@guigus,
Sorry, it is not possible for me to understand that nothing (lack of difference) is a thing. See both Plato and Aristotle on people who confuse "is" with "is not".
Plato--asleep.
Aristotles- a vegetable.
Scripture--dead.
Science--dysfunctional.
etc.,
The binary foundation of language, as has been pointed out since before Aristotle, you only have two choices, no difference and difference, true and false. Is and is not. Absolute and relative.
And since they are first principles, they cannot be predicated of, they are, in ancient terms of the Two-Element Metaphysics, Elements. As, as Euclide pointed out in the first definition in The Elements, all one can do is say that the one is not the other.
Consequently, the title of this post is gibberish. I was being nice.
Unlike the intellectuals of today, it was realized that there are three, and only three primitive categories of names, only one of which can be defined--names of things, the other two, the elements had to be abstracted, i.e. one has to participlate in the naming convention to understand the name and the associate abstraction (or Aristotle, induction.) If you are unable, due to lack of environment, or of intellect, to make the abstraction, you could never manipulate the word in accordance with the principles of grammar--unless you did so by rote.
Any one of intelligence should have figured this out since perception determines conception, conception determines will. In plain terms, we learn by experience, in mysticism the Father (perception), the Son (conception) and the Holy Spirit (will) are One.