Aquinas and the Presence of the Human Rational Soul in the Early Embryo

AQUINAS AND THE PRESENCE OF THE HUMAN RATIONAL SOUL IN THE EARLY EMBRYO STEPHEN J. HEANEY University of Saint Thomas Saint Paul, Minnesota FIRST IN RELATION to evolution and more recently in relation to abortion, there has been a recurrence of Thomas Aquinas's arguments for the thesis that the human rational soul is not present in the human body immediately upon conception. Since soul and body must be proportioned to each other, it is argued, a rational soul cannot be present until the human body is formed enough to support it, i.e., until there are organs in place through which the rational soul can begin to exercise its proper powers. The question of this paper is : Given modern embryological knowledge, would Aquinas be likely to come to the same conclusion ? In regards to such a question Rudolph Gerber has made the following observation: Some scholastic philosophers and theologians insist that it is simply impossible to determine exactly when rational animation occurs. This belief, however, has deterred few prophets in either camp from stating their positions with dogmatic certainty.1 The authors whose interpretations we will be encountering in this paper have generally been less than dogmatic, but they have been insistent on the rectitude of their respective positions. I will attempt to do likewise : I am in no position to be dogmatic (after all, how will we test the thesis?), but I believe I have good grounds for the conclusion I have reached. 1Rudolph Gerber, "When Is the Human Soul Infused?" Laval theologique et philosophique 22 (1966) : 235. 19 20 STEPHEN J. HEANEY We begin with certain positions which both sides in the debate agree upon : the human intellectual soul is produced immediately by God and not through another agency since, as immaterial, it cannot come from a change in matter; 2 further, the human soul is infused, that is, produced directly in a body as the body's natural perfection.8 As we shall see in the texts, Aquinas argues that this latter position requires that, while the embryo is alive, it is alive first through the power of a vegetative soul, then a sensitive soul, and finally, when the body is organized enough to be able to perform the functions demanded of it, by a rational soul, this ultimate form replacing the previous one. This theory of delayed animation--or, more to the point of this paper, the view that Aquinas would today still hold such a theory-has several contemporary proponents. The most prominent spokesman is Joseph Donceel, S.J. He has presented his arguments in a pair of articles' which we will now review. In the earlier article, Donceel blames a latent Cartesianism for the proliferation of supporters of immediate hominization. If you hold, with Descartes, that the soul and body are two separate substances, that the soul is not the form of the body, then there is " no longer any reason for rejecting the presence of a real human soul in a virtual human body," 5 i.e., in matter that has the potential to be a human body (with human shape) but is not one yet. Thus, the soul could act as the efficient cause of the body, molding the matter into the organs proper to human beings. This, however, is not Aquinas's view, Donceel argues; "he did not admit that an actual human sould could be coupled with a virtual human body," 6 because "a substantial form can exist only in and with a human body." 7 If we accept the Cartesian 2 S. Th. I, 90, 3, corp. s S. Th. I, 90, 4, corp. 'Joseph Donceel, S.J., "Abortion: Mediate v. Immediate Animation," Continuum 5 (1967): 167-71; "Immediate Animation and Delayed Hominization," Theological Studies 31 (1970) : 76-105. B Donceel, "Abortion," p. 169. e Ibid., p. 168. T Ibid. THE HUMAN SOUL IN THE EARLY EMBRYO 21 explanation, we would be equating the soul with the architect or builders of a building. These, however, are not the building's form; that exists only in the finished building. Rather, Donceel says that the soul is related to the body as sphericity to a ball. An embryo is like...