Where I'm from, Fillory was created as a joke or entertainment by two gods. It's existence is why humans have access to magic. Ember was bored, decided to destroy Fillory and everyone currently living on it. My friends and I stepped in and killed him first.
Apparently if you kill a god, it doesn't make the other gods happy so they cut off access to magic. So I don't know if that means we have magic here because this world has a different source or because it's an alternate timeline or...
I'm telling you this in case we end up on a world where it simply isn't.