By reader request, I have some comments on some arguments against Sola Scriptura, as presented by Daniel Silliman. Here are the arguments:
1. Neither the creed-like phrase nor the doctrine of sola scriptura are found within scripture and thus must be rejected by the doctrine itself. Sola scriptra is internally unsustainable.
2. Scripture does not posit it's authority alone, but does tell us to obey the unwritten teachings of the apostles and that the Church is the pillar and ground of truth.
3. The apostles never taught such a doctrine. Indeed, it was no part of Church teaching before the Reformation.
4. The historic touchstone of Church teaching and Christian belief was not scripture but liturgy.
5. We cannot have a canon without canonization.
6. Sola scriptura is a product and a perpetuation of individualism, contorting the reading of scripture from a place within the Church and Christian community to a private, solitary and self-authoritative act in contradiction with the communal nature of the Christianity Church.
7. No heresy has ever been stopped by sola scriptura. Legions have been started by it.
I'll work my way through all the arguments but in a different order, starting with the most glaring errors and then seeing how thinking more carefully about those will help with the more subtle problems.
6 misunderstands the view and is therefore a straw man. There are people who make their own interpretation of scripture infallible, but that's not sola scriptura. Sola scriptura is the thesis that scripture itself is infallible and that no other source of information is infallible. This is a common error among those not trained enough in the finer distinctions of epistemology. It's a level confusion. Another example would be confusing the truth of something with someone's knowledge of that truth. Whether something is true does not depend on whether I know it. Similarly, whether scripture is infallible (and no other information source is) does not depend on whether my interpretation is correct or infallible. The only individualistic view is one that places my interpretation as infallible.
7 just seems empirically false. The selling of papal indulgencies were stopped by Sola Scriptura during the Reformation, as was the misunderstanding of James's comments about faith and works (which recent Roman Catholic commentators such as Joseph Fitzmyer and Luke Timothy Johnson have demonstrated to be consistent with Paul, notably an interpretation of Paul that sounds more like Luther or Calvin than Roman theology has traditionally said, at least since the Reformation). Any council that has made its determination based on scripture has in fact stopped heresy by Sola Scriptura. Has any heresy been caused by Sola Scriptura? I don't know of one. Many have been caused by the straw man that Silliman pretends Sola Scriptura to be. How is that relevant?
2 and 3 should be handled together (since the only teaching of the apostles we can be sure of are the NT scriptures). Scripture does indicate an authority to the teachings of the apostles. Why else would Paul talk about the traditions, right? But clearly that can't be just any old teaching of the apostles. You have to admit of some error in the apostles' teachings unless you ignore the conflict between Peter and Paul in Galatians 2, but then once you exclude that as illegitimate then you've admitted error in Paul anyway. Those who believe Sola Scriptura have a solution. The teachings of the prophets that we still have as scripture are the ones we can rely on. 2 Peter 3 includes Paul's writings as sripture, and II Timothy 3:16 clearly says that all scripture is God-breathed and useful for all the primary purposes of the church. This also undermines 1 slightly. It doesn't show that scripture is the only source necessary for life (which I think is false and not implied by Sola Scriptura anyway), but it does clearly imply that scripture is infallible (or it couldn't have been breathed out by God, unless you ignore all the biblical connotations of that). As for historical matters, we need to keep in mind that not everyone views the history in the way 3 assumes (cf. this article). I know less about the details of that stuff, so I'll leave it at that.
The other problem with 1 is that it involves a false expectation. First it's claimed that the doctrine needs to be supported by scripture to be internally consistent. If, however, someone tried to justify it that way then it will be claimed that it's circular. Which is it? Does it need to be supported externally to avoid circularity, or does it need to be justified internally to maintain consisency? It's a false dilemma. Something can be evidenced internally without being circular, and there is external support for the doctrine simply because the church fathers did support their claims by appealing to scripture.
4 has problems related to the old covenant, which recognized only the equivalent of God's direct words in Torah or in prophets, who at the time spoke messages, but only what was preserved continued to guide them. (NT prophets are different, as Carson and Grudem have argued. It's way beyond the scope of this post to get into that here.)
The biggest problem with 3 is that it can't justify Catholic views either. The vast majority of where Roman Catholicism has differed from Protestantism arose far later than the time of the apostles, and much of it is even since the Reformation. The only two ex cathedra statements were in the 20th century. Councils have even conflicted with each other. The standard Catholic line on Luther now is that Luther wasn't a heretic but that the council declaring him one was right to declare the view he didn't hold as heresy. It was wrong in thinking he held it, but it was right to declare it a heresy. Augustine has de facto been declared a heretic (because of a condmenation of groups who agreed with him), though he has also been declared a saint.
Which tradition do you follow? Even if you stick to pre-Reformation stuff, there are problems here. The church fathers themselves included different views on eschatology, whether people can be saved outside the church, whether all OT scripture should be interpreted allegorically, etc. Which ones count as the tradition we follow? You end up with the same problem. We can have the scriptures help us decide, we can make it arbitrary individual choice, or we can have an arbitrary governing body of people decide which one they at the time prefer (but which will change shortly when different individual people are involved). Scripture as authoritative is the only response.
5 involves the trickiest issue. I think its fundamental assumption is another false dilemma, so let me try to make the argument explicit. For a canon to occur, it must involve people putting it together. If these people are fallible, then there's no way to trust their putting it together. If they're infallible, then it's tradition that put it together, and tradition is good enough after all. The problem is that this dilemma ignores a third option, that fallible humans were involved in recognizing which books were scripture. This is another level confusion. The fact that something is scripture is independent of our knowledge that it's scripture. Those are the first two levels. The third level is whether our knowledge that it's scripture is infallible. The level confusion here is between the second and third levels. Something can be knowledge without being infallible knowledge (meaning that you could have been wrong if things were different but turned out to be correct because they're not). A good example of this is the ordinary knowledge of where you left your car. If it's parked in a safe spot and is locked, it's likely to be where you left it. Suppose it is. Do you know that? Well, it's possible someone stole it. If they stole it, you don't know where it is. However, they didn't. You're not wrong, though you could have been. Do you know where your car is? Some people say no, but I think this is a mistake. I think our ordinary use of 'know' in English assumes that you could have been wrong but aren't in fact wrong. Similarly, if the Holy Spirit hadn't been guiding the church fathers accurately, then we wouldn't believe in the same canon. They could have been wrong. That doesn't mean they were, and it doesn't mean we now don't have knowledge of what the canon is. Knowledge doesn't require infallibility. Recognition of a reality doesn't require that such recognition is infallible.
I should say that the Roman Catholic analogue for 5 has to deal with the same issue. You can't have a canon of tradition without a selector of which tradition is canon. It certainly can't involve the contradictory traditions available unless none of it is infallible, in which case you're back to the subjectivity of the individual deciding which sources are authoritative and which aren't.