Not too long ago, the New York Times “Opinionator” blog ran a piece titled “Can Neuroscience Challenge Roe v. Wade?” by William Egginton, a professor of humanities at Johns Hopkins University. Egginton argues that scientific information has no place in the formulation of public policy on matters involving essential human rights. In such matters, he claims, science is irrelevant because rights “have nothing at all to do with the truths of science,” and therefore “should not be dependent on the changing opinions of science.”

Egginton’s piece responds to several states’ recent efforts to restrict abortion prior to viability based upon a fetus’s ability to experience pain. The author dismisses the possibility that a fetus is capable of “reflective” pain awareness and asserts that the “real purpose” of such statutes is “to use potential evidence of pain sentience in fetuses to indicate the presence of something far more compelling—namely, personhood.”

Egginton rejects this effort because neuroscience “has nothing to say about the fundamental question of what counts as a full-fledged person deserving of the rights afforded by a society.” Moreover, Egginton sees such incursions of science into issues of human rights as both inappropriate and dangerous, concluding ominously, “When science becomes the sole or even primary arbiter of such basic notions as personhood, it ceases to be mankind’s most useful servant and threatens, instead, to become its dictator.”

“Humanizing” Humans

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As a practicing research neuroscientist and bioethicist, I disagree with Egginton’s thesis on a number of grounds, most immediately with his odd contention that because a fetus is unlikely to experience pain in precisely the “reflective” manner of a mature human, fetal pain statutes are nothing more than a covert attempt to advance a particular view of personhood.

Imposing avoidable pain on any pain-capable organism is cruelty and most modern societies have enacted laws against cruelty, irrespective of the precise quality of pain involved. We do not need to know if a human fetus is self-reflective or even self-aware to afford it the same consideration we currently afford other pain-capable species. I am pretty confident, for example, that a chicken does not experience pain in the same manner I do, but I support legislation to ensure that poultry are killed in a pain-free, humane manner. Certainly a human fetus that is capable of experiencing pain in any manner deserves at least the same degree of consideration as a chicken that doesn’t even have the regions of the brain responsible for “higher” functions, such as consciousness and self-reflection.

Egginton is clearly concerned about the psychological impact of fetal pain legislation; that if society acknowledges a fetus is capable of experiencing pain in any capacity, the fetus will assume greater value in the minds of many, and therefore abortion may be subjected to more stringent regulation.

Yet concern that laws designed to avoid fetal pain will serve to “humanize” the fetus must be reconciled with a humane position on the prevention of cruelty. Simple fear that “anthropomorphizing” the fetus, to the same degree society currently anthropomorphizes pets and farm animals, might result in a restriction of the abortion license cannot justify the continued practice of cruelty. The knowledge that pets experience pain in some capacity prevents us from “euthanizing” them in the same manner that we currently destroy a fetus during an abortion. Does anyone really consider animal anti-cruelty laws an inappropriate restriction of the practice of animal euthanasia or an unwarranted intervention of science into public policy?

Fetal “Personhood”

Egginton dismisses what he sees as a disingenuous attempt to use neurobiological data to extend legal personhood to a fetus, because “science does not and should not have the power to absolve individuals and communities of the responsibility to choose.” Yet this argument clashes with historical fact. In the two landmark cases that have determined current abortion policy, Roe v. Wade and Planned Parenthood v. Casey, the courts used scientific knowledge to help determine the state’s interests in protecting the fetus after “viability.” If this knowledge has informed current policy, how can it legitimately be excluded as a basis for revising this policy in light of new scientific evidence?

Moreover, it is absurd to claim that states are using neurobiological information as a Trojan horse to extend legal rights to a fetus. Subterfuge isn’t necessary when a concept is already well-accepted in a large body of existing legislation and legal precedent. In virtually every area of law outside the restricted domain of abortion, the courts have both recognized and repeatedly upheld the rights of the fetus.

More than two-thirds of the states have statutes that define killing an unborn child in any context outside of abortion as criminal homicide, and despite numerous court challenges, none of these statutes has been struck down on any grounds. A majority of the states that allow capital punishment prohibit execution of a pregnant woman, in the interest of protecting the life of the innocent unborn child. Similarly, most states prohibit withholding or withdrawing life-sustaining medical treatment from a pregnant woman under the authority of an advance medical directive, in order to protect the rights of the fetus in such situations. Multiple areas of tort law recognize the rights of the fetus, with thirty states admitting fetuses as plaintiffs in cases of prenatal injury or wrongful death. Finally, property law also recognizes the rights of an unborn child to inheritance, and all states permit a guardian ad litem to be appointed to represent the legal interests of the unborn child in such situations.[ref]Paul Benjamin Linton, “The Legal Status of the Unborn Child Under State Law,” 6 U. St. Thomas J. Law & Pub. Pol. (2012)[/ref]

Clearly, in many areas of the law a fetus already is recognized as a legal individual (i.e., the holder of rights, equally protected under the law), independent of the “dictates” of neurobiology.

The Development of the Human Nervous System

Given the potentially significant social and legal impacts of fetal pain, it is important to consider what neuroscience has to say about fetal brain development and whether this information appropriately informs our concept of “personhood.” Consciousness and the kind of pain perception it enables are complex. And the development of this capacity is continuous from very early embryonic stages.

The earliest “rudiment” of the human nervous system forms by twenty-eight days after sperm-egg fusion. At this stage, the primitive brain is already “patterned,” that is, cells in different regions are specified to produce structures appropriate to their location in the nervous system as a whole. Over the next several weeks, the brain will grow enormously and generate many complex connections, but the overall organization of the nervous system is established by twenty-eight days. This is significant because it shows that even at this early stage, the brain is not anything like a mere collection of cells or a “blank slate” to be written upon by later developmental processes. Like all embryonic organs, the structure of the early brain “anticipates” the organization and function of the mature system.

In the region of the brain responsible for consciousness (the neocortex), the earliest neurons are generated during the fourth week.[ref]Tangential networks of precocious neurons and early axonal outgrowth in the embryonic human forebrain. Bystron I, Molnár Z, Otellin V, Blakemore C. J Neurosci. 2005 Mar 16;25(11):2781-92.; ApoER2 and VLDLR in the developing human telencephalon. Cheng L, Tian Z, Sun R, Wang Z, Shen J, Shan Z, Jin L, Lei L. Eur J Paediatr Neurol. 2011 Jul;15(4):361-7.; The first neurons of the human cerebral cortex. Bystron I, Rakic P, Molnár Z, Blakemore C. Nat Neurosci. 2006 Jul;9(7):880-6. Epub 2006 Jun 18.; Development of the human cerebral cortex: Boulder Committee revisited. Bystron I, Blakemore C, Rakic P. Nat Rev Neurosci. 2008 Feb;9(2):110-22.[/ref] The earliest connections between neurons are detected by 37 days and are well established by 8-10 weeks.[ref]Development of axonal pathways in the human fetal fronto-limbic brain: histochemical characterization and diffusion tensor imaging. Vasung L, Huang H, Jovanov-Milošević N, Pletikos M, Mori S, Kostović I. J Anat. 2010 Oct;217(4):400-17.; Insights from in vitro fetal magnetic resonance imaging of cerebral development. Kostovic I, Vasung L. Semin Perinatol. 2009 Aug;33(4):220-33.[/ref] This indicates that the brain is “wiring” itself in the first trimester, well before reaching the fetal stage of life. Early establishment of connections between neurons further indicates that brain formation is an active process of progressively building the structures and relationships required for mature brain function.

There is good evidence that communication between neurons of the brain is established in the seventh week. Synapses, or the molecular structures required for brain cells to communicate with each other, are detected in the cortex at this time.[ref]Synaptogenesis in layer I of the human cerebral cortex in the first half of gestation. Zecevic N. Cereb Cortex. 1998 Apr-May;8(3):245-52.[/ref] In animals, synapses are functional immediately and this is likely also true of humans. Thus, the earliest function of the neocortex as a network (not “consciousness” strictly speaking, but merely communication among large groups of cortical neurons) is likely to commence in the seventh week.

After this point, the communication between different regions of the brain becomes progressively more complex. The long-range connections within the cortex that are believed to be required for consciousness do not arise until much later, around twenty-two to twenty-four weeks of gestation.[ref]Functional maturation of neocortex: a base of viability. Gatti MG, Becucci E, Fargnoli F, Fagioli M, Ådén U, Buonocore G. J Matern Fetal Neonatal Med. 2012 Apr;25 Suppl 1:101-3; 3D global and regional patterns of human fetal subplate growth determined in utero. Corbett-Detig J, Habas PA, Scott JA, Kim K, Rajagopalan V, McQuillen PS, Barkovich AJ, Glenn OA, Studholme C. Brain Struct Funct. 2011 Jan;215(3-4):255-63. Epub 2010 Oct 29.[/ref] And these connections continue to develop for an exceptionally long time. Indeed, recent studies indicate that the anatomy of the human brain, and therefore the pattern of brain activity underlying all higher functions (reason, memory, emotion, language, etc.) is not fully mature until approximately twenty-five years after birth.[ref]Gogtay N et al. (2004) Dynamic mapping of human cortical development during childhood through early adulthood. Proc Natl Acad Sci USA 101(21):8174; Sowell ER et al (2003) Mapping cortical change across the human life span. Nat Neurosci 6(3):309.[/ref]

Consciousness and Personhood

Structures capable of new functions are formed throughout embryogenesis. For example, grasping becomes possible once hands have formed. But the fundamental process of development proceeds continuously, both prior to and after hand formation, and the onset of this function reflects an ongoing developmental process. Given the continuous nature of development, to argue that embryos and fetuses become humans once some anatomical or functional landmark such as “consciousness” has been achieved is to assert some kind of magical transformation; i.e., that at some ill-defined point, a non-human entity spontaneously transmogrifies into a human being, without any change whatsoever in its behavior, its molecular composition, or any other observable feature.

I reject this argument. For something actually to transform into a different kind of thing, a change must take place in its composition or in its pattern of biological activity. For example, sperm and egg are two specific human cell types that fuse to produce a distinct cell (the zygote) with unique molecular composition and with a pattern of organismal behavior that is distinct from the behavior of either sperm or egg. A clear, non-magical, scientifically observable transformation from one kind of entity (two human cells) to another kind of entity (a distinct human organism) has occurred.

Similarly, a living person transforms into a corpse at death, and this is also an observable event. Respiration stops. Heartbeat stops. Brain activity stops. Eventually, all metabolic processes stop and decomposition alters the molecular constitution of what was once a living person. The precise “moment” in time at which death occurs may be difficult to determine, but corpses are clearly distinguishable from living persons based on a large number of observable traits.

Yet in the logic of those who want to assign personhood based on consciousness, no difference whatsoever can be observed between those who possess “personhood” and those who do not. The entity has acquired a new function, based on the maturation of the underlying neuroanatomy, but the entity itself is not distinguishable from the “non-human” entity that preceded it. Such an arbitrary definition can hardly be the basis for determining who is the subject of “essential human rights.”

Building the complex architecture of the brain is a continuous process that is initiated at sperm-egg fusion and proceeds through orderly steps under the direction of a “builder,” that is, a human organism that is present from the beginning. The presence of an agent capable of constructing the mature body, including the brain, is the only sustainable definition of a human being. This agency should not be misconstrued as some kind of mystical or spiritual element that is merely attributed to an embryo or fetus based on personal or religious belief. The fact that the embryo acts as an agent is entirely a matter of empirical observation; embryos construct themselves.

As a scientist, I view the manifestation of this agency as a sequence of biochemical processes that proceeds in a manner characteristic of human embryos. Others may choose to see this agency in more spiritual or poetical terms, but such a viewpoint does not alter the scientific facts; embryos manifest a unique molecular composition and pattern of behavior characteristic of an organism, and this conclusively demonstrates a level of agency that is definitive of a human being.

To assert that a human being is only present once a specific anatomic landmark has been achieved is absurd. The argument is analogous to pointing at a construction site where the foundation has been dug but no concrete yet has been poured, and asserting, “Clearly there is no building company involved in this, because there isn’t yet a structure sufficient to be called a ‘building.’ We must wait until at least six stories have been completed.” This argument confuses the product of construction with the existence of an agent capable of doing the construction. If we must wait until a certain level of structure exists before we conclude a builder/contractor is present, how do we explain all of the many orderly events that occur prior to this point? Does the organized assembly of concrete, girders, glass, wire, pipes, and countless other components just happen spontaneously?

Analogously, does a collection of human cells just so happen to put together eyes, fingers, internal organs, and countless other structures in a coherent, integrated manner, and then wait for “consciousness” to breathe life into this amalgam of random parts? Clearly, this is an argument that cannot be rationally maintained in the face of factual evidence. 

Science and Public Policy

To conclude, we must return to Egginton’s initial assertion: that science should not, and indeed cannot, contribute to the formation of sound public policy on matters of human rights, because human rights are based on some undefined factor that is outside the realm of science. While I agree that the essential rights of humans are not determined by science, what constitutes an infringement of essential human rights and who, in actuality, is the holder of such rights, can and should be informed by scientific facts.

For example, in the past, lead-based paints were not considered a threat to human health. Once scientific studies provided evidence that children’s health could be harmed by accidental consumption of paint dust containing lead, legislation banning the manufacture and sale of lead-based paint was put in place to protect children’s health. Science did not “dictate” that protection of children’s health was required or desirable; this was already a component of our culture and our laws. But science legitimately determined what constitutes a threat to children’s health.

In a similar manner, science does not dictate that citizens have a right to equal protection under the law, but science establishes that individuals with different levels of skin pigmentation are all members of the species Homo sapiens. And this scientific understanding legitimately “dictates” that all such individuals are the subjects of this essential right. In the same way, science has clearly determined when human life commences, and this determination legitimately dictates that equal protection under the law must extend to human beings at embryonic and fetal stages of development.