The internet credits Robert Heinlein with saying "Man is not a rational animal, he is a rationalizing animal," but my dad told me that when I was very young. Since all writers burrow things away in their subconscious, my guess is Heinlein picked it up somewhere, maybe from Twain, or maybe it's just one of those observations that smart people eventually make.
When I was older, Dad phrased it more bluntly: "Your problem is you think people are rational." I can't remember how I answered, but what I've thought for most of my life was that people have the potential to be rational.
But now I think Dad and Heinlein were right. I was citing confirmation bias recently, and I realized that's why people don't change their understanding of the world until their world changes.
Now I'll resume my internet break while I ponder this.