I don't understand this part. A huge advantage of a personhood-based theory of the morality of abortion is that it doesn't rely on binary concepts. Like, what is it you're advocating if not a "magic switch" binary based on (I'm guessing) fertilization? Personhood-based theories can say that personhood is a spectrum, ranging from bacteria at one end to a normal adult human at the other. Maybe it's even multidimensional - a capacity to feel pain may confer a right to not be tortured, while a capacity to anticipate the future may confer a right against being killed (just as examples). Many animals have some degree of personhood, which is why they have some rights but not as many as adult humans. Children have some degree of personhood, which is why they have some rights but not as many as adult humans, although it's probably reasonable to suspect that part of why we treat children so well is that we're partial to them (if ever our human biases were going to color our moral views, it's here, right?). Or, conversely, part of why we treat animals so poorly is that we think they're tasty. As children grow up they gain more and more right to determine what they do with their lives. That's not really controversial - nobody's saying that five year olds should be able to vote.
It depends what you mean by "vegetative state", but lots of people actually are pretty comfortable allowing the killing of people who are in many ways already dead. Often we try our best to let the person who is in the coma or whatever make the decision beforehand, by explicitly writing down what they'd want to have happen or by asking people who knew the person best what they'd have wanted. This ends up looking a lot like respecting someone's wishes for how they want their body treated after death. Of course, if there's a significant chance that someone might come out of the coma, or is conscious in it, we're really just talking about something that looks a lot like a long nap, morally speaking. People who are asleep don't cease to be people. I'm also not sure what's so wholly un-personlike about people with Alzheimer's. I mean, sure, they lack some capacities and so perhaps some rights, which we respond to by doing things like lying to them constantly about whether their long-dead siblings are still alive. But otherwise they're a whole lot more "there" than almost anything else in this world.
But what's the alternative? You've got a totally value-less egg just sitting there, then it contacts a sperm cell and suddenly - magically - you've got something with the moral value of an adult human?
I slipped there, i meant there's no switch or binary state about personhood.
Let me continue the discussion regardin that point, personhood is a complicated issue since you cannot precisely pinpoint where does it starts, and then, it clearly starts after birth, and that would give thumbs up then to killing already born babies, that's why at least for me there's no value in the personhood argument, you cannot put a finger on it, you cannot identify it, it cannot be tested, and it's definition is debatable philosophically and legally.
How can a law exists that's based on something as volatile as the definition of personhood? Abortion law just makes the fact illegal, to change it, should it be then replaced by one that defines where personhood starts?.
I think there's no comparable personhood value or amount (i don't know how you measure personhood) in any stage of life, if personhood is an issue you could argue then that some people deserve to live more than others, but it doesn't work that way since the issue of personhood in these discussions seems to be only questioned when the person is inside the womb of his/her mother.
About coma patients, i wouldn't kill my father if he was in a coma except if he preemptively tells me that in a coma situation he would prefer me to avoid life support, but if it were my decision, i couldn't kill my father, maybe i'm delusional or blindly fooling myself here but he could still wake up someday, i couldn't live with myself with that doubt.
The totally irrational part of me tells me that killing babies is wrong and i don't expect anyone to jump on my bus and preach with my viewpoint since i treasure it greatly, i'm no activist and i don't need people in my life validating mi POV on whatever issue to keep going, i'm a father of two girls and i cannot express the feeling of seeing their first ultrasounds and the feeling of joy by seeing in that garbled image that there's a growing life filled with potential, that we will be happy or sad together, that we're going to struggle on whatever things life puts in our path. So i'm biased, just like everyone else here.
