Going into conversations with the staunch belief that you are correct and that evidence is ad hoc. You can either convert to my way of thinking or be foolish.

Fantastic way to sum up their thought process. I've rambled inanely about it in the past, but there it is, just in two sentences. They refuse to consider that their position is an incorrect one. I wish I knew how to get people out of that mindset, because people like that are the prime target for grifters and con artists.