I wanted to expand on something I mentioned a few posts ago:
It is conducive to an unbeliever's understanding to refute his worldview by employing a necessary precondition of knowledge, like logic, rather than simply quoting Scripture. The more cognitive dissonance one can create in an unbeliever's mind, the better.
I've been writing a few posts as of late about why I think those who make knowledge claims must presuppose an omniscience source for them. In most if not all cases, I've structured the arguments for this from the perspective of epistemic and logical necessity. But as I'm a Scripturalist, one might wonder why I don't simply cite passages of Scripture which entail divine omniscience and illumination and leave it at that. After all, given my first principle, Scripture, any argument I make must follow from it anyways. So why not make the simple argument and leave it at that?
The point of epistemic apologetics is to cut off all retreat. Either the opponent accepts the necessary conclusion or remain hopelessly mired in self-contradiction. In the latter case, I simply just tell him that he accepts the conclusion until he recognizes that he cannot resist without appealing to the necessary conclusion.
Now, God has communicated with His people. Christians know that the truths which Scripture conveys are necessary. But the manner in which these truths are illustrated to be necessary may, as I alluded to in the other post, affect the opponent's willingness to accept the conclusion. It may lead to cognitive dissonance. At least, this is what I suspect.
Why? Well, unbelievers are inundated with claims by false religions who they have the word of God. While guilt-association of Christianity with these false religions is fallacious and inexcusable, it doesn't hurt to show that propositions entailed in a Christian worldview - such as an omniscient source of knowledge - are necessary by means [not mutually exclusive with the answer "because God said so" but] intended to highlight the foolishness of holding the contradictory in such terms that even the unregenerate mind cannot stand it. After all, some unbelievers see the stupidity of skepticism, and while it may be fashionable to taunt those who believe the Bible to be God's word, the more quickly a Christian can not only cut at the actual heart of an opponent's worldview but also at what the opponent himself perceives to be the heart of his worldview and by utilizing types of arguments (e.g. Socratic) the opponent is more likely to respect, the quicker the opponent will be forced to change his tactics.
There is something to be said for respect. If one can address an opponent with some level of what is commonly thought to be philosophical sophistication (think William Lane Craig), then an opponent be more willing to seriously engage or consider an argument, and the greater may be the benefit for other believers: renewed interest in apologetics, confidence that Christian beliefs can hold under scrutiny, etc.
UPDATE: After a little more reflection, I think what I am trying to say is that I want to marry the intuitive appeal of classical apologetics with the necessity of epistemic preconditions for knowledge. This would be done by showing that a proposition such as "One must have recourse to an omniscient source for knowledge" follows from multiple propositions within one's epistemic system. This is useful because while one may inexcusably deny one precondition of knowledge, if he acknowledges another - one[s] more commonly believed, like the laws of logic - then by demonstrating that "one must have recourse to an omniscient source for knowledge" follows from (or more precisely, is mutually conditioned with) the laws of logic, it would seem reasonable to suppose that one will be more inclined to accept what is entailed by what he understands to be a precondition for knowledge than he would if either 1) the premise in question was not a precondition for knowledge, in which case he would simply back off the premise (cf. classical apologetics), or 2) the precondition for knowledge in question was one which is not acknowledged to be intuitive (cf. the Bible is God's word).