An almost painfully simple argument (just three parts, and three extra bits if you want them) showing unequivocally that abortion is equivalent to murder.
Note: 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.
1) It is wrong to kill another human being for personal reasons.
2) A human zygote or fetus is a human being.
3) 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:
4) 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, and [v] the killing is enabled by someone who is under a special duty to protect Harry.
5) 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, and [v] abortion is enabled by the mother, who has a special duty to protect her child at any early stage of development.
6) 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 that 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.”
- “Forty percent of zygotes/fetuses spontaneously abort, so it can’t be wrong to abort them.”
- “The woman’s right to choose what to do with her body trumps any other considerations.”
- “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!“
- “Self-defense is a personal reason to kill someone, and that isn’t wrong.”
- “Experiences are what make us human, or at least what constitute 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 from me. But that’s obviously biologically mistaken – so this objection is a failure.
This is also why the popular butterfly objection fails (i.e., 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 similarly not identical to killing an adult, 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 from 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 killing you would have deprived you not only of the life you have lived, but also of the ability to develop into the person you now are.
5. “Forty percent 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. “The woman’s right to choose what to do with her body trumps any other considerations.”
This feminist knee-jerk is completely unresponsive to my argument. Notice: I explicitly call out this kind of thinking by stipulating that it is wrong to kill a human being for personal reasons. That covers reasons of personal bodily autonomy. Therefore, if you’re raising this objection, I assume that you’re simply asserting it against my conclusion. If so, you’re conceding my conclusion, and agreeing that killing Harry-the-zygote-or-fetus is wrong. Since you presumably wouldn’t say a woman’s bodily autonomy gives her the right to kill (or enable another to kill) Harry in any other circumstances, you need to explain just what gives her that right in this circumstance.
You might claim that what gives her that right here is that Harry is part of her body. But this is obviously wrong, since Harry is a different human being from her. He has different DNA and his own organs. Plus it seems embarrassing to claim that 50% of pregnant women have penises.
You might claim that what gives her the right here is self-defense. I think this is actually a bit different from the right to bodily autonomy, but more importantly it misconstrues what I mean by “personal reasons” to kill someone. Self-defense is not a personal reason, but a civil one. Moreover, even if it were a personal reason, it would be an exception that you must show applies here. Unless the woman’s life is genuinely in peril from Harry – in which case, see objection #9 – self-defense is obviously off the table.
You might claim instead that what gives her that right here is that Harry is imposing on her body – à la Judith Jarvis Thompson’s violinist analogy. But even if the woman’s actions towards the violinist are permissible (which I think is much less clear than people suggest), the analogy fails at two crucial points. Firstly, it hardly seems permissible for the woman to kill the violinist by putting him into a blender – the equivalent of most abortions – or leaving him to die if he still had a chance to live on his own after all – the equivalent of partial-birth abortion. Secondly, and more importantly, her relationship to Harry is not of one adult stranger to another adult stranger, but of a mother to her child. This is conveniently glossed over – indeed, obfuscated – by the language often used in this debate (“woman,” “fetus,” etc). Obviously the maternal relationship carries with it the duty to protect and care for the child, and this duty overrides autonomy. For example, we wouldn’t think a mother was justified in killing her infant just because she doesn’t wish to have to get up several times in the night to feed it. Neither would we think highly of a mother who refused to donate a kidney to her child, knowing it would lead to the child’s death. And so on.
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 loophole to kill Harry. If my argument succeeds, then it succeeds regardless of the circumstances in which Harry is conceived, and regardless of how the mother feels.
This is obvious simply because I’ve shown that 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.
Now, at the risk of giving the impression that I’m diminishing the hardship of rape or incest – which I am not – I also think this is a very odd argument for liberals to make. It seems to treat women in exactly the way liberals despise: as delicate flowers who must be protected or accommodated because they can’t deal with the harsh realities of life. One is tempted to think that, in a similar situation, a man would be expected to buckle down and get through it despite the emotional cost. He wouldn’t be excused for killing his child due to emotional trauma. So why do the very people who believe that women are just as strong as men then turn around and treat them as weaker? Puzzling.
9. “Self-defense is a personal reason to kill someone, and that isn’t wrong.”
I consider self-defense not a personal reason, but rather a civil one, because it involves a duty to oneself or others to prevent injustice. The same applies to capital punishment.
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). Yet this 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. 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 constitute 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 that 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 he or she has 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 that 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 stillborn.
Got any other objections? Feel free to share them in the comments.
Editor’s Note: This article was first published November 21, 2012 at Developing the Mind of Christ and is reprinted with permission.