The background to the point in contention is Scott's argument that there is no 'plain sense of scripture' in the sense meant by Protestants. Now, what is the "sense meant by Protestants"? Scott had explained it in this way:
According to the non-Catholic view, PMS is something that is equally available to any well-informed, rationally competent reader. No one denies that different well-informed, rationally competent readers often come up with different interpretations of the Scriptures--that is why there are so very many Protestant denominations, after all--but the central idea is that disputes of this sort can be settled by well-intentioned and jointly cooperative searches for the truth, in which rational agents rely on their own rational powers, their own private judgment, and a cooperative examination of all available empirical evidence.
And this is contrasted with the Catholic view:
The Catholic view is rather different. Catholic practice has traditionally been to privilege certain readings of the Scriptures over others. In particular, any interpretation that is inconsistent with the Tradition is regarded as out of bounds.
Now the problem with this, as I think Bill is effectively arguing, is that there are many Protestants who would deny the claim attributed to Protestants in general. Bill, as the good Anglican Thomist he is, means 'plain meaning of Scripture' in a sense that would be recognized by Thomas and by Hooker, namely, the literal sense in Thomas's sense of the phrase. And on this view the literal sense of Scripture is something that is indeed independent of the Church, being what God has established in the text, through his instruments, to point to Christ. Thus Bill brings in the analogy of the musical score: as even a beginner can take up a musical score and try to play it, so can even a beginner take up Scripture and read; all that is required is the ability to read the score, the text. As Bill says, this requires no recourse to private judgment; all it requires is that the score or text be intelligible and that the person in question know how to read it. This does require a community, just as there was need of a community for the score or text to be written in the first place; but to interpret this particular score and this particular text requires nothing more than reading this particular score and this particular text.
Now, Scott replies to this:
On the one hand, nobody will deny that the text has a meaning independently of how the Church reads it. It is evident beyond question, however, that disputes over what that meaning is arise with rather alarming frequency, and it is only natural to look for some hermeneutic principle that may be appealed to for the purposes of settling those disputes. In short, in spite of William's rather fatuous claim to the contrary, the question is closely linked to the authoritativeness of the reader to determine what the principal meaning of the text is and, hence, the question is indeed closely connected to the issue of private judgment.
But Bill, I take it, would regard the disputes as being about the plain meaning of Scripture itself; because he doesn't, by 'plain', mean transparent. Indeed, as a Protestant Thomist, taking 'plain meaning' to be basically the same as Thomas's 'literal sense', he can't and won't; he'll say, as he does elsewhere, that matters are rather more complicated than this. And thus the question of how do we determine readings authoritatively (if we can) is a distinct question from the question of whether there is a plain meaning of Scripture to which good readings approximate. The first is epistemological; the second is, so to speak, ontological.
I think it should also be noted that Bill, in the musical score comment, is not directly replying to Scott but to Al, who said of the 'theological reading',
A proper and edifying reading of Scripture as Scripture requires that the reader be fully immersed in the faith and practice of the Church. Apart from this faith and practice, the Scripture is fundamentally unintelligible. Scripture must be read with the Church, in the Church. Only with and in the Church can the profoundly unity of the Bible be discerned. Why? Because it is only with and in the Church that the Bible is in fact and reality one book whose author is the creator of the universe. Divorced from the faith of the Church, Scripture necessarily breaks down into an anthology of texts--interesting and intelligible in themselves, generating infinite speculation and diversity of interpretation, but not the transforming Word of God unto salvation.
And to this Bill replies that this is all quite true, and irrelevant to the question of the plain meaning of Scripture.
Mike, in his response to Bill, also raises the question of authoritative interpretation:
Although knowing just what the human authors intended is often useful, even important, for learning what God wants us to learn through Scripture, only experts can have adequately informed opinions about human authorial intent, because much knowledge about historical context, cultural milieu, literary forms, and the like must come into play for the purpose of discerning such intent. One might argue that there is, or at least can be, consensus among experts about such things, and that such would suffice for a kind of epistemic authority assuring the rest of us about what the plain meaning of Scripture is in disputed cases. But that runs up against the notorious disputes among scholars themselves; even when there is agreement, it is provisional and subject to differing theological interpretation. So, to rely on the epistemic authority of biblical scholars for the sake of learning the plain meaning of Scripture provides us only with opinions that most believers aren't even in a position to form for themselves. Some opinions are more, some less defensible; but regardless, none of that suffices to afford us an object of divine faith, unless one wishes to reduce divine revelation to a matter of opinion, which no party to the debate wishes to do.
But, again, from Bill's point of view it would be hard to see what any of this has to do with the plain meaning of Scripture. If taken as addressing his own point, it would all look like a confusion of 'interpretation' taken as an act of interpreting and 'interpretation' taken as a way the text can be interpreted. Whether there is an authoritative interpretation in the latter sense is a different question from whether there is an authoritative interpretation in the former sense.
So I think Bill's point is not what Scott and Michael have in mind; it's not an argument for a particular conception of authority in reading, but for a distinction between authority in reading a text and a reading of the text that is authoritative, i.e., between the reading of the text and its meaning. Scott wants to say that the plain meaning of Scripture, as Protestants understand that phrase, goes hand in hand with private judgment as the authoritative act of interpreting; Bill is, in this comment, denying this, not saying anything about the proper view we should have about the authoritative act of interpreting. That would require other considerations than Bill brings up here. So everyone is talking about something different. I think Mike is on the right track, though, in recognizing that the real difference between Catholics like Mike and Scott on the one hand, and what we might (rather loosely and perhaps figuratively) call High Church Protestants like Bill (who place great weight on consensus fidelium, the Church Fathers, and the Rule of Faith), has to do with their views of the Scripture as canon in the Church, and what it means for the Church to take a text as canonical. I know that Bill, for instance, tends to think, or, at least, has indicated something like this in various contexts, that the sort of account that Mike offers involves an equivocation on the term 'Church', a failure to distinguish between the Church insofar as it wrote the Scripture (and thus insofar as it was apostolic) and the Church insofar as it accepts them submissively as canon (and thus insofar as it is post-apostolic). This certainly does suggest a different view of canon.
So that, I would suggest, is where the real disagreement lies.