A=A asserts identity.
If A=the weight of my brain... and B=the weight of yours, then A and B are the same thing... not as a matter of identity, but a shared characteristic. Whether my brain and your brain are the same thing, depends on whether we think in terms of a unified or pleuralistic universe.
Some would say that since there is no distinction in the unified universe, there can be no rational reflection upon it. There is no perspective from which you can view the unified universe, because there's no distinction between you and not you
so as to allow any type of viewer.
Nevertheless, I say that when we equate voltage to resistance times current, we are in fact recognizing that potential and actual are not really separate except in the context of the analysis of an event.