21st century physicist: “Define what you mean by ‘empty space’”.
Although for some experiments electrons and quarks act like point particles, generally speaking they behave as if there is “something” there, which is why atoms don’t just fall through one another.*
Topologist: the glass is always full. It’s full of glass. That liquid is not linked to it in any way.
*To be exact, the probability distributions that are solutions of the Schroedinger equations behave as if they were actually the shape of a real physical object. QFT and QED are pretty damn factual, but they are also seriously weird.
