The words "a one inch cube" define a universe.
The words "a one inch cube" define a universe where the words "a universe" describe an infinite expanse of space.
The words "a universe" define a universe, while the words "a one inch cube" define it a bit more.
Where can you put something in just "a universe"? On the other hand, if your universe is defined by a one inch cube, you can put something either in the cube or outside of it, just for starters. In fact, defining a universe with the words "a one inch cube" invites you to put things in quite specific places in that universe, or, I should say, in completely specific places in it.
Looking at the words "a universe" again, what can they possibly mean?! Isn't there just one Universe, The Universe? But, no. The Universe may be the universe we inhabit, but we can imagine any Universe we like. We can describe any Universe we like.
(I am describing imaginary universes, but I want to note that the idea that we simply must inhabit just one Actual Universe seems like questionable logic. I bring that up, not because my purpose, here, is to discuss it, but simply because I don't want to be the one who preaches something that silly sounding.)
