The question of authority is unavoidable, though many well-meaning persons try to avoid it, while remaining unaware that it is in fact unavoidable and that they are not successfully avoiding it. I pointed this out in my post in June titled "You say one must not papalize". Of necessity, either we are submitting to some ecclesial authority, or we are acting as our own ecclesial authority. What does it look like in practice to act as one's own ecclesial authority? Here's an example.
Protestant: "Go read Calvin; see for yourself that what he is saying is true."
Catholic: "But what authority does Calvin have? Why should I follow Calvin's teaching?"
Protestant: "He has the authority of Scripture, because everything he says is right from Scripture."
Catholic: "But what authority does he have to say what Scripture means, or to teach in the Church? Who ordained him, and authorized him to teach in the name of the Church? Who sent him? (Romans 10:15; Acts 15:24)"
Protestant: "Obviously God sent him. Just look at all the theological riches in his writings."
This hypothetical conversation shows how the Protestant and the Catholic are working within two different paradigms viz-a-viz authority. In this conversation, the Catholic is checking for ecclesial authority; the Protestant is not. The Protestant is judging for himself that Calvin's interpretations and teachings are in agreement with Scripture. The Catholic, on the other hand, looks to the magisterial authority of the Church to determine whether Calvin's interpretations and teachings are in agreement with Scripture. "What does Calvin say about the Church?", asks the Protestant. "What does the Church say about Calvin?", asks the Catholic.
Notice what is implicit in that "Read him and see for yourself". It is nothing less than the Serpent's advice to Eve that she look and taste for herself that the fruit was good for her. Implicit in it is the notion that "You have the highest authority [under God] to judge for yourself what is good for you".
Of course the common reply here from the Protestant is that the Catholic did the same thing, in becoming Catholic. There is truth to that, though he does so rightly not by determining for himself which doctrines are orthodox and thereby which institution is "most scriptural". Rather, he does so by determining which institution is the one Christ founded and thus which has the authority to tell him which doctrines are orthodox. (Even from the Protestant point of view, there are no institutions that have the authority to determine for all Christians what doctrines are orthodox.)
Consider the following quotation from St. Irenaeus:
"Therefore it is necessary to obey the presbyters who are in the Church, -- those who, as I have shown, possess the succession from the apostles; those who, together with the succession of the episcopate, have received the certain gift of truth, according to the good pleasure of the Father. But [it is also necessary] to hold in suspicion others who depart from the primitive succession, and assemble themselves together in any place whatsoever." – St. Irenaeus (Against Heresies, 4.26)
If apostolic succession is about form, and not matter, then loyalty to a group of persons is properly subordinate to loyalty to what one perceives to be the content of apostolic succession. In that case, there need be no hesitation in establishing a new group of persons around the form as one sees it (or finding a different group of persons that is closer in doctrine to the form as one sees it), for then the matter of the Church is determined by a certain form, and in that case the matter of the Church is rightly discovered by locating the material instantiations of that form. The alternative is finding form through matter, on the ground that matter determines form (cf. Against Heresies 3.3), as one finds the same life of an organism at a later date by finding the same physical body. I see no middle position. (Luther defined the Church in terms of what he believed to be the "gospel", as I pointed out here.)
For those who believe apostolic succession is about form, possessing what St. Irenaeus calls the "certain gift of truth" must reduce to teaching 'what I believe to be true'. For those who believe that matter determines form, the "certain gift of truth" is not the same as teaching 'what I believe to be true'. Rather, it means that truth is found in and through that matter.
What has this to do with unity? If the "certain gift of truth" is reduced to 'what I believe to be true', there will be as many different 'successors of the Apostles' as there are various beliefs about what is true. This is why the purely formal notion of apostolic succession is intrinsically individualistic and disposed to fragmentation. But if the "certain gift of truth" is understood in the sense that truth is found in and through that designated matter, then the particularity of matter (i.e. its inability to be multiply instantiated) makes this notion of apostolic succession intrinsically opposed to fragmentation, and intrinsically disposed toward unity and perpetuation. Catholics and Protestants cannot be unified until they recognize and resolve their fundamentally distinct understanding of Church authority. Does form determine matter, or does matter determine form?
For those who think that form determines matter, the question is then: "Form as determined by whom?" Since they have ruled out matter determining form, the only remaining answer is by default something reducible to "Me". Can such a position yield true unity? Those who answer affirmatively have traded in the unmatched unity Christ describes in John 17 between Himself and the Father for a democratic consensus around a "mere Christianity" drained of all content except a lowest common denominator of "Jesus" (or "Jesus saves", or "trust Jesus"). But that is if the liberals are excluded. And who will be the one to exclude them, if there is no pre-existing authority? Either there is a pre-existing authority, in which case matter determines form, or there is no pre-existing authority, in which case there is no possible ecclesial unity.
In every case where the Church seems to the critic to have "gone off the rails" with respect to dogma, it is (by the Quine-Duhem underdetermination thesis) no less possible that the Church has in fact stayed on the rails and it is the critic who has gone off the rails. (I raised this point in my article "Two Paradigms".) The Pharisee Gamaliel seems to have been aware of this, when he advised the Council of the Jews: "if this plan or action should be of men, it will be overthrown; but if it is of God, you will not be able to overthrow them; or else you may even be found fighting against God." (Acts 5:38-39)
With that in mind, it is not enough to raise a criticism of Church dogma, as if that establishes the Church's error. Throughout the history of the Church, heretical individuals and sects have believed themselves to be better judges of dogma than were the rightful leaders. That pride is precisely the sin by which they fell into heresy and schism – it can be seen in Korah's rebellion, and the sin of Nadab and Abihu. "We know better than you, Moses, what God wants for His people." The issue was not whether the leaders were fallible, but whether their God-given authority was to be respected, as David refused to kill Saul, and refused to make himself king. In order to unify the Church, we have to return to our rightful rulers. And that cannot consist in finding those who teach the doctrines we happen to think are true (cf. 2 Timothy 4:3). It means seeking out those old lines, the old matter (like Aragorn), and doing justice to their God-given authority over the Church. Either Christ failed to provide a means for ecclesial unity, or He provided to a line of men a "certain gift of truth". Those who deny that Christ provided to a line of men a "certain gift of truth" should be pressed directly on the possibility in their ecclesiology of true ecclesial unity. A careful examination will show it to be quite impossible, and for that reason rightly to be rejected. Grace builds upon nature, but those who deny that Christ provided to a line of men a "certain gift of truth" would need a miracle greater than the filling of the ark to bring about true ecclesial unity. That is Satan's lie, that man himself, by his democratic consensus, can establish the unity of Christ's Body. Implicit in that lie is the notion that the Church is not one. But God already made the Church one, as St. Cyprian explained. She is the "one, holy, catholic and apostolic Church". We do not make the Church one. We become one with the Church, and lead others to do so as well. The notion that Church unity is to come through democracy is the message of a contemporary Wormtongue.