It is all to often debated what sets humans apart the other species, and that will not be agreed any time soon (which a cynic would note is one such thing itself).
Freud would claim it is only our ego, our sense of self, which may explain why people are so capable of being self- ish, and I suspect he was certain he was wholly correct but I would give him only partial credit.
It is far simpler than that: record your voice, record a Sandhill crane and play them back and I assure you that you will say you sound nothing like what the recorder heard while the crane will nervously look all around for his unseen kin.
He’d been searching for ever, or so often seemed, for no-self, and he couldn’t fathom why it was so difficult to attain simple absence, nothing must be less than something, after all. He knew, like Sisyphus, he would continue to search until he succeeded, the gods of his soul decreed it and you don’t fuck with them. It was difficult recalling how much time had been wasted in the search for mirrors and when he found one, looked, there he was selfsame, self-filled, and he imagined, selfish. He took to always carrying a hand mirror and when he thought he might have found it he glanced at the polished surface in his hand and there he’d still be, his endless self older now, but there, very much still there. One day, frustration getting the better of him he wandered deep into a massive forest, hours later sitting on a fallen trunk, he reached for his mirror, gone. There was tree and sky and earth, that was all, as night enveloped everything, even his no-self.
When you look in the mirror are you real, is your reflection real? Be careful what you say, for if I look into that mirror and see you, is the you I see anything other than real? When you go through the gate you say “I am exiting”. When I follow you through the gate I say “I am entering”. Are we both liars?
A Reflection on case 58 of the Shobogenzo (True Dharma Eye)