There's a facet of reality which doesn't lend itself to rational analysis - it's called 'infinity'.

Infinity is an attribute of nature which absolutely defies logical interpretation. It's not exempt from the laws of nature and it's not contrary to reason, but it lies beyond the domain of logic because it's not defined - and logic requires definition.

There is a finite distance between every two points in the Universe, but there is no point - however distant - where the Universe ends. Some mistakenly believe that if there is a finite distance between every pair of points then the farthest point in the cosmos must be a finite distance away. What they don't understand is that just defining two points sways the realm of their consideration from the infinite back to the finite. When dealing with infinity, there is no 'farthest' and there is no 'all' - and the fact that no defined point of infinity exists serves only to further validate the concept.

The old 'balloon' ploy is often put forth as a three-dimensional example of cosmic expansion in a four-dimensional configuration. Stroking the ego of the unwary layman for his ability to understand a hypothetical abstraction, pundits propose this as an example of how the Universe is finite but unbounded. The scholarly sleight of hand to which theorists occasionally descend is, indeed, amazing. Three independent values (XYZ coordinates) are all that is necessary to uniquely specify any point of existence within the Universe - hence there are said to be three 'dimensions' (more accurately, three axes). If the Universe were finite, then for any given point there must exist another point within a finite distance at which travel in any direction will not increase the distance between the two. If someone wants me to believe the universe is finite, then all they have to do is simply convince me that the value of at least one of the XYZ coordinates has a limit. And if anyone wishes me to believe there are more than three dimensions, then prove to me that there are locations in the cosmos which cannot be specified within those coordinates.