Frankly, it’s difficult for me to imagine how the tautology A=A might not be logically true for any imaginable speaker of any imaginable language. Perhaps it could be countered that self-identity is by no means self-evident. But we’re talking about the self-identity of formal abstractions -- signs in a semiotic system -- not the “self-identity of physical objects,” which is, I suspect, a meaningless phrase. The very notion of a sign, being a formal abstraction, implies the of its identity. Things merely are, regardless of what they are, but signs are both what they are (as poetry) and indications of what they’re not (as signs). To say that terms in a semiotic system can be equivalent is just to say that terms are signs.
I can’t imagine any way that a semiotic system could exist -- whether it was a human creation or not -- without the simplest tautology A=A being logically true in it. I fail to see how any new understanding of the nature of a given term could undermine the formal notion of equivalence upon which strict tautology depends. There’s a big difference between our being able to observe that equivalence in the laboratory and our being able to understand the abstract concept of equivalence -- that is, what observation (perhaps physically impossible) would be required to verify self-equivalence. If the possibility of physical observation is required to meaningfully posit self-equivalence, then all talk of self-equivalence would be nonsensical, because there’s no way to twice observe the same object from the same vantage at the same time. Must we discount as nonsensical all talk of similarity -- of degrees of self-identicality -- because self-identicality can’t be observed with absolute certainty? This is a non sequitur: uncertainty about self-identicality makes claims about similarity uncertain (which no one would dispute), not meaningless (which many would).
