What if demons fool people into believing that Christianity is true, when in reality it is not? For instance, it may be that Zeus is the one true God. And there exist demons who hate Zeus and like to play tricks on him. And one of those tricks is to possess people and convince them that the Christian God exists, or perhaps that Allah exists, or Vishnu. Indeed, these anti-Zeus demons could be responsible for inventing the entire edifice of Christianity, just to piss Zeus off.
What possible response is there to this argument, from someone who actually believes in demons? It must be clear to such believers that demon possession subverts a person’s entire way of thinking and behaving, so surely it is feasible for demons to be tricking people into holding false beliefs?
It seems, then, that belief in demon possession must lead to the complete distrust of one’s own cognitive abilities and emotional instincts since they, too, may be under a demon’s control. Consequently, the believer should warn the rest of us that his beliefs may just be fabrications intended to mislead us.
Somehow, I don’t see that happening.