There's a phrase an old friend of mine used over 30 years ago to signify what we might call bulletproof today...now reduced to the name of a silly coffee drink that makes a meaningless distinction between butter and cream.

What he meant was that through swaths of history, someone comes along and changes a lot of stuff. Read on and I'll explain. It's not hard to understand.

...Everyone is biased. It comes from one or more of many sources.