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Four Steps to Determining the Morality of Abortion (6 of 8)

The alternative to life beginning at conception due to a human soul being present is a “functional” definition of personhood. This is the view underlying all pro-choice arguments. If this definition of life is correct, the pro-choice conclusion is completely reasonable. Yet there are at least five problems with the functionalist definition of personhood.


The View Defined

This alternative view identifies a specific function of the fetus as what constitutes its personhood. When the fetus exhibits this function, it becomes a human person. Prior to that it is not.

There is some debate among functionalists concerning which function is the essential to make a fetus a person. Some argue for implantation (the moment the embryo implants on the wall of the mother’s uterus). Others argue for the existence of brainwaves. Others argue it is sentience (the ability to experience sensations, including pain), which confers personhood.

In addition to these and other options, the most popular functional definition of a person is viability—the ability to live outside a mother’s womb. This has become the dominant view since the Supreme Court’s Roe v. Wade decision, in which viability was defined as the essential function determining when life began, and thus when abortion was no longer morally acceptable. This definition also grounded the Supreme Court’s Planned Parenthood v. Casey decision.

This understanding reverberates throughout much of the conversation to this day. For instance, in responses to the Washington Post article “Roe Isn’t Just About Women’s Rights. It’s About Everyone’s Personal Liberty,” those defending the morality of abortion offered arguments such as:

Since a fetus has not been born, a fetus is not a person with rights.

Abortion ends the development of a fetus. It doesn’t end a life. It ends the potential for a fetus to develop further [to the point of viability].

Hey Bob, can you babysit my 4 year old, 18 month old, and fetus next weekend? I can drop them off whenever it’s convenient.

Though many in our culture have come to identify life with viability that does not make it the correct view. Popular vote does not determine truth. As Socrates says, “The unexamined life is not worth living.” I’d add, “the unexamined belief is not worth believing.” So are there good reasons to believe life should be defined functionally, or good reasons to reject this view?


Evaluating Functionalism

A Position In Need Of A Rationale

The fundamental argument given for a functional definition of life is that the essentialist view can’t be right. Therefore the functional definition is the only option left standing. Interestingly this response is never (to my knowledge) argued. It is simply assumed to be correct (undoubtedly due to the influence of physicalism and it’s view of knowledge—scientism, as discussed last week.)

However, for it to be a viable position (no pun intended), an argument must be given in support. There are good reasons to take an essentialist view of the person (as I argued in prior articles in this series). Therefore the burden of proof is on the functionalist to show how the essentialist arguments fail, and offer better arguments in their place. I invite functionalists to offer such arguments and show how these arguments are superior. Until then the essentialist definition of life is the most rational position to adopt (again, no pun attended).


Four Additional Problems

The Functions Are Not Necessary

The essentialist definition identified logically necessary and sufficient conditions for personhood–a feature which all humans and only humans have (a human soul present). What functionalism offers fails on both these counts–the functions are neither necessary nor sufficient to define personhood.

 Functioning in a certain way does not appear to be necessary to be a person. In other words, one can be a person without exhibiting these functions. A person can have a certain capacity to function in a certain way, though not yet be able to express this capacity at a given time. However, this does not mean the person does not possess this capacity. The functionalist view confuses what a person is with what a person does. I have written more about this last week in my discussion of first-order and higher-order capacities.


The Functions Are Not Sufficient

Nor is a functional definition of a human person a sufficient definition. In other words, things can possess these functions and still not be human persons. All types of animals go through a similar gestational process and become viable at a certain point. Yet when they become viable they do not become a human person (the same applies to implantation, brain activity, etc.). This indicates viability, or other functions, are not sufficient to identify that which makes one a human person.


There Turn Out To Be Very Few Persons!

If personhood is defined functionally, why choose implantation, viability, or any other gestational function as the preferred function to define personhood? It would be equally rational to define personhood by the expression of functions such as the ability to interact with the environment in meaningful ways, or enter into sustained relationships with other persons, or to be rational, to act autonomously, to have self-conscience, and so on.

In these cases one would be morally justified in terminating a born “fetus” until two or three years of age! Lest you think this is an extreme example, hear the word of Peter Singer, a leading ethicist at Princeton University and the University of Melbourne, who embraces a functional definition of personhood:

we often use “person” as if it meant the same as “human being.” In recent discussions in bioethics, however, person” is now often used to mean a being with certain characteristics, such as rationality and self-awareness . . .

. . .the fact that a being is a human being, in the sense of a member of the species Homo sapiens, is not relevant to the wrongness of killing it; it is, rather, characteristics like rationality, autonomy, and self-consciousness that make a difference. Infants lack these characteristics. Killing them, therefore, cannot be equated with killing normal human beings, or any other self-conscious beings. (Peter Singer, Rethinking Life and Death: The Collapse of our Traditional Ethics, New York: St. Martin’s Press, 1994, p. 180, and Practical Ethics, 2nd ed. Cambridge: Cambridge University Press, 1993, p. 182, emphasis added).

It gets worse. If we define personhood in functional terms, then why not define those with more functions as having greater personhood (and therefore greater value)? There is no reason not to do so on a functionalist definition of personhood.

No one is fully functional for most of their life. We continually develop functional capacities–from the moment of conception, through the point of birth, through our infancy, childhood, adolescence, and young adulthood. Not until sometime in our late 20s or early 30s are we able to fully express our functional capacities. Therefore, according the functionalist view, none of us are persons until this point in our lives!

Soon after that point we begin to experience a diminishing of our capacities (as they say, “it’s all downhill from there”)—we begin to slowly lose functional capacities the rest of our lives. It follows that if we define personhood in terms of a certain function or functions, we are no longer persons when we cannot (fully) express those functions, and therefore no longer persons or of value. 

For those born with physical or mental deficiencies, they will never develop the full functions of others. Therefore they will never become full persons, or have full (if any) value, on this view.

These are all logical implications of a functional definition of personhood. And they are clearly wrong. Infants, the mentally or physically disabled, and all past their 20s are as fully persons as vibrant, healthy 20-somethings. Some of a baby’s capacities have yet to be expressed in the womb, but that’s true of all us, either because we are still developing the ability to express these functions, or can no longer express them due to age. The inability to function in those ways does not make us less persons. Nor does the baby in utero who is not able to express these functions yet make him or her less of a person.

If a view entails obviously absurd conclusions, this is a clear reason to believe the view is wrong (logically this is known as a reduction ad absurdum argument—if taking a position to its logical conclusion ends in absurdity, we should reject the view). The functionalist view leads to these conclusions. Therefore this is a good reason to reject the view.


The “If In Doubt” Principle

Some time back two friends were hunting together in Michigan. One went into the bush to relieve himself. After some time the other saw movement in another area of brush. He was pretty sure his friend was behind him, so he assumed it was a deer and fired his rifle. He killed his friend. He was tried and convicted of homicide, on the basis that if the movement might have been a person, he should have treated the movement as a person.

This is a reasonable conclusion, and therefore a justified conviction. However, the same reasoning should apply to possible life in utero. Even if unsure whether the fetus is a person, if it is possible it is a person, treat it as a person and do not “shoot” (do not do anything that may cause harm).



There seem to be no good reasons to embrace a functionalist definition of personhood, and at least four additional reasons to reject this view. Therefore the essentialist view of personhood discussed in prior articles is the most reasonable position to take.

This has significant implications for not only the morality of abortion, but many other issues in bio-medical ethics. In my next article I’ll discuss some of these implications.

Until then, grace and peace.


For further reading I suggest Body & Soul: Human Nature & the Crisis in Ethics by J.P. Moreland and Scott B. Rae.

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