「人的位格何時開始存在」是教會內生物倫理領域內最重要的問題。亞里士多德首先提出「延緩的成人化過程」學說：胚胎具有生魂與覺魂，然而其外部肢體尚未形成，因而不具有人的形體，也未有人的靈魂，即理性靈魂。男性胚胎需要等待四十天後才能完整存在，女性則需九十天。多瑪斯建基於亞里士多德的古代胚胎學與哲學思想，將「人何時開始存在」關注點由「身體成形」轉移至「靈魂傾注」的時刻，他更注重「天主創造並傾注靈魂於人身」的時刻，由此建立「延遲賦予靈魂」的思想。在這種神哲學體系的影響下，教會最初有關墮胎的判斷僅適用於「已成形」的胚胎上。那麼，從接合子（現代語俗稱「受精卵」）到早期胚胎的階段則面臨著具有何種倫理道德標準的危機。信理部在《生命的恩賜：有關尊重生命肇始與生殖尊嚴的指示》中提出「人類從受孕的那一刻起就應受到尊重，並應得到如74同一個位格般應有的待遇」 ，然而「如同一個位格」的表述又顯示出教會當局仍未擺脫「延緩的成人化過程」所衍生出有關何時「賦予靈魂」的困境。倘若我們回到《創世紀》「在起初」天主如何創造人以及以色列人對人類「存有」概念的理解，是否有助於幫助我們走出希臘哲學以身體和靈魂的結合體定義人的概念，從而以受造之初人便與天主建立關係的角度來定義人的存在？與此同時，希臘哲學思想與希伯來文化提供給我們對於「人」不同視角的解讀，是否也有助於理解和定義「人的位格」？

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?