I've struggled with how to answer this question ever since I was an undergraduate so maybe I'll get /sci/'s opinion.

Consider a few simple equations, like F=ma or V=IR for a moment. What is the "right" way to interpret the casual relationship between the quantities in these equations?

Take V=IR for example. Does a voltage difference across a conductor cause a current to flow, or does current flowing through a conductor cause a voltage difference? In the case of F=ma, one could ask if a force causes an acceleration or vice versa.

Does it even make sense to talk about one quantity "causing" the other? Or is it that neither quantity "causes" the other, and instead voltage, current and resistance are perfectly correlated in a manner such that V always equals IR (for an ohmic conductor).

More generally, do the physical quantities in any given equation actually influence one another, or are they merely perfectly correlated (for an exact equation)?

Personally I prefer to think that they are just correlated, as a causal relationship implies one quantity "happened" first, which doesn't make a whole lot of sense. But I am open to alternate interpretations.