text: The only way I can see to do so, is to propose a question like this to them.  It IS blatantly obvious to the rest of us, but until you can get them to understand this basic principle, all other arguments are lost on them.\n\nThey will always retreat into the "I have my faith" cave otherwise.\n\nExcellent question.\n\n\nEdit - The funny thing is, you can see by some of the responses here, they're actually using this argument right now, and they don't even realize they're doing it.  Absolutely incredible.