The purpose of this essay is to offer support for the substance view of persons, the philosophical anthropology defended by Patrick Lee in his essay. In order to accomplish this the author presents a brief definition of the substance view; argues that the substance view has more explanatory power in accounting for why we believe that human persons are intrinsically valuable even when they are not functioning as such, why human persons remain identical to themselves over time, and why it (...) follows from these points that the unborn are human persons; and responds to two arguments that attempt to establish the claim that the early human being is not a unified substance until at least fourteen days after conception. (shrink)

A comprehensive study of the ethics of killing in cases in which the metaphysical or moral status of the individual killed is uncertain or controversial. Among those beings whose status is questionable or marginal in this way are human embryos and fetuses, newborn infants, animals, anencephalic infants, human beings with severe congenital and cognitive impairments, and human beings who have become severely demented or irreversibly comatose. In an effort to understand the moral status of these beings, this book develops and (...) defends distinctive accounts of the nature of personal identity, the evaluation of death, and the wrongness of killing. The central metaphysical claim of the book is that we are neither nonmaterial souls nor human organisms but are instead embodied minds. In ethical theory, one of the central claims is that the morality of killing is not unitary; rather, the principles that determine the morality of killing in marginal cases are different from those that govern the killing of persons who are self‐conscious and rational. Another important theme is that killing in marginal cases should be evaluated in terms of the impact it would have on the victim at the time rather than on the value of the victim's life as a whole. What primarily matters is how killing would affect that which would be rational for the victim to care about at the time of death. By appealing to various foundational claims about identity, death, and the morality of killing, this book yields novel conclusions about such issues as abortion, prenatal injury, infanticide, the killing of animals, the significance of brain death, the termination of life support in cases of persistent vegetative state, the use of anencephalic infants as sources of organs for transplantation, euthanasia, assisted suicide, and advance directives in cases of dementia. In particular, the book defends the moral permissibility of abortion, infanticide, and euthanasia in certain cases and argues that brain death is not the appropriate criterion of death either for a person or a human organism. (shrink)

I consider the argument, thought to clinch the moral case for use of a human embryo solely as a means, that only a human individual can be a person, because it can happen at any time before formation of the primitive streak that an embryo splits into monozygotic twins, no embryo in which the primitive streak has not formed is a human individual, and therefore no embryo in which the primitive streak has not formed is a person. I explore the (...) following proffered arguments for : indivisibility is a necessary condition of individuality, nonidentity of an embryo with successor twins impugns the embryo’s individuality, and totipotency of an embryo’s constituents is inconsistent with the embryo’s being a human individual. These arguments are tested and found wanting; so too is an alternative to , the argument that indivisibility is intrinsic to personhood. Whereupon is unsustained. In search of ways to rehabilitate the nonindividuation argument, I canvass alternative metaphysical views and inquire further into biological individuality, but find that the argument cannot be saved. I conclude by analyzing where this leaves matters concerning the morality of embryo use. (shrink)

This paper defends the permissibility of stem cell research against a theological objector who objects to it by appealing to "souls.".

In this essay, I attempt to provide answers to the following four queries concerning the metaphysics of early human embryogenesis. (1) Following its first cellular fission, is it coherent to claim that one and only one of two “blastomeric” twins of a human zygote is identical with that zygote? (2) Following the fusion of two human pre-embryos, is it coherent to claim that one and only one pre-fusion pre-embryo is identical with that postfusion pre-embryo? (3) Does a live human being (...) come into existence only when its brain comes into existence? (4) At implantation, does a pre-embryo become a mere part of its mother? I argue that either if things have quidditative properties or if criterialism is false, then queries (1) and (2) can be answered in the affirmative; that in light of recent developments in theories of human death and in light of a more “functional” theory of brains, query (3) can be answered in the negative; and that plausible mereological principles require a negative answer to query (4). (shrink)

When does a human being begin to exist? We argue that it is possible, through a combination of biological fact and philosophical analysis, to provide a definitive answer to this question. We lay down a set of conditions for being a human being, and we determine when, in the course of normal fetal development, these conditions are first satisfied. Issues dealt with along the way include: modes of substance-formation, twinning, the nature of the intra-uterine environment, and the nature of the (...) relation between fetus and mother (connection, parthood, dependence). (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)

Some philosophers argue that, because it is subject to twinning and fusion, the early human embryo cannot hold strong moral standing. Supposedly, the fact that an early human embryo can twin or fuse with another embryo entails that it is not a distinct individual, thus precluding it from holding any level of moral standing. I argue that appeals to twinning and fusion fail to show that the early human embryo is not a distinct individual and that these appeals do not (...) provide us with plausible reasons for denying the strong moral standing of the early human embryo. I recognize one possible exception to this general assessment, a particular version of the appeal to fusion. Embryo fusion that results in tetragametic chimerism provides some reason for doubting the early human embryo's moral standing. But twinning and fusion are otherwise irrelevant in this context. (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)

Australian legislation at both state and federal levels has been passed in the last two years enabling the creation and use of cloned embryos up until their fourteenth day of development. Yet for this fourteen-day threshold to carry moral weight it must be shown that an embryo may be plausibly attributed some kind of moral standing after this point that it cannot be accorded before it Moral standing may be conferred using Steven Buckle’s account of potential to become (after one (...) problem with his account is dealt with) but such standing has often been withheld from the embryo prior to the fourteenth day due to the possibility of monozygotic twinning and the violation of numerical continuity this represents. This article discusses the influential argument regarding monozygotic twinning articulated by Peter Singer and Helga Kuhse, and finds it insufficient to negate either the ‘identity thesis’ they describe or Buckle’s account of potential to become. (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)

Assigning the appropriate moral status to different stages of human development is an urgent problem in bioethics. Many philosophers have attempted to assess developmental events using strict ontological principles to determine when a developing entity becomes essentially human. This approach is not consistent with recent findings in reproductive and stem cell biology, including the discovery of the plasticity of early embryonic development and the advent of induced pluripotent stem cells. Substance ontology should therefore not be used to determine the moral (...) status of the embryo. (shrink)

Response to Jan Deckers' critique of the author's earlier article on the beginning of personhood from a Thomistic perspective in which the author revises and further refines his view.

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)

This paper re-examines the question of whether quirks of early human foetal development tell against the view (conceptionism) that we are human beings at conception. A zygote is capable of splitting to give rise to identical twins. Since the zygote cannot be identical with either human being it will become, it cannot already be a human being. Parallel concerns can be raised about chimeras in which two embryos fuse. I argue first that there are just two ways of dealing with (...) cases of fission and fusion and both seem to be available to the conceptionist. One is the Replacement View according to which objects cease to exist when they fission or fuse. The other is the Multiple Occupancy View – both twins may be present already in the zygote and both persist in a chimera. So, is the conceptionist position tenable after all? I argue that it is not. A zygote gives rise not only to a human being but also to a placenta – it cannot already be both a human being and a placenta. Neither approach to fission and fusion can help the conceptionist with this problem. But worse is in store. Both fission and fusion can occur before and after the development of the inner cell mass of the blastocyst – the entity which becomes the embryo proper. The idea that we become human beings with the arrival of the inner cell mass leads to bizarre results however we choose to accommodate fission and fusion. (shrink)

This tightly argued, historically grounded study sets out to demonstrate that a 'pro-choice' stance is as fully justified by Catholic thought as an anti-abortion view, and may even be more compatible with Catholic tradition than the current opposition to abortion espoused by most Catholic leaders.