Here is a quotation from the Catholic encyclopedia article on "Protestantism":
[BOQ] Again, it is illogical to base faith upon the private interpretation of a book. For faith consists in submitting; private interpretation consists in judging. In faith by hearing, the last word rests with the teacher; in private judgment it rests with the reader, who submits the dead text of Scripture to a kind of post-mortem examination and delivers a verdict without appeal: he believes in himself rather than in any higher authority. But such trust in one's own light is not faith. Private judgment is fatal to the theological virtue of faith. John Henry Newman says "I think I may assume that this virtue, which was exercised by the first Christians, is not known at all amongst Protestants now; or at least if there are instances of it, it is exercised toward those, I mean their teachers and divines, who expressly disclaim that they are objects of it, and exhort their people to judge for themselves" ("Discourses to Mixed Congregations", Faith and Private Judgment). And in proof he advances the instability of Protestant so-called faith: "They are as children tossed to and fro and carried along by every gale of doctrine. If they had faith they would not change. They look upon the simple faith of Catholics as if unworthy the dignity of human nature, as slavish and foolish". Yet upon that simple, unquestioning faith the Church was built up and is held together to this day.
Where absolute reliance on God's word, proclaimed by his accredited ambassadors, is wanting, i.e. where there is not the virtue of faith, there can be no unity of Church. It stands to reason, and Protestant history confirms it. The "unhappy divisions", not only between sect and sect but within the same sect, have become a byword. They are due to the pride of private intellect, and they can only be healed by humble submission to a Divine authority. [EOQ] (my emphases)
"Let unity, the greatest good of all goods, be your preoccupation." - St. Ignatius of Antioch (Letter to St. Polycarp)