[PatrickHenry]

And that [A is A] brings up the other kind of unquestionable truth -- "true by definition".

I'd prefer to say, in this instance, "true by identity." I think it's more than a quibble. A definition isn't an axiom.

[Doctor Stochastic]

It's definitely more than a quibble. "A=A" is an important principle in resolving some seemingly inconsistent things. For example, an electron isn't a wave or a particle, it's an electron.