The black hole in which my time is swallowed up.
"Right. They [scientists] just determine what's alive and a human being and what is not." -Tom
"Once more, they determine what's "alive" biologically; they don't determine what's alive in terms of the societal value placed upon life." -Brad
Okay. Let's recap.
We both agree that at the moment of conception we have a new human being. No question there. I side with embryologists and biologists who say it is alive; you argue that it may be "biologically alive" but since there is no brain activity in the first 12 weeks or so, it can't really be said to be "a living human being." You base your argument on the Uniform Determination Of Death Act, which defines death as the "irreversible cessation of all functions of the entire brain, including the brain stem." A six week old fetus has no brain activity, therefore it should have the same moral worth (read: none) as a brain-dead human being.
Let me know if you feel I've mis-stated your position here.
And I'll start off by saying that, on the surface of it, your position seems both consistent and plausible. But I also think that upon closer scrutiny it quickly falls apart.
First of all, the UDDA has made sure to use the word "irreversible" in its description of the loss of brain function. To my mind, this is key because were a patient able to reverse his state of brain-death (or, more likely, if we were able to reverse it for him), I think you and I would agree he was never really dead to begin with. I don't know if any such case exists, but in the hypothetical thought experiment it would look much like the real-world case of a man whose heart stops beating. Once upon a time total heart failure meant certain death. That's not necessarily the case anymore, and we've had to modify our definition of death because of it.
Now, what of the 6 week fetus? We know that under normal circumstances he will develop a fully functioning brain within a matter of weeks. His condition is most definitely not "irreversible," and for this reason alone I think any argument appealing to the UDDA collapses and it wrong to declare him "not alive".
Secondly, I think it is important to understand the purpose behind the Uniform Determination of Death Act. Its name is clear enough: to determine death. But it's a fairly modern Act (circa 1980). Why should we need such a definition at all? I mean, haven't societies prior to 1980 been getting along just fine -- knowing full well who among them is alive and who is dead? Yes, but with modern science we're finding that even when someone *appears* dead, there may be a chance he isn't. We might still save him from death. How do we know who is save-able, and who is lost? Today, the best indicator is brain activity.
But the whole *purpose* of the Act is to determine whether or not a person who was once living and breathing on his own has any hope of recovery. It's purpose was not to determine whether or not a 12 week old fetus was a "living" human being. I think you're trying to fit a square block into a round hole here in questioning whether the unborn meet the standards of an Act whose express purpose was wholly different from how you are now choosing to apply it.
It would be something like NASA discovering a Martian -- a creature who for the sake of argument uses something else in place of brainwaves to live and move and breathe -- and declaring, "Nope, he's not alive because he doesn't have a brain stem, and the UDDA says if you don't have a functioning brain stem you're not alive." That's not why the UDDA was drawn up. And we shouldn't be forcing its application onto circumstances for which it was never intended, be that the case of a Martian or of an unborn child.
Thirdly, I've never heard any philosopher, any MD, any professor of biology, any surgeon, or any text remind us that a fetus is a living human being only in the sense that he/she is "biologically alive", and should not be confused with what is otherwise commonly known as "a living human". You are the first person I've met to make the distinction.
Lastly, in the quote above I think you are conflating two separate ideas which, tangled together only make a mess of the argument. We have to untangle them, and keep them that way. The first consideration is whether or not a human being is alive (brain dead patients would not qualify according to medical science; a growing embryo would). And the second idea is the value judgment which society chooses to pass on a particular group of living human beings. With regard to the first point, science is unequivocal. A zygote is a living human being. Period. (I hope, but have serious doubts, that I've convinced you there ought to be no distinction between "a living human being" i.e. a fetus, and "a living human being" i.e. a toddler. They're both "living human beings" -- a phrase which has but one meaning -- and the criteria found in the UDDA should not be applied to the fetus per the three reasons listed above.)
Now, with that in mind we can move forward and address the second notion. Namely, what sort of value society should place on particular living human beings. As for the unborn, our modern American society says "not much". And I see the value-judgment as fundamentally the same mistake made 200 years ago with regard to blacks. In those days we discriminated against human beings based on skin color. Today we do it based on level of development. But discriminating between any two groups of innocent human beings and then declaring one group expendable strikes me as the height of injustice. And the basis on which you choose to discriminate is entirely irrelevant as human rights ought not be reserved for select human beings only. All human beings should qualify.