Of course there isn't a physical distinction. This is a bit like saying there isn't a difference between a novel and a poem, because they're just words on a page. The distinction is nonphysical, but it is also obviously not rhetorical either. I said "intuitive" distinction, I'm not sure why you didn't criticise that directly since it admits that the distinction is not completely precise.

What exactly are you doubting? Is the word "harmony" meaningless gibberish in your opinion? Are there any nonphysical words you admit are meaningful?