On Logic and Alternate Universes

[GrandizerII]

That symbol '5' would still represent the concept 4, no?

No, because to them that isn't logical, remember?

I'm still not sure how you have arrived at that truth. Logically speaking (i.e. using the logic that we hold dear to), we can rule out the logical possibility of concept(2) + concept(2) = concept(5). As such, even if it was somehow true that logic is wrong in this case, it would be true despite our logic. But if it is true despite our logic, then I'm not sure how we can ever know it's true.