Thérèse Wang
The question of “when does the human person begin to exist” is one of the most important issues in the Church’s teachings on bioethics. Aristotle first proposed the doctrine of delayed hominization, arguing that the embryo initially possesses a vegetative soul and a sensitive soul but, since its external limbs have not yet formed, it lacks a human form and, consequently, a human soul—that is, a rational soul. According to Aristotle, the male embryo attains full human existence after forty days, while the female embryo requires ninety days. Building on Aristotle’s embryology and philosophical framework, Thomas Aquinas shifted the focus of the question “when does a human being begin to exist” from the physical formation of the body to the moment of “the infusion of the soul.” He emphasized the instant when “God creates and infuses the soul into the human body,” thereby establishing the concept of “delayed ensoulment.” Influenced by this theological system, the Church’s initial stance on abortion applied only to “formed” embryos. Consequently, the stage from the zygote to the early embryo faced a crisis regarding which ethical and moral standards should be applied. In its document Donum Vitae: Instruction on Respect for Human Life in its Origin and on the Dignity of Procreation, the Congregation for the Doctrine of the Faith suggests that “from the moment of conception, the human person is to be respected and treated as a person.” However, the phrase “treated as a person” implies that Church authorities have not fully resolved the dilemma of when ensoulment occurs, a dilemma arising from the “delayed process of adultization.” If we return to the Genesis account of how God created human being “in the beginning” and the Israelites’ understanding of the concept of human “existence,” might this help us move beyond the Greek philosophical notion of human being as a composite of body and soul? Could it allow us to define human existence in terms of the relationship between human being and God at the very beginning of His creation? At the same time, can the different perspectives on “human being” offered by Greek philosophical thought and Hebrew culture help in understanding and defining the “personhood” of human being?
