In the Summa Theologica, St. Thomas Aquinas warned his fellow Christians, “For when anyone in the endeavor to prove the faith brings forward reasons which are not cogent, he falls under the ridicule of the unbelievers: since they suppose that we stand upon such reasons, and that we believe on such grounds.” This is true of moral and political arguments just as much as theological and philosophical ones.

For those of us who believe in the sanctity of human life and seek to persuade those with whom we disagree, it is essential that the reasons we give actually support our position. Unfortunately, some well-meaning pro-life advocates present arguments that are emotionally moving but shift the focus away from the essence of the sanctity of life ethic: it is always, everywhere, morally wrong to intentionally kill an innocent human person. A shift away from that focus not only gives our critics a mistaken impression about the strength of our position, but also misleads them as to what we actually believe about the nature of unborn human life.

What follows are descriptions of some of these bad pro-life arguments—and explanations of why pro-lifers shouldn’t make them.

The Argument from Killing Beethoven.

There are variations on this argument. They are usually in the form of a dialogue, such as this one, quoted by Garrett Hardin:

Two physicians are talking shop. “Doctor,” says one, “I’d like your professional opinion. The question is, should the pregnancy have been terminated or not? The father was syphilitic. The mother was tuberculous. They had already had four children: the first was blind, the second died, the third was deaf and dumb, and the fourth was tuberculous. The woman was pregnant for the fifth time. As the attending physician, what would you have done?” “I would have terminated the pregnancy.” “Then you would have murdered Beethoven.”

Imagine, however, all the facts about Beethoven’s parents, siblings, and family life were also true of Adolf Hitler’s. Could not a pro-choice advocate then end the dialogue this way?: “As the attending physician, what would you have done?” “I would have terminated the pregnancy.” “Congratulations, you just saved the lives of six million Jews.”

For those who defend the sanctity of life, the wrongness of intentionally killing an innocent human person does not depend on whether or not he or she will become a world class composer or a moral monster. Fetus-Ludwig and Fetus-Adolf are equally human and equally innocent, just as an anonymous homeless person, an asylum-seeking immigrant, and Jeff Bezos each possess the same inviolable right to life. The dignity of each member of the human family is not affected by what we may think he or she is capable of contributing, whether to the country’s gross domestic product or to the world’s cultural riches.

That’s why the Beethoven argument is superfluous at best and misleading at worst.

The Argument from Gruesome Abortion Procedures

Because the aim of an abortion is to terminate pregnancy in a way that ensures that the fetus dies, the woman is not harmed, and all the fetal parts are evacuated from her womb, abortion procedures involve the intentional dismemberment, poisoning, crushing, and/or stabbing of a living human fetus. For this reason, films like The Silent Scream and photographs of aborted fetuses are sometimes effectively used by pro-life groups in their public presentations. Priests for Life, for example, publishes these words on its website above a gallery of pictures that includes aborted fetuses: “The abortion images below show some of the grim reality of abortion. Only seeing such images of abortion can bring us to the kind of indignation needed to sustain the sacrifices that will be necessary to finally bring an end to this injustice.”

But how, precisely, does this show that abortion is gravely wrong? After all, if one believes, as most pro-choice advocates do, that any being’s moral status depends on its having a certain level of conscious existence and self-awareness, and a fetus during most of its gestation has not achieved that level, then virtually no abortions are unjust, regardless of how gruesome the photos of their aftermath may appear. Moreover, there are many events and activities that have been photographed that some would find gruesome, though they are not gravely wrong, such as President John F. Kennedy’s autopsy, the bullet-riddled bodies of Nazi soldiers, the gutting of a deer, or the open-heart surgery of an elderly patient.

On the other hand, suppose that a new technology allows a physician to instantly dematerialize the fetus like a Star Trek phaser set on kill. Because this new technology is cheap, efficient, and safe for the pregnant woman, no more gruesome abortions are performed. But if you think that abortion is gravely wrong, would this absence of gruesomeness make any difference to that moral judgment? Would it make the fetus any less a member of the human community?

It may be that the post-abortion images are being used by pro-life supporters to rebut the claim by some pro-choice advocates that the fetus is merely a “clump of cells” or is not yet an individual human organism. But virtually all sophisticated pro-choice thinkers do not claim any such thing. They recognize the fetus’s humanity, but they deny that it has moral status. They argue, as I noted above, that because the fetus lacks certain presently exercisable powers, e.g., a certain level of conscious existence and self-awareness, it lacks moral status. This distinction has been defended in differing ways by some notable academics, including Ronald Dworkin, Michael Tooley, and Peter Singer, none of whom denies the fetus’s humanity.

Of course, many of us have critiqued this position, arguing that the moral status of the fetus does not depend on what it does, but rather on what it is. For if human ability (or achievement) is the sine qua non of an individual’s right to life, then it is difficult to explain why we shouldn’t abandon the idea of human equality, since all our abilities come in degrees at every stage of human development. As the pro-choice philosopher Jeff McMahan writes: “It is hard to avoid the sense that our egalitarian commitments rest on distressingly insecure foundations” if “the properties on which our moral status appears to supervene are all matters of degree.” Nevertheless, one has to make the argument. Gruesome pictures by themselves won’t do.

The Argument from Abortion Regret and Emotional Pain

Beginning in the late 1990s, certain segments of the pro-life movement started shifting the focus of their opposition to abortion from the wrongness of taking innocent human life to the emotional and psychic injuries that they claim women suffer as a consequence of procuring an abortion. There is, of course, nothing untoward in drawing people’s attention to collateral harms that may flow from elective abortion. But even a pro-choice advocate could concede that point without ever acquiescing to the pro-life view of unborn human life.

Emotional and psychic injuries, by themselves, cannot establish the moral quality of the act that one believes caused them. Suppose you enlist in the Army and are sent off to fight in a just war. While in combat, you kill five enemy combatants, and you know you are morally justified in doing so. Nevertheless, when you return home, you begin to regret your enlistment, since you now suffer from depression, post-traumatic stress syndrome, and anxiety. Your therapist attributes these mental struggles directly to the violence in which you engaged while in combat, even though you know that the war and the killing were both just.

On the other hand, one’s actions do not become right or good just because one has no regrets about them or emotional pain resulting from them. If a sexual predator shows no remorse for his actions, and in fact thinks of his “successes” as romantic conquests that affirm his self-worth, no one would say that his actions are therefore morally just.

By overemphasizing stories of abortion regret, the pro-life advocate sets himself up for the obvious counternarratives by his pro-choice critics. They can simply collect and publicize their own stories of women who either do not regret having an abortion or are pleased that they went through with the procedure, which is precisely what has happened.

Advocates of the sanctity of life must take concrete actions to care for the well-being of both mother and child. But to tightly tether the pro-life cause to the vicissitudes of the social sciences—implying that the wrongness of abortion depends in some way, however modest, on the bad psychological effects of procuring one—teaches the wrong lesson.

A Kernel of Truth Is Not Enough

In each of these bad pro-life arguments, there is a kernel of truth. The killing Beethoven argument appeals to our deep intuition that a human being’s intrinsic worth does not depend on the condition of her parents or the circumstances of her birth, but it fails to acknowledge that her worth doesn’t depend on the prospects of her future either. The argument from gruesome abortion procedures shows us that the unborn child is a human being, but it cannot by itself show us that abortion is the unjust killing of an innocent human person. The argument from abortion regret and emotional pain may tell us that some women who choose abortion suffer psychological injury, but such consequences cannot tell us whether or not abortion is morally wrong.

Because these arguments have a kernel of truth in them, they may very well serve as a catalyst for deeper reflection that leads one to truly see the unborn child as one of us. For that reason, they are not entirely bad. Nevertheless, pro-lifers should remember that these arguments by themselves cannot establish the veracity of our position and principles, no matter how rhetorically powerful they may seem.