This declaration expressly leaves aside the question of the moment when the spiritual soul is infused. There is not a unanimous tradition on this point and authors are as yet in disagreement. For some it dates from the first instant; for others it could not at least precede nidation [implantation in the uterus]
. It is not within the competence of science to decide between these views, because the existence of an immortal soul is not a question in its field. It is a philosophical problem from which our moral affirmation remains independent
.
…We must recognize that it is God’s business as to precisely when He ensouls embryos. We do not need an answer to this fascinating and speculative theological question, like counting angels on the head of a pin, in order to grasp the fundamental truth that human embryos are inviolable and deserving of unconditional respect at every stage of their existence. Rather, this moral affirmation follows directly on the heels of the scientific data regarding early human development, which affirms that every person on the face of the planet is, so to speak, an “overgrown embryo”. Hence, it is not necessary to know exactly when God ensouls the embryo, because, as I sometimes point out in half-jest, even if it were true that an embryo did not receive her soul until she graduated from law school, that would not make it OK to kill her by forcibly extracting tissues or organs prior to graduation.
…What a human embryo actually is, even at its earliest and most undeveloped stage, already makes it the
only kind of entity capable of receiving the gift of an immortal soul from the hand of God. No other animal or plant embryo can receive this gift; indeed, no other entity in the universe can receive this gift. Hence, the early human embryo is never merely biological tissue, like a group of liver cells in a petri dish; at a minimum, such an embryo, with all its internal structure and directionality, represents the privileged sanctuary of one meant to develop as a human person.
…Some scientists and philosophers will attempt to argue that if an early embryo might not yet have received its immortal soul from God, it must be OK to destroy that embryo for research since he or she would not yet be a person. But it would actually be the reverse; that is to say,
it would be more immoral to destroy an embryo that had not yet received an immortal soul than to destroy an ensouled embryo. Why? Because the immortal soul is the principle by which that person could come to an eternal destiny with God in heaven, so the one who destroyed the embryo, in this scenario, would preclude that young human from ever receiving an immortal soul (or becoming a person) and making his or her way to God. This would be the gravest of evils, as the stem cell researcher would forcibly derail the entire eternal design of God over that unique and unrepeatable person, via an action that would be, in some sense, worse than murder. The human person, then, even in his or her most incipient form as an embryonic human being, must always be safeguarded in an absolute and unconditional way, and speculation about the timing of personhood cannot alter this fundamental truth.
