In physics, we have a number of "fundamental" variables: force, mass, velocity, acceleration, time, position, electric field, spin, charge, etc
How do we know that we have in fact got the most compact set of variables? If we were to examine the physics textbooks of an intelligent alien civilization, could it be they have cleverly set up their system of variables so that they don't need (say) "mass"? Maybe mass is accounted by everything else and is hence redundant? Maybe the aliens have factored mass out of their physics and it is not needed?
Bottom line question: how do we know that each of the physical variables we commonly use are fundamental and not, in fact, redundant?
Has anyone tried to formally prove we have a non-redundant compact set?
Is this even something that is possible to prove? Is it an unprovable question to start with? How do we set about trying to prove it?