The illusory self - the self that declares itself something separate & apart from all else - is convincing only to the dualistic mind.
Dualism implies that to be something is to NOT be something else. To be tall is to be not short. To be blue is to be not red. To be me is to be not you.
Dualism is so prevalent in our thinking that we bake its negative implications into our common sense. If I say I'm both light & heavy, the dualistic mind recoils & scoffs. If I say I am I & I am you, and you are I & you are you, the dualistic mind feels pretzeled & calls shenanigans.
The shadow of negative implication is where the illusory self declares itself "I alone."
Bob & Sue are having coffee. Bob looks across the table & a thought crosses his mind: "I am not Sue." More thoughts cross Bob's mind. "My body is distinct from Sue's body." "My thoughts are distinct from Sue's thoughts." "I am here, this; Sue is there, that."
If Bob can let conceptuality go, then these thoughts pass by his awareness like foam on a river, & he returns to the irreducible, inexpressible experience of being, untroubled by matters of self-conception. The illusory self declaring its separateness simply is what it is, amidst the remainder of noticeable phenomena in an unbound field of awareness.
Or, Bob could let dualism go, & explore open conceptuality. "I am not Sue." Huh - well, I don't know all she knows. "I am Sue." Huh - well, we both love cappuccinos. And on from there.
Bob can explore Nagarjuna's multi-value logic: "I am both Sue & not Sue," &, more expansively, "I am neither Sue nor not Sue." Bob can then abide in the superposition of those seemingly irreconcilable claims, discovering his ability to abide in mental states beyond exclusive mental positions.
Interesting questions are begged: what is identity? what does "I" refer to? how are mind & reality related? Who or what is the authority on such questions?
What we truly are is what's able to contemplate such questions & abide peacefully, even gladly & gratefully, in a state of honest uncertainty.
What we believe we are is a set of mental positions that should be declared & defended. Including the insistent position that I am not you and you are not I.
Let's acknowledge the practical benefits of exclusive identity. Bob doesn't wanna be on the hook for Sue's credit card bill. Sue doesn't want Bob strolling into her house & helping himself to her heirloom jewelry. Our civilization has created rights & protections tied to individual bodies at the exclusion of others.
Our dualistic minds take it a big step further: we extrapolate this practical, conceptual arrangement into a declaration of absolute truth. Instead of recognizing nominal identity as a matter of stipulation - something we do as a means to other ends, e.g. making sure a social security check reaches the right person - the illusory self wraps itself in the cloak of nominal identity - the pronoun "I" - and then uses dualistic thinking to shove the remainder of existence beyond its conceptual wrap. Suddenly, there's this self-declared "I" declaring its own absolute exclusivity.
If we recognize the specious steps leading to its audacious self-declaration, we can chuckle & let be.
What we tend to do is take the self-declaration seriously. The mind then marshalls evidence to cement the claim. "Everyone else - everyone sane, at least - agrees I am not you." "I only see the world through these eyes, never those eyes."
The discerning mind will recognize these assertive claims as invitations to contemplate, to gently explore the questions these assertions beg.
The mind addicted to identifying with mental positions will see these questions as forks in a road the mind must travel. Our dualistic conditioning shoves the mind toward the choice point: "yeesh, be reasonable! pick a damn side already!" Eager to do right, or sick of all the pushing, we typically buy into the collective illusion of exclusive selves, not appreciating how much confusion & disregard this position requires, both for its initial adoption & then for its constant & elaborate maintenance.
There's talk of how we only use like 10% of our brains. Maybe what we mean is: 90% of our mental energy goes to sustaining a false sense of self, leaving only 10% to experience the truth beyond the artificial constriction. No wonder we fritter our time away on so much that doesn't truly matter to us. We're following the various mandates of a brash fool we've tragically mistaken for ourselves. dualism & the illusory self related.