The problem here is pseudo-philosophical at most but if there’s an easy answer, it’s definitely not to interpret the metaphor literally. If the entities are ex

The problem here is pseudo-philosophical at most but if there’s an easy answer, it’s definitely not to interpret the metaphor literally. If the entities are exchangeable (as you treat them) then the premise void. Are you sure you understand the problem? Exchanging one for the other may work in semantics but not in physical reality, because only one of them is physically real.