It's Always Sunny In Philadelphia: 10 Most Insane Fan Theories

Again, this theory has a surprising amount of legs to stand on. The degradation of Charlie's intelligence throughout the show has been quite spectacular. In the first season, he's clearly not the brightest star in the sky, but he is at least a functioning adult. However, as the show went on, it became clear that he was much more than a little dumb.

While we did see in a few episodes before that he can't write decent speeches, he at least could write something. This theory suggests that the reason his functionality plummeted so quickly is because of the damage that he endured in Hundred Dollar Baby. It claims that the beatings placed upon him by Mac and Dennis resulted in him developing brain damage.

This is used by many theorists to justify other points about Charlie. It's another reason as to why his secret genius potential wasn't unlocked, and explains why he has been ignoring the carbon monoxide detector that has been going off for nine years.

Poor Charlie really can't catch a break, and it almost seems as though every theory is about him.