Bill Bryson said this quote
“ Presumably, a confused person would be too addled to recognize that he was confused. Ergo, if you know that you are not confused then you are not confused. Unless, it suddenly occurred to me--and here was an arresting notion--unless persuading yourself that you are not confused is merely a cruel, early symptom of confusion. Or even an advanced symptom. Who could tell? For all I knew I could be stumbling into some kind of helpless preconfusional state characterized by fear on the part of the sufferer that he may be stumbling into some kind of helpless preconfusional state. That's the trouble with losing your mind; by the time it's gone, it's too late to get it back. ”