A few years ago, Bob Seidensticker, a Patheos blogger, wrote about an argument he called the Spectrum Argument. I wrote an article in response. Seidensticker just updated a response to me a few days ago, which you can read here. I'd like to respond to the points he's raised in his new article. To summarize his argument, there is no dividing line between "person" and "non-person". It is a spectrum, and the embryo begins as a non-person and eventually becomes a person once it reaches a certain developmental milestone, and this milestone is the number of cells that go into making up a human person. As he says in his original article,
But the vast difference in the number of cells only begins to define the vast difference between the two ends of the spectrum. At one end, we have arms and legs, fingers and fingernails, liver and pancreas, brain and nervous system, heart and circulatory system, stomach and digestive system -- in fact, every body part that a healthy person has. And at the other, we have none of this. We have...a single cell. In between is a smooth progression over time, with individual components developing and maturing. That's the spectrum we're talking about...Note also that the difference between a newborn and an adult is trivial compared to the difference between the cell and the 1,000,000,000,000-cell newborn.He makes several comparisons. A brain with only one neuron doesn't think at all, which is a huge difference between it and the brain with one million neurons, which does think. There is a continuous spectrum from blue to green, but blue is not green. There is no objective dividing line between child and adult.
A refutation of his argument, generally
The argument can really be refuted right away. Seidensticker here completely ignores the fact of human development. Once we develop enough cells, these other structures don't mysteriously come into existence. They develop gradually: a heart develops at around 22 days in utero, arms and legs start to form around the second month, etc. Seidensticker says "this is the spectrum we're talking about," but in what sense is this a spectrum? The reality is we don't exist on a spectrum -- what is human is human from the beginning. It has a human nature which directs its development and grounds its ultimate capacities, and all physical parts of the embryo eventually develop into the adult. Blue may change from green on a spectrum, but green didn't start out as green -- it starts out as blue. A human doesn't start out as a non-human, it starts out as a human and remains human. The single-celled zygote is a fundamentally different entity than the sperm and ovum cells that went in to make it -- and from then on, there is a continuity of existence from the single cell zygote all the way through that embryo's life. The zygote doesn't go out of existence once the cell starts to divide, it develops along the path of human development. But Seidensticker never gives us any sort of argument as to why he believes humans develop on a spectrum -- he only tries to argue for it by pointing to other things that are spectrums and saying "see, they're the same."
Even if we consider Seidensticker's argument as an argument of personhood, he still has to argue for why personhood is a spectrum. This would commit him to a gradualist position, similar to the likes of Wayne Sumner, who believes that sentience (i.e. the capacity to feel pain) is what grounds personhood. However, while Sumner's argument from sentience makes sense (it is at least intuitively plausible that the reason it's wrong to kill someone is because they can feel pain, but of course, this position is open to several counterexamples), Seidensticker's doesn't. Seidensticker places the value-giving property on the number of cells the entity contains because of the differences between a single-celled zygote and a one trillion celled newborn. Of course, if the pro-life position is successful, then these differences are trivial because it's the same individual through all points in its development. After all, although I may be qualitatively different than an embryo (I'm older, I am presently rational, I can talk, etc.), I am quantitatively the same embryo that was in my mother's womb.
A response to Seidensticker's other points
But now let's turn to Seidensticker's other points. It's trivial, but I want to start out by pointing out how amusing it is that Seidensticker claims that conservatives are trying to get votes by making an issue out of abortion, when Hillary Clinton's campaign ran mostly on her support for abortion rights (and ultimately ended up losing the election). Donald Trump made a few comments but for the most part, his campaign was silent about the abortion issue. Was Seidensticker living in an alternate reality last year during the presidential campaign?
The problem with Seidensticker's argument here is that since we are dealing with the life of a human individual, then we must be able to make a determination. One advantage that the pro-life argument has over the abortion-choice argument is that the pro-life argument presents a clear dividing line between non-human and human: fertilization. But abortion-choice advocates generally disagree over when the dividing line is. Is it when sentience is sufficiently present, as Sumner argues? When cortical brain activity is present, as David Boonin argues? Is it when the human is sufficiently rational, as Michael Tooley argues? And even if we can decide which one of these thinkers is correct, there's no clear dividing line at which point the developing human being attains personhood, under that conception of "person." It does not disprove Seidensticker's argument that he can't come up with a clear dividing line (to argue that it does would be to risk committing the sorites fallacy), but it is a disadvantage that it has as compared to the pro-life argument.
Seidensticker responds to my arguments simply: "No, an acorn is not a tree, it is a potential tree." "No, it is a potential brain." Seidensticker presents no new arguments, so I can only point him to Monty Python to show why this isn't an appropriate way to argue. The reality is that yes, the acorn is an immature oak because all of its physical parts will develop into the mature oak tree, and all capacities that mature oak will have are present in the acorn in a latent form (or it might be more accurate to say that it's not the acorn, per se, that is the same as the mature oak tree because the acorn actually contains the oak embryo, and that oak embryo is the same individual as the mature oak tree it will become).
Simply repeating "no it isn't" isn't an argument, it's contradiction.
Personhood spectrum analogy
Something similar to the acorn happens with the brain. Now, I'm not an expert on the brain or how it develops, but according to my research, a single neuron is not the brain itself, but the gray matter of the brain is made up of neurons. The neuron is only a potential brain in the sense that all the neurons will develop into the gray matter of the brain, but the gray matter and white matter must be present for the brain, itself, to actually function as a brain should.
Seidensticker tries to show why his brain analogy works by analogizing it to water. A single water molecule does not have the properties of wetness, fluidity, etc., but these are emergent properties that emerge once a sufficient amount of water molecules are present. Now, let's set aside for a moment that the concept of emergent properties is controversial among philosophers, Seidensticker seems to be conflating the development of the brain with the development of a human. The human being is a human person from the beginning because from that single cell develops everything that the human will eventually be and have (including the brain). However, from that single neuron does not develop the brain -- the neuron must be combined with other neurons in order to form the gray matter of the brain. This is the main, and important, difference between the development of the human and the development of the brain.
Seidensticker finishes off this section by asserting that the embryo is not a baby now but will be in the future. I don't believe I ever used the term "baby" in my response to him, but the unborn child can certainly be seen as a baby. After all, what pregnant woman tells people she's "with clump of cells", or is having a "parasite shower"? She's with child, and has a baby shower. The term baby can be used to refer to a lot of things, including an unborn child or child after he has been born. Many mothers still think of their adult offspring as their "babies." "Baby" does not describe a stage of development of the human being, so it is not technically incorrect to refer to the unborn child as a baby. But neither does it add anything to the pro-life argument to use that emotionally loaded term.
The vastness of the spectrum
For this next section, I'll simply respond to Seidensticker on a point by point basis:
1) Between a newborn baby, a teenager, and an adult, they have the following in common: a brain, a pancreas, skin, eyes, nose, bones, muscles, hands.
The problem is that these are all arbitrary commonalities. If I set a newborn and an adult down in front of me and ask, "raise your hand if you understand this command," how many will raise their hand? One. There are large differences between an adult and a newborn: the adult can engage in rational thought. The adult can read this article. The adult can use language with intentionality. The newborn can't do any of these things. To say that these are negligible differences would simply be an ad hoc defense of Seidensticker's argument. Yet none of these differences justify killing the newborn and protecting the adult. Why? Because the newborn is a human being and has all of these capacities the adult has presently inherently (i.e. latently), just as the human embryo/fetus is and has. In fact, just as a late-term fetus has. The difference between a late-term fetus and newborn are negligible (hence why philosophers like Tooley and Peter Singer support infanticide), but Seidensticker hasn't told us if he believes late-term abortions are wrong.
2) "The commonality across the spectrum is that they all have eukaryotic cells with Homo sapiens DNA. That's it." That's an important commonality. But there are others: the unborn embryo has a human nature (in other words, even at the single-cell stage, the zygote behaves exactly as all humans do that early in their development). The developing embryo also has all the capacities the adult will develop at a latent level. Human embryos develop the ability to have rational thought because they have this capacity inherently. Human embryos never develop the ability to breathe underwater because they do not have this capacity inherently.
3) "That's not something that many of us get misty-eyed about. Very little sentimental poetry is written about the kind of DNA in the cells of one's beloved." This is a non-point. I don't get misty-eyed when I think of homeless people on the streets. But that doesn't mean those homeless people are any less human or valuable because of it, and it doesn't mean I have any less of an obligation to help them. Just because I don't have an emotional attachment to the developing embryo does not give me justification to kill it. Humans are rational animals and should use their rational faculties to rise above their emotional, animal instincts.
What do we call the spectrum?
Here's where Seidensticker really seems to misunderstand my response to his spectrum argument. I fully concede that there are differences between a single-cell zygote and the newborn or adult it will one day become. But my response is philosophically nuanced and Seidensticker's argument conflates many ideas together and fails to make important distinctions. Of course there are differences, differences in size, level of development, environment, and degree of dependency, between a zygote and an adult. But these are all qualitative differences and don't justify being able to kill the developing embryo.
So it's not about needing to "rename" the spectrum to show why the spectrum is a determiner of personhood. It's about no matter what name you give it, none of the differences Seidensticker fixates on are enough to justify killing the embryo in the womb.
1) PETA: Seidensticker points to the fact that PETA uses their slogan, "a rat is a pig is a dog is a boy" and argues they are trying to "collapse the spectrum" between these animals. The problem is Seidensticker, again, never addresses why he thinks this is a spectrum at all. He seems to assume that everything is a spectrum. But why assume that animal DNA exists as a spectrum? Certainly arguing that a member of a different species, say comparing a dog with a fish, is a fundamental difference and not a spectrum. Yes, they are all animals, but in what sense does fish and dog exist on a spectrum? Perhaps Seidensticker would do well to define what, exactly, he means by "spectrum." But whatever he means, it is clear that human person is not a spectrum, it is an all-or-nothing thing. Either you are a person or you are not. Seidensticker has yet to refute the pro-life argument.
2) Evangelicals thirty years ago supported abortion: This is, again, irrelevant, but Seidensticker tries to save it by saying it's not irrelevant to people who use religious arguments in this discussion. Except that it still is irrelevant. What matters is the truth of the arguments, not whether the group, as a whole, have switched their positions.
Again, Seidensticker misconstrues human development by asserting humans develop along a spectrum and fails to take into account that what is human is human from the beginning. He fails to make several important distinctions which show his argument to be faulty. It's clear that Seidensticker's argument fails to do the work of justifying abortion.