When two people with competing theological beliefs each claim to have received knowledge directly from God through the process of divine revelation, how does an objective observer determine which person actually received knowledge from God and which person is mistaken or if they are both mistaken?
Oh...you're not paying attention again!
I specifically said NOT "believe." But now here you go right back and couple me with those who "believe."
Try harder.
However, to answer your question: An "objective observer" under those circumstances should determine that one is not telling the truth and one perhaps is. But that doesn't help, because those are not the circumstances here. You should not be searching for the one who "believes" the correct information and trying to determine how or why they are different from all the other believers. That would be a gamble (and I don't blame you for your objections). But instead consider how a blind person would "objectively observe" the claims of those claiming to have sight. Such an exercise should show you that your approach is flawed and will get you nowhere.
The correct approach would be to determine if it is possible that there is life beyond the bonds of the organic man. Ask yourself: Is humanity only organic...do I care? If you care to pursue it and have any idea that it might be possible, then pursue it. If not, then don't. But nothing will come of a blind man debating sunsets with those who may or may not have sight.
The real question then, becomes: On what shall I establish my own trust and belief? If on the words of another--take your pick, or do your homework. In which case there is only one consistent (however confusing) ribbon of witness testimonies since the beginning of time...and the others are all organic, man-made junk. Or you could appeal to the Source. The alternative is to waste this time allotted for this purpose.
In your search, consider this parable: If you were born into a large room and no one inside the room had been out or seen outside the room, who in the room could tell you what is outside...a teacher, a scientist, a great leader? No. The only way that anyone inside such a room could actually "know" anything about the outside...is if the knowledge came
in to them from the outside. This is the knowledge that you are looking for.