What is the basis for not believing sola scriptura?

The basis is that you run into a self-referentiality problem trying to figure out what the Bible says about itself. There was no such thing as "the Bible" when it was being written. Not even the concept of "writing the Bible" existed, the way we think of writing books today, because the Bible isn't a book; it's a collection of several individual books. Each book was its own work that (originally) stood on its own, and they weren't compiled into a collection until centuries after the last of them was written. So if you're looking for a biblical doctrine that says "only the Bible can be considered authoritative," you won't find any such thing, because you can't.

1. Sola Scriptura is itself a heresy (i.e., a heterodox teaching condemned by the Catholic Church). To change from not believing in it, to believing in it, would make you a heretic. (not an argument, but a very important reason for not believing)
2. The Bible is the complete source of public revelation, but we are permitted to believe private revelation, which has the approval of a Bishop (apparitions of Our Lady of Fatima, Lourdes, Guadalupe, Kibeho, Akita, etc). Protestants would find this to be 'extra-scriptura'
3. Papal / Magisterial infallibility is pretty pointless if nothing they teach on faith and morals could be extra-biblical. Two of the four Marian Dogmas are about events before and after the Gospels (Immaculate Conception of Mary and Assumption of Mary).
4. The Natural Law, the philosophy of the Doctors of the Church (Augustine and Aquinas), mainly extends from the teaching of Aristotle. Catholics believe that we get to know God through reason alone and that we can know quite a bit more through reason alone too.
5. The Eucharist is the source and summit of our faith. The Church is the Mother of the Bible, We believe Jesus comes to us in the Eucharist, we can worship Him directly and commune with Him fully.
6. Besides the bible, we have 2 other pillars which make up the one Faith. Magisterial Teaching (The teaching of the Pope in communion with the Bishops) and Sacred Tradition (all the stuff nobody thinks anyone believes anymore)
7. There are also the 7 Sacraments, which are the invisible realities made real with the help of the Clergy and the Faithful. Baptism, Matrimony, The Eucharist, Confirmation, Holy Orders, Anointing of the Sick, and Reconcilliation (Confession). The sacraments are all thourghouly biblical but more an extension of traditional apostolic Christianity than detailed biblical edicts.

However, there is no basis for contradicting the bible or any Divine Law. So the argument I'm trying to make here is not that 'Scriptura' is bad or wrong or even insufficient to gain salvation. I'm just saying that 'Sola Scriptura' is insufficient to understand what is meant by the 'Fullness of Truth', which can only be found in the Catholic Church.

There are a number of ways to approach the question of sola scriptura.

The Eastern Orthodox Church, the Oriental Orthodox, and the Catholic Church all maintain that the Scriptures are not the only medium by which revealed truth has been transmitted; there is also the oral tradition that comes ultimately from the Apostles. (For the Catholic perspective, see Catechism of the Catholic Church [CCC] no. 76.)

(When Catholics speak of traditions that are apostolic in origin and doctrinal in character, they generally use the term Tradition, or Sacred Tradition, with a capital T, at least in English; popular legends and devotional practices are sometimes called traditions, with a lowercase T.)

Generally, Catholics would argue that there are a number of problems with the sola scriptura position.

• Sola scriptura is a relatively recent innovation. John Wycliffe (ca. 1320–1384) and Jan Hus (ca. 1372–1415) seem to have been the first important figures to propose that idea in the modern era. The idea was foreign to the Church Fathers and the first councils; in fact, the Fathers and councils constantly cite the previous generations of Fathers (in addition to the Scriptures, of course).

• Tradition existed prior to the Sacred Scriptures. Both the Old Testament and the New Testament existed in an oral form before their compilation into the canonical text. At the time of the Apostles, the “Scriptures” consisted in the Old Testament only. Only by the end of the first century were the texts we know as the New Testament written, and the canon of both testaments was not fixed until the fourth century. (It seems to have been fixed by the time of the synods of Carthage and Rome). Tradition is what filled the gap between the events recorded in the Scriptures and their compilation.

• Tradition is necessary in order to be sure that the Scriptures are reliable. Without Tradition, there is a danger of begging the question (or petitio principii): for instance, by arguing that the Scriptures are a rule for the Faith, because the Scriptures claim to be such a rule. The Catholic Church would argue that we can be sure that the Scriptures are reliable, because (in the case of the New Testament), they were written with the authority of the Apostles or else (in the case of the Old Testament) accepted by Apostolic authority into liturgical use. However, only Tradition is a witness to which works are under Apostolic authority.

• As a consequence, only Tradition can establish the canon of Scripture. (In fact, the Bible does not contain a “table of contents” listing which books belong to it. Only Tradition maintains that list.)

• The Scriptures do not teach sola scriptura. St. Paul teaches that the Scriptures are extremely useful:

  All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness that the man of God may be complete, equipped for every good work. (2 Tim. 3:16-17).

  It should, however, be observed that when Paul wrote this letter, most of the New Testament did not exist yet (including the Gospels); therefore “scripture” in this context must be referring to the Old Testament. In any event, the passage nowhere affirms that the Scriptures alone are a valid source of doctrine.

  Moreover, Paul actually affirms the need for oral teachings or traditions:

  So then, brothers, stand firm and hold to the traditions (παραδόσεις) that you were taught by us, either by our spoken word or by our letter (2 Thess. 2:15).

  Therefore, if the Bible is to be regarded as the only rule of faith (such that, if a doctrine is not found in the Scriptures, then it cannot be affirmed), then sola scriptura itself must be discarded.

The teachings of the Scripture of the time of Jesus (the Torah) was the only Scripture that they had then. All other teachings, by Jesus and by His disciples, were orally transmitted. The saints of the Church hadn't even started to write things down, compiling the Gospel accounts as we know it, until years after Jesus' death, when they realized that He wasn't returning within their lifetimes. And, before Jesus' time, back in the days of the Prophets, the Law was passed down orally, before ever getting written down by someone later on. In this way, adhering to a non-Sola Scriptura view (which actually predates Sola Scriptura, historically), is how Christianity (and Judaism before it) always operated.

You could say that in this way, there is a Biblical basis for operating non-Sola Scriptura, because the Bible clearly describes the faith being passed down in that manner. And if you believe that Jesus lives on through the Church, just as the Jews believed in the prophets, then I think it's pretty rational to do so in this manner. If you try and look, there isn't really a hard line or date where you can say "OK, from here on out, no new insights can be gathered--all that could ever be True has been written, and there is nothing more for us to figure out". In fact, I believe that the Church will forever be learning and growing deeper in understanding of God. He has been slowly revealing Himself more and more throughout the millenia, and so there is no reason to think that God stopped at some point.

In short, I guess you could say that it's traditional to not be Sola Scriptura, and that might sound like an odd reason at first glance, but I think it's precisely the point. The Church traditionally was not Sola Scriptura for centuries, and so that's why it might continue to this day.

Sola Scriptura isn't taught in the Bible

Sola scriptura is a self-refuting doctrine because it is extra-Biblical and therefore not consistent with its own principle of "Scripture alone." Rather, we find the following biblical instructions to maintain traditions that were not passed down in biblical writings:

"I commend you because you remember me in everything and maintain the traditions just as I handed them on to you" (1 Corinthians 11:2, NRSV).

"So then, brothers and sisters, stand firm and hold fast to the traditions that you were taught by us, either by word of mouth or by our letter" (2 Thessalonians 2:15, NRSV).

In other words, the Bible itself teaches Scripture plus tradition(s).

Some might argue that verses such as 2 Timothy 3:16-17 or Revelation 22:18-19 provide support for sola scriptura, but it should be kept in mind that γραφή (graphē | "writings"/"Scripture") almost always refers to the Hebrew Bible ("Old Testament").¹

Sola scriptura did not originate until the 14th century and did not become widespread until the 16th century. It's already been established that the Bible does not teach sola scriptura, so where did it come from? It was clearly invented by men (Wycliffe, Luther, et. al.).

Most Christians didn't have Bibles

The books of the New Testament were likely not completed until the end of the first century.² This means there were approximately 60 years between Christ's ascension and the completion of all of the works of the New Testament.

But even then, those works weren't compiled into any official canon until hundreds of years later in history, and many Christians only had some of the works and often several that are not part of the modern Christian canon. Also, the concept of 'canon' at that time had little to do with determining what books had 'authority' or were 'Scriptural' (that word simply means 'writings'), but rather which books would be read during public worship (in fact, Revelation was always excluded from this list until much later in history). It should also be noted that the 'Hebrew Bible' read by most Christians for hundreds of years was the Greek Septuagint which contained numerous books that are not in the modern Protestant biblical canon, and the text conflicts with the Hebrew/Masoretic in numerous places (and this is also the version of the Bible most frequently cited in the New Testament—not the Hebrew version used by Protestants today). In fact, Jesus himself quoted books that have been excluded from Protestant Bibles.³

To complicate things even further, literacy rates were generally low until the medieval period in the West (and history shows that heresy and higher literacy rates are strongly correlated⁴). Add to this the fact that books were generally too expensive for the common person until after the invention of the printing press in the 15th century, so for most of Church history, the majority of Christians have not had access to a Bible (including many clergy). This means that Christianity was largely passed on through tradition and word-of-mouth instruction for most of its history.

The Church produced the Bible—not vice versa

As evidenced above, the Church predates the formation of the Bible. Not only were there numerous books that were disputed and read in many Christian communities (even to this day), but there were also notable manuscript differences between existing copies of texts and vast differences between various translations of those texts and their supposed originals. In addition, the formation of the biblical canon was a long and complicated process with underlying pragmatic, theological, and even political concerns. Ultimately, various factions of the Christian church decided which books were 'canonical'—and there is still disagreement among Christians on which texts these are to this day.⁵ The basis for these decisions was usually whether or not these texts were faithful to the apostolic tradition(s) that has been passed down in the Church (keep in mind that no one agreed on which texts were 'authoritative' yet).

Proponents of sola scriptura must trust that the Church got the biblical canon right. If the books were 'self-authenticating' (as many Protestants like to claim), then why would so many Christians have disputed their status, to include folks like Athanasius, Jerome, and Augustine? Why would 'self-authenticating' works take hundreds of years to be accepted? The 'self-authentication' idea simply does not hold up under historical scrutiny. The Bible itself contains no authoritative list of what books are 'Scriptural' / 'canonical' or not (and even if it did, claims of authenticity are not guarantees of it, or else numerous Gnostic texts that the Church unanimously excluded would not have been).

None of the original biblical manuscripts are extant

All that we have are copies of copies of.... We have to rely on the copyists. The field of textual criticism has shown that copyists were far from being inerrant and infallible. The manuscript evidence shows that scribes sometimes modified the biblical texts to harmonize passages, to correct historical errors, and to establish later theological doctrines. The Bible itself makes no claims about God divinely protecting the transmission of manuscripts, and even if it did, it is clear that there are numerous transmission errors. Granted, many of these differences do not affect major teachings or sections of text, but some do. Even if one insists on God's preservation of the biblical texts, then would he not also perfectly preserve Jesus and the apostles' oral teachings as well?

The reality is that many proponents of sola scriptura also believe in an inerrant and infallible Bible that doesn't exist. It's just as much a leap of faith as belief in the preservation of apostolic tradition(s).

The 'fruit' of Sola Scriptura is division and disunity

Jesus taught that one of the criteria for identifying false prophets is to watch for 'bad fruit' (Matthew 7:15-20), and he prayed to his Father for his disciples "that they may all be one... so that the world may believe that you have sent me" (John 17:21, NRSV). The apostle Paul also often exhorted Christians to remain in peace and unity (1 Corinthians 1:10-17, Ephesians 4:1-16), pointing out that

"There is one body and one Spirit, just as you were called to the one hope of your calling, one Lord, one faith, one baptism, one God and Father of all, who is above all and through all and in all" (Ephesians 4:4-6, NRSV).

Given that there were at least 33,000 Protestant denominations in the US alone in 2005, it's safe to say that Protestantism is extremely divided. Granted, Roman Catholicism and Eastern Orthodoxy are not without their own controversies and divisions, but they handle them quite differently—generally remaining Catholic/Orthodox despite disagreement on some issues (and there is rarely disagreement on the big issues such as salvation, Eucharist, justification, etc. as in Protestantism, where most groups have distinctive teachings about such issues). This shows that Protestant teaching on many issues continuously changes over time, showing that biblical interpretation within a sola scriptura framework is often subjective and mutable. Indeed there are few Protestants who even maintain the teachings of their Reformation forebears (e.g. Luther believed in the perpetual virginity of Mary).

Sola scriptura is a logical fallacy

In addition to the self-refuting axiom that the Bible itself doesn't teach sola scriptura (and thus it is a man-made doctrine), the argument can be shown to rely on faulty assumptions as well. A fundamental assumption of proponents is that the meaning of Scripture is clear enough that anyone could understand it by simply reading it, and thus no one needs the Church's (or any authority's) help in the process (despite the text itself saying the exact opposite about itself in Acts 8:26-40 and 2 Peter 3:16¹). If this were true, then why are there 33,000+ Protestant denominations all claiming to correctly interpret the Bible?

The reality is that subjective human reason is the ultimate authority for proponents of sola scriptura. One cannot read a text without having first learned the language in which it was written (this alone brings a huge subjective bias/context to the text, hence the study of hermeneutics). Since a majority of Bible-readers do not know Greek, Hebrew, nor Aramaic, most of them rely on translations. Setting aside translation bias (another significant factor), this means that most readers use a secondary source to read the text. On top of this, most folks are largely ignorant of the historical, linguistic, and literary setting(s) forming the context(s) of the biblical text(s), and scholars are continuously learning new things about these contexts that affect biblical interpretation. When variant readings are present, or a variety of possible meaning is present in a text, how is the correct interpretation decided? By subjective human reason and the choice of the individual. Thus sola scriptura elevates human reason as the final authority over the meaning of the text (regardless of how thousands of years of Christians have interpreted it in the past).

_{¹ The notable exception is 2 Peter 3:16, which is likely pseudepigraphal and most likely written much later than a majority of other New Testament texts. Even so, scholars who accept 2 Peter as 'canonical' also recognize that γραφή refers exclusively to the Hebrew Bible for most NT authors. Even if it doesn't, much of the NT was not yet written nor compiled at the time of many such references (how could Timothy know Scriptures 'from infancy' that hadn't been written until he was a young adult?). In addition, 2 Peter 3:16 actually teaches that some texts are hard to understand, and 1:20 teaches that individuals should not derive the meaning of prophecy from private interpretation. Combined with texts such as Acts 8:26-40, a strong case could even be made that the Bible teaches that Scripture requires proper interpretation—and not privately by individuals.}

_{² I'm aware of the numerous disputes about the dating of various texts. For a hyper-conservative estimate, subtract 30 years from my calculations.}

_{³ For some examples, compare the following passages: Matt. 6:14-15 with Ecclesiasticus (Sirach) 28:2; Matt. 6:7 with Ecclesiasticus (Sirach) 7:15(14); Matt. 7:12 with Tobit (Tobias) 4:16(15); Luke 12:18-20 with Sirach 11:19 (Ecclus. 11:19-20); Acts 10:34 with Ecclus. 35:15 (Sirach 35:12); Acts 10:26 with Wisdom 7:1; and Matt. 8:11 with Baruch 4:37.}

_{⁴ Yes, yes, I know. Correlation does not equal causation. To evaluate this claim for yourself, cf. Peter Biller & Anne Hudson. Heresy and Literacy, 1000-1530 (Cambridge Studies in Medieval Literature) (Cambridge University Press, 1996). Cf. also Brian Stock. The Implications of Literacy: Written Language and Models of Interpretation in the Eleventh and Twelfth Centuries (Princeton University Press, 1987). It is interesting that the only historical proponents of arguing solely from Scripture were heretics (and even Protestants consider most of them to be heretics).}

_{⁵ Cf. Lee Martin McDonald. The Biblical Canon: Its Origin, Transmission, And Authority, 3rd ed. (Hendrickson Publishers, 2007). McDonald is an evangelical scholar. There is much more dissenting scholarship on the issue but this is a good start.}