What are the doctrinal objections to this Protestant lynchpin. From the vantage of any denomination.
To me, it seems foolish to be against Sola Scriptura. It just makes too much sense that God's inspired word should be the first, middle and last word on all things pertaining to the faith. If this were not so, why do we even have the bible?
Discuss ty and God bless
Sola Scriptura is the "obvious choice", right? Of course! Just like it's equally obvious that, since planet Earth is God's focus, it is positioned in the center of the universe with all planets and stars revolving around it. Geocentrism is the obvious and correct choice! As is the global flood! And a flat earth! If you don't believe me, just ask any theologian for the first 1,000 years of the church!
Unfortunately, the "obvious choice" doesn't always bear up under scrutiny. Indeed, Sola Scriptura is obviously a falsehood, if understood to mean that biblical exegesis (the use of human reasoning and scholarship to interpret Scripture) is the only final authority on questions of religion.
Scripture cannot be our highest authority because such begs the question, "On what authority do I accept the Bible?" Suppose for example I accepted the Bible on the basis of Reason. That would imply that Reason is, for me, a higher authority than the Bible since it dictated my decision to accept or reject the book. For example, if I accepted it on Reason, and tomorrow my reasoning leads me to conclude that the Koran is actually a more rational choice, I will abandon the Bible in favor of the Koran, thereby confirming that, for me, Reason is a higher authority than the Bible since it dictates my decision to accept or reject the book.
The point is that the Bible can never be legitimately construed as our highest authority, because some higher authority dictated our decision to accept or reject that book. Protestants have never been willing to face this obvious fact.
Ok, now that we see there is a problem, let's investigate. On what authority/basis do Protestants accept the book? Actually there is a consensus on this, a consensus usually credited to John Calvin's work. Calvin rightly insisted that a Direct Revelation known as the Inward Witness of the Holy Spirit persuades us of basic biblical truths (such as the inspiration of Scripture and the divinity of Christ).
This implies that Direct Revelation (the Inward Witness) is a higher authority than Scripture because it dictates my decision to accept or reject the book.
How does it work? As Calvin insisted, the Inward Witness persuades us of particular truths, ultimately causing us to feel certain about them. Calvin was very insistent that the Inward Witness, from the standpoint of experience, is feelings of certainty.
This leads us to a corollary - feelings of certainty have a higher authority than Scripture because they dictate my decision to accept or reject the book. For example if tomorrow I feel certain that the Koran, instead of the Bible, is God's inspired book, I will forthwith reject the bible in favor of the Koran.
Feelings of certainty are our highest authority because there are no exceptions to the following rule, which I like to call the "rule of conscience":
"If I feel certain that action-A is evil, and action-B is good, I should opt for B".
So that's how Direct Revelation works. When God speaks, His Voice must cause us to feel certain about it, otherwise we would have no obligation to obey it. And when we already feel certain about it, there is no need to "check it out with Scripture" because the rule of conscience is ALWAYS authoritative (i.e. obligatory).