@JLNobody,
I believe the point being made is that while we all notice -- and often praise -- the physical attributes which surround an emptiness, we fail to realize that, in fact, it is the emptiness itself which has become useful. I'm reminded of something I posted on edgarblythe's daily quotations thread which also speaks to this. It's from an interview with renowned pianist Artur Schnabel who told a reporter:
"I don't think I handle the notes much differently from other pianists. But the pauses between the notes -- ah, that is where the artistry lies."
The silence is every bit as important as the music. It makes the music possible. The emptiness of a room is as important as the walls that surround it. We live in the empty space, not in the wall.
So, yes, JL, I'm not arguing that the surrounding matter is unimportant; it is what creates the very useful emprty space.