I think this brings us to some interesting questions of how the mind works and how people form and hold beliefs. When someone disagrees with us-especially when its a matter that seems extremely clear to us-we assume that they are misinformed or uninformed. We present facts and if they fail to convince the opposition we assume that they are stupid or evil. Might be true and it might not, but neither one helps us.

There is always the possibility that our belief, reasonable as it seems, is wrong and we are the ones missing the point, so it is good to run this particular exercise in reverse as well.
So, I’d recommend asking people what would convince them. If the answer is nothing, there’s no point in talking. If the answer is X,Y, and Z, then there is a basis for discussion. It is always wise to check on that, though. I have heard someone say she would be convinced if “X” but when the person debating her said, “suppose I could show studies by the organization you mentioned that show X”, her response was “I wouldn’t believe you.” Obviously that conversation wasn’t going to go anywhere.