Hypothesis
A hypothesis is an educated guess, based on observation. Usually, a hypothesis can be supported or refuted through experimentation or more observation. A hypothesis can be disproven, but not proven to be true.
Theory
A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. A theory is valid as long as there is no evidence to dispute it. Therefore, theories can be disproven.
Law
A law generalizes a body of observations. At the time it is made, no exceptions have been found to a law. Scientific laws explain things, but they do not describe them. One way to tell a law and a theory apart is to ask if the description gives you a means to explain 'why'.
Above are the definitions of Hypothesis, Theory, and Law as it pertains to science.
Math is a law of science.
The laws of current flow (Ohm's Law) state the difference between current and voltage. Only one of these will have any effect on a GFCI device and it is current.
It is not a hypothesis nor is it theory that current is what opens a GFCI device but it is the law of current flow that states that current will open a GFCI device.
It doesn’t matter if you agree or disagree but the law of current flow does not change, it remains the same. What opens a GFCI device is a difference of 4 to 6 milliamps of current between the conductors.
Agree or disagree will not change this fact of law (Ohm's Law).