I’ve revised this article several times to strengthen it against new objections and criticisms. You may find quotes in the comments, or elsewhere on the web, that don’t match up with what is now written. Lo siento.
- It is wrong to kill another human being for personal reasons
- A human zygote or fetus is a human being
- Therefore, it is wrong to kill a human zygote or fetus for personal reasons
If  is a sound conclusion, then we can also strengthen the argument as follows:
- It is especially wrong to kill a human being (Harry) to the degree that [i] Harry is innocent; [ii] Harry is defenseless; [iii] Harry has more to lose; [iv] the killing is premeditated; [v] the killing is enabled by someone who is under a special duty to protect Harry
- A human zygote or fetus is [i] as innocent and [ii] as defenseless as a human being can be; a human zygote or fetus has [iii] the most to lose in terms of the life it could still live; [iv] abortion is always premeditated; [v] abortion is enabled by the mother, who has a special duty to protect her child at any early stage of development
- Therefore, it is especially wrong, to the greatest degree possible, to kill Harry if he is a human zygote or fetus
Obviously  would have to be built out for a complete and full defense, but I think it is pretty clear and unobjectionable as it stands.
You’ll notice the question of whether Harry is a person is irrelevant to the argument. Indeed, if he is not a person, then killing him is even worse, as per objection #4 below.
You’ll also notice the argument’s premises are very modest. They don’t require you to believe in God, or even in objective moral laws. Only that you have basic intuitions about murder, innocence, and familial duties which all people seem to share.
But you will object…
- “A human zygote or fetus is not a human being after all”
- “A blastocyst can twin, therefore it is not the same organism as the human being in its later stages of development”
- “It may be wrong to kill a more developed human being, but it’s not wrong to kill a zygote or a fetus”
- “The relevant distinction between myself now and myself as a zygote/fetus is that I am now a person, whereas I wasn’t back then”
- “40% of zygotes/fetuses spontaneously abort, so it can’t be wrong to abort them”
- “Although Harry is a human being, the mother is justified in killing him because he is using her body without consent or recourse”
- “The zygote/fetus isn’t properly alive because it can’t survive independently; therefore you cannot properly kill it”
- “But, but, rape, and, and, incest!“
- “There are lots of personal reasons to kill someone that aren’t wrong—self-defense for example”
- “Experiences are what make us human, or at least what comprise human life, so Harry isn’t really human, or perhaps isn’t alive, or at least his life has less value than his mother’s”
1. “A human zygote or fetus is not a human being after all”
But how can this be true? To call something a human being is to say that it’s an organism of the species homo sapiens. I, for example, am a human being, because I am an organism of the species homo sapiens. But obviously I have always been an organism of the species homo sapiens, regardless of my stage of development. And that stage of development included being a zygote and a fetus.
If you want to deny that, you’ll have to show that I never was a zygote or fetus—perhaps that I was created spontaneously out of a fetus, which was a different organism to me. But that’s obviously biologically mistaken—so this objection is a failure.
This is also why the popular butterfly objection fails (ie, if I’m right then killing a caterpillar is identical to killing a butterfly). The analogy breaks down exactly where it needs to hold up. A caterpillar is literally liquefied and destroyed, and then a new organism, the butterfly, takes its place out of the same material and genetic code. Obviously nothing like this happens for a zygote or fetus—these are not destroyed and then replaced by a baby.
The related frog objection—“well then, killing a tadpole is identical to killing a frog”—fails for a different reason: equivocation. The term frog is being used to describe both the organism, and its adult stage of development—and the objection trades on this confusion. But killing a baby is not identical to killing an adult either; yet both are identical to killing a human being.
2. “A blastocyst can twin, therefore it is not the same organism as the human being in its later stages of development”
But what relevance does the possibility of twinning have to whether I am the same organism as that blastocyst was? Even assuming that twinning involves the creation of a new organism (which is unclear, philosophically), I did not twin. Now, if you observe an amoeba for two hours and it doesn’t split in two, would you then conclude that the amoeba is a different organism than before, just because it could have split?
3. “It may be wrong to kill a more developed human being, but it’s not wrong to kill a zygote or a fetus”
This objection runs aground pretty quickly on premise , which seems to have a great deal of intuitive strength. And it’s obvious you can’t make a special exception for zygotes/fetuses, because I was once those things (as were you). If it is wrong to kill me or you now, then it was at least as wrong to kill us then, because the victims are the same. Unless you can come up with a relevant distinction between yourself as a victim of murder today, and yourself as a victim of murder at your earliest stages of development, there is just no reason to think it would have been morally permissible to kill you then, but not to kill you now.
4. “The relevant distinction between myself now and myself as a zygote/fetus is that I am now a person, whereas I wasn’t back then”
But this isn’t a relevant distinction. Indeed, if you really weren’t a person when you were a zygote and fetus, then premise [4-iii] is strengthened and the objection refutes itself—because not only would killing you have deprived you of the life you have lived, but also of the ability to develop into the person you now are.
5. “40% of zygotes/fetuses spontaneously abort, so it can’t be wrong to abort them”
Even if this figure it accurate, 100% of human beings die, so by this logic it can’t be wrong to kill them. It baffles me that anyone would raise this as a serious objection, yet I’ve seen it many times.
6. “Although Harry is a human being, his mother is justified in killing him because he is using her body without her consent”
I think this is the most staunchly-defended objection I’ve come across. The idea is that no one is entitled to make use of your body without your consent, and especially not for extended periods. Should someone violate your personal liberties and your bodily integrity in such a way, you’re entitled to take steps to prevent it, up to and including killing the other person.
I think this is quite plausible as far as it goes. An obvious example would be rape, which is a form of assault. It’s hard to imagine a woman being unjustified in killing a rapist in self-defense.
But how can we get from being justified in killing a rapist, to being justified in killing Harry? There seem to be several insurmountable hurdles along that path:
The first hurdle is that in nearly all cases, the woman gives implicit consent by having sex in the first place. She knows that sex is the means by which conception takes place. And she knows that contraceptives are not 100% effective. And even if she somehow doesn’t know these things, we don’t take ignorance to be an excuse for not accepting the consequences of your actions if you choose to engage in other kinds of risky activities. Rather, we think you should have educated yourself properly first. So it seems quite impossible for a woman to say that she consented to have sex, but she did not consent to the consequences of having sex—namely Harry. That is rather like saying that she consented to go joyriding, but not to spend 9 months doing community service after she accidentally drove through a fence. So we can see that except in fringe cases, the consent argument fails immediately.
The second hurdle is the idea of reasonable force. I’ve already said a woman is justified in killing a rapist. But what about a less extreme situation, such as being groped? Surely that does not justify lethal force against the perp—nasty as he may be. So clearly not every case of abuse or assault permits killing the perpetrator. Which raises the question: is it justified to kill someone who is in the process of causing you discomfort and inconvenience for nine months? Is that really a reasonable or proportional response? It isn’t at all clear to me that it is.
The third hurdle lets us go further in regards to reasonable force, by acknowledging the role of intent. In the examples I’ve suggested so far, the perp is intentionally imposing on another person’s body, while they have done nothing at all to bring on the imposition. But what if he were doing so unintentionally? What if it were her intentional action that had caused his unintentional imposition? What if, through no fault of his own, he was unaware of what he was doing and helpless to prevent it, while she had initiated it in the first place? Would we still feel justified in killing him? It seems very unlikely. Even in rare cases where the woman’s actions had not led to the perp’s imposition upon her, it still seems very difficult to justify killing him, and thus making him as much a victim as she is. As the old saying goes, two wrongs don’t make a right.
Yet some pro-abortionists are adamant, almost vindictive, about killing the perp. I wonder if, as with the prisoner’s dilemma on the ferries in The Dark Knight, they are all talk. If Harry were a child, would they really be willing to kill him themselves in order to defend their bodily autonomy and personal liberty? I think very few people really would—at least, I very much would like to believe that the pro-abortionists’ bark is worse than his bite here. If not, it would seem that pro-abortionists are largely sociopaths, or at least are inclined to act sociopathically toward human beings who are “out of sight, out of mind”.
The fourth hurdle is, I think the most significant, and that is the largely glossed-over social responsibility we are subject to in certain situations. Let me give an example: imagine you live in the arctic circle, and for several months of the year you are unable to contact the outside world due to weather conditions. One day, just as the weather is setting in, you discover a box outside. Upon opening the box, you find it contains a baby.
It seems extremely clear that although you have not consented to look after this baby—indeed, it is a significant imposition given your limited supplies and lack of preparation—you are nonetheless under a responsibility to do so, simply by being put into that situation. We would condemn someone who, rather than taking the baby inside to care for it, instead left it out on the doorstep to die of exposure or starvation. That is sociopathic behavior. And we would especially condemn someone who fetched a machete and hacked the baby to pieces, arguing that she was justified in doing so because she had not consented to look after the child (most abortions involve a similar method of destroying the fetus).
If even a stranger has an obligation to a child that cannot fend for itself, how much more does its own mother have such a responsibility when it is even less able to fend for itself? To deny this maternal duty seems plainly sociopathic—an ethical price so high that if you pay it to claim that abortion is “ethical”, your claim ends up saying nothing like what we take it to mean on face value.
There is a fifth and final hurdle: I can find no relevant distinction between modes of physical imposition. In other words, why is it unacceptable for a woman to be imposed on via direct physical means, such as a fetus living inside her (or Judith Jarvis Thompson’s violinist being grafted onto her), but not via indirect means, such as having to prepare meals for her child, work to provide for him, drive him from place to place, care for him when he is sick, and so on? Both are obvious impositions on her personal liberty and her bodily autonomy.
You may say the difference in the case of pregnancy is that she has no other recourse. Once Harry is born she can adopt him out, or have willing family members help her, etc. But my analogy of the remote arctic location seems to put paid to that idea. It’s not permissible to kill someone just because you can’t fob your responsibility off on another person.
You may say the difference in the case of post-partum children is that, by consenting to give birth, the mother implicitly consents to everything which follows—even things like terrible diseases where she will be forced to give up great personal liberties and bodily autonomy for Harry’s sake. But this response immediately backfires by conceding my argument about implicit consent: that by consenting to have sex, the woman implicitly consents to everything which follows, including Harry’s conception. You can’t eat your cake and still have it, too.
And in fringe cases where sex is nonconsensual, the arctic analogy comes into play again. If non-consent doesn’t justify killing a human being in a similar situation post-partum, why should it justify it in utero?
When you combine these hurdles, what you get is a cumulative case showing that, rather than justifying a woman in killing Harry, the consent argument actually condemns her. To kill him on the basis of this argument seems to qualify as sociopathic behavior. In all the analogies pro-abortionists give, the perp is acting maliciously toward a woman who did nothing to merit his actions against her. But even if this were accurate, killing the perp seems like a staggeringly disproportionate response—it isn’t reasonable force at all. Yet in the vast majority of pregnancies, the “perp” is in fact acting helplessly toward a woman precisely because she caused him to do so! And moreover, she is not simply “a woman” and he is not simply “a perp”—rather, she is his mother and he is her child—with all the duties and responsibilities that entails. Again, denying these maternal duties, far from being enlightened and freeing, seems sociopathic. And finally, since there’s no obvious moral difference between a fetus imposing on a woman’s autonomy and liberties, and a toddler doing so, it seems to imply that a woman is justified in killing her toddler for the same reasons as having an abortion.
7. “The zygote/fetus isn’t properly alive because it can’t survive independently; therefore you cannot properly kill it”
This is admittedly the most bizarre objection I’ve come across to date, and one that’s obviously just balderdash. As a matter of definition there isn’t a creature in existence that can survive independently of the environment it depends on for life. So why should we think that the womb is a unique kind of environment in this regard? Or, if the objection is that Harry can’t survive independently of the physical systems of another organism (his mother), then why think this is relevantly different from people who can’t survive independently of the life support systems in a hospital? It’s also hard to find a principled way to exclude infants, toddlers, small children and the infirm from this logic, because they also rely physically on other organisms for their survival. Why should a physical connection be relevant to distinguishing whether they are properly alive? But once you realize the logic extends this far, it obviously extends to every organism possible, since every organism survives by physically eating other organisms.
8. “But, but, rape, and, and, incest!“
While these are obviously awful things to happen to someone, I don’t see the connection between Harry being conceived in such situations, and there being a moral loophold to kill him. If my argument succeeds, then it succeeds regardless of the circumstances in which he is conceived, and regardless of how the mother feels.
This is obvious simply because I’ve shown there’s no relevant difference between killing Harry as a zygote/fetus, and killing him as baby, toddler, child, teenager or adult. And since it would be wrong for a mother to kill Harry at any of those stages of development—even if he was a constant reminder of a very traumatic event, or even if she hadn’t wanted him—it is also wrong for her to kill him before he is born.
9. “There are lots of personal reasons to kill someone that aren’t wrong—self-defense for example”
I don’t consider self-defense a personal reason, but a civil one, because it involves a duty to oneself or others to prevent injustice. The same applies to capital punishment. In fact, i think the “personal reasons” part of my argument is pretty robust precisely because we can see clear differences between the reasons for most abortions, and the reasons for killing axe-murderers or home invaders. The notion of personal reasons has a commonsense connotation which I think is quite clear to people who are willing to interact with the argument honestly.
But let’s say this objection goes through anyway. This would suggest that abortion is permissible in cases where the mother’s life is genuinely in peril from the pregnancy (assuming Harry can’t survive outside the body), or where justice demands that Harry be killed. Yet the first instance seems like an uncontroversial exception, since it is impossible to save Harry’s life here in any case, and it would be a greater wrong to let both him and his mother die. And the second instance seems plainly impossible, since Harry cannot yet be guilty of any significant wrongdoing.
What this objection does not show is that, because it is permissible to kill Harry in self-defense, it is therefore permissible to kill him for any other reason. And so it fails to refute my argument.
10. “Experiences are what make us human, or at least what comprise human life, so Harry isn’t really human, or perhaps isn’t alive, or at least his life has less value than his mother’s”
This objection is so incomprehensible to me I’m honestly not sure I can recreate it in my own words—so here’s how one pro-abortion advocate put it to me:
I believe that experiences make up life. Touch, sound, sight, taste, the sun hitting one’s face, making memories with another person, etc. A fetus has had none of those things…it is being removed before it has a chance to have any experiences that would make qualify as “life.” We put SO much significance on this fetus that we ignore the rights and well being of a fully formed, functioning woman who has already breached the canal and had the experiences that make her “human”.
Now, obviously it’s mad to think that someone is “less human”, or perhaps even not alive or not human at all just because they’ve had minimal experiences. Either you are human or you are not. Either you are alive or you are not. I already dealt with this under objections #1 & #7. But what about the idea that maybe Harry’s life is less valuable, or he has less of a right to life, because he hasn’t had the quantity or diversity of experiences his mother has had?
Well clearly that’s wonky too, because nearly all young humans—babies, children, teenagers, and even younger adults—have fewer and less diverse experiences than older adults. Therefore, if this objection succeeds, all these people should have less valuable lives, or less of a right to life, than those older adults. Yet I doubt many people will agree with this notion, since it’s plainly mental. We especially don’t believe this about babies and children: most of us, if push comes to shove, have a very strong intuition that not only does a child have just as much right to life as an adult does, but its right trumps the adult’s. For example, we think an adult ought to give up her life to save a child if only one of them can live, such as when having to deal with a lifeboat shortage on the Titanic.
This really comes back to premise [4-iii]. This objection is completely unresponsive to that premise. So if the premise is sound—and it seems very hard to find something wrong with it—then the objection is still-born.
Got any other objections? Feel free to share them in the comments.