In every text on Logic today, in all the works of wannabe intellectuals, when told that they have to define their terms, what do they miss?
Well, we have two types of identity, arithmetic and geometric. However, what else is a rule by which we use either one? It is in Theaetetus.
Assertion or denial, can never be absolute, i.e. if I say A = B. is not either true or false until I define the equality, "What relative difference is it in reference to? " Everyone misses this.
We are a multi-sense organism. Which sense, or group of senses, does the equation refer to? Not said, not formal grammar. If it is not formal, it is then informal, and open to question and answer until the issues are agreed upon.
Those who argue in absolutes, unwilling to establish the relative, are simply senseless.
So, in pure mathematics, the sign of equality is universal, absolute, but when used for any particular example, it is wholly metaphorical, or proportional. It is then false, to claim that common grammar is literal.
This is also one of the reasons that Set Theory, Predicate Calculus, attempts to diagram a sentence, Group Theory, Theory of Relativity their fake geometries, et., are provably wrong. Just one reason. If one is not literate, they cannot follow the binary recursion, explained by Plato, demonstrated by the computer,