Peter Kreeft

Pro-Life Philosophy—Transcription

The text of the Pro-Life Philosophy audio lecture
Table of Contents Audio Reference
Introduction 00:00
A Review of Logic 00:00
An Argument's Role 00:39
An Argument's Rules 02:05
An Argument's Structure 03:16
An Argument's Criteria 03:56
The Pro-Life Argument 05:31
Premise One 07:06
Premise Two 09:58
Conclusion 15:01
Three Pro-Choice Arguments 19:44


Thank you. Does this work? Can everybody hear me? If not, raise your hands. (Whoever's absent, please raise your hand.)

A Review of Logic

A couple of preliminary rules. I'm a philosopher, I like to argue, so I'd like to say something about the role of argument in addressing an issue like abortion, and then something about the rules of argument, and then something about the structure of an argument, and then something about the criteria for evaluating an argument. Maybe a minute or so each, but without these preliminaries we're in the wrong ball field.

An Argument's Role

The purpose of arguing is not to win. Arguing is not a game. It's not, "I'm cleverer than you are." The purpose of argument is like the purpose of science: to know. It's a means, not the only means, of knowing, of transferring us from ignorance to knowledge, a way of getting out of that cave. Philosophy is, in some obvious ways, not like what we today call science, but in some other less than obvious ways, it's very similar to what we today call science.

The purpose of an argument is to know

First of all, it's about the real world. Not about ideas, concepts, ideologies; those are the poker chips but not the money that you play for. Secondly, philosophy, like science, tries to prove things. There are tests, there are criteria. It's not just exuding your personal opinions or dreams. Some of the proofs claim to be certain, some of them claim only to be probable. A probable proof is still a good one. And finally, like science, philosophy uses experiments, only the laboratory is mental, not physical. An argument is a thought experiment. A syllogism is something like mixing two chemicals in a laboratory and seeing what comes out. Mix two true propositions, click them together in your mind, and see what conclusion comes out. There are objective standards for being right and wrong.

An Argument's Rules

Something about the rules of argument. Arguing is absentmindedness; that is, you abstract from a whole list of other things, like x-rays. You don't look at the skin, you don't look at the nerve endings, you don't look at the patient's face, you don't look at the reactions, you just look at the bone structure. So, argument appeals to objective facts; it doesn't appeal to subjective feelings. It doesn't ignore them, it doesn't say they're worthless, it just abstracts from them. An argument wins not because the rhetoric sways the emotions of the audience, but because the facts line up. That's like science.

One particular rule of argument, about the pro-life/pro-choice debate, is, I think, that the onus of proof has to be on the pro-lifer. Just as, in our courts, a person is innocent 'til proved guilty, I think it's quite fair that an act is innocent 'til proved guilty. So, unless I can prove that abortion is wrong, the jury is out and it's okay. So, I accept that burden of proof. That's, I think, a fair rule of procedure.

An Argument's Structure

Something about the structure of arguments, especially moral arguments, arguments about good and evil. All moral arguments seem to have two parts, two premises. One of them is a value judgment, and the other is a fact. One is a principle, and one is a particular case. And then when you apply the principle to the case, you get the conclusion. X is wrong, this is a case of X, therefore this is wrong. Well, "X is wrong" is a value judgment; "this is a case of X" is simply an empirical fact. You can disagree with either of the two premises, but they're different.

An Argument's Criteria

Finally, the criteria of any argument; what makes an argument work, and what makes it not work. This is just basic common-sensical logic. Since an argument is composed of propositions—classic argument, a syllogism, has two premises: an assumption and a conclusion—and since a proposition is composed of two terms, a subject and a predicate term, there are three parts to the argument: the terms, the propositions, and the logic of the argument. So there's three things that can wrong with any argument. The terms can be ambiguous, the premises can be false, or the logic can be invalid. If none of those things goes wrong with the argument, then honesty and intelligence demand that you agree that the conclusion is true. So, there's five things you can say to anybody's argument.

  1. I agree with your conclusion. You have proved your case. You have no ambiguous terms, no false premises, and no invalid logic, therefore your conclusion is true. Or,
  2. I disagree with your conclusion because your logic is invalid, or
  3. I disagree with your conclusion because one of your premises isn't true, or
  4. Finally, I disagree with your conclusion because one of your terms is ambiguous.
  5. You cannot honestly say a fifth thing, but you can say a fifth thing, namely: Your premises are true, your terms are clear and unambiguous, and your logic is perfectly valid; nevertheless, I do not agree with your conclusion. You've proved it to be true, but I will not admit it. I am a willful, stubborn-headed, pig-headed fool. No one has said that, ever. I hope.

The Pro-Life Argument

There is one very simple argument that is the essence of the pro-life side. I hope that somebody tonight can refute this argument. I really do, because that would make it so much easier. That would relieve my worry, my conscience. That would make it not necessary anymore to make a big to-do of this. If somebody can prove to me that it's okay, then I'd sigh a relief. I haven't found it yet.

Here's the argument. The value premise comes first, then the factual premise, then the conclusion. There are various ways of wording the value premise. You could use some of the language in a very familiar document which begins, "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their creator with certain inalienable rights, that among these is the right to life and liberty." I'd prefer not to argue about rights. I have nothing against it, but it gets complicated. There's an easier way to do it.

There's a second way you could formulate the basic principle, and that's a little too easy. All murder is wrong; and then the minor premise would be abortion is murder, therefore abortion is wrong. That's too easy because murder doesn't mean just one thing. It means one thing legally, it means another thing morally.

Premise One

It is wrong to deliberately kill an innocent person

So, I prefer to word my first premise this way: It is always morally wrong to deliberately—that is, intentionally; that is, knowingly and willingly, one part—kill—that is, force death upon by an act of violence; not necessarily an omission, not necessarily letting die; that's different than killing—an innocent person. By innocent, I simply mean a person that does not deserve death, has done nothing to justify being killed. I put that in in order to abstract from the whole argument about capital punishment. I personally am morally ambiguous about capital punishment. I think I'm against it, but I'm not sure, so I don't want to argue on something that I don't feel totally confident about. But I do feel confident that it is always wrong to deliberately kill an innocent person.

What's a person? I'm a person, you're a person. Are all persons human persons? Are all humans persons? What's the relationship between persons and human beings?

Well, there's three possibilities.

  1. One is that all humans are persons and all persons are humans. There aren't any non-human persons, and there aren't any impersonal humans. That's a fairly common-sensical position.
  2. A second option is that there are human persons and there are also non-human persons. Martians, E.T., elves, angels, persons of the Trinity, the Greek gods. You can at least imagine non-human persons—most fantasy is about them—so it's a meaningful concept, whether you believe they exist or not.
  3. A third option is that the term person is not larger than the term human, but smaller. Some of us members of the human race, some human beings, are persons and some aren't. The Nazis believed that Jews were not persons. The Communists believed that Capitalists were not persons. The Supreme Court, according to the Dred Scott decision, believed that black slaves were three-fifths persons, not full persons. That's an option; if you want to argue for that, then you've got an out, because you don't quite agree with the first premise, or you think that the term "person" is ambiguous in the first premise, but in order to justify that you're going to have to make common cause with company that's a little compromised. But we might come back to that option.

All right, there's the first premise: Always morally wrong to deliberately kill an innocent person.

Premise Two

Second, the factual premise. An unborn human being, the product of human conception, is an innocent human person. And abortion is the deliberate killing of that person. What is an abortion? You can't argue about abortion unless you ask what it is. And if you say, "I don't know what anything is, I'm a skeptic," then you don't argue anything at all. You don't even know what an apple is.

Is a fetus a person? Well, is a teenager a person? Is an adult a person? These words—fetus, teenager, embryo, adult—are nouns that come from adjectives. Embryonic human: embryo. Fetal human: fetus. Infantile human: infant. Childish human: child. Teenaged human: human. These are stages of development. Of what? Of one entity. So what is that entity? Philosophically, it seems that that's the crucial issue, because most moralists would agree that the first premise is true. If deliberately killing an innocent person isn't wrong, what is wrong? So it seems that the strongest pro-life case would be to deny that abortion kills a person.

An unborn human being is an innocent human person

All right, when do you become a person? Is it a gradual process, or does it happen suddenly? It's got to be one or the other. Well, if it happens suddenly, at what point? Well, according to the law of the land, it's birth. When the doctor's scissors cuts the umbilical cord, you become a person. Scissors makes you a person. When you move from one room to another, you become a person. When you move from your mother's womb to the larger room called the world, that's when you become a person. So the external environment makes you a person.

Or maybe technology makes you a person. If you're viable—that is, if you can live outside the womb—that makes you a person. Well, viability depends on the technology available to keep you alive. In the jungle, you're not a person; in a hospital, you are. That doesn't make much sense.

So if it's not the scissors that makes you a person, what is it? Well, every biology textbook in the world, before Roe v. Wade, was not in doubt in answering the question, "When does an individual life of any mammalian species begin?" The answer is, "When the genetic code is complete." When instead of the haploid ovum and the haploid sperm, you get the diploid embryo. And at that point, something happens that is totally different, because the thing that's there seems totally different. Cells replicate immeasurably, and a pattern emerges, and gradually organs develop. Granted, there's nothing like a human brain in an embryo, but a human embryo grows a human brain, and an ape embryo grows an ape brain, and a bird embryo grows a bird brain. So that's a bird embryo, not an ape embryo. That's a human embryo, not an ape embryo, even though it doesn't yet have a brain and can't think.

Well, maybe this absolute dividing line of conception or fertilization is too simple. Maybe it's a gradual process. Maybe "person" is not either/or. Maybe you gradually become more of a person. All right, in that case it's not so bad to kill somebody who doesn't have all their systems in place, like a child whose reproductive systems are still immature, as it is to kill an adult. Does anybody seriously believe that it's not as bad to kill an eight-year-old as a eighteen-year-old? Of course not.

Well, the process of growth and development doesn't begin at birth, it begins at conception. And part of it takes place in the nine months in the womb, and then the rest of it takes place in the years after the womb. There is no point during that process where you see any absolute break.

I hesitate to argue this way because once I thought I won an argument and I really lost one, because often that happens. You win the argument, you lose the person. Sometimes you lose the argument but win the person. I was arguing with a very intelligent pro-choice feminist and I argued, "Give me one argument that defends abortion that doesn't also defend infanticide." And we argued for a while, and I felt it was going nowhere, but afterwards she came up to me and said, "You know, I didn't think you could do this, but you convinced me, you made me change my mind." I said, " Oh really? Congratulations, you've seen the logic." She said, "Yeah, now I'm for infanticide." So, sometimes logic is dangerous.


The conclusion of this argument is, of course, that if it's always wrong to deliberately kill an innocent person, and if abortion deliberately kills an innocent person, then abortion is always wrong. Always. Just as rape is always wrong. There's an addition to the argument, a third premise that you can add, that brings it into the social, political, and legal area. Some people will say, "There's nothing wrong with this argument, but I still don't want to legally force my views on people who don't agree with me. I'm personally opposed to abortion, but I wouldn't make it illegal."

An innocent person is killed

So, why do I also believe not only that it is immoral, but that it ought to be illegal? Not everything that's immoral ought to be illegal. The structure of legal reasoning has a moral premise, but then it has a legal premise. If a thing is not morally bad, we don't want to prohibit it by law. But some things are morally bad that we don't want to prohibit by law. Maybe smoking is morally bad, maybe it's irresponsible. I don't think there should be a law against smoking. Maybe not wearing a seatbelt is bad, irresponsible. I don't know whether it's a good idea or not, but I'm sympathetic to those that say there shouldn't be a law about seatbelts. I don't think smoking marijuana's a good idea, but I'm not sure whether illegalizing it is a good idea or not; maybe so, maybe not.

So, you have to add a legal premise to the moral premise, to get a conclusion that this thing that is morally ought also to be legally prohibited. All right, so what's the purpose of law? Law is to protect people. If law doesn't do that minimal job, it's not doing anything. Law has to at least protect the innocent and weak against the guilty and strong. Nobody seriously maintains that there shouldn't be laws against theft, rape, or slavery, because those are clearly cases of misusing human beings, oppression. Well, the legal premise that can be added to this argument is that the law must protect the rights of the innocent and weak against the powerful and strong. Well, if abortion is killing a person, and if that person is innocent and weak, shouldn't he be protected?

I used to call myself a liberal, back in the days of the Civil Rights Movement, because I was on the side of the poor, the oppressed. Blacks and women and the poor, and they had to be liberated. They had equal rights, they were the little guy. I still feel that way, very strongly. And that's precisely the reason why now I vote—and now I'm going to say an obscenity I suppose at Wellesley —Republican. There are a lot of things I don't like about Republicans, but at least they don't justify this slaughter. I think I'm against capital punishment too, and I agree with the liberals there. I tend to be very suspicious of conservatives because they don't show a sensitivity to conserving things like the environment. But those issues pale in significance if abortion is what I just described, if it is the legalized murder of a million of our children every year. So, that's a judgment call.

Why be "personally opposed" if it is not murder?

"I'm personally opposed, but I wouldn't want to make it illegal." That sounds a little bit like Pontius Pilate: "I'm personally opposed to crucifying innocent people, but on the other hand, I wash my hands of responsibility here." That's almost like saying, "I'm personally opposed to slavery, but I'm pro-choice. If you want to have slaves, go ahead." I want to ask one of these politicians, "Why are you personally opposed to abortion? Is it because you believe that abortion is the deliberate killing of an innocent person. If not, why are you personally opposed to abortion? It's just, it's yucky? Like you're personally opposed to yogurt?" If abortion doesn't kill a human life, I agree with the pro-choicers: it is an intolerable oppression of women's freedom and women's bodies to tell them what to do. If that's their body and not somebody else's body, you have no right to tell them what to do. But if it's somebody else's body, they have no right to kill that other person.

Three Pro-Choice Arguments

Well, there's three kinds of pro-choice arguments. I can get out of this syllogism of mine. What are the three premises? There's a.) the moral premise, there's b.) the factual premise, and there's c.) the legal premise. You can deny any one of the three premises and these are the main three escape clauses.

Well, suppose you say, "Yeah, it's a good case, but who knows? You're dogmatizing. Just because you've got a good argument there doesn't mean that somebody won't refute you someday." You're right. You're right, we don't know. Let's be humble, let's be skeptical, let's be like Socrates. He's wise that he knows how little he knows. So now give me an argument from the skeptical point of view.

If you're not sure, don't shoot

There's two possibilities. Either we know what this argument claims, or we don't. Let's assume that the crucial argument is the factual. Let's assume that maybe you know that a fetus is a person with rights and shouldn't be killed, and maybe you don't. That's the Supreme Court's argument in Roe v. Wade: "We do not know when human life begins." Human life is a vague term, by the way. Life. Did you ever see life? What color is life? What size is life? The human person, on the other hand, is concrete. I don't think it's wrong to take life, I think it's wrong to take life from a person who has it. When does a person begin? That's the crucial question.

Well, there's two possibilities: a.) maybe you know that and b.) maybe you don't.
And then there's two possibilities. a.) You are right or b.) you are wrong.

  1. So, number one: the fetus is a person, and you know it. You're right.
  2. Number two: the fetus is not a person and you know that. You're right.
  3. Number three: the fetus is a person and you don't know that. You think it's not. You're wrong.
  4. Number four: the fetus is not a person and you think it is. You don't know the truth. You're wrong. (Like a Pascal's wager, two chances of being right, two chances of being wrong.)

What is abortion in each of these cases? The only four possible cases, logically.

So, if you can give me some argument that the fourth case is true—not just that a fetus is not a human person, but also you know that it is not a human person, then fine. You're right. But if you don't know, if you're a skeptic, if you say "These pro-lifers are dogmatists, they claim the fetus is a person. Who knows?" Well, that's all the more reason for not shooting. Exactly because you don't know.

I'm not going to end with anything rhetorical, I'm just going to end there. That's the argument.

For a compassionate guide to today's most controversial issue, see:
Three Approaches to AbortionExternal link (opens new window)

For a dramatic debate on the issues surrounding abortion, see:
The Unaborted Socrates
External link (opens new window)