The Tradition of Probabilism and the Moral Status of the Early Embryo

Abstract

WITHIN THE PAST few decades, a number of Catholic theologians have raised questions about the moral status of the human zygote and early embryo. Richard McCormick describes the embryo during the first two weeks as nascent human but does not consider it an individual human until later; Charles Curran concurs, stating that truly human comes into being two to three weeks after fertilization; Albert Di Ianni proposes that the bodily continuity of a human existence begins only several weeks after conception; and Karl Rahner asserts that during the first few weeks the existence of a human subject is seriously doubtful. Such speculations have arisen within the context of an authoritative Church teaching: the Catholic Church, in its official magisterium, asserts that human life must be given equal protection at all stages from fertilization through adulthood. In raising questions about this authoritative teaching, theologians rely on three types of material. They examine the history of Catholic teaching on prenatal life, a tradition which is somewhat less uniform than is often recognized. They investigate the implications of philosophical theories of human nature, especially the Thomistic anthropology which is traditional in the Church and believed to be most consistent with its doctrinal position. And they study the relevance of the biological facts uncovered by contemporary scientific research, some of which appear to raise problems for the Church's current position. Theologians have found good reasons for calling present Church teaching into question, and hence appear to be justified in their speculations.