If you are really serious about this question then you would also consider what mathematicians have to say about "space". Unfortunately, this is pretty much the whole of mathematics, but I think special attention should be given to the duality between geometry and algebra. This stuff goes back to Descarte. For example, you can consider the points equidistant from a specific point, which gives a circle. Or you can consider the algebraic expression X^2+Y^2=1. Both of these viewpoints are in a sense, two sides of the same coin. What is that coin? Deep answers can be found when you start doing funky things like change your definition of numbers, to say, a finite field. Even just having two numbers 0 and 1 is quite interesting to consider. What is the corresponding geometry? Or, more confusing still, let's drop the requirement that xy = yx (commutativity). Now what are the non-commutative geometries on the other side of the coin?

Considering the wide variety of these apparently fanciful ideas that have made their way into theoretical physics fills me with wonder. I wonder if the authors of the article mention any of this stuff in their book.