I think the question is more along the lines of -
"okay, we have things like concrete and we have things like love and we have things like dreams. It's a noun, so we know it's a thing. But is a 'force' a thing like love or a thing like concrete or is it something entirely different?"

"okay, we have this bunch of equations that describes something we're observing pretty well. Now of course those equations are real, per se, but are they *the* reality or is there something else that's *the* reality and these equations are just fortuitous?"

I guess Popper would say they are part of the third level of reality - objective knowledge. But maybe what we want to know is are they a part of physical reality. Maybe I'll just browse that book a bit.


k