Clumsily put, Let's say we were in a bar, having a few pints, and talking about the nature of Universe.
You point out that most of what we consider "matter" is made up of empty space; the distance between a nucleus, it's electrons, and the nearest adjacent atom is comparatively large; why, that barstool over there shouldn't even be considered a solid!
I respond by saying that as far as we can actually prove, that barstool might simply be a hallucination, for we're not actually seeing the barstool, we're processing electric signals in our heads generated by our optic nevrves that claim certain wavelengths of ligh have bounced off an object, but none of that says anything about whether or not the barstool actually exists.
Then ECH comes along, picks up the barstool, and proceeds to beat the shit out of us with it for being such pretentious assholes.