The science definition of life encompasses the human unborn, since the unborn shows all the criteria of life. A single cell bacteria is considered alive. Each cell in the embryo is alive in that sense, while combined it also is alive. The political strategy is to ignore science, and then say the unborn is not a person until it is born, is pseudo-science. The Atheists, who claim to be on the side of science, need to step up.
In terms of the argument of personhood, if you compare the unborn during pregnancy, to a new born baby, the new born baby is much more dependent on the efforts of the mother, than it is the unborn The unborn is much more autonomous. It takes what it needs from the mother, with no conscious effort by the mother. Mothers can ignore the unborn for months and may not even know she is pregnant, since unborn is quietly self sufficient within the matrix of her body. Some women will even continue to burn the candle from both ends, while pregnant. The unborn adapts, often with little long term harm. The born baby, on the other hand, is very vulnerable. It is cut off from its unborn instincts, and now has many new dependencies. Lefties always think upside down and fool themselves.
OK, I'll step up. My stance on abortion
is based on personhood. Personhood is not so much science-based, as based on self-awareness and self-interest. I object to causing unnecessary harm or distress to
persons.
In atual practice, people are all over the board on this. Actual public attitudes and actions often differ from the principles they cite.
As you pointed out, it's not life itself that's considered sacred, despite the slogans. If we eschewed taking all life we'd starve -- effectively taking our own lives.
Likewise, it's not human-based. Surgeons remove human parts every day, with noöne raising an objection. The parts are not persons.
Nor is it species-based. We think nothing of killing chickens and cows, but most people would consider little green men in flying saucers full persons, and afford them moral consideration, despite their species being totally unrelated to anything on Earth.
In practice, people usually think in terms of intelligence, specifically, human-like intelligence; or of familiarity. We have laws pertaining to cruelty toward cats and dogs, though these are rarely applied to the aforementioned food animals. Nor do pets enjoy the same legal protections or moral consideration we afford our fellow humans, however much we love them.
And people sometimes call for special consideration for elephants or chimps -- because they're intelligent.
All in all, we form hierarchies of moral consideration. Animals we like get special consideration, horses and dogs, for example. It's OK to kill or mistreat animals we eat or, till recently, who picked cotton for us. Our needs and interests come first, and might makes right.
These are the public attitudes and actions I mentioned. I find them morally inconsistent.
Personhood is based on self-awareness as an independent organism, and self-interest, in desiring to continue to exist, which is, itself, based on a prerequisite anticipation of futurity.
Persons also show likes and dislikes, joy and sadness, pleasure and pain, and are capable of suffering. These, in my book, affords them moral consideration.
A fœtus shows no indication of self-awareness. It has no anticipation of futurity, so no concomitant self-interest. It's not even aware it exists.
It is not thought capable of likes or dislikes, joy or sadness, pleasure, pain, or suffering.
So whence the claim to moral consideration or right-to-life? It has none of the factors prerequisite to these. Yes, it's human, but species is not what I base moral consideration on; nor does the general public, with any consistency.
This is what we base our claim of personhood on, not science.
