It's very possible that all universes are related in some way, however distantly or closely. I could be from your universe, even, just a very faraway galaxy. In my own universe, we have only explored about one half of our galaxy, that's how big it is. Who even knows what else might exist out there, in the far reaches and well beyond the limits that we have so far mapped out?

[ Maybe a kind of magic like what Kirigan and other people in his reality have exists somewhere; what's more unlikely to Jim is that Humans would have somehow managed to evolve in exactly the same way, even in a completely different world. The circumstances would be too specific for it to happen in the same way. ]