for all x: x = x
for all humans: human = human
There are two ways I can interpret that:
1. An axiom. It says "All humans are the same".
2. A proposition. A claim that all humans are the same.
If it's an axiom - there's nothing further to discuss. You either accept or reject axioms. Like 1 = 1.
If it's a proposition then one asks: Is that true ? How would you test if any two humans are "the same"? This is precisely my demonstration where B ≠ В (and I have put it in Python for you so you can scratch your head again. Click 'Run' here: https://repl.it/repls/BouncyOlivedrabMass )
So it begs the question: What do you mean by the symbol = when you say "X = X" ?
The symbolic representation of human (X) contains zero actual information about the positive OR negative properties of 'humans'.
And since no two humans are ACTUALLY "the same" one can conclude that the symbolic representation, as well as the concept of 'human' is just an abstraction. Go ahead and make any positive/negative claims about "all humans" and I will show you edge cases.
TL;DR of https://en.wikipedia.org/wiki/Type_theory
We are of TYPE humans. It is a categorization, not a claim about our nature. It's just an abstract model/label.