Sometimes my children are working through a problem in math and find, by looking at their final answer, that they must have gone wrong at some point. The approach I have taught them is a time-tested approach: go back to the beginning and start over. Rework the problem forward step by step. Show all your work. See if you can spot the mistake.
I think this is why there is such a renewed interest in patristic studies in the church. We can look at where we are, and it is very plain to most of us that Christian theology and fellowship have gone very wrong in some ways. So we go back to the beginning and trace forward.
It is very tempting in patristics studies to look at the details, attempting to locate what is the problem. We can trace through doctrines, views of Christ, views of Scripture, views of church authority, views of the sacraments, and any other difference that plagues us we can review in all its history. But patristics is a vast field, and our current differences in Christian belief are a vast field. So pursuits like that -- as informative as they are -- have so far been unfruitful.
Sometimes, when tracing through a problem, we think we realize how a mistake occurred -- we spot a mistake in method. I very nearly wrote this post on Vincent of Lerins' Commonitorium as a case study in how problems of church doctrine were solved in the middle of the patristic age. The idea is that once a method could be established and agreed upon, then it was a matter of tracing forward from the earliest days of the church using that method, and we could then determine exactly when and in what way we made a wrong turn in method. We could apply the right method and see what results should have followed. Still, the very matter of method -- of how problems should be solved -- has become part of the field of disagreement.
Sometimes, when there is so much disagreement all around, the first thing to do is to determine when a problem occurred. I think this is our first necessary step because it is often possible to recognize when a mistake occurred even before we identify what the mistake entailed or how it was made. For example, in my own field of programming, when a certain type of problem occurs and resists a quick analysis, the thing to do is debug the program: trace through step by step looking for tell-tale signs not of what the problem is or how it came to be, but of when the problem begins. Finding exactly when the problem begins is then the biggest clue in identifying the exact nature of the problem and setting things right.
In order to spot a problem, we need a flag to say when a misstep has occurred. If we take "one, holy, catholic (all-encompassing) and apostolic church" as our benchmark for spotting a problem with the church, then we look for when the church stopped being one, holy, catholic (all-encompassing) and apostolic; the problem must have occurred before then.
Tracing through step by step, I think we're on safe ground to say that the apostolic church was still one, holy, and catholic (all-encompassing) at the end of the apostolic age, roughly 100 A.D. Likewise, the church still met those criteria in 200 A.D. and 300 A.D. By the time we get to 400 A.D. I'm not quite sure. Inching forward from 300 A.D., we get to the Council of Nicea in 325 A.D. and find the apostolic churches are still in fellowship. At the Council of Constantinople in 381 A.D. the apostolic churches are still in fellowship, but it is strained. The Bishop of Rome did not attend the Council of Constantinople and some of the decrees of that council were, to say the least, involved in later controversies. By the time we get to 451 A.D. the apostolic churches have split into at least three separate groups which still exist and have never reconciled. So I would, just in broad terms, place the date when serious mistakes were made no earlier than 325 A.D. and no later than 451 A.D.
But, given that there were such early splits, can't we set aside those and concentrate only on the more recent ones? Aren't the more recent ones the most relevant? What about the split between the Eastern Orthodox and the Roman Catholic church, often dated to 1054 A.D.? What about the Protestant Reformation, beginning in 1517 A.D.? Why focus on such early splits?
Again, it is tempting to trace the roots of the disagreements in those later splits back to the earlier disagreements between 325 A.D. and 451 A.D.; the roots are certainly there. But that would be a misstep for my present purposes; it is not necessary for later disagreements to be the same ones as those earlier disagreements in order for those earlier disagreements to be relevant, even for those earlier disagreements to be critical. No, the more pressing point here is that these later disagreements cannot possibly be resolved without first having resolved the earlier disagreements on more basic things. It is possible, in working a long and complex math problem, for there to be more than one mistake. But when there are two or more mistakes, fixing only the latest one does not fix the entire result. In fact, much work fixing a late mistake may well be wasted effort if there is an earlier problem underlying it.
So I would invite everyone reading along, and all those who would direct their studies towards the eventual reunification of the church, to rework the problem with me. The study of patristics is, in that sense, the record of the church "showing its work" as it worked out the meaning of the amazing things that happened among us.