When a system of belief lacks evidential support, it must compensate for this weakness by surrounding itself with defense mechanisms. These defense mechanisms do nothing to address the flaws themselves, rather they attempt to divert attention away from the vulnerabilities of the system, drawing fire in an alternative direction. By far the laziest (and therefore the most popular) way to do this is the ad hominem attack, in which you impugn the character of the person making the argument. Note that this does nothing to address the argument itself—it only serves to change the subject to something easier to defend.
Her: I think belief X lacks evidential support.
Him: Your argument is invalid because you’re wicked.
It’s an especially manipulative tactic when you turn to question the motives of the other person, evaluating her by measures which are subjective and therefore impossible to falsify, like values peculiar to your own belief system (the very system under investigation). This is a logical fallacy, and yet it is the standard response to almost any challenge to the Christian faith you hear these days.
Yesterday a Facebook friend pointed out that apologetics rarely persuades non-Christians to become Christians. I agreed, adding that apologetics is primarily for the “saved,” not the “lost.” It serves to assure the faithful that their beliefs are intellectually respectable, despite the apostle Paul’s insistence to the contrary. One of my friend’s Christian friends dutifully chimed in, saying:
A truly Biblical/Christian worldview posits that the aversion to God is much more deeply-seated than at the intellectual level…The Bible says people believe what they want to believe. When someone is genuinely converted, it’s because what they want to believe has been changed.
Now imagine if the situation were changed. Imagine if a young man began to question the historicity of Joseph Smith’s golden plates, or if a young Muslim questioned the authority of either Muhammad or the Koran. Would Christian apologists disparage the young man’s motives then? Would they accuse him of selfishly wanting to be free from the authority of the Koran or the Book of Mormon, or rather would they join him in honestly consulting the facts as we find them? Would they consider the motivation of the inquisitor an overriding factor in this discussion? No, they wouldn’t. Even if they chose at some point to condemn the character of the young man (and I’m confident they will at some point, for they must) they would still see the intellectual questions as separate from the question of motives or character. They would see the intellectual questions as valid in themselves and address them to the best of their abilities. So why don’t they do this when someone challenges the Christian faith or the Bible? Why in those moments do they insist on moving the discussion away from the intellectual sphere toward the very subjective sphere of hidden motives? It’s because like any organism fighting for its own survival, the Christian belief system must employ an array of defense mechanisms to hide its most vulnerable places from the harsh light of rigorous questioning.
Your motives for asking probing questions is beside the point. Whenever someone tries to shift the discussion away from the evidence of falsifiable things to the very squishy subject matter of “the human heart,” you can be sure you’ve just struck a nerve, a vulnerability in their belief system. Don’t fall for that old trick. It’s a diversionary tactic.