Sola scriptura (Latin ablative, "by scripture alone") is the doctrine that the Bible contains all knowledge necessary for salvation and holiness. Consequently, sola scriptura demands that only those doctrines are to be admitted or confessed that are found directly within or indirectly by using valid logical deduction or valid deductive reasoning from scripture. However, sola scriptura is not a denial of other authorities governing Christian life and devotion. Rather, it simply demands that all other authorities are subordinate to, and are to be corrected by, the written word of God. Sola scriptura was a foundational doctrinal principle of the Protestant Reformation held by the Reformers and is a formal principle of Protestantism today (see Five solas)
1 Corinthians 4:6
And these things, brethren, I have in a figure transferred to myself and to Apollos for your sakes; that ye might learn in us not to think of men above that which is written, that no one of you be puffed up for one against another.
Reformation statement> Martin Luther
"Your Imperial Majesty and Your Lordships demand a simple answer. Here it is, plain and unvarnished. Unless I am convicted of error by the testimony of Scripture or (since I put no trust in the unsupported authority of Pope or councils, since it is plain that they have often erred and often contradicted themselves) by manifest reasoning, I stand convicted by the Scriptures to which I have appealed, and my conscience is taken captive by God's word, I cannot and will not recant anything, for to act against our conscience is neither safe for us, nor open to us. On this I take my stand. I can do no other. God help me. Amen."
- Martin Luther
Sola Scriptura as an Epistemological Principle?
It is objected by Roman Catholics and Eastern Orthodox that there is no verse that teaches sola scriptura. But I tend to disagree with this assessment because I believe that 1 Corinthians 4:6 teaches sola scriptura. But suppose I am all wrong about that and it in fact does not teach sola scriptura, does this entail that I should be a Roman Catholic or an Eastern Orthodox? In other words: What are the implications if one rejects that sola scriptura is taught in the Bible? My contention is that there is really no major implication to Protestantism if scripture alone is not taught in the Bible.
So let us suppose for the moment that sola scriptura is not taught in the Bible and that we reject the Eastern Orthodox and the Roman Catholic arguments (as I have done elsewhere on this blog) then all we are left with is scripture. So we could modify our view of God's revelation to be as follows: Scripture alone is the only infallible and authoritative rule for faith and practice that we have knowledge of. As for there being additional revelation other than the Bible we should withhold belief that such additional revelation exists. In other words, with respect to the proposition that there is additional revelation other than the Bible we should be agnostic with respect to this proposition.
Once one has accepted this epistemological form of sola scriptura (the criteria given above) then it seems like the Roman Catholic and Eastern Orthodox claims of incoherence lose their weight. This is because the conjunction of reason and scripture warrant the conclusion that these are the only scriptures we know of (this is of course assuming that the other church authority arguments fails). Therefore, there is no logical incoherence with this epistemological version of sola scriptura.
So even if Protestants cannot provide a proof text for sola scriptura this still does not entail that one should be a Roman Catholic or Eastern Orthodox. In fact it would appear that the epistemic status of Protestantism is not effected at all if one cannot give a proof text.
Jehovah's Witnesses who were formerly known as the Bible Students have always used the Bible as the only source of spiritual inlightenment.