Jason T. Eberl

Aquinas's Account of Human Embryogenesis and Recent Interpretations

In addressing bioethical issues at the beginning of human life, such as abortion, in vitro fertilization, and embryonic stem cell research, one primary concern regards establishing when a developing human embryo or fetus can be considered a person. Thomas Aquinas argues that an embryo or fetus is not a human person until its body is informed by a rational soul. Aquinass explicit account of human embryogenesis has been generally rejected by contemporary scholars due to its dependence upon medieval biological data, which has been far surpassed by current scientific research. A number of scholars, however, have attempted to combine Aquinass basic metaphysical account of human nature with current embryological data to develop a contemporary Thomistic account of a human persons beginning. In this article, I discuss two recent interpretations in which it is argued that a human person does not begin to exist until a fetus has developed a functioning cerebral cortex.

Metaphysical and Ethical Perspectives on Creating Animal-Human Chimeras

This paper addresses several questions related to the nature, production, and use of animal-human (a-h) chimeras. At the heart of the issue is whether certain types of a-h chimeras should be brought into existence, and, if they are, how we should treat such creatures. In our current research environment, we recognize a dichotomy between research involving nonhuman animal subjects and research involving human subjects, and the classification of a research protocol into one of these categories will trigger different ethical standards as to the moral permissibility of the research in question. Are a-h chimeras entitled to the more restrictive and protective ethical standards applied to human research subjects? We elucidate an Aristotelian-Thomistic metaphysical framework in which to argue how such chimeras ought to be defined ontologically. We then examine when the creation of, and experimentation upon, certain types of a-h chimeras may be morally permissible.

Brain Life and the Argument from Potential: Affirming the Ontological Status of Human Embryos and Fetuses

The moral status of human embryos and fetuses is one of the most vexed questions in bioethics and various responses often stand or fall on the answer to the question of the ontological status of such entities: whether they count as “persons,” “potential persons,” or merely “human biological material.” The “argument from potential” is intended to support the claim that embryos and fetuses, while not yet persons, are more than mere biological material insofar as there is a high degree of probability that they will develop into persons. A stronger foundation for contending that embryos and fetuses bear the same basic right to life as persons is to establish that such entities are not potential, but actual persons due to their intrinsic potentiality to develop themselves into beings who can engage in those activities definitive of personhood. In addition to critiquing the argument from potential, those who deny that embryos and early-term fetuses count as persons charge that those who understand “whole-brain death” to be necessary and sufficient for a human person to go out of existence inconsistently deny a symmetrical criterion of “brain life” to mark the beginning of a person’s existence. We respond to this charge of inconsistency while further arguing that embryos and fetuses possess the ontological and moral status of persons due to their intrinsic potentiality to develop a brain supportive of self-conscious rational thought.

A Thomistic appraisal of human enhancement technologies

Debate concerning human enhancement often revolves around the question of whether there is a common “nature” that all human beings share and which is unwarrantedly violated by enhancing one’s capabilities beyond the “species-typical” norm. I explicate Thomas Aquinas’s influential theory of human nature, noting certain key traits commonly shared among human beings that define each as a “person” who possesses inviolable moral status. Understanding the specific qualities that define the nature of human persons, which includes self-conscious awareness, capacity for intellective thought, and volitional autonomy, informs the ethical assessment of various forms of enhancement. Some forms of cognitive and physical enhancement may be desirable from the perspective of what constitutes the “flourishing” of human persons in our fundamental nature; while other forms of enhancement, such as emotive or so-called “moral” enhancement, run the risk of detracting from human flourishing when evaluated from the virtue-theoretic perspective Aquinas promotes.

Exercising restraint in the creation of animal-human chimeras.

Autumn Fiester’s proposed “Presumption of Restraint” (PR) has much to recommend it as an applicable moral principle to guide the moral evaluation of various forms of biotechnological research. It seeks the “golden mean” between allowing unethical research to go forward unchecked and prohibiting potentially beneficial research to which only prima facie ethical concerns apply that may be absolved on further analysis. One form of research to which PR is applicable is the creation of animal–human (a/h) chimeras. Broadly speaking, the term chimera refers to a biological entity composed of genetic material from members of two distinct species. Although it is important to note that there is a technical distinction between a chimera and a hybrid, most legal and ethical discussions use these terms interchangeably (Ballard, in press). An embryonic a/h chimera results from grafting stem cells—pluripotent cells that have the capability of developing into specialized cells and tissues—from one species with an early embryo of another species, or, in the case of a hybrid, by implanting the nucleus of a human somatic cell into an enucleated animal ovum. There are several potential uses of a/h chimeras—using this term to refer to a/h hybrids as well—that may justify their creation (Prabhune 2000; NRC/IOM 2005). First, a fullterm a/h chimera—one that is implanted and allowed to develop beyond the embryonic and fetal stages—could serve as a source of transplantable organs. Second, full-term a/h chimeras can be used as novel research models with the potential to offer great insight into the study of cellular maturation and migration, as well as oncogenesis. Third, a/h chimeras may serve as an alternative source for human embryonic stem cells (hESCs). Because the harvesting of hESCs from a chimeric embryo may not involve the destruction of a human embryo, but rather that of an animal embryo which contains hESCs, the ethical quandaries surrounding the use of human embryos to derive hESCs would be circumvented. Despite these and other positive reasons supporting research with a/h chimeras going forward, there are several potential ethical barriers that justify the application of PR. At the forefront is the concern that a/h chimeras may cross the species boundary between “human” and “non-human.”

The Complex Nature of Jewish and Catholic Bioethics

Ari Zivotofsky and Alan Jotkowitz (2009) provide a welcome comparison of the bioethical views of the Roman Catholic Church and Orthodox Judaism on issues at the beginning of human life prompted by a new instruction issued by the Vatican’s Congregation for the Doctrine of the Faith [CDF], Dignitas personae [DP]. The CDF, in fact, encourages such interreligious dialogue, as well as engagement with secular bioethicists, when it states that it is addressing not only the “Catholic faithful” but also “all who seek the truth” (CDF 2008 §3). Zivotofsky and Jotkowitz’s (2009) presentation of the Church’s perspective is oversimplified, however, by neglecting the philosophical and theological foundations for various conclusions of DP. This can be partly attributed to the structure of DP itself, which, as an “instruction” issued by the CDF, does not seek to argue so much as to present the Church’s ethical judgment on the issues at hand. Nevertheless, the various conclusions presented in DP were not reached in an academic vacuum, as noted in DP §2, and there is a wealth of scholarship representing supportive arguments from both Catholic and non-Catholic bioethicists for DP’s pronouncements that may be more amenable to discussion in the public square. In this brief commentary, I will highlight a key example of how the authors do not adequately represent the Church’s viewpoint, as well as call attention to an apparent inconsistency in how they construe the respective rational foundations for the Catholic and Jewish perspectives. Zivotofsky and Jotkowitz (2009) allege that the CDF, in DP §5, considers it “obvious” that a human zygote is a person possessing full moral status as a conclusion from the “natural moral law.” The CDF’s view, thus represented, can immediately be called into question by the fact that Judaism “gives the zygote very little legal status and even the more developed fetus is not yet considered fully human”(Zivotofsky and Jotkowitz 2009, 26). This rendering of the CDF’s conclusion, however, does not take note of the fact that it is based on ontological and ethical conclusions already arrived at from a systematically formulated Aristotelian–Thomistic view of human nature. According to this philosophical perspective, a being’s moral status is re-

The Moral Status of ‘Unborn Children’ Without Rights

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A Thomistic defense of whole-brain death

Michel Accad critiques the currently accepted whole-brain criterion for determining the death of a human being from a Thomistic metaphysical perspective and, in so doing, raises objections to a particular argument defending the whole-brain criterion by Patrick Lee and Germain Grisez. In this paper, I will respond to Accads critique of the whole-brain criterion and defend its continued validity as a criterion for determining when a human beings death has occurred in accord with Thomistic metaphysical principles. I will, however, join Accad in criticizing Lee and Grisezs proposed defense of the whole-brain criterion as potentially leading to erroneous conclusions regarding the determination of human death. Lay summary Catholic physicians and bioethicists currently debate the legally accepted clinical standard for determining when a human being has died—known as the “wholebrain criterion”—which has also been morally affirmed by the Magisterium. This paper responds to physician Michel Accads critique of the whole-brain criterion based upon St. Thomas Aquinass metaphysical account of human nature as a union of a rational soul and a material body. I defend the whole-brain criterion from the same Thomistic philosophical perspective, while agreeing with Accads objection to an alternative Thomistic defense of whole-brain death by philosophers Patrick Lee and Germain Grisez.

Metaphysical and Moral Status of Cryopreserved Embryos

Those who oppose human embryonic stem cell research argue for a clear position on the metaphysical and moral status of human embryos. This position does not differ whether the embryo is present inside its mothers reproductive tract or in a cryopreservation tank. It is worth examining, however, whether an embryo in “suspended animation” has the same status as one actively developing in utero. I will explore this question from the perspective of Thomas Aquinass metaphysical account of human nature. I conclude that a cryopreserved human embryo counts, both metaphysically and morally, as a person; and thus the utilization of such embryos for inherently destructive research purposes is impermissible.

Fetuses Are Neither Violinists nor Violators

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