It may not be everything. There may be other universes. As to what our universe - which admittedly may be the only one - expands into, saying "nothing" doesn't make much sense in any manner.

We are already way beyond our intuitions when speaking about this, so the short answer is that we don't know. Can the universe contain itself, sure, why not? It makes no sense? Well what's up or left in space? There isn't an up or a left in space, but we manage to navigate this somehow.

The universe contains all objects. — Benj96

Does it contain all objects that don't contain themselves?

I am not sure the universe is everything. I think there are lots of things that are non-material but cannot be considered part of a universe or inside the universe.

Can the universe contain itself? — Benj96

It can and it does, quite successfully, even as it expands beyond light speed. It would seem that to apply the sort of everyday reasoning to which we are accustomed to either the cosmic or the quantum may not be appropriate.

What is Russel's paradox?

It may not be everything. There may be other universes. As to what our universe - which admittedly may be the only one - expands into, saying "nothing" doesn't make much sense in any manner. — Manuel

See I would be inclined to agree except when I think “universe” I think “that which encompasses everything” or some “totality of possibilities or existence” So multiple universes in this sense would still be components of “the” universe so im reserved on the notion of replying to attempts to make the universe discrete by saying well it might not be discreet (there might be more of them) when I’m already considering the universe as including everything. It kind of doesn’t address a question but rather redefines the terms of the question so it can go on for infinity and never be answered.

I dunno if I explained that well enough. But basically if we answer the universe is contained in more universes then what contains those universes? And what contains that which contains the container of universe ad infinitum.

Yeah, this then goes into Russellian self-paradoxical situations of the set of all sets containing itself and so on. We can only wildly guess, but I suspect that in principle, everything could be contained in everything. The puzzles arise because we think the way we do, given that we are human beings. I assume there must be a "stopping" point in nature, unless the universe is infinite. If it is infinite, I can't even guess what the answer could be.

If such a being as God existed (and I'm non religious, I'm just making a statement), it would understand the whole of nature without any problems.

So either our mode of cognition leads us to paradox, or we are considering the whole idea of "containment" in such a manner that it leads us into paradox: for example, Zeno's arrow is only paradoxical if you consider reality to consist of mathematics, but when you realize it does not consist of numbers alone, you won't be puzzled when arrows hit targets.

Can the universe contain itself? Ie. Be simultaneously the container and Contained? — Benj96

The universe (one circle) is like a Venn diagram. It is the class of all real things. But there may be another circle that is the class of all possible things. The image below is not exactly what I'm talking about, but it's the closest I could find on short notice. It shows all possible things from two perspectives, from inside the universe (relative reality), and from an outside divine vantage (absolute ideality). :smile: