That's why I clarified. But again, knowing God exists is important to understanding the Bible. Lutheran theology claims it won't work the other way round - to study the "evidence" first and expect belief in God to follow.
I really don't believe that's a good way of coming to a conclusion about truth. If you believe first and then you're able to interpret the evidence, where did that belief come from in the first place? Short of a miraculous intervention, it had to come from an internal source. That would mean either a desire to believe that a particular faith is true, which is pretty unreliable because it's so focused on emotion, or a fear of Hell/hope for Heaven, in which case all of the problems with Pascal's Wager are invoked.
If it does come from a miraculous intervention, then you have the question of why it only comes to some people. Or, if it comes to everyone, why it's so relatively minor. It's easy to ignore a gentle pull toward belief in something when you have evidential reasons not to believe.
And I'm saying that from the direction you're coming, I can't know that. In the end, I may just be the Expert Fool. I'm willing to take that chance because my experiences are strong enough to say otherwise - they are of a nature I've never experienced anywhere else.
When I was more religious, I had experiences like that, too. I even had prayers answered. The problem with that is that, in some cases, those "answered prayers" were things that were really bad for me in the long run. I had a tendency to ask for signs about whether a particular fear was legitimate when I was a younger child, and sometimes, I would get those. I had an anxiety disorder, so you can imagine that wasn't a good thing.
Of course there are differences. But there are also similarities - more than I think you realize.
I think that a better analogy would be to the concept of scientific consensus instead of peer review. A point that's been tested and retested overtime, to the extent that it seems like the only possible explanation. Obviously there are still differences, but that's true with any analogy. Peer review, at least in political science (which is my field of study) is more of a methodological vetting process.
I purposely omitted the part where you started to define the Church. It's not the place of an unbeliever to do that just as someone outside a scientific organization can't declare who its members will be.
But the differences are not so large as you say. This idea that scientific organizations are formed "objectively" is nonsense. That might be the intent, but it is not the practice (I know both from studying the history of science and from personal experience). Similarly, churches have a noble intent that doesn't always come to pass.
And just as there are multiple scientific organizations with membership requirements and member roles that explictly define who can review a paper, there are multiple churches with membership requirements and member roles that explicitly define who can perform certain offices.
The definition of the Church that I used is a pretty commonly used one within Protestantism. Lutherans generally don't use the terminology of the visible and invisible church/Church (it's more common in Calvinist strands of Protestantism), but the underlying concept is still there. In that concept, members of the Church don't get to declare its membership. Only God can do that. The best that human beings can do is speculate.
Since we can't know who belongs to the true Church, then, it becomes impossible to differentiate between opinions that have been vetted by the Church and opinions just vetted by the church. If members of the Church constitute a minority of members of the church, then true opinions might slip through and be declared heresy, while false opinions rise to prominence. The response of the Catholic Church to the Protestant Reformation would be something that you would likely consider an example of this happening in actuality, so it's not simply theoretical.
I understand that seeing the Church's dirt laundry frightens some people, frustrates some, and disgusts others. But honestly, if there were a church claiming 100% agreement among all its members would you believe it? Would you take that as a sign it was the "true" church? I doubt it.
It's better to just get it out in the open and deal with it.
I would be pretty weirded out by a group that claimed 100% agreement. I'm not going to lie, I would think that it was a cult.
That said, it makes it impossible for someone to know which of their opinions are truly guided by the Holy Spirit if they don't have any solid source to appeal to. If I can't tell whether John Calvin, Martin Luther, or the leaders of the Anabaptists were divinely led, then I have no outside scale against which to measure my own interpretation. Therefore, I'm adrift. If you're confused about infant baptism, you have no way to know whether the appeals to scripture made by the Anabaptists are correct or whether the appeals made by John Calvin or Martin Luther are stronger. They both have good evidence, but ultimately if Biblical interpretation requires the guidance of the Holy Spirit, you're on your own in determining if your interpretation is guided.
And I'll repeat my point. This is the most important point of the post: it doesn't matter. You must start and end with Christ.
This goes back to my initial point. Belief preceding evidence is difficult to reach and impossible to validate. In grasping for belief, you're likely to default to whatever you grew up with, or to side with a particularly charismatic evangelist (or the religion of your spouse/significant other). Because of that, it doesn't seem like a very good way for God to reach out to humanity with the only means of salvation.
