It might be philosophy, so I apologise in advance.
Does current understanding in cosmology or even general relativity itself rule out the existence of a larger empty space containing the expanding universe? I mean in such a case, nothing should change to the description and fate of the expanding and matter containing one... so it can be seen a redundant speculation and perhaps we might apply the razor of Occam.
I rephrase for clarity. On which bases we rule out (if we indeed do so, perhaps it just unnecessary and not giving any results, as I said above) that the Universe and its expansion are happening in existing space? Does GR prevent to conceive an empty space surrounding one in which matter dictates curvature? I don't think so. Perhaps the cosmological principle can be used, but it would implied an always infinite Universe.
I hope my question is clear enough. I think that the two situations might be mathematically and, of course, practically indistinguishable but yet conceived.
