@ Thucydides:
>What is the difference between an embryo and a fetus (i.e. where is the line specifically drawn?)
Here are the stages and how they change from one to another:
* Ovum (unfertilised egg), which after fertilisation becomes …
* Zygote (fertilised egg), which after it begins to divide becomes …
* Blastocyst, which after it implants in (usually) the uterus becomes …
* Embryo, which after 8 weeks becomes …
* Fetus, which after birth becomes …
* Infant.
The 8-week division between embryo and fetus seems to be pretty arbitrary, but standard. It roughly corresponds to looking recognisably human (but still distorted) and the beginning of movement, so it would seem to match the common-law ‘quickening’ that I mentioned earlier, as well as the Septuagint version of Exodus 21:22–23 (which is a law about feticide, not abortion, but it has meaning for some religious groups in the U.S. debate, so I mention it).
The other divisions seem clear cut to me, but the terminology varies. Some people count the zygote as still an ‘ovum’, some people count the blastocyst as still a ‘zygote’, some people count both the zygote and blastocyst as already an ‘embryo’. But that's to be expected, I guess, when the terminology began with anatomists' cutting up dead bodies and only later did people come in with microscopes and ultrasound. I'll try to be precise with terms like ‘implanted embryo’ instead of just ‘embryo’. Also, ‘blastocyst’ has other technical connotations, and some people might want to use other words to indicate that they're not including the stuff that becomes the placenta and things like that, but I don't think that any of that matters to us (unless an embryologist wants to come in and tell us otherwise!).
Source: http://en.wikipedia.org/wiki/Stages_of_human_development and pages linked from there
According the language promulgated by the AMA, a ‘pregnancy’ begins with implantation, the change from blastocyst to implanted embryo. Anything that kills an ovum, a zygote, or a blastocyst, like the morning-after pill, is only a ‘contraceptive’, while an ‘abortion’ has to kill an implanted embryo or a fetus (that is abort a pregnancy). The law in the U.S. mostly follows this language, despite the efforts of anti-abortion (or anti-contraception?) groups. Embryonic stem-cell research, throwing away unwanted byproducts of artificial insemination, and so forth, all happen to blastocysts, not to implanted embryos.
>I am willing to consider that an embryo may not be a person per se, given in part what you have said. But even then, unless there is incredibly compelling evidence that this embryo has no cognitive processes, I would still come down on the side of "we just don't know enough, so better to safe than sorry."
Well, a blastocyst certainly doesn't have a brain, or even nerve cells. A fetus does; it's hard to draw the line with an implanted embryo, since the brain forms gradually. As for pain, the mainstream view seems to be that a human fetus feels no pain before the third trimester, although some studies put the first ability to feel pain much earlier or instead later, even some time after birth. There is also some evidence that, whatever else, every fetus is asleep until birth.
Source: http://en.wikipedia.org/wiki/Fetal_pain and the references linked there
But there is a larger philosphical difference between us here. I make a clear distinction between what is *moral* (behaviours that make for a good society) and what is *licit* (behaviours that society should accept). If I have doubts about what a fetus wants or can feel (although I don't think that is all that matters for you, it's what matters for me), then I should err on the side of caution and not participate in an abortion. But for me to interfere in what somebody else is doing —and I hold the state through its laws to this same standard—, then I need more than just doubt; I need good evidence. Again, I would err on the side of caution (a different kind of caution this time) and not try to prevent an abortion, and I think that the state should do the same.
>It's the same reason I oppose capital punishment, and more specifically, lethal injection. There is reason to believe that the inmate's death is not actually painless. So as long as we don't know, I oppose it. And again, even if it was painless, I would still oppose it on the grounds that we don't know where we're sending them when we kill them.
And I would oppose it on the grounds that they don't want to die. Even convicts have human rights, after all.
>You, or someone else, had said that opposing it on the basis of a lack of knowledge about an afterlife is flimsy. This person said that when people die, they're buried or cremated or something, and they generally don't seem to care about what happens to their body, etc etc. They are saying in effect that since dead people do not communicate with the living, that is evidence enough that there is no afterlife.
Yes, that was me. Again, I don't offer this as evidence that there is no afterlife; all I'm saying is that there is no evidence that there is an afterlife. And without such evidence, the state has no business intefering with other people's decisions about their own lives (and deaths).
>There could be any form of afterlife. […] And it is that basic assumption that causes people and animals and all life in general to fight for survival.
No, it isn't. Those animals that don't have any understanding of tomorrow, much less the afterlife, have an instinct to fight for survival. I don't believe in the afterlife any more than I believe in the invisible fire-breathing dragon in my garage, but I still want to live. Why? Nothing particularly rational (except when I think about how my mom would feel if I died); I just feel like it. Instinct, not fear of hell.
>Since you can't know if it will be better or worse, better to stick with where you are. It's like being in a dream, and trying to keep from waking up.
I really don't follow you here. I have sometimes tried to wake up from dreams, usually because I'm afraid of oversleeping but sometimes because they're nightmares. And better to stick with the status quo when you have no idea whether the alternative is better or worse? If that's what you feel like for yourself, OK, but I can't accept that as logical!
>It also assumes that the only place the consciousness resides is within the body. There is no reason to believe that either.
There is plenty of reason to believe that consciousness resides in the brain. It looks like http://www.time.com/time/magazine/article/0,9171,1580394,00.html is the Time article that you wanted me to read. That's full of reasons why consciousness is in the brain; it even begins by testing someone for consciousness by measuring her brain! There is no evidence there, or anywhere else that I know, that my consciousness lies outside of my brain. Maybe it is also somewhere else, like in my gut (a lot of nerves there, but apparently all subconscious), my heart (traditional, but seems unlikely now), or on Comet Hale-Bopp (if only I'd joined Heaven's Gate!). If you think that there's a reasonable chance of this, then let it affect your moral judgement, by all means. But please don't interfere with my decisions about my life because you think that my consciousness might lie elsewhere.
That was an interesting article, by the way, and I did learn from it. But the more that I learn about the brain, the more that I'm convinced that the standard to go by is what people want for their own lives according to their own testimony, and not any outsider's judgement about what consciousness, or pain, or life may exist somewhere, or what the people in question really want but don't know. I'm worried that someday I will be told that I can't undergo major surgery because it's inhumane —to myself— since the anæsthetic doesn't really stop me from feeling pain, only from remembering it. Maybe I will be required to attach sensors to myself to wake me up if I have a nightmare. Already the state outlaws some dangerous medical procedures (even when patients understand and accept the risks) and requires me to wear seat belts (although I would anyway), all for my own good; I don't see by what legal theory those laws are OK but these hypothetical ones that I worry about are not. So I fight against them all on the grounds of personal freedom, and I support court decisions (usually based on the 4th and 9th Amendments in the U.S.) that sometimes help to fight them.
Since you've given me something to read, I'll give you something, although it probably won't change your mind about anything (and does not really argue for any point of view). Bu my opinions on death and consciousness have been shaped by Transition Dreams (or rather, by thinking for several weeks about why it disturbed me so much), a short story by my favourite science fiction author, Greg Egan. Unfortunately, it's not online, but here's bibliographic information if you want to read it: http://gregegan.customer.netspace.net.au/BIBLIOGRAPHY/Bibliography.html#p36