SR answers “Humans less than animals?” by arguing for his own personally held view (or even a “consensus” of personally held views) with minds such as Peter Singer and H. Tristan Englehardt. The latter’s qualifications for person hood moves well into childhood.
If you move away from what we know of embryology, comparative anatomy, and the fact of our own knowledge that these are the children of the only species having this conversation (not all, and not all the time – but why is that relevant when none of the animals will ever mature or develop the ability to do so?) then you turn the definition into a personally held viewpoint or opinion. From there comes definition by raw, brute power or the threat of same.
Robert P. George has answered all your questions,:
George pounces on the person/body dualism implicit in this remark and forces the class to confront the implications of affirming it: “If ‘I’ was not an embryo or fetus, neither was ‘I’ once an infant,” he says. “To have destroyed the fetus or infant that later became ‘me’ would not have been to destroy me. So at what point then do we say ‘I’ began to exist? At what point do we draw the line on killing?”
George then drops a cerebral smart bomb: “If dualism is true, the answer won’t be ‘birth,’” he notes. Will it be six months after birth? A year? Two years? Three? After all, when does a child achieve thoughts, beliefs, and desires?
Pro-choice students must now confront an uncomfortable fact: The logical implications of their position entail believing that killing three-year-old children is morally acceptable.
But the potentiality of the human embryo, like that of the human infant, is precisely the potentiality to mature as the kind of being it already is — a human being.
As Sandel himself implicitly concedes, we value human beings precisely because of the kind of entities they are. (That is why he has staked his entire argument on the proposition that human embryos are different in kind from human beings.) Indeed, that is why we consider all human beings to be equal in basic dignity and human rights. By contrast, we value oak trees because of certain accidental attributes they have, such as their magnificence, their special beauty, or a certain grandeur that has taken perhaps seventy-five or a hundred years to achieve. If oak trees were valuable in virtue of the kind of entity they are, then it would follow that it is just as unfortunate to lose an acorn as an oak tree (though our emotional reaction to the two different kinds of loss might, for a variety of possible reasons, nevertheless differ). Sandel’s purported analogy works only if he disregards the key proposition asserted by opponents of embryo-killing: that all human beings, irrespective of age, size, stage of development, or condition of dependency, possess equal and intrinsic dignity by virtue of what (i.e., the kind of entity) they are, not in virtue of any accidental characteristics, which can come and go, and which are present in human beings in varying degrees. Oak trees and acorns are not equally valuable, because the basis for their value is not what they are but precisely those accidental characteristics by which oak trees differ from acorns. We value the ugly, decaying oak tree less than the magnificent, still flourishing one; and we value the mature, magnificent oak more than the small, still growing one. But we would never say the same about human beings.
George finds fault with such scenarios for many reasons, including the fact that the little girl “would experience terror and horrifying pain, while the embryos would not.” For the same reason, he says, “one might rescue the little girl rather than several terminally ill adults in deep comas without denying that the adult patients are human beings who ought not to be killed and dismembered for their body parts.”
You missed the implication that it’s just as significant that our children can cause us to love as it is that they be able to love.
I might identify and feel more concern for someone that I do know than for a stranger across the world. But that is not relevant to the right not to be killed or enslaved. It does not mean that I do not see the two as deserving equal legal and societal protection. That is part of the nature that is human. The woman in my local battered women’s shelter is just as deserving as my daughter, and the woman in Iran is just as deserving as either.