of the Schism, differences inevitably arose between the Orthodox East and the Roman West. However, these differences seem far more numerous from the viewpoint of an Orthodox Christian than they do from the perspective of a Catholic.

What do we mean by this? Imagine for a moment: a black American travels to Africa and sees a black African there. He looks at the African’s appearance and after assessing him for a moment, says to himself, “We are so similar.” But the black African looks back at the black American, studying him deeply, and thinks, “He could not be more different from me.” The black American in this story is the Catholic, while the black African is the Orthodox Christian.

Most Catholics (and quite a few Orthodox) are not aware of what makes us so different from another. Aside from the papacy (which we will cover in a moment), the other differences between our churches escape our minds. Let’s try to correct that, shall we? 🙂 Here we go!

  1. Papal Supremacy
  2. Papal Infallibility
  3. The Filioque
  4. Absolute Divine Simplicity
  5. Created Grace
  6. The Immaculate Conception
  7. Purgatory

#1. Papal Supremacy

Papal supremacy is the teaching that the Pope of Rome has immediate, supreme, universal jurisdiction over every Christian. In effect, he is the physical head of the Church. No one, not even an ecumenical council, can supposedly overturn the ruling of a pope. Further, rejection of this dogma endangers your salvation. In other words, if you do not submit to the pope, you will not be saved (Pastor aeternus, Vatican I, 1870).

This teaching stems from a certain view of Saint Peter. The Roman church claims the bishop of Rome is Peter’s sole successor, because Peter allegedly – there is very little evidence of this – served as bishop there and received the “keys” to the Kingdom of heaven to “bind” and “loose” (Matt. 16:19). Interestingly, the rest of the Apostles receive these same keys to bind and loose in John 20:23, and the Lord Himself says He is the One with the “keys of hell and of death” (Rev. 1:18). The Orthodox certainly acknowledge that Peter occupied a special place among the Apostles as the first among equals. But we do not acknowledge any claims of supremacy, because these claims have no basis in Scripture or in the writings of the Fathers.

Additionally, Scripture never refers to Peter as head of the Church in any sense. Rather, we see that Christ is the head of His Church (Eph. 1:22, 5:23; Col. 1:18) and thus has no need for a vicar. Peter never appeals to any supreme authority, and none of the other Apostles legitimize that authority. Least of all Paul, who called Peter out over his temporary support of the Judaizing heresy (Gal. 2:11).

#2. Papal infallibility

Papal infallibility teaches that the pope cannot err in questions of faith and morals when speaking ex cathedra (“from the throne”; note: this doesn’t make the pope sinless or perfect).

This dogma did not exist prior to the First Vatican Council (1870), which defines it as follows: “This see of St. Peter always remains unblemished by any error, in accordance with the divine promise of our Lord and Savior to the prince of his disciples” (Pastor aeternus; emphasis added). It goes on to say that when the Roman pontiff speaks ex cathedra, “he possesses […] that infallibility which the divine Redeemer willed his Church to enjoy.” This “divine promise” refers to Luke 22:32, in which Christ tells Simon Peter that his faith would not fail. In other words, the Holy Spirit would protect the pope from teaching heresy. While Catholicism uses Luke 22:32 as justification for papal infallibility, the Orthodox (and the Church Fathers) do not.

Curiously enough, there does not exist a single, agreed-upon list of infallible statements made by the pope, or a list of criteria – a formula, if you will – for what constitutes a statement made ex cathedra, in all of Roman Catholicism. The most obvious concern here is this: what do you do if the pope is a heretic? Can he be deposed? If so, who has the authority to do that? The Orthodox hierarchy need not trouble itself with these sorts of questions, since Orthodox clergymen (including ecumenical patriarchs) can and have been deposed on a number of occasions, without presupposing the utter collapse of the entire Christian Church.

#3. The Filioque

The filioque (Latin, “and the Son”), is an addition to the Nicene Creed. In that context, it essentially states that the Holy Spirit proceeds eternally from the Father and the Son, rather than from the Father only. Rome officially declared this doctrine at the Second Council of Lyons. We also see similar language in the current Catechism of the Catholic Church (246). Despite Rome’s official position, many Catholics argue that the filioque does not refer to the eternal procession of the Spirit, but to His temporal mission. The Orthodox can agree with such an approach, though we ultimately reject the way the filioque was inserted into the Creed. It goes without saying, but the Orthodox do not share Rome’s official position here.

The Orthodox object to the filioque for several reasons. First, it deliberately changes the words of Christ in John 15:26, when He said, “But when the Helper comes, whom I shall send to you from the Father, the Spirit of truth who proceeds from the Father, He will testify of Me.” Second, it violates the perfect balance of Trinitarian theology. In this balance, any particular attribute can belong either to the divine Nature (the Godhead) or to one Person (Father, Son, or Holy Spirit). If the eternal origin of the Spirit’s spiration belongs to both the Father and the Son, the Spirit is subordinated, because He does not possess something the other two Persons do.

And thirdly, the addition of the filioque was uncanonical. The Second Ecumenical Council ratified the Creed as it now stands. Its inviolability was confirmed by several popes anathematizing any changes to it. Therefore, Rome’s deliberate altering of the Creed without the consent of an Ecumenical Council spells conflict.

#4. Absolute Divine Simplicity

Another difference between the Orthodox and Catholics’ understanding of God is absolute divine simplicity. This can get a bit complex, but we will try to simplify the differences here as much as possible.

Catholicism posits that the essence of God (who He is in Himself) is identical to the attributes of God (what can be said about Him). Absolute divine simplicity classifies God philosophically as a “substance,” and it insists that God’s oneness is an undifferentiated singularity, with no facets, aspects, or distinctions. This makes the Catholic version of God far less approachable or near to us, because He is only Himself. We cannot experience Him in any tangible, realistic way.

The Orthodox faith, on the other hand, teaches that God is both unknowable essence and knowable energies, following the teachings of Gregory Palamas and the ancient Church Fathers (i.e. St. Basil the Great). While being both unknowable essence and knowable energies, God is still Himself, One God in Three Persons, undivided. Imagine the sun. The sun is unknowable in its essence (its primary substance), because any human being who attempts to get close enough would be destroyed. Yet as human beings, we can interact with the sun through its energies (the heat it radiates, the light it provides, and the energy it gives off to feed plants, which in turn provide oxygen for us to breathe). The same is true of God. We will never know Him in His essence, but we can know Him through His energies, most particularly Grace.

Ultimately, this doctrine within Catholicism betrays Rome’s desire to define God’s nature than to simply experience God as He revealed Himself to us. We experience God concretely as Three Persons, not as a nature.

#5. Created Grace

Because Catholicism does not understand God as both essence and energies, problems arise in its understanding of both the presence of God in the believer and the effects that occur because of His presence. Unlike the Orthodox, who believe grace is uncreated, Catholics therefore believe grace is both uncreated and created. (Note: this is not a dogmatic teaching. As such this is one difference between the Orthodox and Catholic churches that could be worked out more easily.)

Roman Catholic theology teaches that there is both uncreated grace (God) and created grace, which is granted or conferred upon the believer and gives him “merit”. In other words, created grace is an effect. It is only understood by analogy to God’s work, and is therefore not really grace at all. Instead it is another way of describing the state of the believer under the influence of God’s uncreated grace.

In Orthodox doctrine, divine grace is uncreated and therefore represents God Himself – His energies. The believer is sanctified through synergy with God and His energies. If the grace the believer experiences is simply an “effect,” then he remains separate from God. Naturally, true communion with God is impossible if we remain separate from Him.

#6. The Immaculate Conception

Yet another difference between the Orthodox and Catholic churches is our understanding of the conception of the Virgin Mary. The Immaculate Conception (IC) is a Catholic dogma that states the Theotokos was preserved from the stain of original sin upon her conception in the womb. In other words, Mary’s immaculate conception is what made it possible for her to assent to Christ’s Incarnation. While the Orthodox agree Mary’s womb was sanctified to prepare for the coming of the Lord, we believe this purification instead took place at the Annunciation.

Orthodox rejection

Throughout history, Eastern Orthodoxy finds no support in Scripture or patristic writings for the IC. Further, the Orthodox never embraced St. Augustine’s approach to original sin. According to this approach, the guilt of Adam’s sin, which all are born with, deserves a sentence of condemnation and separation from God. Thus, unless that stain is removed, logic requires all who came before Christ to be in a condition of gracelessness and damnation. However, Mary also came before Christ and she was holy and blameless before God. Therefore, in order to maintain consistency, the Virgin Mary must somehow be conceived without original sin in order to be a pure vessel for the Incarnate Son of God. (An “exception to the rule,” if you will.)

But, if God could bestow upon her freedom from original sin, why did He not do so with everyone else? What need was there for Christ’s Incarnation in the first place?

The Orthodox maintain the approach of the Church Fathers re: sin, mainly viewing it as a spiritual illness in need of healing, not as a condition of guilt requiring retribution. Thus, the IC is superfluous. In the eyes of the Orthodox, this dogma actually demeans the Theotokos. As St. John Maximovitch wrote, “This teaching […] denies all her virtues. After all, if Mary, even in the womb of her mother, when she could not even desire anything good or evil, was preserved by God’s grace from every impurity, and then by that grace was preserved from sin even after her birth, then in what does her merit consist? […] then for what did God glorify her? If she, without any effort, and without having any kind of impulse to sin, remained pure, then why is she crowned more than everyone else? There is no victory without an adversary.”

#7. Purgatory

The final difference between the Orthodox and Catholic churches we’ll discuss here is about what happens when we die.

According to Catholicism, all those who are “saved” will go to purgatory when they depart this life. In the most basic terms, purgatory is a place of temporal punishment, which allows those who “die in God’s grace and friendship” to “achieve the holiness necessary to enter the joy of heaven” (CCC, 1030). In other words, even after you are saved and God has forgiven your sins, you must still make satisfaction for them after death.

The Orthodox Church does not believe in purgatory. While the Orthodox agree with the idea that we experience a “waiting time” between now and the Final Judgment, we object to the Catholic satisfaction model, which posits that God requires payment even after He forgives our sins. Within the Orthodox theological paradigm, there is either forgiveness or punishment, not both.

Some Church Fathers believed in purification after death. However, the character of this purification is never clarified, and it seems there is no true distinction between heaven, hell and “purgatory”. In other words, all souls partake in the same eternity, but experience it differently depending on their spiritual state: bliss for those who are in communion with Him; purification for those in the process of being deified; and remorse/agony for those who hated God during their earthly lives.


We could write books upon books detailing all the theological and doctrinal differences between the Orthodox and Roman Catholic churches. But suffice it to say that these 7 differences are some of the more noticeable, well-known ones.

Keep an eye out for our next post in this series, in which we explore the main differences between Orthodoxy and Evangelical Protestantism.

Read More >> Why are Catholic and Orthodox Easters Different?

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