@AlbinusFalco @FrDesposito You are required indeed to have a right notion of the Church founded by Christ. This is the work of apologetics. Then you know that by schism someone is necessarily leaving the Church. In the same way, an apparent authority teaching a new religion is disqualifying itself.
@AlbinusFalco @FrDesposito I will add one thing on the question of universal acceptance. The goal to have a revolution in the Church coming from the "pope" himself is well known. Pius IX himself ordered the Alta Vendita document to be published. Which means he did not consider it impossible.