I worked in academia for awhile at one university and earned a master's of science at another, and something that really surprised me at both schools were how non-rare it was for there to be people with PhDs who were total morons. For example, one of the PhD students who was finishing up around the same time I was working at University #1 could not reliably take the pH of a solution despite spending thousands of hours in the lab over the course of his 5 years in graduate school, and his thought processes were such that he once tried to convince me his experiment failed because the solution inside one of his test tubes had MAGICALLY teleported inside another one of his test tubes and mixed with the contents. He genuinely believed that was the explanation. He now has a PhD.
Another person I know who will be defending her PhD soon is an old coworker of mine who thought I was a genius because I knew how to get back to our vehicle after we had walked one mile in a straight line directly south from it (we were using a compass). She was 23 and did not know north and south were opposite directions. She also had no idea what a 90 degree angle looked like and gave up sunscreen after deciding it was more cancerous than sunshine. I've known several other PhD holders and PhD candidates like comparable to her.
What is the deal with these people and their advisors? How do people like this earn PhDs? And why do universities allow students like this to be pushed through?