The pro-life argument in four premises and where each one gets attacked

Most arguments about abortion are not arguments at all. They are two people holding up signs. One sign says "my body, my choice." The other says "it's a baby." Each side hears the other's sign as an insult, and the conversation ends at the speed of a slammed door. I would like to do something different, which is to lay out the pro-life case the way a philosopher or a debate coach would: as a chain of premises, any of which you are free to attack.

If you are on my side of this question, I want you to know where the chain gets pulled. If you are on the other side, I want you to see the strongest form of what you disagree with, because you are owed that, and because beating a cartoon proves nothing. A note on method before we start. This is an argument from philosophy and law. It makes no medical claims, and where an answer would require a doctor, I will say so and leave it there.

The idea underneath: a claim about equality

Strip away the slogans and the pro-life position is a claim about equality. It says that every human being has the same basic worth, and that this worth does not depend on how useful you are, how strong you are, how old you are, or whether anyone is paying attention to you. It rests on what you are, not on what you can do.

That is not a fringe idea. It is the idea in the Declaration of Independence, which says that all men are created equal and that they are endowed with unalienable rights. The country spent a good deal of its history arguing about who was included in "all." The pro-life movement says the unborn child belongs inside the circle.

You can reject that. Plenty of thoughtful people do. But if you want to reject it, you have to say where the circle should be drawn and why, and that is why this debate comes down to line-drawing rather than slogans. So let me put the case in four premises.

The four premises

1. Every human being has equal and inherent worth. This is the equality claim. It is a value claim and I will label it as one. It cannot be proved in a laboratory, but neither can its denial.
2. That worth comes from what a being is, not from what it can currently do. Size, stage of development, level of ability, place and degree of dependence on others do not change a person's basic standing. A newborn cannot reason, a man in a deep coma cannot speak, and we do not say either has less worth.
3. The child before birth is a member of the human family, a living human being at an earlier stage of life. This is the premise where philosophy meets biology, and it is the one the other side disputes most. I'll say plainly that I am not going to settle questions of embryology in a column. What I will do is show how the argument works if the premise is granted and what the strongest objections to it are.
4. It is wrong to intentionally kill an innocent human being, and the law exists in large part to protect those who cannot protect themselves. Therefore, the law should protect the child before birth, with the details of how left to the elected branches.

Now let me attack my own premises, in order, the way a good opponent would.

Attack on premise one: "Who says we are equal?"

The opponent says: equal worth is a pretty sentiment, but you have no argument for it. A human life contains many degrees of capacity, and we treat people differently on that basis all the time. We let adults vote and not toddlers, we let doctors practice and not teenagers.

The reply is that the examples confuse rights that depend on capacity with the basic claim not to be killed. Voting requires maturity, so it is fair to set an age. A license to practice medicine requires training. But no one thinks a toddler may be killed because she cannot vote. Basic standing is a different category, and the whole tradition of human rights depends on treating it as equal. Once you let basic standing depend on a trait that comes in degrees, such as intelligence, awareness or independence, you have to say how much of the trait is enough, and the line you draw can be moved by whoever has the power to move it. That is the lesson of every ideology that sorted people into more and less worthy.

Attack on premise two: personhood

This is the best-known objection and it deserves a careful treatment. The objection says that being a human organism and being a person with full moral standing are two different things. Persons have certain capacities, such as consciousness, self-awareness, the ability to reason and plan, and a being that lacks them, such as an early embryo, does not have the same claim as one that has them.

Here is the strongest version. Philosophers like Mary Anne Warren, in her 1973 essay "On the Moral and Legal Status of Abortion," proposed a list of traits that make a person, and argued that a fetus lacks them. The view has an appealing logic: rights belong to those who can use them.

Now the answer, in three parts.

1. The capacity view proves too much. If personhood depends on present self-awareness and reasoning, then a newborn does not qualify, and neither does a person under anesthesia or a patient with profound cognitive disability. Some philosophers accept this. Peter Singer, in Practical Ethics (1979), has argued that newborns are not persons in the full sense, and defended the permissibility of killing some of them. I give him credit for consistency. But nearly everyone, including most people who support abortion rights, recoils from that conclusion. If a theory implies something nearly everyone knows to be monstrous, the theory is in trouble. I am not saying every supporter of abortion rights holds Singer's view. They do not. I am saying that the personhood argument, followed through, has to either accept it or find a different line.
2. The "different line" is hard to find. Birth is a natural place to draw it, because birth is visible and the law can administer it. But birth changes the child's location, not the child's nature. The same being is on one side of the line a minute before and the other a minute after. A line that does not track any property of the being itself looks more like a convenience than a principle.
3. The burden of proof. Even if you think the question is open, the argument applies when you are unsure. If you cannot say whether a being is a person, you should hesitate before ending its life. A hunter who is not sure whether the rustle in the brush is a deer or a person does not fire.

I'll be fair about the strength of the opposing position. Many thoughtful people hold that moral status develops by degrees, and they do not reach Singer's conclusions. They say the earliest stages count for less and later stages for more. That is a serious position and it explains why many people feel differently about early and late abortion. The pro-life reply is that a sliding scale has the same line-drawing problem as the others: who picks the slope, and on what basis?

Attack on premise three: viability

The law for nearly fifty years leaned on viability, the point at which a child can survive outside the womb. In Roe v. Wade (1973) and again in Planned Parenthood v. Casey (1992), the state's power to protect prenatal life grew stronger once a child could survive on its own. For a long time that was the line of the law, and you will hear it from people who want a principled middle.

The objection to my side runs: viability is an objective marker, it is where the child can live independently of the mother, and so it is a reasonable point at which the state's interest becomes compelling.

The answer is that viability is a moving target and a strange moral line. I'm not making a medical claim here; I'm making a logical one. Viability depends on the technology available, so the same child could be viable in one place and not another, or in one decade and not the next. A moral status that goes up and down with the hospital equipment would be a strange kind of moral status. And a child who depends on a ventilator or a feeding tube is not thereby less of a person. A fundamental right should not depend on the state of the technology on the street where you live.

The honest concession is that viability has one advantage: it picks a point a court can administer. That is an argument about administration, not about the underlying worth of the child.

Attack on the overall argument: bodily autonomy

This is the objection that carries the most emotional weight, and it deserves a respectful answer. It does not deny that the child is a person. It says that even so, no one may be forced to use her body to keep another alive.

The classic version is Judith Jarvis Thomson's 1971 essay "A Defense of Abortion." Thomson asks you to imagine waking up in bed, connected to a famous unconscious violinist with a fatal kidney ailment. The Society of Music Lovers has kidnapped you because only you have the right blood type, and the violinist needs to use your kidneys for nine months. Thomson says that you would be morally allowed to unplug, even if it means he dies, because no one has the right to use another person's body without consent. She grants for the sake of argument that the violinist is a person. That is why the essay matters: it is the strongest argument for abortion rights that does not depend on denying the child's personhood.

I'll state it at full strength. The burdens of pregnancy are real, serious, and fall on one person's body. A law that restricts abortion asks a woman to bear those burdens, and the objection says that asks too much of anyone.

Here are the replies that pro-life philosophers have made.

1. The violinist is a stranger, and the child is not. Thomson's example involves a kidnapping, which is a situation where you had nothing to do with the connection. In most pregnancies the connection arose through an act the woman chose, and in any case the child is her own offspring. We recognize in many other areas that parents owe their children duties that strangers do not owe each other. Parents who do not choose to be in the child's life can be required to support the child. That duty does not depend on a signed contract.
2. Killing and letting die differ. The unplugging case involves withdrawing help. Critics say that an abortion does not merely withdraw support but acts directly to end the child's life. People differ on whether that distinction holds up in every case, and Thomson herself said that a right to detach is not automatically a right to ensure the death of what is detached. That is a notable concession within the pro-choice tradition.
3. The analogy fails at its edges. The violinist case is a kidnapping that nobody would defend. Most pregnancies are not like it, and the hard cases, such as rape, are a different problem that pro-life people debate among themselves and address differently in law.

I would add one more point. The autonomy argument is often stated as if the other side doesn't care about women. That is a caricature, and I reject it. A pro-life position that does not support the mother who faces a hard pregnancy, with help for housing, for medical care, and for the first years of a child's life, is half a position. If you want the argument about whether the movement does that, read 'Pro-life stops at birth' is the line to answer, so let's answer it, which takes it head on.

From premises to law

Even if all four premises are granted, the argument does not write a statute. Between "the law should protect the child" and "here is the text of the bill" lie a hundred decisions. At what stage? What exceptions? What penalties, and for whom? Should the law reach the woman, the provider, or neither? Should it be state or federal? Pro-life Americans disagree about these, openly and often. The IVF question, for instance, divides people who agree on the four premises; see The IVF question that splits pro-life conservatives, argued fairly.

Since Dobbs v. Jackson Women's Health Organization in June 2022, those decisions belong to voters and their legislatures. That is the right place for them, because the premises are things you persuade people of, not things you can impose by court order. The mechanics of why the law differs from state to state are in why abortion law differs from state to state, mechanism by mechanism, and the opinion itself is explained in What the Dobbs decision actually decided, step by step and in plain English. The money question, whether taxpayers should be made to pay, has its own history in The Hyde Amendment rider and the conscience laws that keep taxpayers out.

One more thing about persuasion. A movement that wants to win a democratic argument should expect to lose some rounds, and should handle the losses with grace. Calling opponents monsters guarantees that the persuadable stay unpersuaded. Many people who disagree with us are motivated by compassion for women in hard circumstances, and meeting that with contempt is both wrong and a terrible strategy. If you want ideas for conversations you will actually have, twelve pro-life dinner-table questions and honest answers is a good place to start.

How to test your own view

Here is an exercise that works whatever your position. Write down, in one sentence, what makes a human being worth protecting. Then check your sentence against four cases: a newborn, a person in a coma, a person with a severe disability, and a child just before birth. If your sentence protects the first three and excludes the fourth, ask what feature does the work, and whether it is a feature of the being or merely of where the being is. If your sentence excludes some of the first three, ask whether you really want to defend that. Either answer teaches you something, and it keeps the argument honest.

The bottom line

• The pro-life case is at bottom a claim about equality: human worth rests on what a person is, not on what a person can do. Argue it as that, and not as a slogan.
• The four premises are open to attack, and the strongest attacks come from personhood theory, viability and bodily autonomy. Know them by name, including Thomson's 1971 violinist.
• Pro-life Americans disagree on exceptions, penalties and IVF, so do not treat the movement as a single bill. Argue the premises first and the statute second.
• Treat people who disagree with fairness. The best way to make the case is to state their argument so well that they say, "that is what I think."
• If you want to act, start local: support the pregnancy centers, adoption and foster programs, and legislators in your own state who take both the child and the mother seriously.