Anthropology

and there are still non-human persons. What makes humans unique is their ability to bring about their own demise.

I think social order and governance arises to guard against sociopathy and selfishness. Persons realize they have minds that can't be read, so they rely upon each other to survive the choices that conflict with retaining balance within their domain.

I think octopi may be persons, certainly the great apes and cetaceans are persons. Perhaps certain pigs, cats, and dogs as well.

We don't necessarily have to limit personality to humans. Communication between species is within the existential plane of personhood. Which beings among us have a sense of self beyond the triggers of instinct?