What? Are there not some giant elephants between the Earth and the top turtle?
there must always be something beyond it.
As I feel more and more mortal with each passing year, I think about death. To me death is where I cease to exist. Like passing out or fainting except you never wake up again. But while I do not believe in an afterlife, I can see why many do, because it is about impossible to imagine my non-existence. Any time I think about it, it winds up being somehow me off to the side aware of myself being dead. I am not equipped to envision not existing.
SO with that human limitation in mind, we think of where we are as some place. And from life experience, anything not in that place must then be outside the place. Outside is "somewhere". But what if the universe is finite in some way? I don't think we are equipped to envision that a limit can have nothing beyond itself. That there is no existence beyond the edge of existence.