Since Scripturalist Sean Gerety took issue with my appeal to extrabiblical evidence, I'd like to point out that his rejection of extrabiblical evidence generates a dilemma–dare I say, "paradox"–for his position.
You see, Sean needs extrabiblical evidence to locate Scripture. A particular copy of Scripture.
Suppose Sean reads the Bible in translation. Suppose it's the NKJV. But how does Sean know he's reading the NKJV rather than the NRSV? Well, both versions are labeled. But the titles and labels are editorial additions to Scripture. It's not as if the original Bible identifies itself as the "NKJV" rather than the "NRSV". Editorial additions are extrabiblical evidence. Sean relies on extrabiblical evidence to determine which version of Scripture he's reading.
The Bible alone can't determine that, because he's comparing one version of Scripture with another version of Scripture. Which one is Scripture? Both? He needs something over and above the Bible alone to compare and contrast the relationship between one version of Scripture and another.
And that's not all. Translations of the Bible depend on a preliminary decision regarding what text to translate. Take the NT. Will it be an eclectic text? Will it be the Byzantine text-type? Will it be supplemented by early papyri?
Or take the OT text. Will that be based on the MT alone, or will it be supplemented by the DDS, LXX, &c.? Sean relies on scholars to produce a critical edition of the Greek and Hebrew text that forms the basis of the subsequent translation. So that's another layer of extabiblical evidence. That requires extensive editorial activity.
Or suppose, for the sake of argument, that Sean wishes to bypass reconstructed texts and read an extant MS like the Codex Vaticanus, Codex Sinaiticus, or the Leningrad Codex. But how does he know where to locate these codices? How does he identify them? How does he distinguish the Codex Vaticanus from the Codex Sinaiticus? How does he know their dates?
That requires extrabiblical evidence. Scholarly evidence about these MSS of Scripture.
Now, that's not a problem for mainstream Calvinists. We subscribe to God's meticulous providence. God can orchestrate the variables. But you have to start from the outside to get inside. You can't start from the inside unless you know where the inside is, which requires extrabiblical evidence.
"Sola Scriptura" was never meant to rule out extrabiblical evidence. It rules out an illicit appeal to church authority. It rules out a religious authority that's coequal to Scripture. But sola Scripture certainly allows for sense knowledge, without which Scripture can't be located in the first place. Sola Scriptura allows for critical editions of the Bible.