Does It Matter Whether We Know If a Fetus Is a Person or Not? Peter Kreeft’s Logical Analysis of Abortion Rights

I’ve long appreciated Justin Taylor’s great blog Between Two Worlds. A while ago he shared a helpful summary of Peter Kreeft’s logical analysis of the prochoice position that “we don’t know whether an unborn child is a person or not.”

It’s a good reminder that it’s not the prolife position, but the prochoice position that relies on emotionalism more than truth and logic. When we apply logic to abortion advocates’ arguments and claims, we can see how they break down. What we’re left with is the obvious truth that abortion kills a living person.

Here's Justin's summary:

The logic of the landmark abortion ruling Roe v. Wade was that ignorance about when human life begins entails that the government not impose restrictions upon abortion practice.

If you go back to August 16, 2008, Rick Warren asked presidential candidate Barack Obama when a fetus gets human rights, and Mr. Obama (who opposes any abortion restrictions for any reason, in line with Roe v. Wade) famously responded that the answer was “above his pay grade.”

Peter KreeftPhilosopher Peter Kreeft of Boston College helps us think through the logic of this position.

He makes the commonsensical point of formal logic that “either we do or do not know what a fetus is,” explaining:

Either there is “out there,” in objective fact, independent of our minds, a human life, or there is not; and either there is knowledge in our minds of this objective fact, or there is not.

The first set is an ontological claim (what is or is not); the second set is an epistemological claim (what we know or do not know). The result yields four logical possibilities:

  1. The fetus is a person, and we know that.
  2. The fetus is a person, but we don’t know that.
  3. The fetus isn’t a person, but we don’t know that.
  4. The fetus isn’t a person, and we know that.

Peter Kreeft diagram

What are the implications for these four positions? Kreeft analyzes them as follows:

Abortion in Scenario #1: The Fetus Is a Person and I Know That

In Case 1, where the fetus is a person and you know that, abortion is murder.

First-degree murder, in fact. You deliberately kill an innocent human being.

Abortion in Scenario #2: The Fetus Is a Person and I Do Not Know That

In Case 2, where the fetus is a person and you don’t know that, abortion is manslaughter.

It’s like driving over a man-shaped overcoat in the street at night or shooting toxic chemicals into a building that you’re not sure is fully evacuated. You’re not sure there is a person there, but you’re not sure there isn’t either, and it just so happens that there is a person there, and you kill him. You cannot plead ignorance. True, you didn’t know there was a person there, but you didn’t know there wasn’t either, so your act was literally the height of irresponsibility. This is the act Roe allowed.

Abortion in Scenario #3: The Fetus Is Not a Person and I Do Not Know That

In Case 3, the fetus isn’t a person, but you don’t know that. So abortion is just as irresponsible as it is in the previous case.

You ran over the overcoat or fumigated the building without knowing that there were no persons there. You were lucky; there weren’t. But you didn’t care; you didn’t take care; you were just as irresponsible. You cannot legally be charged with manslaughter, since no man was slaughtered, but you can and should be charged with criminal negligence.

Abortion in Scenario #4: The Fetus Is Not a Person and I Know That

Only in Case 4 [you know that the fetus is not a person] is abortion a reasonable, permissible, and responsible choice.

But note: What makes Case 4 permissible is not merely the fact that the fetus is not a person but also your knowledge that it is not, your overcoming of skepticism. So skepticism counts not for abortion but against it. Only if you are not a skeptic, only if you are a dogmatist, only if you are certain that there is no person in the fetus, no man in the coat, or no person in the building, may you abort, drive, or fumigate.

Peter Kreeft diagram

Browse more prolife articles and resources, as well as see Randy's books Pro-Choice or Pro-Life: Examining 15 Pro-Choice ClaimsWhy ProLife? and ProLife Answers to ProChoice Arguments.

Photo by Pavel Danilyuk

Randy Alcorn (@randyalcorn) is the author of over sixty books and the founder and director of Eternal Perspective Ministries