The question is what difference the interpretive authority of the Magisterium makes, or could make, as a medium of the Spirit for "the plain reader."As evidenced especially in the comboxes, Brandon seems to believe that the difference is only one of relative completeness. Thus, you can get a lot of saving truth out of Scripture without the Magisterium's interpretive guidance, but you can only get all you can if you accept and utilize such guidance. That too, I should think, is true. But if one leaves matters at that, one is giving short shrift to a fundamental point about the Magisterium's role, one that John Henry Newman recognized well back in the 19th century.
St. Thomas Aquinas argued thus:
Neither living nor lifeless faith remains in a heretic who disbelieves one article of faith.
The reason of this is that the species of every habit depends on the formal aspect of the object, without which the species of the habit cannot remain. Now the formal object of faith is the First Truth, as manifested in Holy Writ and the teaching of the Church, which proceeds from the First Truth. Consequently whoever does not adhere, as to an infallible and Divine rule, to the teaching of the Church, which proceeds from the First Truth manifested in Holy Writ, has not the habit of faith, but holds that which is of faith otherwise than by faith. Even so, it is evident that a man whose mind holds a conclusion without knowing how it is proved, has not scientific knowledge, but merely an opinion about it. Now it is manifest that he who adheres to the teaching of the Church, as to an infallible rule, assents to whatever the Church teaches; otherwise, if, of the things taught by the Church, he holds what he chooses to hold, and rejects what he chooses to reject, he no longer adheres to the teaching of the Church as to an infallible rule, but to his own will. Hence it is evident that a heretic who obstinately disbelieves one article of faith, is not prepared to follow the teaching of the Church in all things; but if he is not obstinate, he is no longer in heresy but only in error. Therefore it is clear that such a heretic with regard to one article has no faith in the other articles, but only a kind of opinion in accordance with his own will.That is essentially the same point Newman was to make centuries later about the contrast between "faith" and "private judgment." The latter, whether individual or corporate, yields only "a kind of opinion in accordance with" one's own will; by contrast, the habitus of faith can only be enjoyed by one who reads Scripture while adhering "to the teaching of the Church as to an infallible and divine rule." Newman's point was that the Protestant as such is only exercising private judgment when they read Scripture while rejecting the interpretive authority of the Magisterium. They do not have the habit of faith, even when what they come to believe by reading Scripture is true and "of faith." They have only opinions—even when the content of the opinions coincides tolerably well with that of the faith-once-delivered. And I hold that position myself, as evidenced in my essay Faith, Private Judgment, Doubt, and Dissent.
One might well ask how that position compatible with Brandon's point and the teaching of Vatican II, both of which I also accept. At least I've asked myself that question. After some thought, here's my answer.
The key lies in Aquinas' distinction between "obstinate" heresy and mere "error." An "obstinate" heretic is one who both persists in rejecting the authority of the Magisterium and can be held morally accountable for that persistence. One who either does not so persist, or if they do so persist cannot be held blameworthy for persisting, is merely "in error." Now I agree with that as well. But I doubt I would agree with Aquinas— or indeed with most Catholic theologians between the time of Augustine and the mid 20th century—about the precise conditions one would have to meet in order to count as morally blameworthy for persistence in heresy. In that stance I follow Vatican II, which in UR explicitly denied that people brought up in non-Catholic Christian traditions can be presumed morally blameworthy for not being Catholic. Given that denial, it is possible for Protestants who, as such, are merely "in error" by virtue of rejecting the authority of the Magisterium in relation to Scripture, to begin developing the habit or virtue of faith partly by virtue of their Spirit-guided reading of Scripture. How?
It is well known that the major branches of Protestantism are divided from each other chiefly by virtue of conflicting interpretations of Scripture. Catholic apologists, including yours truly, often cite that as evidence of the need for Tradition and the Magisterium to condition the interpretation of Scripture. Yet despite the bewildering variety, I have found that remarkably many Protestants interpret Scripture as the Magisterium does on what are perhaps the most important points: the divinity of Christ, the Trinity, the Atonement, and the bodily resurrection of Christ. Given all the variety that obtained even in the early Church, as well as the variety that obtains today in Protestantism, that fact calls for explanation; and to my mind, the explanation is ready to hand. The reason so many Protestant interpretations cohere with the Magisterium's on the most important points is that the Magisterium, throughout the first millennium and before the definitive East-West schism, authorized the correct interpretations in light of Tradition and thereby solidified a traditional hermeneutic for reading Scripture on those points. Many well-disposed Protestants, whatever their disagreements with both the Magisterium and each other, remain beneficiaries of that hermeneutic. Thus the sound doctrinal core one can find in some versions of Protestantism is the historical product of how Tradition and the Magisterium have always conditioned the interpretation of Scripture. That core embodies an implicit reliance on "the teaching of the Church as to an infallible and divine rule." And that is what enables the faith of some Protestants to be more than just opinion, so that they can begin developing the habit or virtue of faith despite being "in error" (as opposed to being "obstinate" heretics). It is just that phenomenon that Fr. Al Kimel, in an article now lost to the blogosphere, last year called the "parasitic Catholicism" of some Protestants. The phrase itself understandably raised some hackles, but the substantive point was essentially the one I have just been making.
That point is confirmed for me by my experience with many Protestants in RCIA, when I was in charge of that process for a parish. Many of them said what a reader of this blog, a former Jehovah's Witness now in RCIA, has e-mailed me to say:
I spent many many years learning and teaching heresy. But even in the midst of that heresy, the actual Bible reading that I engaged in left an indelible mark.
When I attended a Catholic Mass for the first time (a little over a year ago), everything about the service resonated with me. All the seeds planted by the Holy Spirit in those years of reading the scriptures were finally watered. It was an overwhelming experience.
When I read Catholic literature or study the Catechism, scriptures come back to my memory. They inundate me. I have also learned that this experience is not unique. Friends who are Catholic converts from Protestantism have told me that they had the same experience.
Reading the scriptures without fully understanding the scriptures (or while holding a totally wrong understanding of the scriptures) still serves a very real purpose. All that truth gets stored up in one 's heart, and when the message coming in matches the message that has been stored in that way, the chorus of truth is like a beautiful orchestra playing in concert.
The Church today encounters this sort of thing all the time among her adult converts. It is salutary that, beginning with the formal teaching of Vatican II, she has gone beyond Aquinas, beyond even Newman, to recognize how "elements of sanctification and truth" outside the visible boundaries of the Church can lead those inhabiting the periphery to develop the virtue of faith. It is that virtue which impels them to Catholic unity even when they do not realize it. Fortunately, some do come to realize it and act accordingly.