The Wikipedia definition of non-duality is that it’s a fuzzy concept that everything in the universe is united, and that the human mind is capable of seeing this.
Like, who wrote that? It’s not a fuzzy concept; it’s just a statement of reality. Everything in the universe is united; it just simply has to be. Physics shows us this. Einstein figured out the equation E=MC².
Everything is united: energy moves to matter, matter moves to energy. Everything’s united because it cannot be any other way. Energy and matter go in and out. And really… you go deeper into quantum physics, and energy is matter, and matter is energy. So, everything’s united. We know it is. There’s no fuzzy concept involved.
And wrong… because this is not a teaching that the human mind is capable of seeing this. When it’s a concept we don’t see it. But. If you stop trying to define it with your mind, then it’s just obvious.
So, Not Two, Advaita, non-duality, means stop using your mind to define everything. Anytime you make a definition, you’ve made that a separate thing.