There’s nothing new about arguing that not all human beings are persons with a right to life. What is new in these past weeks, though, is the proposal that we make killing some humans less troubling by renaming infanticide “after-birth abortion.” In their paper “After-birth abortion: why should the baby live?” Alberto Giubilini and Francesca Minerva argue that since fetuses and newborns share the same moral status, we should feel no more qualms about killing newborns (especially disabled newborns) than we would about killing unborn children. But since infanticide remains a queasy subject for most people, we should make it sound more acceptable by changing the words we use to describe it.

Giubilini and Minerva were rewarded for their article with death threats. In a response at The Chronicle of Higher Education, Peter Singer notes the irony of this reaction, then points out that many people who consider themselves pro-life “do not know how to argue against anyone who agrees with them that the fetus and newborn infant have the same moral status, but then denies that merely existing as an innocent living human being is enough to give a being a right to life.” Singer’s comment highlights the important difference between supporters and opponents of abortion: we might agree that newborns and fetuses have the same moral status, but we fundamentally disagree about what that status is. In other words, Singer, Giubilini, and Minerva bring us back to a critical question that we’ve been debating for years: Are fetuses and newborns persons with a right to life or not?

If we break down Giubilini and Minerva’s definition of personhood, we’ll see that it’s grounded by the following argument:

1)      If X is a person, then X has rational capacities.

Start your day with Public Discourse

Sign up and get our daily essays sent straight to your inbox.

2)      If X has rational capacities, then X can immediately think (thought includes self-awareness, making free choices, and forming and maintaining consciousness of one’s desires).

3)      Therefore, if a human being is a person, then it can immediately think.

In other words, humans are persons if they have rational capacities. But the only way we can be sure that they have rational capacities is if they can immediately exercise them. So since fetuses and newborns cannot immediately think, they are not persons.

On Giubilini and Minerva’s view, if Susan is a person, then she can assign value to her own life and make goals. A person, they write, is “an individual who is capable of attributing to her own existence some (at least) basic value such that being deprived of this existence represents a loss to her.” But how else can humans assign value to their lives unless they are both conscious and thinking? Accordingly, for Giubilini and Minerva fetuses and newborns are not persons because they have not yet reached “the point at which they will be able to make aims and appreciate their own life.”

If Giubilini and Minerva took the view that we can judge whether a human is rational, and therefore a person, based on the kind of being that a human is—a rational being—they could argue, as I will soon, that all humans are persons from conception because all humans are rational beings with a root capacity for thinking. But since they would judge Susan’s rationality only by whether she can immediately use her capacity for thought, they have to pick an arbitrary starting point for personhood.

Their position is arbitrary because Giubilini and Minerva clearly aren’t arguing that a human must always be thinking and valuing his or her life to be a person; otherwise when Susan falls asleep she is no longer a person. No, on their view, humans are persons with a right to life if they are harmed by the decision to deprive them of life. But in order to be harmed, humans must at least be “in the condition to value the different situation [they] would have found [themselves] in if [they] had not been harmed.” In other words, Susan must be able immediately to think about what her life would have been like had she not been harmed, but she needn’t always be thinking along those lines.

So Giubilini and Minerva must allow that persons have some distance between immediate thinking and remotely being able to think (as when we are asleep or have fainted temporarily). But how much distance can we allow before a human is not yet or is no longer a person? A sleeping Susan seems to have an acceptable distance, but what about Linda, a woman who has just suffered a brain aneurysm and is now both unconscious and on life support? It may be a month before she regains consciousness—do we wait until that point to say that she is again a person with a right to life? In the meantime, why give her treatment if she isn’t a person? Should I label a family friend with Down syndrome a non-person, or less of a person, since he can’t value his life to the same degree that I can value mine? Are our grandparents with Alzheimer’s still persons if they can’t speak or recognize us consistently?

There is no non-arbitrary way for Giubilini and Minerva to answer these questions—they have to pick which beings have the right distance between remote and immediate thinking. And they do; they tell us that “many non-human animals and mentally retarded human individuals are persons.” They justify their choice by telling us that the condition for personhood requires a certain “level of . . . mental development.” But at what point is this level achieved? Is it when the brain has reached its full maturity in a healthy adult? Is it when a child’s brain has reached semi-maturity? Can a two-year old immediately think? What about a fetus just prior to birth? Giubilini and Minerva avoid answering this question; instead they note that “it is hard to exactly determine when a subject starts or ceases to be a person.”

So, are we to settle for an arbitrary criterion for personhood like the one that Giubilini and Minerva give us? Or is there a better starting point that we can reasonably adopt?

Rather than make personhood a matter of arbitrary choice, we should say that all humans are persons from conception because all humans have a rational nature. To say that humans have rational natures is not to adopt some obscure, medieval view of humans, as some scholars would argue. No, this view’s reasonableness lies in the basic trajectory that every human life takes toward a state of mature rationality.

To say that my friend has a rational nature is simply to say that her status as an organism means that her bodily growth and development is organizing toward something. Just as I can know that her stomach, intestines, liver, pancreas, and gall bladder do not exist independently of each other, but rather function together as the digestive system for one purpose, digestion, I can also see that all her other bodily systems—her nervous system, muscular and skeletal systems, and reproductive system—do not exist as isolated sets of atoms, but instead function together for a larger purpose: her bodily good, which includes not only the preservation of her life, but also the form that her life takes—a series of desires, self-reflections, and choices in pursuit of certain ends (Giubilini and Minerva’s “aims”) that are not made by a brain or a set of organs, but by a unified rational agent—a person.

The most basic sign we have of our rational nature is this fact: from the time of an organism’s conception, its biological development is directed toward becoming a mature, healthy member of its species. Mature, healthy humans are rational creatures. So, from the time of a human embryo’s conception, its biological development (through the coding of genes, the multiplication of cells, the growth of organs, and so on) is directed toward becoming a mature rational being. In order to reach the stage of mature rationality, the development must progress unimpeded and certain basic environmental conditions must be met—no human infant can survive without care.

A genetic defect (or other cause of disability) blocks some humans from reaching the stage of mature rationality, but if these humans are alive, their bodily development is already directed toward mature rationality, whether by the human brain’s growth toward maturity (even though this growth may become stunted), or the development of other bodily organs that support the brain’s function (for example, the heart, or the kidneys, which help preserve the organism’s life). Even the presence of a low-functioning damaged brain, preserved by and functioning in (oftentimes imperfect) coordination with other bodily systems, reflects the natural target of normal human bodily development.

To say that all humans have rational natures affects how we understand rational capacities. Giubilini and Minerva would have us see rational capacities only as present if they can be exercised immediately. But since at every point of life a human’s rationality could not develop and be sustained without the body’s coordinated functioning, humans can be said to have a radical, or root, capacity for reason from conception until death. The extent to which a human exercises this capacity (through consciousness, thinking, free choices, and so on) decides the extent to which he or she reaches mature rationality. But the body’s self-directed development toward this stage is already a partial exercise of this capacity. This is true even of the infant with severe brain damage, who may never reach this stage because his body’s self-directed development toward it is limited by genetic defects.

To make the concept of a fetus’s or a newborn’s radical capacity for reason more compelling, consider the following argument: All humans have a radical capacity to speak fluent French. The steps required to speak fluent French vary with a person’s stage of life and level of exposure to French. A native French speaker can immediately exercise his capacity to speak fluent French. An English-speaking person may live in France, understand some French, and even speak a few French words, but cannot immediately exercise her capacity. To do so, she might need to take an intensive French class and practice conversations in Paris. An American high school student who has never heard or read a word of French beyond “bon appétit” or “bonjour” may need to take several years of classes, practice conversations in and outside the classroom, and participate in a student exchange program in order immediately to exercise his capacity. A young child of English-speaking parents whose school does not offer French classes may require a further step—the passage of time—before she can take the high school classes that will teach her to speak French fluently.

Let’s go all the way back to an unborn child. The fetus’s physical and neurological hardware may not be developed enough to exercise the capacity to learn a language. Yet with the passage of time, natural development, the presence of French-speaking parents or the help of French classes, and maybe a year abroad in France during college, the fetus can become able to speak French fluently. In the case of brain-damaged infants or humans with Alzheimer’s, these conditions entail further steps before the human could speak fluent French—the genetic defect would have to be removed, and the Alzheimer’s would have to be reversed. The point of these arguments is to suggest that if humans never lack the capacity to speak fluent French, then they never lack the capacity for reason, because the capacity to speak French is a rational capacity. To be able to exercise this capacity immediately does not mean that a human suddenly has a new capacity. Rather, the same root capacity is developed and exercised to different degrees during the human’s life. To argue that humans always have a root capacity for reason further shows us that humans are always rational creatures, even when they are fetuses and newborns.

Most importantly, a human’s rational nature and radical capacity for reason are points of equality with all other human beings, so all humans are equally persons. Contrary to Giubilini and Minerva’s view, fetuses and newborns are equally persons with us. In sum, we don’t have to accept the arbitrary criterion for personhood that these scholars give us; namely, that to be rational and a person a human must be able immediately to think (so he or she can give value to his or her life and make aims). Instead, we can reasonably argue that all humans are persons from conception because that point marks their beginning as rational organisms.