Theology, philosophy, science, math, and random other things

A moral evaluation of abortion

(This post is still incomplete. Check back later when it's done, and don't take anything below as something that I've "officially" said, especially in an issue as controversial as this one.)

Roe v. Wade was overturned last Friday. I think this is an opportune time to organize and express my thoughts on the abortion issue. This will focus mostly on the morality of the action itself, and less so on the legal or political analysis of the court decision.

Let's begin with an overview of the typical arguments. Pro-choice advocates say "my body, my choice": they argue for the right of women to get an abortion based their right to bodily autonomy. The pro-life side says "abortion is murder": they say that life begins at conception, and that intentional killing of that life is wrong.

The first thing I notice here is that these two of arguments are not equal and opposite in their interaction. That is to say, if we grant both arguments their full force, we don't end up with a neutral conclusion: the pro-life side wins. The right to life is a stronger right than the right to bodily autonomy. Bodily autonomy doesn't mean that you get to kill people with that right. Like all rights, it's limited in scope and stops when it starts infringing on the rights of another human being.

This is why the pro-choice side needs to go beyond its original argument. They need to establish that not only do women have a right to bodily autonomy, but also that this overrides any right to life that a fetus may have. Unfortunately, the pro-choice advocates have generally failed in this respect. Probably the most common pro-choice slogan here is "it's just a clump of cells", which I find to be utterly unhelpful: I'm a clump of cells. You're a clump of cells. We're all clumps of cells - and the value of any such clump is to be determined by further reasoning, not by mere assertion.

The pro-life side, by contrast, doesn't deny a women's right to bodily autonomy. They don't need to. They can simply stick to their original argument - that life begins at conception - and just play defense, knowing that the right to life is intrinsically stronger than the right to bodily autonomy.

Many miscellaneous arguments follow this form. For instance, from the pro-choice side, there is supposed to be a legal right to privacy that allows women to get abortions. But again, the pro-life side doesn't need to deny the right to privacy. They can just play defense and argue for the intrinsic value of a fetus as a human being, relying on the fact that the right to life trumps almost any other. Nobody would argue that you can kill someone as long as you do so in the privacy of your own home.

O course, noticing that strategic layout of the argumentation favors the pro-life side doesn't mean you have to grant those arguments. But it does allow us to focus our attention to the crux of the whole debate: what is the value of a fetus? Does it have the right to life? Answering this question will effectively settle the issue.

But before we really get started, I have to address one particular class of reasoning on the pro-choice side: that the value of the fetus is assigned to it by the whims of the society. There's often a lot of words used to dress up this idea, such as "social context" or "separate, participating member", but it all amounts to the same idea, that the fetus has value if the mother or the society or some such group of people simply deems it to have value.

This is an abhorrent idea. If you believe this, I have little to say to you. I consign you to the lot of the racist slavers and the genocidal tyrants of the past, who also enabled their evil by denying the personhood of their victims. No; whatever value the fetus has, it must be found through well-established principles applied to its intrinsic properties, and not on arbitrary whims.

So, then, what gives value to a fetus? A great deals has been said on this issue. Is it the ability to feel pain? Is consciousness, or independence? Or the presence of a heartbeat, or brain waves, or a unique DNA? Some discussions of this type can be interesting, but I often don't find them to be too helpful. They're occasionally suspect (is that REALLY what gives value?), and often involve going too far into the minutiae.

Instead, I propose that we consider the one property that everyone agrees that a fetus has - indeed, its chief intrinsic property: the POTENTIAL to become a fully valued human being. I then apply the principle that we use to evaluate ANY potentiality: by valuing it through the probability of actualization, minus any ancillary costs. That is to say, the value of a fetus can be calculated as:

probability of actualization as a full human - costs required to bring about the actualization

The units here are in full human lives - in "natural units", as it were. This is the only proper basis for this kind of calculation, and should be used for any evaluation of trade-offs: life for life, as that's what's at stake here.

Note the robustness of this formula: whatever else a fetus may or may not be, whatever other properties it may or may not possess, it's certainly a potential human being. That is indeed its primary nature. Furthermore, take a moment to consider the universal applicability of the principle: all potentiality is evaluated through the probability of its actualization. A job interview is not yet a job, but you evaluate it through the probability of that actualization. A date is not a relationship, but you evaluate it through the probability of that actualization. A lottery ticket is not the payout, a college acceptance is not a degree, and a seed is not yet a tree, but they're all evaluated through the probability of their actualization, minus the costs to bring it about.

Note furthermore that this is the MINIMUM value, because it's only evaluating the fetus through its potential. That is to say, the fetus may have additional value beyond just potential. If the fetus has any value as it currently exists - if it can feel pain, or has brain waves, or some form of consciousness (which it almost certainly does as it progresses to the later stages of its development), then it would have value in addition to the above formula. Just as your time in college may have value merely for your experiences there apart from getting a degree, a fetus may have value in addition to its potential to become a full human being.

Note additionally how this correctly evaluates the myriad of branching concerns that come up in the abortion question. So no, a sperm or an egg do not have anywhere near the same value as a fetus: they may be "potentially human", but they have a very low probability of actualization. This probability jumps up enormously upon conception - the first and probably the biggest of the major "filters" in the development of a full human being - but it's still far short of certainty.

After an egg is fertilized to form a zygote, it may fail to implant in the uterine wall, and thereby fail to develop into a fetus. This is definitely a loss, but the low probability of full actualization at this point means that the loss is small. In addition, this loss carries no moral imperative, as there are no direct intervention methods available that can definitively alter the outcome. 

We now consider the second term in the formula: the cost required to bring about the actualization. Certainly, being pregnant is hard - especially during the later months - and giving birth is among the most painful and difficult physical endeavors that anyone can experience. There is also the direct danger to the life of the mother during the whole process. All this is costly, but when measured in human lives, it amounts to a tiny fraction. Mothers: what fraction of your life would you have given up to simply deliver your child without all the pain, risk, and hassle? I'd imagine that it's some small-but-nonzero number.

So when we apply the formula to the zygote pre-implantation, we have a small probability, then we subtract from it a small cost. I will not venture a more precise calculation, but it's clear that the net value will be some quite small fraction of a full human life. So we need not be overly concerned about losing a zygote pre-implantation. Perhaps it merits about as much mourning as the peaceful passing of an elderly relative. This is, in fact, about the weight of concern given to infertility in our society, which shows that our evaluation criteria is tracking reasonably well with reality.

After the egg is successfully implanted, the probability of a successful birth increases rapidly in the first few days and weeks. By the time that a woman knows she's pregnant, the probability is reasonably close to certainty: only about 10-20% of recognized pregnancies end in miscarriages. A miscarriage is definitely a huge loss, and there is rightfully a great deal of mourning over such a tragedy. But again, because there isn't much that can be done to definitively affect the outcome, it carries little moral judgement. Again, our evaluation criteria is tracking reasonably well with reality.

This now brings us to the question of abortion. As we've just mentioned above, by the time a woman knows she's pregnant there is a good chance of a successful birth. At this point, the "cost" term to bring about that birth is negligible in comparison. So, the value of such a fetus is quite high - let's say 80%, for the sake of the discussion.

Abortion is the active, premeditated, and often violent intervention to reduce that number to zero. It therefore carries nearly the full moral weight of killing a human being. When the act is considered in and of itself, in isolation, it is a grave evil. And anyone who participates in such an act (again considered in isolation) are moral monsters.

So - that's it, right? End of argument, open-and-shut case? I'm obviously 100% pro-life, abortion is murder, and should be universally outlawed? Not quite. For one, you'll notice that the evaluations above don't quite line up with the standard pro-life talking points. Yes, life starts at conception, but not every fetal life is of equal value: they must be weighed through the probability of actualization. A zygote pre-implantation is of some value, but the value of a 10-week fetus is much greater. A third-trimester fetus has more value still, and if it’s viable outside the womb it’s effectively a full baby. This does mean that an abortion is “better” if we can do it early. Note again that all this lines up exceedingly well with all of our strongest intuitions.

If “not every fetal life is of equal value” doesn’t sit well with you, then think of it this way: if you can only save one of the lives listed above, by all means save the one that’s furthest along its development. You will get closest to saving an actual baby that way. If, on the other hand, you chose to save the zygote over a viable fetus, there is a very good chance that it’ll die anyway, and nine months later your choice will have likely cost the life of an actual baby that’s now missing from the world. 

But remember, we’re ALWAYS in this situation. We’re always choosing between lives to save. We have finite resources. We cannot save everyone. How do we make the decision? Life for life: that’s the exchange rate. In this way, weighing the value of a fetus by the probability of actualization is actually the most fair, egalitarian decision you can make.

This brings us to the next point that I have against some in the pro-life camp: some people say life is of infinite value. I disagree. A human’s biological life (I'm not speaking of the soul here) is a finite, material entity, and has a finite worth. We evaluate, trade, and spend it all the time, at every moment. We often exchange a fraction of it for economic gains, in work. We spend it for political or military gains, in war. We trade it for other lives, in raising children. If we make wise decisions - if we make the right tradeoffs - we will better preserve or increase our resources, which in turn allows us to save more lives. In this way, human lives can be evaluated to have some equivalent value in other things, like dollars or hours of work, or bodily autonomy.

So in short, I disagree that abortion should be universally outlawed because it’s the killing of a human life. Sometimes, the killing of a human life is allowed. We know what we’re losing in an abortion: the fetus has been well-established as typically having about 80% value of a human life. We now must discuss the other side of the coin: what are we gaining in an abortion? And is the exchange worth it, when considered on the basis of life for life?

One possible exchange for the life of the fetus is the life of the mother. In fact, the life of the mother may be considered quite a bit more valuable, since any risk to the mother is likely a risk to the fetus as well. Such a risk may also significantly impact her role as a mother, which may then affect her other children beyond just the fetus in question. Thus any serious risk to the mother’s life is to be given a very wide berth in terms of allowing an abortion.

What about other exceptional circumstances? For example, what do we do in the case of fetal anomalies? This is actually fairly easy to evaluate, since it’s already covered under the “value of a fetus” which we considered above. If the abnormality would seriously compromise the fetus’s likelihood of a full human life, then its value must be discounted accordingly. There are, of course, greatly varying degrees of fetal anomalies, and they all have to be judged individually. I will again not venture a more precise calculation here, except to say that In some extreme cases an abortion would certainly be justified.

What about cases of rape or incest? “Incest” could probably be skipped over, as the concerns here would mostly be covered as a part of “fetal anomalies” or “rape”. That is to say, if we have a healthy, normal fetus which was produced as a result of a consensual incestuous relationship between two adults, then there is little reason for an abortion here, regardless of any judgement about the morality of such a relationship.

“Rape” is the most difficult of the cases, for it involves the evaluation of a very complex set of possible “benefits” to an abortion. Most importantly, this is where the “my body, my choice” argument is by far the strongest. As this is the main argument on the pro-choice side, it's worth going into it in some depth.

We had hitherto basically ignored the "my body, my choice" argument. In effect, we've been considering what the woman SHOULD want upon discovering that she's pregnant. The above discussion demonstrates that the woman should generally WANT to carry the baby to term, barring a few exceptional circumstances. She should "choose life". That is the moral thing to do.

But what if the woman wants to do the immoral thing? What if she wants an abortion? Can we then deny her this choice, on the grounds of its inherent immorality? Or should she be allowed, on the grounds of "my body, my choice"?

The question is no longer on what the woman should do, but on what we should do in response to the given fact that she wants an abortion. This is, of course, the heart of the controversy. So let us carefully consider the new scenario that arises in this new question. What is the net value for the whole situation, when a pregnant woman is denied from getting an abortion? Picking up from where we left off, we can break down this value as follows:

  1. Value of the fetus,
  2. minus the cost to the fetus/child from being unwanted,
  3. minus the cost to the woman from the violation of her bodily autonomy

The value of the fetus is the same as before: about 80% of a human life. But if the mother wants an abortion, this must be modified by the second, 'cost of being unwanted' term. An unwanted fetus is likely to lead to an unloved child, and they're likely to suffer some harm as as a result. A mother's love is crucial: so this harm amounts to some non-negligible fraction of a human life. But on the other hand, such unloved children can still grow up to be good, valuable adults, which must mean that this cost is limited to a minor fraction of a human life. So after subtracting this cost, on the balance of probabilities, we still have most of the value of a human life.

The third term is the "my body, my choice" term. Some pro-choice rhetoric uses this as a decisive claim that brooks no counterargument, implying an infinite value to this term. But of course, that cannot be. Yes, everyone has the right to their own body. but like all rights, this is a limited right. Let's see some examples that highlight this limit.

Imagine that you see a woman about to jump off a bridge in a suicide attempt. You run over, grab her, and forcibly drag her away from the edge. What happened here? You took away a woman's bodily autonomy to save a life, and you'd be rightly be hailed as a hero in this scenario. What does this mean for the "my body, my choice" argument? It's simple: bodily autonomy, important as it may be, doesn't extend enough to cover the loss of a whole human life. This effect is greatly magnified when the life in question is not your own - for example, if you had stopped a murder instead of a suicide.

Now, what if the woman was actually a thrill seeker jumping off the bridge with a parachute? Such stunts are dangerous, and she may still die as a result. Say that the chance of her death is 0.1%. Would you be justified in forcibly stopping her? Probably not. Again, what does this mean for the "my body, my choice" argument? This gives us a lower bound - the argument IS powerful enough to cover 0.1% of a human life, in this particular scenario.

We can further refine this idea in numerous other examples. Say that you restrict someone to prevent an amputation instead of a suicide. You would still be rightly praised for doing the right thing. Here, bodily autonomy doesn't even cover the loss of a limb, let alone a life. Consider furthermore the case of mandatory vaccinations against contagious diseases. If the threat and the benefit are reasonably well-established, we're generally agreed that this is a good thing. Here, we're taking away people's bodily autonomy, en-masse, for rather abstract gains. Lastly, motherhood is, if anything, a larger restriction on a woman's autonomy than a pregnancy, but we don't allow mothers to kill their children, no matter how badly they want to.

I do not mean for the above examples to be an exact analog to abortion. For one, forcing a woman to carry a pregnancy to term is a much more serious matter than restricting her body for the several minutes required to prevent a jump. However, I believe we can extract some key principles from these examples, which can then be applied to the problem of abortion. We want to quantify the "my body, my choice" argument, beyond just saying that it can't make up for the loss of a human life.


In non-rape cases, I’m not particularly fond of this argument: we’re generally expected to bear the natural consequences of our actions. Yes, a pregnancy is a major cost to a woman, but that’s already taken into account as part of the formula, in the “cost to bring about the actualization”. We furthermore know that this cost is actually fairly small when measured human lives.

Shouldn't the fact that the woman doesn't want the baby get any additional concern? Am I simply ignoring the logic in "my body, my choice"? Not at all. Of course we all have the right to our own bodies, and can generally do whatever we want with them. But this is, again, not an absolute right, and when compared on a life-for-life basis, it is of negligible value. This can easily be seen in some fairly clear examples.

Can we further refine these scenarios, so that they're actually analogous to abortion? I think so. There's a lot of silly abortion analogies out there about violinists or houseguests, but I think a good analogy can illuminate the moral calculus and set the record straight.

Fortunately, we can

am I double counting? No. Value is value and separate from cost.

cost term - if responsible, direct. if not, huge multiplier.

how much autonomy for how much life? breakeven formula? responsibility term?

what should the woman choose to do? What should she be forced to do?

and compared to the other terms in our well-established formula, it is of negligible value. That is, when compared on a life-for-life basis, w

Concerns about a woman’s bodily autonomy certainly amplifies this cost, but it’s absurd to say that it can make up for the killing of a full human life. Lastly, motherhood is, if anything, a larger cost to a woman than a pregnancy, but we don't allow mothers to kill their children.

All this changes if the pregnancy is due to rape. Here the woman is NOT bearing the natural consequences of her actions, but a condition inflicted on her by her rapist: this VASTLY increases the "my body, my chose" multiplier. We furthermore acknowledge that rape is a grave crime - one of the few that's actually comparable to murder, and therefore comparable to an abortion on the life-for-life scale. Forcing the woman to carry the pregnancy to term would likely re-inflict this level of trauma, and the repetition would be its own form of injustice. There is also the question of child-rearing: forcing the woman to bring up the child would be unthinkable, but there are significant downsides to other alternatives, such as raising the child as a ward of the state. The outcomes of these alternatives are often bad enough to count for something on the life-for-life scale.

On top of all that, there's also the details of the rape case itself, which may ameliorate or exacerbate any of the above factors. How "severe" was the rape? Is the rapist still at large? What's the age of the woman in question? All this makes this the most complicated of the "exceptional circumstances". Again, I will not venture a more precise calculation here, except to say that in many cases an abortion would be allowable. The "benefits" of the abortion can outweigh the loss off the fetus, on the life-for-life scale. To be sure, any woman who could choose to save such a baby would be a hero - one of superhuman virtue, who made the hard but right choice, at a tremendous cost to herself. But we cannot demand superhuman sacrifices as the general rule from the population of ordinary women.

Of course, the above cases are the exceptions. The vast majority of abortions do not fall into those categories. Rather, women often give reasons like "I can't afford a baby now" or "I don't have the right partner". These are much harder to justify, on a life-for-life basis.


context, overview, analysis of large structure of arguments
focus on life - what gives a fetus its value?
- an aside on arbitrary values
value though probability of actualization
- conformity to intuition
- what it means for various stages of development
evaluation of abortion according to the formula
- in isolation
- in context
exceptional cases
- possible benefits
- life/health of mother
- fetal anomaly
- incest
- most other cases
- rape? (to be left for later), launch into next section

the "my body, my choice" argument
- distinguish between what the woman should want, and what we should force the woman to do
- changes to the calculation
- of finite value - enumerated factors: who, magnitude of imposition, what's at stake, consent, accident, violation
- restrictions: other persons
- restriction: value to "self" still limited - examples, involuntary commitment
- restriction: responsibility/consent, accident without malice, assault/intentional harm
- adoption option: not zero, but smaller than parenthood
- possible double counting: adoption+unwanted? unwanted + cost of parenthood?
- possibility: "I wish you were never born" case
- general application (including the "I wish you were never born" case)
- specific application to rape

Summary of cases, possible laws
the judgment of history

"additional factors", even if granted, can't add up to more than the cost (~0.3), and not if you're responsible for it anyway
"additional factors" become completely negligible if adoption is taken into account
"my body, my choice", even if granted, can't add up to more than the cost, and not if you're responsible for it anyway
"my body, my choice" doesn't apply if you're responsible for it anyway, to another party
"my body, my choice" is limited, even if it's your body, to a fraction of the consequences
"I wish that you were never born" scenario - that may be within reach, and allow for abortion.

"my body, my choice" fails when someone else is involved (in generating additional value
if we say that the fetus is not another person, "my body, my choice" still fails when the value exchange is too big. We do not allow suicide or amputations, and anyone assisting such actions is criminalized
you cannot count the harm to the fetus as being agaist another individual for the purposes of negative cost, and count it as the woman in allowing freedom.
If the fetus is another individual, "my body, my choice" is not allowed at all.
If the fetus "belongs" to the mother's "body", it is still of value - you would easily, for example, commit a woman to a psychiatric ward for several months to keep her from commiting suicide, or just to prevent self-amputation. (even if the woman would be healed afterwards regardless) (involuntary commitment periods are generally 3-5 days with extentions up to 60/90 days available if deemed necesary, for a CHANCE of self-harm)
"my body, my choice" in such cases is at most limited to the value of the "restriction", when they arise naturally or accidentally.
difference between consent/responsibility and accident and malevolence:
you bet $100, you lose $100, you're robbed of $100.
you crash your car, someone else crashes into you, someone else intentionally crashes into you.

I wouldn't say that such abortions are impossible to justify, but that justification needs to meet an incredibly high bar. So, for instance,

One cannot help but feel that many women are using abortion as an incredibly irresponsible form of birth control.

social context arguments are evil

pro life side wins, pro choice arguments don't address the pro life argument

we need to evaluate the value of a fetus

probability - significant fraction of a human life, at a minimum

an abortion, taken in and of itself, is a monstrous decision

mitigating factors: life for life - rape, incest, life of the mother. Even economic factors can contribute, but the natural unit is a human life

Rare, really rare, but safe and legal.

Not to be made in private.

the judgement of history

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