In addition to the two problems presented by looking at Scripture in a deeper way, there is a third. Actually, the first two aren't problems; they're observations which present problems when their truth is acknowledged. The third is a bonafide problem: What does the Bible say? Even granting the fact that figuring out what the Bible says is not the entirety of what Christians are to believe, it's a very important question. So what method will you teach us so that we can know and do what it says? You cannot retreat to lexical and exegetical expertise, because nearly all interpreters have experts and schools where that expertise is taught. We cannot appeal to the Holy Spirit; anyone holding any position can appeal to Him whenever he wishes. We owe it to ourselves to rule out everything that is not unique or dispositive, and then examine the presuppositions undergirding the rest.
In fact, when we bring this problem into the ecclesial dimension of our Christian lives, we see the problem most clearly. What are denominations, if not authority structures to promote the favored interpretation? The biggest reason we cannot simply accept the reasoning that these formulations apply only to the people in those communities, and that the 'Church' is wider than one interpretation is that no one acts that way, practically. It's a restatement of what I said earlier: We need to know what God says in the places closest to our lives lived in order to be Christians. We've opted for a theological relativism in order to serve our ecclesiology. We have been unwilling to challenge the premise underlying that ecclesiology: that we possess the ability and the authority to decide for ourselves the content of revelation.
When we see the witness of history for what it is, it does not matter that Catholic doctrine does not appear obvious in its particulars from where we stand. Rather,--and this is a point often overlooked--what matters is that the new ecclesiology does not achieve its goal on its own terms. Call it the Presumption of Return; if we are not holding at least what we started with when we follow the paradigm to its logical end, it cannot be correct. We know that as Protestants we were the arbiters of revelation because our authority structures do not carry weight outside themselves, and our subjection to them is voluntary, and always contingent upon their agreement with us. This is the full implication of ecclesial fallibility.
If there is a distinction between doctrines outside the "tribe," and doctrines outside of Christ, it cannot be made clear from either the exercise of ecclesial authority, or the contemplation of the extent of that authority. When we talk next time, we'll talk about history and comparing paradigms.