I hate to break this to you, but humanity is quite filled with just this type of being. Able to speak eloquently, even put word to paper quite well, yet incapa

I hate to break this to you, but humanity is quite filled with just this type of being. Able to speak eloquently, even put word to paper quite well, yet incapable of basic, logical thought. "Politicians" come to mind first, of all stripes and types. Quite literally, speech + the ability to communicate seems to have little bearing on logic, deep thought, reasoning. Even artists. Music, painting, these are things which communicate greatly. Yet some of these are devoid of all intelligent, capable thought. Note that not all politicians, musicians, or artists fall into this category. It is merely that good artists, or politicians, need to communicate something, and well, else they cannot be effective at their primary profession. So it is a good source of "can communicate well", where some of the sample is in the "but spews gibberish" category.