In Thor:Ragnorak Bruce Banner mentions that he has 7 PhDs. Gee, I wonder how he managed to slip that into a conversation casually. Later in the movie:
Bruce: I don't know how to fly one of those (it an Alien Spacecraft)
Thor: You're a scientist. Use one of your PhD's
Bruce: None of them are for flying alien spaceships.
On the episode Double Date of Archer (Season 11, Episode 6) Gabrielle notes that she has 2 PhD's whereas Lana only has 1 PhD.
I am sure there are other examples of a work of fiction using number of PhDs as a way to say that someone is smart. In reality the number of PhD's one has is... not really a thing.
In reality if a scientist wants to do work in another field they... do work in that field.
Godel did research in Physics in the 1950's, but it would have been silly to go back and get a PhD in it.
Fortnow did research in Economics, but it would have been silly to go back and get a PhD in it.
Amy Farrah Fowler worked in neurobiology and then in Physics. Her Nobel prize in physics (with Sheldon Cooper) is impressive, getting a PhD in Physics would be ... odd. Imagine someone looking at here resume: She has a Nobel Prize in Physics, but does she have a PhD? Did she pass her qualifying exams? This is the flip side of what I mentioned in a prior post about PhD's: Not only does Dr. Doom want to take over the world, but his PhD is from The University of Latveria, which is not accredited.
There are other examples.
There ARE some people who get two PhDs for reasons of job market or other such things. That's absolutely fine of course. However, I wonder if in the real world they brag about it. I doubt it.
Is there anyone who has 3 PhDs? I would assume yes, but again, I wonder if they brag about it. Or should.
WHY do TV and movies use number-of-PhDs as a sign of genius? I do not know- especially since there are BETTER ways say someone is a genius in a way the audience can understand: number-of-Nobel-prizes, number-of-times-mentioned-in-complexityblog, number of Dundie's (see here), etc.