I have been thinking about this subject for quite a while, and find the problem quite interesting. Basically, the problem is as follows. Is the Bible the sole authority for all Christian doctrine and practice. Protestants affirm that it is - Sola Scriptura. However, the positive affirmation brings forward a further problem - the Bible as interpreted by whom? There are many divergent interpretations of the Sacred Scriptures, frequently upon subjects that are important doctrines or practices, such as Justification, the Lord's Supper, baptism, the gifts of the Holy Spirit, etc. The differences of interpretation are not only between such groups as the Catholics and Protestants. Within the ranks of Protestantism there are many important differences (such as the debates between Calvinists and Arminians). Which interpretation of the Bible is authoritative?
In working through this argument I began with the assumption that any authority must,of necessity, be infallible. However, upon reflection, it seems that such a declaration is, itself, highly debatable. By definition, an authority is any trustworthy source of knowledge or truth. A human authority, on any given subject, will be prone to error, however, the fact that they are considered to be an authority means that when they make an affirmation in that subject, they are probably speaking the truth. All human authorities can only approximate to the truth (that is, they may pronounce many truths, however it seems impossible for the unaided human mind to grasp all truth, therefore, whatever truths are pronounced there will always be some error). In order for a being to be able to pronounce the truth, without any error, that being would have to be, intrinsically, without error, or, at least, informed by a being that is intrinsically without error, in which case only those declarations that were informed by an infallible being would be infallible. (It goes without saying that any document that is written by, or whose author was inspired by, an infallible being, would, itself be infallible.)
In discussing church authority it is important to note that it is possible for a declaration to be infallible, all while the authority making the affirmation is fallible. That is, a true statement is true, whether it be stated by a fallible being, or an infallible being, by a liar, cheat, pagan, heretic, scientist, philosopher or orthodox theologian. Though an infallible being, by its very nature, can not make a fallible declaration, a fallible creature may be the source of both fallible and infallible statements.
In light of the above, it seems that we must distinguish between authoritative statements, and people who are authorities in church doctrine and practice. It seems that authoritative statements will always, of necessity, be infallible, whereas, church authorities will only be authoritative insomuch as they utter that which is true. Therefore, the problem of authority in church doctrine and practice, becomes less a question of who or what is the authority, and more a question of determining which declarations are authoritative.
These are some preliminary thoughts on the question; I will continue to discuss this question in the next couple blogs.