What is particularly interesting to me about that post is that Jonathan is giving what amounts to a legal version of the argument that Mike and I made, albeit in different ways, about the nature of authoritativeness.
What I would like to demonstrate is that the appeals to the authority of the "plain meaning of Scripture" invariably succumb to the reification fallacy given the definition of authority I have outlined above. The concept that is most central to this definition of authority is the power to produce a formal act of normative communication. It is communication of some definite form, qua normative, from the authority to someone bound by the authority.After quoting briefly from Ineffabilis Deus and Pastor Aeternus, he goes on to say:
The point is not that the binding teaching is so apparent that its form should be clear to anyone who reads it, but that it is ontologically clear, certain, and manifest. The nature of the dogma itself is that it includes no mixture of error but definitely separates right from wrong, even if it wasn't apparent until later that this was the case! In other words, the necessary ontological consequence is that the binding act of the issuing authority obeys the law of non-contradiction. The form of the act excludes this and not that; it separates the correct and the incorrect. Moreover, the act of communication itself either is or is not. Just as there is no such thing as half a principle, there is no such thing as half an authority. The communication either is or is not authoritative in a certain respect; it cannot admit of contraries.This is a line of argumentation that can be traced back through St. Thomas, to St. Anselm, to St. Augustine, to that old pagan Aristotle. In the second book of his treatise Posterior Analytics Aristotle outlines a conception of scientific explanation (where "scientific" just means "pertaining to a domain of demonstrable knowledge") that is downright Hempelian in its desire to provide accounts that both explain why something is necessarily true and, at the same time, excludes other possible explanations.
Aristotle's approach represents a variety of metaphysical realism. On his view, language, while certainly conventional in some respects, is nevertheless partly structured in such a way as to reflect an underlying predicational structure in which there is an isomorphic relationship between ontological correlates, on the one hand, and our cognitive grasp of what it is for those correlates to be the things that they are on the other. This is why truth, for Aristotle, is defined in terms of a certain kind of correspondence relation (as he says in the Metaphysics, "to say of what is the case, that it is, is true"). On this view of the relationship between cognition and reality, there can be only one truth, and it is not, to borrow Aristotle's phrase, "up to us" what that truth is: it is possible for any given individual to be mistaken about such things. Aristotle would not follow the Christians in their commitment to the possibility of a charism guaranteeing freedom from such error, but the Church follows him in denying that such guarantees pertain to single individuals as such. Instead, all such guarantees pertain either to the Head, that is, Christ himself, or to His Body, that is, the Church. On the Christian view of things, those are the only two sources of authority that there are: Head and Body, the one subordinated to the other. To speak of a particular individual having access to anything like such a guarantee is virtually meaningless. As I argued in this post, even the Pope does not enjoy such a guarantee unqualifiedly.