In another thread, an anonymous poster writes:
"No one (and I mean no one) disputes the existence of Orthodoxy throughout the ages. An historical remnant is far less plausible (though, to be sure, not impossible)....If historical evidence alone is our guide, then there is far more evidence for the continuity of Romanism and Orthodoxy then there is for Protestantism. If, on the other hand, the argument is one that answers primarily to theological considerations, then what established theological criterion makes your position superior? And does the theological criterion have a *clear* basis in sola scripture?"
Those comments were directed to Steve Hays. But they're common sentiments, and I want to comment on the issues involved.
If the writer has Eastern Orthodoxy in mind when he refers to "Orthodoxy" in the first sentence, then I reject the concept that "No one (and I mean no one) disputes the existence of Orthodoxy throughout the ages". Any group outside of Eastern Orthodoxy that claims to be the true church, such as Roman Catholicism, would deny that Eastern Orthodoxy has existed throughout church history. They might acknowledge that Eastern Orthodoxy has some degree of continuity by means of a succession of bishops, for example, but they would maintain that the earliest bishops in such successions differed in their beliefs from the beliefs of modern Eastern Orthodoxy. They wouldn't call the earliest links in the chain "Eastern Orthodoxy". And just as Roman Catholics would make such an assessment of Eastern Orthodoxy, Eastern Orthodox would say the same about Roman Catholicism. Neither group accepts the entirety of the other group's claims about its origins. Neither group can claim that its historical roots are undisputed. And the same is true of any other such group that professes to be the true church.
If the anonymous commenter wants to say that he's only referring to a group having a degree of continuity, such as the sort of succession of bishops I referred to above, then why did he only mention "Orthodoxy"? Eastern Orthodoxy isn't the only group that traces itself back to the apostles through something like a succession of bishops.
And why should we think much of such a succession? Successions are claimed by groups that contradict each other to a significant degree in their teachings. There are significant doctrinal contradictions within single lines of succession, and Roman Catholics, for example, disagree among themselves about which bishops of Rome have been legitimate and which haven't been. The fact that people in ancient times were interested in maintaining a church in the capital of the Roman empire isn't of much significance. Christians would want there to continually be a church in such a heavily populated area of the world, and there was some significance to the city in Christian memory (the martyrdom of Paul and Peter there, etc.). The location of the Roman church would attract a lot of esteem and wealth. It's not as if the continuing existence of a church in a city like Rome is something that should impress us as highly significant. Similarly, the fact that religions like Buddhism and Islam have survived for so long isn't something that ought to impress us much. There are multiple, doctrinally inconsistent (self-inconsistent and inconsistent with others) groups that claim a succession from the apostles.
When somebody like Steve Hays refers to theological reasons for thinking that God maintained a church since the time of the apostles, I would assume that he's making a judgment based on what scripture tells us about God and the church. He would justify his conclusion by appealing to the authority of scripture, and this blog has a lot of material arguing for that authority. The anonymous poster I've quoted above makes some comments (that I didn't quote) about how Steve's interpretations of scripture would be disputed by other people, but the fact that the interpretations are disputed doesn't prove that they're wrong or that Steve can't be confident about those interpretations.
The anonymous poster claims that "An historical remnant is far less plausible", but offers no argument that would lead us to that conclusion. To begin with, why would we think that we need documentation of each individual or group involved in the remnant for belief in that remnant to be plausible? There are periods of Old Testament history for which we have no historical records of anybody faithfully following God, yet it's plausible to think that God probably had some faithful followers known to Him, but not to us.
The issue isn't whether a denomination or a highly specified system of doctrine can be traced throughout church history. For example, while people identify Protestantism by sola scriptura, I don't know of any Protestant who maintains that belief in sola scriptura is necessary for salvation or was an appropriate belief for every Christian in history. I often cite the example of Papias. He apparently didn't believe in sola scriptura, but the form of extra-Biblical tradition he held wasn't Roman Catholic or Eastern Orthodox, for example. He believed in some extra-Biblical traditions that he received through men like Aristion and John the Elder (probably the apostle John). His rejection of sola scriptura would prevent us from considering him Protestant. But we have no reason to consider him a Roman Catholic, Eastern Orthodox, Copt, etc. either. And he doesn't have to be considered a Protestant for it to be considered plausible that he was part of a remnant of Christians preserved by God. A Protestant could even consider it plausible that many Roman Catholics, Copts, etc. have been believers and, thus, part of the church God has maintained.
When people ask about identifying a church God has preserved since the time of the apostles, they often have in mind a church with a particular degree of verifiable presence in extant historical records, visibility, and doctrinal continuity. And those assumptions often aren't stated or defended. They're just assumed. But if such assumptions are false or unverifiable, why should we accept them? Nobody reading Jeremiah 31 could have known much, from that text alone, about how God would preserve Israel in accordance with His promises mentioned in that passage. If there are multiple ways that such promises could be fulfilled, we should acknowledge our uncertainty rather than claiming to know that the promises would have to be fulfilled as we'd prefer them to be fulfilled.