Do Adventists believe in Sola Scriptura: Is Ellen White an infallible authority?

 It is often claimed by critics that Adventists don't hold to Sola Scriptura because we allegedly believe Ellen White is an infaillable authority. How true is this claim? 

First off, let's define the terms we are using. Sola Scriptura means that Scripture is the only infaillable source of authority for Christian faith and practice. Sola Scriptura is incompatible with any idea of a secondary infaillable authority (like a magisterium), or with the idea of "biblicism" or commonly called "nuda Scriptura", which is the idea that the Bible is the only source of information for faith, and rejects all kinds of tradition. Sola Scriptura recognizes a place for reason, tradition and experience; one that is subordinate to, and meant to guide people to Scripture. In classical protestantism, the Ecumenical creeds, the confessions, the church councils serve as authoritative voices in the universal church, however they are not infaillable authorities of faith and practice, or in other words, lacking the possibility of error. The Reformers are clear: Scripture alone is universally binding and an infaillable rule of faith and practice for the Christian, even if tradition can be validly used for edification, it is always reformed and judged by the words of the Holy Bible. 

How do adventists understand Sola Scriptura and what role does Ellen White play into the theology of the adventist church? 

We do affirm Sola Scriptura the way it has been classically defined by the Reformers, even though there have been some people in our church who have espoused different opinions on the matter. The official teaching of the SDA church is Sola Scriptura, and this was the teaching of Ellen White herself, as we will demonstrate. In the Fundamental Belief nr. 1 "On Holy Scripture" we confess that the Scriptures are "the supreme, authoritative and the infaillible revelation of His will". In fundamental belief nr. 18 "On the Gift of Prophecy" we affirm that "her writings provide guidance, comfort, instruction and correction to the church", things that are done by Scripture also. We also say that both the Scriptures and Ellen White are inspired by the same Holy Spirit. What is the difference between them? Ellen White is just authoritative as a "prophetic authority", not infallible; while Scripture alone is the infaillable rule of faith and practice by which all teaching and experience must be tested. Let's have a look at Ellen White's own claims: 

"I do not claim infallibility, or even perfection of Christian character."- Letter 27, 1876

"God and heaven alone are infallible" (Selected Messages, book 1, p. 37).

"God's Word is infallible" (ibid., p. 416) 

"With regard to infallibility, I never claimed it; God alone is infallible. His Word is true, and in Him is no variableness, or shadow of turning."- Letter 10, 1895

Ellen White is clear that she is not infallible and that she never had this pretention. What she says of Holy Scripture is significant: 

"The Bible, and the Bible alone, is to be our creed, the sole bond of union; all who bow to this Holy Word will be in harmony. Our own views and ideas must not control our efforts. Man is fallible, but God's Word is infallible."—Selected Messages, bk. 1, p. 416.

"The word of God is infallible; accept it as it reads; look with confidence to God; trust him to qualify you for his service."—Advent Review, Feb. 11, 1896.

"We need not depend upon the conjectures and opinions of men, but upon the infallible decision of the word of God."- ST, August 21, 1893 

"God's Word is full of precious promises and helpful counsel. It is infallible; for God can not err."- ST, June 26, 1901 

"Then let every man read, study, and search the SCRIPTURES for himself and TAKE NOTHING AS INFALLIBLE BUT THE WORD that you can see for yourself, after much prayer and searching in an humble, teachable spirit."—The Ellen G. White 1888 Materials, p. 835.

"The more he searched the Scriptures, the clearer appeared the contrast between their truths and the heresies of Rome. He submitted himself to the Bible as the word of God, THE ONLY SUFFICIENT, INFALLIBLE RULE . He saw that it must be its own interpreter. He dared not attempt to explain Scripture to sustain a preconceived theory or doctrine, but held it his duty to learn what is its direct and obvious teaching. He sought to avail himself of every help to obtain a full and correct understanding of its meaning, and he invoked the aid of the Holy Spirit, which would, he declared, reveal it to all who sought it in sincerity and with prayer..."GC 173.2

Not only does she explicitly teach the infallibility of Scripture, she proclaims that the Scriptures alone are infallible, since we are to take no source as infallible but the Holy Scriptures, the Word of God. Never once does she refer to her own writings as "Scripture", but in using this word she only implies the obvious meaning of it "the Holy Bible". If we are to take nothing as infallible but the Word of God which represents the Holy Scriptures, and Ellen White denies any claim to infallibility, we can safely conclude that her doctrine of Sola Scriptura and thus the doctrine that we teach and believe as seventh-day Adventists is the same principle as that taught by the Protestant Reformers. Unfortunately some Adventists treat Ellen white as an "infallible interpreter", but that wasn't intended by the adventist church, goes against our teaching and against the Reformation principle of Sola Scriptura. To make a short summary, Ellen White is:

1. Prophetic, not canonical

2. Inspired, not infallible 

3. Prolific, not exhaustive