I had an interesting discussion about this with a co-worker of mine one time. He's one of these libertarian types, you know, fiscally conservative but socially liberal. He kept insisting that believing that life begins at conception is a "religious argument". I explained to him that it is simply illogical - religion having everything or nothing to do with the argument - to think that life begins anywhere BUT conception, since from conception on the development of the child is a continuum on which there is no place at which a stage is abruptly passed whereby you can markedly say that something has happened to the growing child which would say "life began at this point". The only place where something like this happens is at conception, and this argument includes the act of giving birth. One MUST accept that life begins at conception, unless one wishes to be entirely arbitrary and question-begging.
He tried to argue with me that life begins at the point where the child is viable to live on their own. I pointed out to him that, depending on how you define that, this could mean children all the way up to 12-18 months old aren't really "alive" since they're pretty much incapable of fending for themselves even in the sense of finding food on a table to feed themselves with. He got a little red in the face at this point.
If you can’t mark the point at which there is a bright line between “no human life” and “human life”,
killing that life is gross criminal negligence.
There are those that claim the USSC has defined this bright line at 3 months. I’ve actually heard someone argue this - that one day prior, it is not a human life, and one day after it is. (Yet they didn’t support outlawing partial birth abortion - go figure)
I once read where someone said “Everything is present at fertilization. Nothing is added, only developed” A simple statement but it contains all the truth.
Actually it could be a lot older than that. Would we turn a ten year old loose ? If he'd had no training, no interaction, been "nailed into a barrel and fed through the bunghole" ?
Your argument is even better than you think. And your libertarian needs to try his argument at a meeting of Libertarian Party members. He'd get creamed by at least 50%.
Of course, the other ~50%, acting on the "alien intruder" idea (demonstrably false) would disagree.
Saying something is essentially "religious" means that its confirmation depends on faith—which St. Paul called "evidence of things not seen." Well, with electron microscopy, you can't say the beginning of life is not seen. I've seen the pictures. What's "religious" is the denial in the face of physical evidence of the fact that life begins at conception.
What the socially liberal fellow meant to say is that the origin of life is a fact with moral implications—which many people who are religious happen to be interested in. He finds those implications inconvenient, but has no facts to protect himself with. So he makes recourse to his "faith" that the videos do not show life beginning, even though they plainly do.
Michael Tooley has a fairly (in)famous essay that defends both infanticide and abortion, not only because an infant can’t take care of itself but because the reality is that infants are born with brains that are still developing and with capabilities not all that different from those found in many adult animals. So the debate boils down to two criteria which are looking at the capabilities of the child (being able to take care of itself, mental capacity) which is going to lead you to draw the line (as honest abortion supporters like Tookey and Peter Singer do) after even birth and looking at the likely future capabilities and existence whichis goint to lead you to draw the line at fertilization. Any line drawing between those points is arbitrary. The only other argument one can make is that an unborn child is, in fact, a person but that a pregnant woman should have the authority to kill that person, anyway.
Put any adult in the wild and they’re not likely to live on their own. Even “being able to live on its own” is a vague standard.
After 9/11 they identified victims from a chunk of finger or other flesh and long shed hair from hair brushes.
At the moment of conception there is the complete complement of 23 chromosomes that uniquely identifies that individual for ever..even after death.