A few days ago, I was leading a cave tour in Wind Cave for a full group (40 people), when I stopped to show everybody some Brachiopod fossils in the limestone of the cave. A large family consisting of a mom, dad, and several teens passed by to see the ancient shells, and as they did, they exclaimed, "Oh look! Evidence of Noah's flood!"
Of course this is ridiculous. But I said nothing.
In the next room, everybody sat on some benches, and I proceeded to talk about some of the speleothems found in the cave. At some point, a gentleman in the group asked me, "How old is this cave?"
I braced myself for some glares from the fundamentalists and confidently declared, "Geologists tell us that the rock in which this cave is formed dates back to about 150 million years ago."
To my surprise, the fundamentalists didn't glare. In fact, they did something even more ridiculous - they laughed. Out loud. Heartily. I was shocked for a moment and paused, but quickly regained my composure and proceeded. "But the cave itself didn't start forming until the the uplift of the Rockies, about 65 million years ago."
Initially, I felt conflicted. By showing them the Brachiopods, I fueled the idiotic fire burning through their brains. However, I though about this incident for a while and came to this conclusion:
* My response was appropriate. Challenging the fundamentalists would have been a waste of time for everybody.
* The fundamentalists probably wanted me to start an argument.
* No matter what I said, they would still cling to their unscientific delusions.
* By ignoring them, I simply made them look foolish in front of all others involved, which is the best thing I probably could have done at that point.