Tuesday, August 26, 2008

The Problems of Functional Definitions for Personhood

An Introduction to Personhood

A myriad of ethical problems is contingent upon the definition or understanding of what constitutes a person. From an embryological or biological point of view, there is no doubt that human life begins at conception.(1) However, following the footsteps of John Locke, some ethicists make a distinction between a human being and a human person. (2) According to Locke, “person” and “human” are distinct categories. That is, not all humans are persons, and perhaps not all persons are human. Locke defined a person as, “A thinking intelligent being, that has reason and reflection, and can consider itself, the same thinking thing, in different times and places.” It seems that Locke is furnishing us with a functional definition of personhood, which describes a person as one who is capable of rationality and self-consciousness.

Similar functional definitions of personhood are likewise described by contemporary ethicists and moral philosophers. Some had argued that the early detection of fetal brain waves is the key to defining the beginning of personhood, which is positioned roughly at 40 to 43 days gestation. (3) Still others define a person as a being who can engage in cognitive acts such as sophisticated communication, consciousness, reasoning or the ability to solve complex problems, self-motivated activity, and having a self-concept plus self-awareness. (4) Apparently, this would place the unborn child outside the class of persons, and would even justify infanticide. L. W. Sumner, however, argues that the fetus is not a person until it is sentient and possesses the ability to feel and sense as a conscious being. This generally occurs during the middle of the second trimester of pregnancy, and undeniably by the end of that trimester. (5)

While the criteria for personhood varies from ethicist to ethicist, functional definitions for personhood share a common denominator: each definition states that if and only if an organism functions in a particular manner as defined by the criterion of personhood, we are otherwise not warranted to call that organism a person. In other words, unless the fetus (be it born or unborn) acquires a set of functions - be it sentience, consciousness or brain waves - it is not entitled to be called a person. These ethicists do not deny that fetuses or embryos are alive and are human beings, but they reject the claim that fetuses or embryos are persons according to some arbitrary criteria.Thus, fetuses and embryos are denied moral status.

Some Problems of Functional Definitions for Personhood

Let us arbitrarily take a personhood criterion for the purpose of our discussion here. For example, Mary Anne Warren defines a person as a being who can engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems or the ability to reason, self-motivated activity, and having a self-concept. (6)

In her essay, Warren does not argue that each of her five conditions is individually sufficient for personhood. (7) She thinks that some of them may be, and that the conjunction of these three - consciousness, reasoning, and self-motivated activity - is probably sufficient for personhood. In other words, it is probably true that if a being is conscious, able to reason, and engages in self-motivated activity, then that being is a person. The fulfillment of all three of these conditions is sufficient for being a person.

It must be noted that Warren does not maintain that any of her five conditions is individually necessary. (8) But she does insist that the disjunction of the five conditions is necessary; that is, a necessary condition for personhood is that something satisfy at least one of these five conditions. She argues that if none of these five conditions is true of something, then that being is not a person. This criterion is controversial at best, as we would discover below.

For the sake of our discussion, we would look at Warren’s criterion logically, albeit simplistically. Putting her criterion into a conditional statement, we have:

If A then B.

Where A = “A being can engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept,” and;

B = “It is a person.”

Therefore, according to Warren, if “a being can engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept,” then it is “a person” (also known as modus ponens). Here, we give Warren the benefit of doubt that her criterion in modus ponens is valid.

Perhaps Warren is saying that A is a sufficient condition for B. But this does not mean that A is a necessary condition for B. Although it is considered a given (for the sake of argument) that certain “cognitive acts” are sufficient to define a person, it does not follow that those “cognitive acts” are necessary conditions for personhood. Furthermore, they might be other criteria that suffice as conditions for personhood without even resorting to the identification of cognitive abilities.

In other words, “cognitive acts” might constitute a part of a set of conditions that are (jointly) sufficient without being individually necessary for personhood. In view of this distinction between sufficient and necessary conditions, “if not A, then not B” is a logical fallacy (called denying the antecedent). It does not mean that, if “a being cannot engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept,” then it is “not a person.” There might be another criterion that qualifies the being as a person even though it cannot perform cognitive acts. My Uncle Sam might be sleeping (or even comatose) and cannot, in that particular state, perform cognitive acts. It does not follow that he is consequently not a person.

This fallacy must be further differentiated from its valid counterpart, modus tollens:

“Not B, therefore not A,” i.e. it is “not a person,” therefore, it “cannot engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept” is valid logically. For example, the table is not a person, therefore, it “cannot engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept.”

Another common fallacy we encounter in bioethics debates is the converse error:

If A, then B.


Therefore A.

To put it within the context of Warren’s criterion for personhood, it is not true that:

“It is a person,” therefore, “it can engage in cognitive acts such as sophisticated communication, consciousness, solving complex problems, self-motivated activity and having a self-concept.”

As hinted before, my Uncle Sam (who is arguably a person) could have been hit on the head with a baseball bat by a vicious burglar, and for a period of two weeks lost consciousness and all cognitive abilities. Intuitively, he did not cease to be a person when he was comatose. Eventually, he woke up fully functional, and gleefully free from any cognitive disabilities. Intelligibly, we ought to think that Uncle Sam was the same Uncle Sam before and after the period of coma. If this is what we think, than we should assume that Uncle Sam continued to exist as a person even during his period of coma. If we deny this, then Uncle Sam would have ceased to exist as a person upon going into a coma, and a new person (who looked, sounded, felt, and smelt like Uncle Sam) had popped into existence upon his recovery. Obviously, the latter thesis is quite absurd. If Uncle Sam have existed prior to, during, and after his coma, then his personhood (and his existence as a person) is not dependent upon his ability to perform those cognitive abilities stated by Warren. But if one were to adhere to Warren’s criterion of personhood, then it would be difficult to see why it would be wrong for physicians to kill Uncle Sam while he is in a coma.

Now let us take this example a little further. Suppose we argue that Uncle Sam’s life is valuable because he functioned as a person prior to his coma, and he most probably will continue to do so after his recovery from his comatose state (c.f. a fetus who has never been cognitively-abled). But what if Uncle Sam wakes up from the coma with severe disabilities e.g. losing all his past memories, language skills, and rational thought? In this case, he might never recover his cognitive abilities, although it might be possible that he recovers them eventually. The point is: in his comatose state, Uncle Sam is like a fetus in his mother’s womb - devoid of any past memories and cognitive abilities as defined by Warren, while retaining a potential to develop these functions upon recovery. Would it then be justified to kill Uncle Sam?

Or suppose Uncle Sam had a his twin brother, Ham. Sam was born, attained full self-consciousness, but subsequently lapsed into a coma; he recovered ten years later. Ham, however, never attained self-consciousness; he lapsed into a coma, and recovered at the same time as Sam did. Using the functional definitions of personhood, Sam was a person before he became comatose, whereas Ham was not. Sam had at one time achieved personhood (according to functional definitions), but his twin brother did not. Would it then be permissible to kill Ham but not Sam while they were both in a comatose state?

Ontological and Logical Problems

The aforementioned examples only serve to emphasize the fact that functional definitions do not even begin to elucidate the depth and breadth of the sufficient and/or necessary conditions for personhood. They fail to capture the full meaning and true essence of a person who deserves moral status and protection from harm.

The problems with the methodology of using functional definitions for personhood are both ontological and logical in nature.

1) Ontological Problems

Intuitively, the functions of a human being do not make him a person; a human person does not come into existence simply because certain functions are being demonstrated or attained. Rather, he is a person, and therefore, he exhibits certain functions. More specifically, it seems correct to think that it is the being of a person (or him being a person), and not his or her functions, that confers moral status.

Every living organism or substance has a nature (essence) that enables the organism to attain certain functions or abilities in the future. It is the nature or essence of the human being that makes certain functions or abilities possible. According to Moreland, “A substance’s inner nature is its ordered structural unity of ultimate capacities. A substance cannot change in its ultimate capacities; that is, it cannot lose its ultimate nature and continue to exist.” (9) Take for example the tiger cub. Because of the tiger nature or essence present in the tiger cub, it has the capacity to develop the abilities of hunting and roaring. The baby tiger might die before full maturity, and might never acquire the ability to hunt or roar, but it is still a tiger. On the other hand, we do not say that a chipmunk lacks something if it cannot roar like the tiger, for the chipmunk nature in it does not anticipate the development of such an ability. Nevertheless a tiger that cannot roar, perhaps due to some laryngeal pathology, is still a tiger because of its nature or essence.

Likewise, we can envisage a human person who lacks much cognitive abilities. A paranoid schizophrenic called Adam Hitler might have lost all sense of reality. He lacks all sense of social inhibitions (like controlling his carnal urges), is not aware of self, is unable to communicate, is not able to make rational decisions or any form of reasoning, and is rambling unintelligibly day in and day out. He develops hyperpyrexia and goes to bed after taking some paracetamol - presumably fed to him by his cognitively-abled mother. This places him within the category of being “unconscious.” According to Warren’s criterion of personhood, Adam Hitler is not a person. Does that mean that he has no moral status, and is therefore not entitled to the rights of personhood? Would it then be justified for the mother to kill Adam Hitler, as he is not a person by definition, and would his mother be not guilty of homicide if she were to kill him? Intuitively, killing Adam - before, during or after the period of his high fever - is to be regarded as homicide. Adam deserves moral status, not because of his abilities or disabilities, but by virtue of his being.

Let us take this example a little further. What if there is a robot that qualifies for personhood according to some functional definitions? Perhaps passing the Turing Test would be considered a sufficient, though not a necessary, condition for “personhood.” If so, then it would be morally right to kill a comatose human or an Adam Hitler, while it would be morally wrong to destroy a robot which passes the test.

A human being deserves moral status; a human being has a human nature that allows him to have the “ultimate capacities” of a human person. You were once a zygote, then a fetus, then a neonate, then an infant, a toddler, a teenager, and eventually an adult. It is obvious that you have changed physically, mentally, and psychologically. But it is still you - whoever you are and whatever your identity - who have changed; you have remained you throughout all these years of development. If you have moral status now, yesterday, and the day before, it seems extremely arbitrary and unreasonable to say that the same you have no moral status as a fetus or as a zygote some years ago.

2) Logical Problems

Furthermore, those who deny moral status to certain human beings by saying that these humans do not qualify as persons according to some arbitrary criteria of personhood, however well argued, seem to be committing the fallacy of reification. In reality, the concept of personhood is an artificial category or idea in the mind, and it obviously does not have the metaphysical property of existence in nature. There is no single occasion in time where the fetus or conceptus becomes a person. Such a moment cannot be pinpointed or observed because the event does not literally happen. I would even argue that there seems to be no valid distinction between the terms “human being” and “human person,” and such a distinction is apparently arbitrary and unnecessary.

Finally, from our discussion thus far, functional definitions (and cognitive theories) do not justify the apparent distinction between a “human being” and a “human person.” Beauchamp has aptly perceived that, “Cognitive theories all fail to capture the depth of commitments embedded in using the language of "person." It is more assumed than demonstrated in these theories that nonhuman animals lack a relevant form of self-consciousness or its functional equivalent. Although nonhuman animals are not plausible candidates for moral personhood, humans too fail to qualify as moral persons if they lack one or more of the conditions of moral personhood. If moral personhood were the sole basis of moral rights, then these humans would lack rights - and precisely for the reasons that nonhuman animals would.” (10)


1. See my previous post.
2. John Locke, An Essay Concerning Human Understanding, ed. R. Woolhouse (Harmondsworth: Penguin Books, 1997), II. xxvii.
3. See Baruch Brody, Abortion and the Sanctity of Human Life: A Philosophical View (Cambridge, MA: MIT Press, 1975).
4. See Mary Anne Warren, "On the Moral and Legal Status of Abortion," in Do the Right Thing: A Philosophical Dialogue on the Moral and Social Issues of Our Time, ed. Francis J. Beckwith (Belmont, CA: Wadsworth, 1996), 171-175.
5. See L. W. Sumner, Abortion and Moral Theory (Princeton, NJ: Princeton University Press, 1981).
6. Warren, “On the Moral and Legal Status of Abortion,” 171-175.
7. Definition of sufficient: A condition A is said to be sufficient for a condition B, if (and only if) the truth (/existence /occurrence) [as the case may be] of A guarantees (or brings about) the truth (/existence /occurrence) of B.
8. Definition of necessary: A condition A is said to be necessary for a condition B, if (and only if) the falsity (/nonexistence /non-occurrence) [as the case may be] of A guarantees (or brings about) the falsity (/nonexistence /non-occurrence) of B.
9. J.P. Moreland, “Humanness, Personhood, and the Right to Die,” Faith and Philosophy 12.1 (1995): 101.
10. Tom L. Beauchamp, “The Failure of Theories of Personhood,” Kennedy Institute of Ethics Journal 9, Number 4 (December 1999): 309-324.

1 comment:

Joe Blackmon said...


Very insightful post. I think your point that some people want to put a human embryo outside the realm of personhood is dead on. Many blessings, brother.