[Question_Assumptions]

Personhood is essentially the trickier question of when the human individual can't be casually killed by another human individual like a plant or animal. In my experience, it's easier to address the two as seperate issues than as a single issue, since one of the favorite tactics of abortion advocates is to confuse and flip between the two so that nothing can be nailed down. The issue of personhood is a bit more complex but boils down to there being only two non-arbitrary points where a human becomes a person -- fertilization and about two years of age. See Michael Tooley's (in)famous essay In Defense of Abortion and Infanticide for a good pro-abortion argument of why that's the case, though Tooley picks the wrong point to support abortion.

[RobbyS]

I think they also --deliberately-confuse legal personhood with the person. Positivism allows us to define and redefine things to suit our needs. Legal personhood IS something that the law can create: one can arbitrarily say that a corporation is a person because it is useful to say this. Our system allows the courts the power to vest meanings in words, meanings that sometimes contract the evidence of our senses. The court says that a child of human being is not a human simply because it is useful for the child not to be human. Talk about priestcraft!