I think there's a degree of market segmentation (as it were) when it comes to arguing. The fastest way someone can discredit themselves in my eyes is to be too

I think there's a degree of market segmentation (as it were) when it comes to arguing. The fastest way someone can discredit themselves in my eyes is to be too certain about something. In your example I'd be much more open to someone who admits that their side could be in the wrong than someone who says that it's impossible. Especially where there's not enough evidence for that kind of claim. But you're right that certainty does appeal in other contexts.