One of Thomas Aquinas’s primary philosophical concerns is to provide an account of the nature of a human soul. He bases his account on Aristotle’s De anima, wherein Aristotle gives an account of “soul” (psuchē) as divided into three distinct types: vegetative, sensitive, and intellective. Aristotle defines an intellective soul as proper to human beings and the only type of soul that may potentially exist separated from a material body. Aquinas argues that an intellective soul is indeed separable from its (...) body and conceives of it as essentially, or unqualifiedly (simpliciter), immortal and separable from its body, and relatively (secundum quid) mortal and conjoined to its body. Pietro Pomponazzi (1462-1525), a Renaissance philosopher concerned with ridding neo-Aristotelianism of Platonic or Averroistic influences, criticizes Aquinas’s account as not being properly Aristotelian and having been influenced by Platonism. In this paper, I will present summaries of Aquinas’s arguments concerning an intellective soul’s essential immortality, as well as Pomponazzi’s criticisms of Aquinas’s position. I then propose ways in which Aquinas may respond to these criticisms. (shrink)

Although there is a significant number of books and essays in which Aquinas's thought is examined in some detail, there are still many aspects of his writings that remain unknown to those outside the field of Thomistic studies; or which are generally misunderstood. An example is Aquinas's account of the origins of individual human life. This is the subject of a chapter in a recent book by Robert Pasnau on Thomas Aquinas on Human Nature (Cambridge: CUP, 2001). Since there will (...) be readers whose only knowledge of the issues in question will come from Pasnau's account, and since that account is contentious in substance, and advanced in advocacy of a particular moral interest, it is necessary to provide another, and, we believe, more credible account of the issue of when human life begins, as this may be determined on the basis of known empirical facts and Aquinas's metaphysics, and a more accurate representation of how (and how extensively) this matter has been treated hitherto. The morality of abortion turns on two important sets of issues: the first metaphysical, concerning the beginnings of human life and the specific status of the embryo; the second, ethical, having to do with the nature and scope of value and associated moral requirements. Besides engaging in exegesis we address both issues in philosophical terms. (shrink)

The phenomenon of twinning in early fetal development has become a popular source for doubt regarding the ascription of moral status to early embryos. In this paper, the possible moral basis for such a line of reasoning is critically analysed with sceptical results. Three different versions of the argument from twinning are considered, all of which are found to rest on confusions between the actual division of embryos involed in twinning and the property of early embryos to be divisible, be (...) based on highly questionable ethical assumptions, or to imply inconsistent claims regarding the moral importance of potentiality and/or the moral status of embryos. This is taken to expose a number of related inconsistencies in the moral basis of pro-life positions. In particular, ascribing moral significance to the property of being (in)divisible is found to be incompatible with the claim that human individuals possess unique values which could underpin an absolute moral ban on murder. (shrink)

From fertilization to approximately the sixteenth day of development, human embryonic cells are said to have the capacities of totipotency and monozygotic twinning, both of which are problematic to a theory of ensoulment at fertilization. In this article I will address the problems which these capacities pose to such a theory and present an interpretation of the biological data which renders ensoulment at fertilization more plausible. I will then argue that not only is an ensoulment theory consistent with current biological (...) data on the human embryo, but it may offer an explanation for the phenomencon of monozygotic twinning. (shrink)

‘When did I, a human person, begin to exist?’ In developing an answer to this question, I utilize a Thomistic framework, which holds that the human person is a composite of a biological organism and an intellective soul. Eric Olson and Norman Ford both argue that the beginning of an individual human biological organism occurs at the moment when implantation of the zygote in the uterus occurs and the ‘primitive streak’ begins to form. Prior to this point, there does not (...) exist an individual human organism, but a cluster of biological cells which has the potential to split and develop as one or more separate human organisms (identical twinning). Ensoulment (the instantiation of a human intellective soul in biological matter) does not occur until the point of implantation. This conception of the beginning of human personhood has moral implications concerning the status of pre‐implantation biological cell clusters. A new understanding of the beginning of human personhood entails a new understanding of the morality of certain medical procedures which have a direct affect on these cell clusters which contain human DNA. Such procedures discussed in this article are embryonic stem cell research, in vitro fertilization, procured abortion, and the use of abortifacient contraceptives. (shrink)

In addressing bioethical issues at the beginning of human life, such as abortion, in vitro fertilization, and embryonic stem cell research, one primary concern regards establishing when a developing human embryo or fetus can be considered a person. Thomas Aquinas argues that an embryo or fetus is not a human person until its body is informed by a rational soul. Aquinas's explicit account of human embryogenesis has been generally rejected by contemporary scholars due to its dependence upon medieval biological data, (...) which has been far surpassed by current scientific research. A number of scholars, however, have attempted to combine Aquinas's basic metaphysical account of human nature with current embryological data to develop a contemporary Thomistic account of a human person's beginning. In this article, I discuss two recent interpretations in which it is argued that a human person does not begin to exist until a fetus has developed a functioning cerebral cortex. (shrink)

ABSTRACT In a paper published in Bioethics, Jason Eberl has argued that early embryos are not persons and should not be granted the status possessed by them.1 Eberl bases this position upon the following claims: (1) The early embryo has a passive potentiality for development into a person. (2) The early embryo has not established both ‘unique genetic identity’ and ‘ongoing ontological identity’, which are necessary conditions for ensoulment. (3) The early embryo has a low probability of developing into a (...) more developed embryo. This paper examines these claims. I argue against (1) that a plausible view is that the early embryo has an active potentiality to grow into a more developed embryo. Against (2), I argue that neither ‘unique genetic identity’ nor ‘ongoing ontological identity’ are necessary conditions for ensoulment, and that ‘ongoing ontological identity’ is established between early embryos and more developed embryos. Against (3), I argue that the fact that the early embryo has a low probability of developing into a more developed embryo, if true, does not warrant the conclusion that the early embryo is not a person. If Eberl is right that the human soul is that which organises the activities of a human being and that ensouled humans are persons, embryos are persons from conception. (shrink)

One strategy for arguing that it should be legally permissible to create human embryos, or to use of spare human embryos, for scientific research purposes involves the claim that such embryos cannot be persons because they are not human individuals while twinning may yet take place. Being a human individual is considered to be by most people a necessary condition for being a human person. I argue first that such an argument against the personhood of embryos must be rationally conclusive (...) if their destruction in public places such as laboratories is to be countenanced. I base this argument on a popular understanding of the role that the notion of privacy plays in abortion law. I then argue that such arguments against personhood are not rationally conclusive. The claim that the early embryos is not a human individual is not nearly as obvious as some assert. (shrink)

The author, a member of the U.S.President's Council on Bioethics, discussesethical issues raised by human cloning, whetherfor purposes of bringing babies to birth or forresearch purposes. He first argues that everycloned human embryo is a new, distinct, andenduring organism, belonging to the speciesHomo sapiens, and directing its owndevelopment toward maturity. He then distinguishesbetween two types of capacities belonging toindividual organisms belonging to this species,an immediately exerciseable capacity and abasic natural capacity that develops over time. He argues that it is the (...) second type ofcapacity that is the ground for full moralrespect, and that this capacity (and itsconcomitant degree of respect) belongs tocloned human embryos no less than to adulthuman beings. He then considers and rejectscounter-arguments to his position, includingthe suggestion that the capacity of embryos isequivalent to the capacity of somatic cells,that full human rights are afforded only tohuman organisms with functioning brains, thatthe possibility of twinning diminishes themoral status of embryos, that the fact thatpeople do not typically mourn the loss of earlyembryos implies that they have a diminishedmoral status, that the fact that earlyspontaneous abortions occur frequentlydiminishes the moral status of embryos, andthat his arguments depend upon a concept ofensoulment. He concludes that if the moralstatus of cloned human embryos is equivalent tothat of adults, then public policy should bebased upon this assumption. (shrink)