You're right, but to be honest, all of physics is the same.
Theoreticians come up with a mathematical model to explain observations, those models make predictions about stuff that hasn't been observed yet, and experimentalists check those predictions.
If the experiments come out as the theoreticians predicted, we say the mathematical model is "reality".
However, there are clear examples where this method fails: the various competing models of exotic physics, that we can't experiment on, because the experiments are too expensive.
So we never prove that the mathematical model is the perfect description of the underlying reality, we just prove that it is undistinguishable, within experimental error, from the perfect description.