Plausibility is fickle. What sounds right to one person can sound ridiculous to another. I would say the most plausible explanation for this is that while people want to be [or at least appear to be] consistent, they vary in respect to certain beliefs. How well some proposition coheres with beliefs about which one is relatively inflexible will influence how disposed one will be to accept it.
Now, psychology doesn't really interest me. If I make a good argument, I shouldn't feel responsible for how a person responds to that argument. And, in general, I don't. Then again, there's not much point to making an argument in the first place if I have no hope that it will succeed in convincing the listener. I may better convince myself, but in any case, it is natural to want something more.
What I am getting at is that while arguing for Scripturalism is fine, to convince more people, it seems that some time should be spent in making it more plausible. Who, after all, would admit to believing what he thinks is implausible?
But how would one go about making something more plausible? Is there an exact science to it? I don't think so. In fact, my advice here is based on intuition and experience, but that should be fine since the goal is not to explain how to erect a sound argument but rather how to take a sound argument, the conclusion of which you think a person opposes, and make the conclusion more plausible. There's room for generalizations, allowances for context, etc., here. So most of what follows will be rather informal.
In general, for example, I wouldn't recommend stating the conclusion first. People don't like to backtrack, so instead of immediately provoking them into disagreement with a conclusion and, by extension, one of the as-yet unstated but underlying premises of a valid argument, it would seem better to state those premises which you believe are both agreeable and integral to the conclusion, and then show why they entail the conclusion. Take the following, well-written statement by Fred Dretske:
If your reasons for believing P are such that you might have them when P is false, then they aren't good enough to know that P is true. You need something more. That is why you can't know you are going to lose a lottery just because your chances of losing are 99.99 percent. Even with those odds, you still might win (someone with those odds against him will win). That is why you can't learn - can't come to know - that P is true if all you have to go on is the word of a person who might lie about whether or not P is so. This is just another way of saying that knowledge requires reasons or evidence (in this case, testimony) you wouldn't have if what you end up believing were false. You can learn things from people, yes, but only from people who wouldn't say it unless it were true. (Contemporary Debates in Epistemology, pgs. 43-44)This is what I would call a plausible argument. You can't know a proposition if it is false, so you can't know a proposition if there is, for all you know, a chance that it is false. A simple, common-sense argument for infallibilism buttressed by an example of how his argument applies to something like the lottery. Examples are good tools when trying to make an argument plausible.
For the purposes of Scripturalism, Dretske cites an even more useful illustration: the possibility of learning from people, where learning implies knowledge-acquisition. Dretske acknowledges it is possible to learn from people, but only from people who wouldn't lie. An excellent deduction from his previous remarks. But would Dretske agree that only one who cannot lie - say, God - satisfies? How else could Dretske be in a position to know who would and wouldn't lie? He may have a suspicion or opinion one way or another, but the real question is would he infallibilistically know? Since we've come this far in agreement, could Dretske really just go back and forget his own arguments? [I don't know how Dretske would respond to any of these questions, of course.]
Or take the following by Richard Fumerton:
We will agree here, therefore, that we cannot avoid knowledge skepticism with respect to the physical world if we understand knowledge as requiring justification so strong that it eliminates the possibility of error.
Of course, the moral most contemporary epistemologists draw is that we should reject Cartesian standards from knowledge. Our only hope of avoiding skepticism with respect to knowledge of the external world (the past, the future, other minds, and so on) is to accept more relaxed standards for knowledge. (Contemporary Debates in Epistemology, pg. 86)That one contemporary epistemologist admits there can be no empirical "knowledge" in the strong sense in which Dretske, another contemporary epistemologist, intends above is quite a concession. While this doesn't show that empirical knowledge is impossible - again, a sound argument can do that even without a so-called plausible presentation - what it does do is show a willingness to respectfully engage and even heartily agree with acknowledged top minds of a given field.
We can even allow for discussion as to more relaxed standards for a colloquial understanding of "knowledge" so long as we in turn can push the point that everyone implicitly holds some beliefs must adhere to the stricter standards (infallibilism, cf. here). I am not aware of any Scripturalist who would necessarily deny we can "know" about an "external world" in a loose sense, but that's because, as I pointed out in my last post (link), Scripturalists are more interested in defeating skepticism. That is, they are more interested in "knowledge" in the "strong" sense outlined by Dretske and alluded to by Fumerton. Focusing a discussion on a few, key points and agreeing with peripheral issues when appropriate will be more conducive when attempting to explain why Scripturalism is true, because at the same time you alleviate concerns that it doesn't cohere with pre-established beliefs.