Core Doctrines and Pastoral Concerns
The Church, in its doctrinal matters, distinguishes those that touch upon the very essence of faith, while disagreements may arise over issues of church discipline, customs, and practical pastoral considerations.
For example, when it comes to marriage, discussions on a less critical level involve questions related to the pastoral approach to the marital relationships of clergy and the specifics of canonical legislation (as in the case of the prohibition of marriage after ordination), where disagreements are driven more by practical considerations than by fundamental doctrinal differences. In one fragment it is noted:
"When discussing the second and third questions, one should first keep in mind that they are related to very different problems. ... There is a pastoral aspect to the problem, and personally I do not think that changing the current canonical requirements is truly desirable." (source: link txt)
However, the principled—that is, truly doctrinal—issue that the Church recognizes is the dogma derived from the New Testament teaching on marriage. It is stated:
"The situation is much more serious in the third case. Here we are indeed talking about a principled issue, namely the dogma derived from the New Testament teaching on marriage." (source: link txt)
It is also noted that differences in customs and church discipline (for instance, in matters of church organization or rituals) are not an obstacle to the unity of the Church. According to one author, the only doctrinal issues capable of leading to a schism were "the Latin addition to the Creed and the doctrine that it reflected." In other words, it is precisely here that the fundamentals of doctrine are at stake, whereas the diversity of customs is seen as acceptable within the context of unity:
"He did not consider the diversity in customs and church discipline an obstacle to church unity. The Latin addition to the Creed and the doctrine reflecting it were, in his opinion, the only doctrinal questions that led to schism." (source: link txt)
Moreover, in the history of theological thought, special attention was given to the matter of the "Filioque"—a doctrinal dispute concerning the origin of the Holy Spirit which, according to several prominent Byzantine theologians, became the sole issue dividing East and West:
"This approach was generally predominant among the leading theologians of Byzantium. Peter of Antioch (around 1050) and Theophylact of Bulgaria (around 1100) openly asserted that the 'Filioque' was the only issue dividing East and West." (source: link txt)
Thus, the Church acknowledges as doctrinal matters those questions that are directly related to the exposition of the fundamentals of faith (for example, the dogma on marriage based on New Testament teaching, or issues related to the formulation of the Creed, as in the case of the Latin addition and the dispute over the "Filioque"). Meanwhile, disagreements may arise over matters of church order, liturgical customs, and pastoral and canonical considerations, which do not innately touch upon the essence of faith.