Why Sola Scriptura Doesn't Work

There is perhaps no more important disagreement between Catholics and Protestants than the question of whether or not any authority outside of Scripture can bind the believer’s conscience.

The whole Protestant system rests on the claim that Scripture alone is the Christian’s rule of faith. If they are correct, then the Catholic Church may have asked too much of believers by requiring they submit to certain beliefs which Protestants argue are unscriptural, whether they be dogmatic (such as the Immaculate Conception) or ethical (such as on contraception and remarriage).

On the other hand, if the Catholic Church is correct, Sacred Tradition plays a vital role in God’s revelation, and failure to take heed of tradition is failure to take heed of God’s word.

This article argues that there is no way of determining which books are divinely inspired without appealing to Sacred Tradition. From this, it is evident that Tradition is conscience binding and as such Sola Scriptura is false.

This argument is not that Sola Scriptura is false because Protestants have an ‘fallible list of infallible books’. The Catholic also has a fallible list of infallible papal statements, and for a considerable period of time, had not infallibly declared the books of the Bible.

Instead, the argument can be laid out as follows:

P1: The fact of inspiration is something unknown by natural knowledge or reason, but is instead something known only through God’s revelation.

P2: The Bible does not itself reveal which, if any, of its parts are inspired (in every part).

C: Therefore, God must have revealed the books’ inspiration through another means, namely Tradition.

Before moving on, it is worth pointing out that the classical defence of the Protestant in this regard is to claim that the Bible self-authenticates its inspiration. That is, the Bible tells us which books are in the Bible, and it is to this claim that I will be responding.

More recently, some Protestant apologists have claimed that they do accept Tradition as a ‘rule of faith’ - only not one that is infallible. This firstly misunderstands how the term rule of faith has traditionally been used. A rule of faith doesn’t mean ‘something we can listen to to help us work out Christian doctrine’. A rule of faith is something that binds the conscience by its own authority.

Classical Protestantism, whilst believing there is some place for traditions, creeds and councils, does not believe they bind by their own authority; they are not ‘rules of faith’ (Westminster Confession of Faith 31.4). Hence, something can only be authoritatively accepted as Christian belief if it is found in the one rule of faith that is Scripture.

The Classical Protestants, therefore, knew they could not rely on tradition to explain the books of the Bible (regardless of whether such tradition was considered fallible or infallible). They knew that doing so conceded the point that God speaks through Tradition as well as the written word. Certain modern Protestant apologists, however, have fallen into the self-contradictory claim of defending the Protestant belief in the Bible alone by appealing to ‘what was accepted by the Church’.

There is a reason no classical Protestant apologist did this and instead had to use the argument of self-authentication. To claim that we are bound by what was accepted by the Church demonstrates that we need to follow Tradition. One could argue that we can take what the Church received, but it doesn’t bind our conscience. In this case, one would have to admit that Protestants are free to argue for the addition or removal of certain books from the Bible. The criteria for such would then become somewhat contentious, but regardless, I know of no Protestant who desires such a thing.

Hopefully, with that argument dismissed, I can move on to the Classical Protestant argument of self-authentication. Bearing in mind the syllogism laid out above, I will address the two propositions and then the conclusion in turn.

Proposition 1: Inspiration cannot be known through nature or reason, but only be Revelation.

When we say that a particular book is ‘scriptural’, we are claiming that the work is ‘inspired’. This is not the same as ‘infallible’, because though those things which are inspired are infallible, not everything infallible is inspired (e.g., an ex-cathedral statement).

In His act of inspiring a certain hagiographer of Scripture, God does not impart any new information to the person who is inspired. Instead, God moves the inspired person in such a manner that the author writes down what he already knows (a) without error and (b) in such a way that He is God’s instrument, such that God can be said to be the true author (that is, he writes down precisely what God wants him to write).

The question then follows as to how one can identify which books are ‘inspired’.

There are certain things about God or salvation we can know without God revealing them to us. God’s revelation refers to God’s words or actions that indicate something to man that he would not otherwise know. That is, the only ‘place’ one can find this information is in the mind of God, and as such, God has to tell man for him to know it. A classic example of this is the doctrine of the Trinity, which theologians have declared can only be known through God’s revelation (whether that be Scripture or Tradition), rather than through the other two possible means—reason or nature.

So, is the quality of ‘inspiration’ in a text something that can only be known through revelation, or can it be known through nature (like God’s existence c.f. Romans 1:19-21) or reason (e.g., the immortality of the soul)?

Imagine the canon of Scripture was an open question. St Paul hands you a letter. How do you work out whether or not this is Scripture? Not everything Paul writes is Scripture (e.g., the Epistle to the Laodiceans). There’s nothing in the natural world that would help you determine this fact, nor is there anything we can reason from the text to decide it. It seems the only way we would know is if God revealed it to us. That is, the fact of who God inspired exists only in God’s mind - it cannot be determined through natural investigation or reason, such that someone who was not already told which books should be in the Bible could work it out if they were handed a letter from an Apostle.

Now, at this point, a Protestant well-versed in the Fathers may point out that specific arguments from reason were used in the early centuries of the Church to make judgements about the canon. For instance, they may point out that there are certain qualities a text has, such as orthodox doctrine, apostolicity and loftiness of speech, that indicate a work may be Scriptural.

However, these judgements were not the result of reason in determining which books were in the Bible. Instead, they are what’s called a motive of credibility. Motives of credibility are those things which accompany something to prove it is authentic. For instance, miracles served as a motive for credibility for both Christ’s divinity and apostolic authority. That is, the fact that Christ and the Apostles could do miracles helped authenticate their claims to be, in Christ’s case, divine and in the Apostles’ case, Christ’s legates on earth.

However, these motives of credibility did not make Christ divine, nor are they suitable for knowing Christ’s divinity; they are there to help make Christ’s claim to be divine credible. The motives alone are not enough. Take, for example, miracles - that alone cannot verify Christ's divinity, for there are many in the Old Testament who performed miracles too. We know Christ is divine because Christ told us he was (that is, it was given to us via revelation). The motives of credibility accompany this revelation, but do not cause or allow someone to work it out simply through reason.

Likewise, the Church Fathers appeal to motives of credibility to demonstrate which books are Scriptural and inspired. But they are not saying these things make them inspired. This has to be revealed; the motives of credibility work alongside this. On their own, they prove nothing, for there is no criterion to prove inspiration, as this is a fact in the mind of God, hidden to man, until God reveals it. That the motivates of credibility are insufficient is shown, for instance, that there are some letters in the New Testament not written by Apostles, and there are many lofty and orthodox works not written in the canon. There are also some orthodox, apostolic letters (St Paul’s Letter to the Laodiceans, for instance) which are not canonical. It is also worth mentioning that in order for the Fathers to appeal to orthodox doctrine, they must have believed there was a source outside of Scripture to which they could compare it to.

All this is to say, to know which books are in Scripture, one must have the fact that the book is inspired revealed to them. Therefore, St Paul (who had the fact revealed to Him by God) would have to tell you it was inspired for you to know.

Proposition 2: The Bible does not reveal its own inspiration in every part

So, if a text’s inspiration cannot be known through nature or reason, it must be known through revelation. This is self-evident: who God has inspired is known only to God and to the one inspired. Either God or the inspired person would have to tell you for you to know.

At this point, although I will not yet defend the position, I will lay out what Catholics believe in brief. Catholics argue that Christ gave authority to His apostles, and taught them everything they needed to know for their task of establishing the early Church and preaching the Gospel to every nation. Public revelation ceased at the death of the last Apostle, such that no new public revelation could be made after this point. This one deposit of revelation given to the Apostles, both of which are channels from which the one Word of God flows, is passed down both through writing (Scripture) and orally (Tradition).

On the other hand, for the Protestant, this deposit of apostolic teaching is passed down entirely through Scripture. Therefore, if we want to know the content of revelation, the only place we can look for it is in Scripture.

It is for this reason that Classical Protestants defended the canon based on self-authentication. Namely, the Bible itself tells us which books are in the Bible.

Yet nowhere in the Bible are we told which part of Scripture is inspired. We could make some sort of case for the prophetic books in the Old Testament, which begin by saying something like “the Word of the Lord sent to the Prophet x”. There’s also a case for the Pauline Epistles as Peter refers to them as Scripture (though of course, this doesn’t answer which of Paul’s letters are inspired, only that some of them are). Furthermore, this rests on weak ground because one would first have to prove the inspiration of Peter’s epistles to use this proof.

The case becomes even more complicated when it comes to books like Hebrews, where we do not even know who wrote it, thus it may not have been written even by an Apostle (which is, of course, the case for James and Jude). There has been much ink spilt on trying to justify the Bible’s self-authentication, with some even claiming that the books ‘speak to us’ of their scriptural status. Yet, this is very easy to say once the canon has been established - it is a lot harder to say when it hasn’t, hence why there were numerous disagreements among theologians in the Church's earlier history.

Conclusion: Therefore, Tradition is Necessary to Recognise the Canon

If inspiration needs revelation for us to know it, and Scripture (one source of revelation) cannot tell us of its own inspiration in every part, it instead means that we need another source of revelation to know which books are in the canon. The other source is Tradition.

When a Protestant hears that Catholics believe in Tradition, they tend to respond, referencing Matthew 15:3 (or a parallel) that Christ admonished the Pharisees for following the “traditions of men” over the Word of God. They will then argue that even if there is some place for tradition, it cannot have the same authority as the Bible.

This position, I think, reveals a misunderstanding of what Tradition is. The Catholic Church teaches that Christ revealed to His Apostles the whole rule of faith, that is, everything they needed to pass on to believers. Because this came (was revealed) from Jesus, who is God Incarnate, everything that the Apostles then passed on could rightly be called the Word of God. We know that in the time of the Apostles, this took both written and unwritten forms (2 Thessalonians 2:15). This is self-evident because we have no written works from the vast majority of Apostles, who we know were engaged in the task of preaching throughout the Roman Empire.

This is why Paul can speak of tradition in a positive way, and so we know that when Christ chastises the Pharisees, he cannot be chastising tradition per se, but rather those traditions that make Scripture null. But a Catholic, of course, agrees with this position. A Catholic believes Sacred Tradition - that which comes from the Apostles - is authoritative. They do not believe that everything that claims to be Tradition is truly authoritative or the Word of God (in the same way that neither Catholics nor Protestants believe that everything that claims to be Scripture is Scripture). In fact, part of the reason that the Church teaches that the Magisterium is necessary is because there needs to be someone who can arbitrate between correct and incorrect interpretations of the Word of God, both written (Scripture) and unwritten (Tradition).

When a Protestant says that one shouldn’t elevate Tradition to the same level as the Word of God, they are using the term in a different sense from the Catholic. This is because for a Catholic, the Word of God consists of both the written and the unwritten. And although the unique nature of Scripture as inspired means it has a place of prominence in theological reasoning, to argue that Tradition does not also bind authoritatively makes no sense because both are the same Word of God. By analogy, a child is required to listen to the instructions of their parents, whether it is codified in a text message or said aloud, because both have the same source (the binding authority figure). Likewise, the Christian is bound by both Scripture and Tradition because both have the same source; both are the Word of God.

The question then becomes whether or not this Tradition was passed down after the Apostles. Although it is beyond the scope of this article to demonstrate as such here, it is evident that the earliest Christians, after the time of the Apostles, believed that apostolic authority extended to the leaders of the Church who continued to appeal to both Scripture and Tradition.

Furthermore, it was not for a considerable length of time that the question of canon began to be debated and established. The lack of demand to quickly provide a formal list of which books were in or out suggests that believers may not have been relying solely on Scripture as their authority.

Furthermore, the view that only Scripture is the rule of faith essentially did not exist in Church history until the Reformation. Now, if you believe in sola Scriptura, this isn’t really a problem - but I certainly think it should make us stop and think why nobody thought this way for 1,500 years.

Furthermore, nobody is capable of reading Scripture in a vacuum - we all read it having inherited traditions from our upbringing, denomination and history - whether we realise it or not. One of the Catholic arguments for the necessity of the Magisterium is that this is precisely why there needs to be an infallible interpreter to determine which understandings and ‘traditions’ are correct. However, this article is not about defending the Magisterium per se, so I will leave this point for another time.

However, the strongest argument rests on the fact that one cannot even get to which books are in Scripture without appealing to Tradition.

Therefore, to gain an understanding of the books in the Bible, one must be able to identify which works are inspired, a task that can only be accomplished through their revelation by God. Given we cannot know such books from Scripture itself, we must appeal to Tradition, which (as the canon list binds the believer) is thus rightly understood as a 'rule of faith'.

When taken as a whole, the Holy Scriptures never claim to be the only source or rule of faith. In fact, if God had wished for the Bible alone to be our source, one would think that its design and structure would be such that it was a comprehensive theological manual which could anticipate any theological issue that might arise. As it is, the Bible instead forms a collection of different genres of work, which are central to the theologian's task of understanding God's plan of salvation, but it does leave certain questions unanswered, which, as the Church began to grow, became central to the faith.

But the perspective of the Catholic is that the rich gift of the Scriptures which God has given to the Church is not left alone as a 'dead' word, but rather the Word of God Himself continues to speak - in Scripture and Tradition - through the Church so that she can be a constant teacher and guide in what Christians must believe.

Aside: Is the Catholic argument circular?

See further reading below for a more in-depth explanation of this.

Some may argue the Catholic argument is circular: the Church is authoritative because the Bible says so, and the Bible is authoritative because the Church says so.

However, the Catholic only needs to prove the Bible's historical reliability, not that it is inspired, to use it as a source for Christ giving the authority to the apostles and their successors.

Further Resources

Such resources were very helpful to me in writing this article, and often go into considerably more depth than I have done.

Doronzo, Emmanuel - The Science of Sacred Theology, 1973 (from this comes the distinction between inspiration, revelation and the assistance of the Holy Spirit)

Fernandez, Kevin - https://www.youtube.com/watch?v=EJhTnA0oAY4 (from here comes the analogy of the motives of credibility between Scripture and Christ's divinity)

Wagner, Christian - Sola Scriptura, the Canon, and the Church, 2025 (see: https://www.christianbwagner.com/post/sola-scriptura-the-canon-and-the-church) (Wagner's argument here is important as to why the Catholic claim is not circular)

Wagner Christian - https://www.youtube.com/watch?v=EJhTnA0oAY4 (Wagner's arguments here are a more in-depth version of my argument above)