Methodists and Roman Catholics

There are some significant differences between Methodists and Roman Catholics, though Methodism is more similar to Roman Catholicism than are many forms of Protestantism (such as Calvinism). Some areas of theological difference for you are as follows:

Faith, Works and Justification: Methodism argues that people are justified by faith apart from works (Rom. 3:20-28; 4:1-5; 9:30-32; Gal. 2:16; 3:1-14), by which it means that we are forgiven entirely on the basis of grace. For some Methodists, such justification is sufficient to keep a person out of hell, but not to get him into heaven. For these, in order to get into heaven, one has to earn positive merit by doing good works (enabled by grace, for the most part). Other Methodists believe that faith is sufficient both for forgiveness and for the positive merit required to enter heaven. Many Methodists also argue that salvation/justification can be lost if one falls into sin.

There are great similarities between Methodism (especially those forms which believe that good works are required to earn the positive merit necessary to enter heaven) and Roman Catholicism in this area. In Roman Catholicism, one is forgiven on the basis of grace, but must do good works (enabled by grace) in order to persist in salvation, to avoid purgatory, etc. Roman Catholicism does define its term somewhat differently (Methodism tends to think of being "justified" as being "forgiven," whereas Roman Catholicism teaches that that one is "justified" one after one has earned the positive merit necessary to enter heaven).

For the record, though, those forms of Methodism that do not affirm the necessity of positive merit procured by good works, and thus which teach that faith alone is sufficient to get a person into heaven, are irreconcilable with Roman Catholicism. This is because the Roman Catholic Council of Trent anathematized (officially cursed and condemned to hell) all who teach "justification by faith alone" (per the Roman Catholic definition of "justification"). These two systems are really two different gospels.

The Church and Apostolic Succession: Roman Catholics teach that the Roman Catholic Church is the only true church, and that the pope is the supreme authority over the church, having received his authority by direct apostolic succession from Peter. Methodism teaches that apostolic succession does not hand down Peter's authority from person to person, and that there is no single visible entity or church that may be identified as "the true church."

Infallibility: The Roman Catholic Church teaches that the pope when speaking ex cathedra, as well as the church when met in ecumenical council, can never err. On this basis, all official Roman Catholic doctrine is infallible, and can never change. Methodists deny this claim as unfounded in Scripture.

Scripture and Tradition: The Roman Catholic Church teaches that church tradition is equally authoritative with the Bible. Methodists ascribe supreme authority to the Bible alone, observing that tradition has often strayed from the Bible.

Interpretation of Scripture: The Roman Catholic Church teaches that it has the final say regarding any interpretation of Scripture, such that no one may ever correct the church by suggesting that its official doctrines are not in accordance with Scripture. Any challenge to the Roman Catholic Church's doctrine can be refuted by its claim to authoritative interpretation. Methodists believe there is no authoritative human interpretation, and that authority belongs to God. For Methodists, interpretations are authoritative only insofar as they are true, and they believe that the Roman Catholic Church has frequently misinterpreted Scripture.

Historically, the Methodists derive from the Church of England, which broke with Rome near the time of the Reformation. That break was at least as political as it was theological. However, it included a theological rejection of Roman Catholic and papal authority as its basis. The theological impediments to reunion include both these issues, the different views of the sacraments (Methodists recognize only two of the Roman Catholic seven: baptism and the Lord's Supper; and they do not ascribe the same meaning to either of them).

Regarding comfort level, this has as much to do with the particular churches to which you belong than with the denominations to which you belong. Different churches do things differently; different ministers make you feel different ways. You would likely be a little less comfortable in her church than she would be in yours, unless your church still employs high Anglican liturgy. She, if she is a regular Mass attender, may be uncomfortable in any service not held in a great Cathedral and following the liturgy she has known for years - it may not feel like church to her. The personal theology of the ministers in each church will also impact how comfortable you feel - will they affirm both of you, or will they challenge you; will they hold you accountable, or just let you do your own thing; etc.

If, however, we speak of theological comfort, your girlfriend will probably be uncomfortable being excommunicated by her church and being told she is going to hell if she joins your church. On the other hand, if you are theologically inclined, you may feel uncomfortable eating Christ's actual body and blood, relying on your good works to earn your way into heaven, accepting every official doctrinal statement by the Roman Catholic Church as equal in authority to the Bible, etc.

If I may humbly suggest, however, you may not be approaching this question in the best way. From the way you phrased your question, it appears to me that you are contemplating marriage, and that this decision is more important to you than the decision to remain in one church or the other. That is, one of you is going to convert. I would suggest that both of your primary commitments should be to Christ and to the truth, and that you should not convert for the sake of love. According to the Roman Catholic Church, Protestants are going to hell. This basically makes Roman Catholicism and Methodism two different religions. Since both of you belong to religions that teach that the fate of your eternal souls hang in the balance of your religious commitments, neither of you should be willing to change them unless he/she is convinced on the truth of the other position. It should not be a decision based on comfort level or on a greater commitment to marriage than to Christ and the gospel.

I myself am neither Methodist nor Roman Catholic, but I do believe that the gospel the Methodists (especially those who do not believe that our good works earn the merit that gets us into heaven) teach is much closer to the biblical gospel than is the gospel the Roman Catholic Church teaches. My personal encouragement would be for your girlfriend to convert from Roman Catholicism to Methodism, abandoning the works-based gospel of the Roman Catholic Church and embracing the true gospel of grace that the Bible actually teaches.

Related Material:

Can Catholics be Saved?
Are all Protestants going to Hell (Catholic Dogma)?