The first thing the indoctrinated Christian is taught is not to ever question his own faith. No matter how sound an argument is supporting another belief, or debunking existing beliefs, the strength of the argument is proof positive of its evil origins. In the Christian's mind eye, it is Satans foremost duty to make them question their own faith and thus make them more susceptible to the Dark Lord's evil machinations. It's an almost foolproof built-in defense system, for no matter how reasonable, logical, sound, or sure an argument is, if it at all makes one question their belief, it by definition must be evil and untrue. In fact, the only unforgivable sin in Christianity is to question one's own belief, or to hold it up to the light of reason. Conversely, the denial of even the most obvious facts that don't jibe with the belief is proof positive of the steadfastness and purity of one's faith.