Here's a response to Marquis I find intriguing/bewildering. Eugene Mills says if I was once a zygote, I was also once an egg. I wasn't also once a sperm. No, I was just once an egg. So if it's wrong to take the FLO from a zygote, it's also got to be wrong take the FLO from an egg. We have to be deeply concerned about using contraception to block conception. That's (surely) absurd, so there must be something wrong with Marquis's stance on abortion.
Was I really once an egg? An editorial in the New York Times last summer, written by a biologist (so he should know!) says yes, I really was. Greg Hampikian writes (here)
Your life as an egg actually started in your mother’s developing ovary, before she was born; you were wrapped in your mother’s fetal body as it developed within your grandmother.So (says Hampikian/Mills) I go back a long way--to child-me, to baby-me, to fetal-me, to zygote-me, to egg-me. There is one continuous entity there, though picked out by different terms at different stages (child, baby, fetus, zygote, egg). The sperm is crucial for making me go on from being an egg to being a zygote, but there is no symmetry here. I was once an egg but I was never a sperm. Importantly, the sperm does not induce "substantial change". The sperm does not make one thing go out of existence (the egg) and a second thing come into existence (the zygote). One thing is prodded to continue existing, because of the sperm, instead of a new entity coming into being.
After the two of you left Grandma’s womb, you enjoyed the protection of your mother’s prepubescent ovary. Then, sometime between 12 and 50 years after the two of you left your grandmother, you burst forth and were sucked by her fimbriae into the fallopian tube. You glided along the oviduct, surviving happily on the stored nutrients and genetic messages that Mom packed for you.Then, at some point, your father spent a few minutes close by, but then left. A little while later, you encountered some very odd tiny cells that he had shed. They did not merge with you, or give you any cell membranes or nutrients — just an infinitesimally small packet of DNA, less than one-millionth of your mass.
Now, here's why I'm bewildered: Mills and Hampikian say I was once an egg, but when I look closely at the "facts of life" it doesn't look to me like this is true. Watch the crucial clip of this video, which was made by what appears to be a reliable medical media company. Sperm penetrates egg. As a result, the sperm generates a haploid pronucleus and so does the egg. Each pronucleus appears to be a separate entity--EP and SP, let's call them. They then fuse, forming the diploid cell, Z. If EP and SP are two distinct entities, and they fuse, the logic of identity precludes saying that Z=EP. No, EP and SP go out of existence; Z is a third and new entity.
Here are the crucial frames. There are two separate entities, EP and SP; they are pulled together by "threads" and fuse.
In this clip, the egg is just the site in which EP and SP fuse, forming the new entity Z. Z is inside of the egg, not identical to the egg. We are invited to think Z is the start of a new human being, not the containing egg. In fact, the narrator calls the newly formed single cell a "zygote", instead of using that term to refer to the whole fertilized egg.
Another video tells the same story. Here's the crucial clip of that video with the key frames below. Again, separate pronuclei exist inside the egg and fuse.
Once again, this diagram of fertilization tells a story that suggests two entities fusing to generate a third--
From what I can see, Story (1) is true: EP and SP fuse to become the diploid cell Z, a whole new thing. Z develops inside the egg, using some materials from the egg. If you were once any entity in this complex, you were once Z, not the larger, containing egg.
Can you read things any other way? I guess the eggcentrists see it this way:
Story (2): The egg lives on, after fertilization, just altered profoundly. Both EP and SP go out of existence, after forming Z, but the egg keeps growing. Getting Z as its nucleus does not cause substantial change in the egg, making a new entity come into existence. No, it's the same ol' egg, just doing some amazing new stuff. If you were once any entity in this complex, you were once the egg, with EP, SP, and Z just very important parts of you.
At the very least, I think Story (1) is coherent. Nobody has to read the biological facts as Story (2) has them. I can reasonably think my earliest life was as Z, not as an egg in my mother's ovary.
There's another way to block the idea that I was once an egg in my mother's ovary. Marquis actually says it may not be true that I was once a zygote--the entity that exists in the first 14 days after fertilization. He doesn't explain the basis for his doubts, but I would speculate he may be drawing on the very interesting book When Did I Begin? by Norman Ford.
Ford argues that in the first days, a zygote is a collection of separate things, not a unified, single entity. In the first few days, it's so ununified that each cell can develop into a separate entity (making for identical twins, quadruplets, or octuplets).
It's also significant that the early zygote contains the makings of a placenta, umbilical chord, and amniotic fluid. If I was once a 5-day old zygote, then it's also true that my placenta was once a 5-day old zygote. By the logic of identity, it follows I was once a placenta! Not just absurd, but yucky-absurd! Conclusion: I was not once a 5-day old zygote.
Bottom line: I was never an egg. No, condemning the killing of a fetus does not drive us to the absurdity that we mustn't block the fertilization of an egg. You can say a fetus has a FLO but an egg doesn't, because it's not true that we were once eggs. There is no continuous entity that starts off existing before fertilization and continues for the first 14 days and then for the duration of pregnancy, and then through ordinary life, so that it has a FLO. If you want to refute Marquis, you need something else besides the idea that his reasoning turns contraception into murder.