As far as the laws of mathematics refer to reality, they are not certain, as far as they are certain, they do not refer to reality. – Albert Einstein
This is all Plato’s fault – he founded Western philosophy on a theory of absolute reality, which humans vainly attempt to discern, like cave-dwellers pondering the source of shadows dancing on a wall.
A good metaphor, but modern science has given the existence of absolute reality a few hard knocks. Heisenberg showed that you can never perfectly know the location and velocity of an object. The more accurately you measure where it is, the less accurately you know where it’s going. It doesn’t even make sense to speak of particles as having absolute attributes, they are better understood as clouds of probability distributions. Space, time, mass stretch depending on the motion of the observer.
Interactions between particles seem more tangible than the particles themselves; you either observe an interaction, or you don’t. And what is a particle except how it interacts with other particles? Suppose there were only a single electron in the universe, would it still be meaningful to say that it has a charge of -1.602 x 1019 coulombs, if there were no other particles and fields for it to interact with? What is the sound of one hand clapping?
Is there a ‘form’ of a chair? Or is it a chair if it’s something you can sit on?
Which brings us to money.