"I love science except when it comes to...abortion"

I've been participating in a Facebook debate on abortion. Several pro-life commenters have made some good responses in the debate to the pro-baby killers abortionists. Here are my own replies so far:

[Rich Edwards:] Naturally, 70% of all fertilized eggs don't make it to term, so by this warped logic, when most couples try to get pregnant, two babies have died before they successfully give birth. Every attempt at pregnancy has a greater chance of a dead baby than producing a child.

What's your source for the claim "70% of all fertilized eggs don't make it to term"?

Many or perhaps most spontaneous abortions are non-human entities such as choriocarcinomas, hydatidiform moles, blighted ova, etc.

[Rich Edwards:] There are no definitions in the original post, so how are we going to define "human?" Be careful here. Don't say any cell with a human genome is a human or else a hot shower would qualify as a holocaust.

The sloughed off skin cells are cells from the stratum corneum layer of the skin:

These cells do not contain any nuclei.

In fact, these cells (corneocytes) are functionally dead cells.

Moreover, they're at the end of their differentiation cycle, not beginning.

In short, these skin cells are significantly disanalogous to the zygote, and as such cannot be used to argue for abortion. At least not without denying medical science.

[Em Eegee:] Morula, blastocyst, zygote, fetus, neonate, infant, toddler, child, adolescent, adult, geriatric. All stages of development in a human being. If that's not enough, a DNA assay at day 5 after conception will be the same as the day before death (controlling for epigenetic methylation and such).

I thought it'd be helpful to further clarify for people. Roughly speaking:

Day 1 zygote
Day 3-4 morula
Day 4-5 blastocyst
Days 6-10 implantation
Week 8 embryonic period ends
Week 9 fetal period begins

[Eamon Concannon:] mammalian foetuses are almost identical and clearly have no consciousness prior to development of the nervous system. Being a 'libertarian' you probably support the gutting of welfare provision for those who desperately need it. Also, you probably eat pigs and cows which actually have more awareness than even new born human babies. So you see it is actually unscientific, callous and irrational to prevent a human mother in desperate circumstances from aborting a fetus that most likely hasn't even begun to develop a nervous system.

What makes you think human fetuses "clearly have no consciousness prior to development of the nervous system"? Or "pigs and cows which actually have more awareness than even new born human babies"? What's "unscientific" is making bare assertions without supporting evidence or argumentation. What's your source for these wild claims?

Besides, you're just wrong: the nervous system begins development before the fetal period. The nervous system begins to develop as early as week 3 with the notochord arising from the midline mesoderm, the neural plate from the overlying ectoderm, then (most importantly) the neuroectoderm and neural tube, which closes by week 4. This period is classified as the embryonic period. It's well before the fetal period, which doesn't begin until week 9. Hence, if the development of the nervous system occurs before the fetal period, then by your own logic, the fetus could very well be "conscious."

[Eamon Concannon:] Patrick chan, check this link http://www.factcheck.org/2015/05/does-a-fetus-feel-pain-at-20-weeks/

1. You originally claimed the fetus does not have "consciousness" if it doesn't have a nervous system. I demonstrated how that's wrong above.

Now the article you cite speaks primarily about "pain." Pain and consciousness are not the same thing. You're equivocating.

2. Just because someone can't feel pain doesn't mean they're not human. For example, someone could be born with congenital insensitivity to pain. They can't feel pain. But does this mean they're not human? Of course not. It's an absurd argument.

3. Btw, FactCheck.org is hardly an impartial website. Just look at them on political issues for example. Indeed, a lot of websites which purport to be objective in checking facts are actually quite biased.

[Nick Tiesi:] Wrong. It's not a baby at conception. Read a science book.

Okay:

1. "The formation, maturation, and meeting of a male and female sex cell are all preliminary to their actual union into a combined cell, or zygote, which definitely marks the beginning of a new individual. This penetration of the ovum by spermatozoon, and the coming together and pooling of their respective nuclei, constitutes the process of fertilization." (Leslie Arey. Developmental Anatomy.)

2. "Zygote. This cell is the beginning of a human being. It results from the fertilization of an ovum by a sperm. The expression 'fertilized ovum' refers to the zygote. (Keith Moore. Before We Are Born.)

3. "Human development begins at fertilization when a male gamete or sperm unites with a female gamete to produce a single cell - zygote." (Keith Moore and T.V.N. Persaud. The Developing Human.)

4. "Embryonic life commences with fertilization, and hence the beginning of that process may be taken as the point of departure of stage I." (William Larsen. Human Embryology.)

5. "It needs to be emphasized that life is continuous, as is also human life, so that the question 'When does (human) life begin?' is meaningless in terms of ontogeny. Although life is a continuous process, fertilization is a critical landmark because, under ordinary circumstances, a new, genetically distinct human organism is thereby formed." (Ronan O'Rahilly and Fabiola Muller. Human Embryology and Teratology.)

[Eamon Concannon:] A bunch of cells in the human womb with no nervous system is no more sentient than a bunch of human skin cells and therefore cannot have the same rights as the mother. As a matter of fact it is easy to argue that it has less of a 'right to life' in the case of trying circumstances for the mother than a pig used for food when plant food options are available.

1. This is an argument from analogy minus the argument. In what respect is the zygote, embryo, or fetus analogous to "human skin cells"?

For one thing, human skin cells at the stratum corneum have no nuclei, are terminally differentiated, and for all intents and purposes are dead cells (corneocytes). How is that akin to the zygote, embryo, or fetus which not only contains nuclei in its cells, nuclei which in turn contain DNA and indeed a complete human genome?

The zygote begins to divide from day 1.

It eventually becomes a blastocyst by day 5 and implants in the mother's womb around days 6-10.

The bilaminar disc from which the embryo comes is formed within week 2.

The process of gastrulation within week 3. All this will eventually lead to formation of our entire bodies including its organs (e.g. muscles, bones, skin, brain, heart, stomach).

A neural tube formed within the neuroectoderm from which most of the rest of the central nervous system arises in weeks 3-4. Btw, this defeats your argument that the fetus hasn't developed a nervous system and thus isn't conscious, because the nervous system begins to develop before the fetal period.

The heart begins to beat within week 4.

Likewise upper and lower limbs begin to bud within week 4.

Fetal movements start within week 8.

Genitalia have male or female characteristics within week 10.

I could go on, but I think you get the picture.

2. At the end of the day, you're just an echo chamber for Peter Singer. But other scholars have defeated Singer's arguments. See people like Robert P. George, Patrick Lee, Christopher Kaczor, Francis Beckwith, etc.

[Rich Edwards:] Corey. Solid argument, but at the moment, we are not debating a zygote--we are debating the very moment of conception. I would argue that a zygote has more value than the single celled organism that exist in the moment of conception.

What? I don't think you understand the science. A zygote is what's formed at conception. A zygote is single-celled. The zygote subsequently undergoes rapid mitotic cell divisions. Each cleavage doubles the number of cells (for a time). After there are 16-32 cells, the zygote is known as a morula. Then a blastocyst. Later an embryo. Later a fetus. But these are all continuous developments of the human being from the zygote stage.

[Rich Edwards:] What I'm objecting to the opinion that a single-celled, fertilized egg is a person entitled to the full rights of a living baby. The implications of such a position are mind-boggling...This entire debate is about the very instant of conception and whether or not full person-hood is granted at that moment. I concede that once a fertilized is implanted and starts to grow, it gains value

The blastocyst is implanted around day 6 or so. However, the blastocyst exists prior to implantation as well. The blastocyst hasn't significantly changed from, say, day 4 to day 6. It's the same blastocyst. Prior to implantation, the blastocyst is traveling down one of the uterine or Fallopian tubes to be implanted in the mother's womb (i.e. the endometrium of her uterus).

So let me ask you: why does the same blastocyst pre-implantation have less value than the same blastocyst post-implantation? How does the process of implantation confer value? It's the same blastocyst.

What makes you think it's a potential person rather than a person with potential?

[Rich Edwards:] but 50% of fertilized eggs die before they reach that stage.

1. Earlier you said 70%. I guess you're backpedaling.

2. I presume you're referring to spontaneous abortions. Many (maybe most) spontaneous abortions are not human persons. They're choriocarcinomas, hydatidiform moles, blighted ova, etc.

3. According to "Subfertility and risk of spontaneous abortion" (2000) by R.H. Gray and L.Y. Wu:

Spontaneous abortion rates were 23.0% in pregnancies preceded by subfertility and 14.0% in pregnancies without impaired fertility.

In other words, according to the paper, it was found the spontaneous abortion rates are 14% in healthy women.

3. Besides, what do mortality rates have to do with personhood? How does failing to implant and eventually dying make it a non-person? What's your argument connecting death to non-personhood?

[Rich Edwards:] If you are claiming person-hood is granted at "the moment of conception," fertilized eggs that fail to implant are an entirely overlooked group of dead people that are very relevant to this discussion.

If they're "overlooked," then you should advocate using modern medical science, technology, and research to help reduce the amount of these spontaneous miscarriages.

[Rich Edwards:] Second, no, most women do NOT experience an emotional response to the loss of a fertilized egg that was not implanted. Those deaths represent the majority of the deaths we are discussing here and most women would not even be aware the event happened.

You haven't cited a source for this. At this point, you're just a man telling "most women" what they do or do not feel about their miscarriage(s). That's a bit ironic in light of the topic under debate.

Edit: The next debate installment is here.