In my experience, Scripturalist epistemology is infallibilist and internalist. I think both have philosophical antecedents in Descartes.
The danger lurking in this brand of epistemology is the specter of self-delusion. Recently, I had this exchange with a Scripturalist. He said:
If this task can be so performed, how can one verify the reliability of these propositions? The empiricists usually admit that hallucinations and dreams are unreliable.
To which I replied:
When Scripturalists appeal to the Bible, how can they verify that they are reading the Bible rather than hallucinating or dreaming about a "Bible" that's not the real Bible?
Doesn't this pose an intractable dilemma for the Scripturalist? His epistemology depends on having intellectual access to the word of God embodied in Scripture.
But given his general skepticism, how can a Scripturalist be internally justified in his belief if he can't exclude the possibility that the "Bible" on which he relies might be a hallucination? And how can he rule that out, given his epistemology?
If he already had access to the Bible, that would be a benchmark. But he can't appeal directly to the Bible to prove that he's not self-deluded about his source of information, for that would be viciously circular. If he were self-deluded, if the "Bible" he relies on is a hallucination, rather than the real Bible, then that can't correct his delusion, for t hat's the very source of his delusion!