Keith thinks that a person giving an opinion is an extension of being a historian therefore you can't argue with the opinion.

That's a bit like the mental leap that vicars know a bit about theology therefore their opinion that sky fairies exist (well, not all of them believe in that tosh but I digress) isn't one you should argue with.

Historians set the scene. Your own intelligence provides the opinion. The only people who borrow opinions are shallow God botherers.

Slowly but surely, the Keith in the couch is revealing his condition. Once we have the diagnosis we can get nurse to rig up the enema hose.