In his blog post entitled Questions about Sola Scriptura, Robin Phillips raises some very good questions about the relationship between Sola Scriptura (Scripture Alone) and the Church. If the primary or only source of spiritual authority is the Bible, how do we determine which Church Body or tradition properly interprets the Bible? Which set of doctrines are authoritative in the life of the Church? Of the individual Christian (if there is any such thing as a Christian apart from the Church?)
If Scripture is your primary authority, it becomes difficult to determine exactly which secondary authority may be used to interpret the Sacred Scriptures. Indeed, Protestantism — following the lead of Martin Luther — asserts the primacy of reason and the individual conscience as a means of interpreting Scripture. It must therefore be acknowledged that any number of people have approached the scriptures prayerfully, with great care, and in all sincerity, and have devised all manner of doctrinal systems from the pages of Sacred Scripture. Which dogmatic system is correct, and how do we know? There are many different contradictory positions within Protestantism, and differences on doctrine seem invariably to give rise to new denominations.
If you are a Protestant, you will likely point to your church or denomination as the true and visible church because it best understands the Bible. If you are Lutheran, you will point the the Lutheran Confessions as your guide to the understanding of Scriptures, and claim your Church as the true and visible Church, (although which branch of Lutheran, and on what basis do you decide?) If you belong to some other Church communion (Rome, Eastern Orthodox, Coptic, etc.), you will point to the traditions of the fathers as a guide to understanding the Scriptures; the question then becomes which tradition, and which set of church fathers?
The problem is that if the Scriptures are self-authenticating, which is to say they attest to their own inspiration apart from the Church, then it becomes extremely difficult to determine which is the true and visible Church. The answer, according to some, is to differentiate between the visible and the invisible church. The invisible church, comprised of all the saints of God past, present, and future, is the true church; the visible church is the local manifestation of the invisible church — indeed, is a branch of the one, true Church. Thus, the branch theory of the Church, first postulated by the Church of England.
The problem with the branch theory is that it separates church and doctrine, in that a church may be doctrinally in error, and even heretical, and yet be a branch of the one, true church. Sola Scriptura and the Branch Theory provides no objective way to determine truth from error, making the choice of visible church a subjective affair. Moreover, it is almost impossible to draw any objective criteria by which a particular group claiming the name of Christian may be understood as apart from the invisible church. Indeed, that is the point, in that the saints are known to God alone. Thus, does it even matter which visible Church we belong to as long as we are part of the invisible Church?
As Robin Phillips points out, there is an element of circular reasoning at work here. We say the Scriptures are inspired by God, but so do other religions. How do we know our Scriptures are inspired, apart from some testimony external to the Scriptures themselves? And if we accept an external source that attests to the inspiration of Scripture, how then may we hold to the doctrine of Sola Scriptura (especially as interpreted by the modern Fundamentalists and Evangelicals as Solo Scriptura, also known as Nuda Scriptura, the naked Scriptures?)
It is possible to accept a subsidiary authority attesting to a superior authority. Indeed, this is the general position of Lutherans, who accept the Lutheran Confessions and the testimony of the Church Fathers as secondary and tertiary authorities. Yet this does not resolve the question of which doctrinal system, derived from Scripture Alone, is correct.
The idea of Scripture Alone creates more problems than it solves. The sole reason for the assertion of the Scripture Alone was to separate Scripture from the Church of Rome. If that is the rationale, then the foundation for Scripture Alone is weak indeed.