The Logical Fallacy at the Heart of the Anti-Abortion Movement

Dustin Arand
5 min readSep 15, 2021

I grew up in the pro-life movement. I’m intimately familiar with the imagery and arguments of anti-abortion activists. A friend of mine who had been pro-choice his entire life recently asked me to explain how someone could be so vehemently anti-abortion, a worldview that struck him as so alien, and this is what I told him: it really comes down to two things. The first consists of exposure to grotesque imagery of late-term abortions. Pictures of baby body parts elicit disgust and frame supporters of abortion as barbarians, even if late-term abortions are actually extremely rare and almost always medically indicated due to complications with the pregnancy or severe fetal abnormalities.

The second is a simple logical syllogism, so seemingly airtight as to make anyone who doubts its truth appear stupid or dishonest. It goes like this:

Major Premise: All persons have a right to life.

minor premise: A fetus is a person.

Conclusion: A fetus has a right to life.

But as with the gory photographs, this argument succeeds through a form of deception. In this case the deception is what logicians call the fallacy of equivocation, when a key term in the argument is used ambiguously.

Take another look at the major premise, “all persons have a right to life.” This is a moral claim, and a relatively recent one to boot. For most of human history there was no general agreement that people had a right to life. But for the sake of argument let’s assume they do. Still, who, or what, counts as a “person”? That’s a key question, and it’s a hotly debated one.

Many people believe that apes and cetaceans ought to be accorded moral rights on the grounds that their high degree of intelligence, and social instincts that are uncannily similar to our own, make them every bit as deserving of moral consideration as we are. Many animal rights activists and vegans would go even further, arguing that any being capable of suffering should be afforded a right to life. If tomorrow a race of aliens came down to Earth, and could converse with us intelligibly on matters of religion, science, art, politics, etc., is there any doubt we would treat them as persons? And the HBO series Westworld makes a strong case that, if artificial intelligences looked and acted like us, we would have no reason not to accord them the same moral rights.

In my book Truth Evolves I posed the following thought experiment:

“Imagine all your ancestors lined up one behind the other (in the male or female line, it doesn’t matter). Now imagine you are sweeping over that line, watching as the physical appearance of the figures grows less and less like modern day humans and more and more like Homo erectus, Homo habilis, etc., all the way back to the australopithecines, about three million years ago. Which of your ancestors was the first ‘person’?”

If you are inclined to regard them all as persons, just keep the thought experiment going back as far as you need to until you reach some kind of organism that, in your estimation, has no claim on us to moral consideration. The point is that there is no one generation at which personhood suddenly appears. The accumulation of those traits that elicit our moral response occurs only gradually.

So the concept of a person, in its moral sense, is a fuzzy category in that it encompasses more than just homo sapiens. But it’s also fuzzy in the sense that we can conceive of it applying to some beings only to certain degrees. Plenty of meat eaters support animal cruelty laws and see in this no contradiction. The aliens and AIs I talked about in the last paragraph seemed like obvious instances of “persons,” but what if the ones we actually encountered or invented didn’t? What if, as seems more likely, they fell into a kind of gray area between something that elicited a moral response and something that didn’t? Might we be willing to accord to them some moral rights, but not others?

If the concept of “person” as it appears in the major premise is irrevocably blurry, its meaning in the minor premise is taken to be perfectly clear. Here, “person” refers to a human being. We know this because of the many lines of evidence pro-lifers use to support the assertion that a fetus is a person. The Catholic Church is perhaps the most consistent on this point. At the moment of conception, you have a fertilized embryo with twenty-three pairs of chromosomes carrying distinctly human DNA. But for those uneasy with the idea of banning all abortions, other physiological criteria can be used. “Heartbeat” bills like those just passed in Texas push the advent of personhood back a few weeks, but ultimately they also assume that the fetus’ personhood is a function of its ontological status as a human being, rather than its moral status as a person.

Some persons in the moral sense will also be persons in the ontological sense, and vice versa, but the two categories do not perfectly overlap. The failure to see this is what leads to the blind acceptance of the syllogism’s conclusion, and to the perennial inability of either side to see the reason why they are consistently talking past one another. Each side assumes the moral status of the fetus most convenient to its own aims, and fails to broach the question what that status ought to be, and why.

My own view is that when evaluating a candidate for moral consideration, we need to ask ourselves whether extending that consideration would make us more or less sensitive to the moral claims of those whose personhood we already accept. Does acceptance of abortion really lead to a “culture of death,” as I was always warned? If anything, the evidence we have seems to point in the opposite direction. Societies with relatively liberal abortion laws tend to be wealthier, with lower crime rates and more spending on social welfare. On the other hand, societies that ban abortion tend to have abysmal human rights records, particularly with respect to women’s rights.

Fetuses may indeed be persons in the ontological sense, but we should exercise caution before according them personhood in the moral sense. We have to understand the trade-offs this would entail. For my part, while I could envision moral personhood coming into flower at some later stage of the pregnancy, I cannot see how we could adopt, say, the position of the Catholic Church without doing unmitigated harm to the moral status of women and girls, and surely their claims to moral consideration deserve precedence.

Dustin Arand

Lawyer turned stay-at-home dad. I write about philosophy, culture, and law. Author of the book “Truth Evolves”. Top writer in History, Culture, and Politics.