The utter confusion created by heresies is evident in this thread. We have views spanning the full spectrum of possibilities. As JB notes, we have people happy to embrace mutually exclusive options; we have an implicit admission that either Scripture is so ambiguous that very few can agree on even the requirements for salvation, or that it is just plain contradictory. And yet, apparently, God willed for Scripture to be a primary means for people to come to knowledge of the truth. And the Mormons and JWs have yet to arrive...
Or perhaps God foresaw such an absurd situation and appointed an arbitrator, like is done in every other aspect of human life in which communities form.