We now know, that if someone is an ignorant, arrogant, apathetic narcissist they can go completely senile and continue to ramble nonsensically with vigor and confidence, because they never had any self doubt, nor did the reaction of the audience mater in any way, all along.
Their ranting, with a mind full of holes, is indistinguishable to themselves from who they already were.
Fascinating and dreadful.