This volume focuses on Thomas Aquinas’ metaphysical account of human embryogenesis. Fabrizio Amerini seeks to provide a textual reconstruction of Aquinas’ account in comparison to alternative interpretations formulated in light of current scientific understanding. Amerini argues that, despite the flawed biology Aquinas inherits, the metaphysical principles he applies to the question of how a human being comes into existence remain sound. He further argues that the contemporary biological understanding of conception, along with embryonic and fetal development, does not alter Aquinas’ conclusion that a human being does not come into existence until the necessary organs develop to have the capacity for rational thought. Amerini thus disagrees with other Thomistic interpreters who argue that a human being comes into existence once sperm and ovum genetically fuse at conception. Nevertheless, he notes that Aquinas condemns early-term abortion as intrinsically immoral, even if it does not count judicially as “homicide,” for even though an early-term embryo or fetus is not yet a human being, it is the numerically same subject that will progress through a series of substantial changes from a vegetative life-form into a sentient animal and finally into a rational human person.
Amerini also discusses how death should be defined for human beings. He addresses the case of human beings who fall into a “persistent vegetative state” and are considered by some interpreters of Aquinas as having ceased to exist as a person prior to the end of their existence as a biological organism. Amerini argues against this interpretation and contends that the end of a human person's existence is coextensive with his or her death as an organism.
This volume presents a valuable contribution to the debate concerning when a human being first comes into existence and later dies. These metaphysical questions inform responses to further ethical questions regarding the moral permissibility of abortion, embryonic stem cell research, certain forms of assisted reproductive technology, cloning, the creation of animal-human chimeras, the treatment of irreversibly comatose patients, organ donation, and other bioethical issues. Amerini engages the entire Thomistic corpus, drawing on writings that represent the span of Aquinas’ intellectual life, and noting the contextual and historical development of his thought. He also advances a provocative interpretation that, while similar in conclusion to that of other contemporary Thomistic scholars, challenges alternative interpretations in an exacting textually based and philosophically nuanced manner.
For Thomistic scholars and Catholic bioethicists, this volume offers a significant advance in the interpretive debates surrounding a foundational and perennially influential thinker. Although the topics at hand have already been subject to extensive discussion over the past fifty or so years, a thorough textual analysis has been lacking, and this book fills that lacuna. Furthermore, Amerini's argument provides a well-founded challenge to standard contemporary interpretations and thereby offers an original and thought-provoking contribution to the field.
The volume lacks, however, any direct engagement with contemporary non-Thomistic philosophers, theologians, or bioethicists who argue for alternative views of the metaphysics of human embryogenesis. Thus, Amerini's work will be more relevant to those interested in understanding Aquinas’ thought on these subjects, rather than those who critically engage the Thomistic view from an alternative theoretical perspective. Additionally, while Amerini draws broad conclusions regarding the moral permissibility of some actions, such as abortion, a full-fledged moral analysis would necessitate importing Aquinas’ natural law ethic into the discussion, but that would require a whole other volume.
More critically, Amerini's conclusions are not sufficiently contemporized by offering a more careful, in-depth consideration of how current biological understanding of embryological and fetal development delineates the ontological boundaries that mark the substantial changes from vegetative to animal to human life. The reader is left with the impression that not only Aquinas, but also Amerini, believes that approximately forty days gestation is when a human being first comes into existence (236). This seems to be too soon, given Amerini's overall analysis, as neural development has a long way to go before the capacity to engage in rational thought may be reasonably inferred to be present. Also, although the functional role of DNA is discussed at a few points throughout the text, a more thorough analysis of the impact of the genetic identity of an embryo on its metaphysical nature would be helpful, because this is the primary basis on which Thomists who disagree with the author's conclusion argue for hominization at conception. These critical points aside, Amerini has done a tremendous service to the scholarly community with his detailed textual analysis of the development of Aquinas’ thought on matters of importance to both Thomists and non-Thomists alike.
