Conveniently rejecting the proclamations of synods and councils as well, which seem, by the way, have been who decided was what Holy Scripture and what was not. As for “infallibility ‘ is is something like sovereignty and supremacy. The ultimate authority might lie somewhere in society, and Luther chose to invest that in the “baptized,” which is —on one level, true. But in every society there are officers who must speak for that authority. And that, according to the New Testament itself, must be in the Apostles and their successors. Early on that was settled in the bishops and priests, in a hierarchy, a holy order of “government.” Since Luther’s time, in the Protestant symbolized by the Geneva gown, the highest office has been that of Biblical scholar. It could hardly have been so in the 2nd century, when it had yet to be determined what the New Testament was to be, when the canon was finally —especially after — Marcion, decided those Christian works authenticated by their connection with the Apostles.
As to the historic structure, which we see in East and West, whatever the cultural differences, the development of the papacy came about, if not of necessity than from the evident need for a place of appeal. As to Westminster, it is a bit ironic, since every Englishman, at that time, Catholic and Protestant, was convinced that Christian had more or less stated in England, what with Joseph of Arimathera, the Holy Grail and all that , taken on faith alone. If an English synod said, it it must be infallibly true. ;)
Conveniently rejecting the proclamations of synods and councils as well, The point is that Scripturally they are not infallible, and you have failed to give a coherent answer to my basic questions, thus my response must wait.