A jar, huh. All right. At least it's easier to picture - not as a literal jar, but a world with a clear boundary, stuck in some sort of metaphysical container. Sounds awful, but perhaps if it was where he grew up and didn't know any better, it would be acceptable enough.

The second part of Ephrim's comment is something he's thought about here from time to time, though he still doesn't have a great answer for it. These topics are too big and too above him. "Why do you say they couldn't be in the same universe? It sounds like universes are enormous places. Lots of worlds all across that sky up there. We have our ocean sphere, you have your jar, and they might be years apart from each other."