Reductio ad Absurdum: How to most efficently communicate with theists

[Mister Agenda]

I've found that kindly planting a seed of doubt is more likely to lead to a sprouting of skepticism, though perhaps years later, than a decisive victory in an argument.

If I do challenge someone in RL, it's because they've sought it out, and the challenge I like to give is for them to read their holy book cover to cover without asking anyone else what to think about what they've read. The worst that can happen is that they wind up more knowledgeable about their own religion, and fundamentalists often discover that they don't want to be fundamentalists anymore. Some react like I did, and conclude that if there is a tri-omni God, their favorite holy book was not authored by him/her/it/them.