The doctrine that it is wrong to end the existence of something because it is a human life I call “the standard view.” I argue that attempts by proponents of abortion choice to avoid the implications of the standard view by suggesting that we don't know when life begins or by suggesting that fetuses are only potential lives fail. Nevertheless, opponents of abortion choice should not base their arguments on the standard view, for the standard view is false. I propose (...) a substitute for the standard view that avoids the difficulties with it, that explains why most people believe that the standard view is true and that also underwrites opposition to abortion choice. (shrink)

In this paper I defend the view that a zygote is a human from the fission objection that is widely thought to be decisive against the view. I do so, drawing upon a recent discussion of this issue by John Burgess, by explaining in detail the metaphysical position the proponent of the view should adopt in order to rebut the objection.

The paper by Magill and Neaves in this issue of the Journal attempts to rebut the "natural potency" position, based on recent advances in direct reprogramming of somatic cells to yield "induced pluripotent stem" (iPS) cells. As stated by the authors, the natural potency position holds that because "a human embryo directs its own integral organismic function from its beginning . . . there is a whole, albeit immature, and distinct human organism that is intrinsically valuable with the status of (...) inviolability and deserving full moral respect" (p. 26). The authors boldly assert that "The recent production of iPS . . . highlights a prima facie absurdity for the natural potentiality argument" (p. 29). Yet the argument against natural potency is both logically flawed and based on a characterization of the scientific evidence that is factually inaccurate. (shrink)

Scientific breakthroughs rarely yield the potential to engage a foundational ethical question. Recent studies on direct reprogramming of human skin cells reported by the Yamanaka lab in Japan and the Thomson lab in Wisconsin suggest that scientists may have crossed both a scientific and an ethical threshold. The fascinating science of direct nuclear reprogramming highlights empirical data that may clarify the ontological status of cellular activity in the early stages of what could become a human fetus and justify ethical options (...) for research in this controversial field. The ontological and ethical implications that accrue here are connected with the biological or natural potentiality of these cells. (shrink)

During the first 16 days after fertilization, the developing embryo has the capacity to separate into two genetically identical embryos, or monozygotic twins (triplets, etc.). Because of this capacity, philosophers typically argue that the pre-16 day embryo is not a human being. On a Biological Account of Personal Identity (BAPI), which considers us human beings as essentially organisms, the development of the embryo into an organism at 16 (or 21) days marks our origins. The development of an embryo into an (...) organism is also said to mark the point at which the embryo loses its potential to give rise to monozygotic twins. This is considered a strength of the Biological account of our origins. I will argue here that it is the BAPI's own criteria that will have to allow cases of monozygotic twinning occurring even after 16 days, and that in virtue of this a Biological Account faces twinning puzzles usually reserved for earlier accounts of our origins. (shrink)

What are you and I essentially? When do you and I come into and go out of existence? A common response is that we are essentially organisms, that is, we come into existence as organisms and go out of existence when we cease to be organisms. Jeff McMahan has put forward two arguments against the Organism View: the case of dicephalus and a special case of hemispheric commissurotomy. In this paper, I defend the Organism View against these two cases. Because (...) it is possible to devise more McMahanian-type cases, I also provide a more general solution to these kinds of cases. (shrink)

What moral status should we attribute to stem cells? To answer this neglected question, we look in this essay at the properties of embryos and other entities that could develop into beings who have uncontested moral status, namely, adult humans. Our analysis indicates that those who grant moral status to embryos should also grant it to stem cells. This has implications that verge on absurdity, since even if we were to try to do what we can to protect these entities, (...) we would face the dilemma that the development of any embryo requires the destruction of other potential beings. We respond to objections, including the claim that the destruction of human embryos is wrong not because of the potential of human embryos but because human embryos are actual beings with a rational nature. We conclude that the more plausible position is to deny moral status to embryos, and thus to stem cells as well. (shrink)

We argue in this essay that (1) the embryo is an irredeemably ambiguous entity and its ambiguity casts serious doubt on the arguments claiming its full protection or, at least, its protection against its use as a means fo research, (2) those who claim the embryo should be protected as "one of us" are committed to a position even they do not uphold in their practices, (3) views that defend the protection of the embryo in virtue of its potentiality to (...) become a person fail, and (4) the embryo does not have any rights or interests to be protected. Given that many are willing to treat the embryo as a means in other practices, and that human embryonic stem cell (hESC) research holds the potential to benefit many people, one cannot but conclude that hESC research is permissible and, because of its immense promise for alleviating human even obligatory. (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)

This paper is about the neglected question of what sort of things we are metaphysically speaking. It is different from the mind-body problem and from familiar questions of personal identity. After explaining what the question means and how it differs from others, the paper tries to show how difficult it is to give a satisfying answer.

Is the mammalian embryo/fetus a part of the organism that gestates it? According to the containment view, the fetus is not a part of, but merely contained within or surrounded by, the gestating organism. According to the parthood view, the fetus is a part of the gestating organism. This paper proceeds in two stages. First, I argue that the containment view is the received view; that it is generally assumed without good reason; and that it needs substantial support if it (...) is to be taken seriously. Second, I argue that the parthood view derives considerable support from a range of biological and physiological considerations. I tentatively conclude in favour of the parthood view, and end by identifying some of the interesting questions it raises. (shrink)

What is the metaphysical relationship between the fetus/embryo and the pregnant organism? In this paper I apply a substance metaphysics view developed by Barry Smith and Berit Brogaard to argue, on the basis of topological connectedness, that fetuses/embryos are Lady-Parts: part of the maternal organism up until birth. This leaves two options. Either mammalian organisms begin at birth, or we revise our conception of organisms such that mammalian organisms can be part of other mammals. The first option has some advantages: (...) it is numerically neat; aligns with an intuitive picture of organisms as physically distinct individuals; and ties ‘coming into existence’ to a suitably recognisable and important event: birth. But it denies that the fetus survives birth, or that human organisms existed prior to their birth. The second option allows us to recognise that human organisms exist prior to and survive their birth, but at a cost: it leaves the question of when an organism comes into existence unanswered, and demands potentially far-reaching conceptual revision across a range of domains. (shrink)

Opponents of human embryonic stem cell (hESC) research claim that such research is incompatible with the moral principle that it is always wrong intentionally to end a human life. In this essay, I discuss how that principle might be revised so that it is subject to as few difficulties as possible. I then argue that even the most defensible version of the principle is compatible with the moral permissibility of hESC research.

When does a human being begin to exist? Barry Smith and Berit Brogaard have argued that it is possible, through a combination of biological fact and philosophical analysis, to provide a definitive answer to this question. In their view, a human individual begins to exist at gastrulation, i. e. at about sixteen days after fertilization. In this paper we argue that even granting Smith and Brogaard's ontological commitments and biological assumptions, the existence of a human being can be shown to (...) begin much earlier, viz., with fertilization. Their interpretative claim that a zygote divides immediately into two substances and therefore ceases to exist is highly implausible by their own standards, and their factual claim that there is no communication between the blastomeres has to be abandoned in light of recent embryological research. (shrink)

When did we begin to exist? Barry Smith and Berit Brogaard argue that a new human organism comes into existence neither earlier nor later than the moment of gastrulation: 16 days after conception. Several critics have responded that the onset of the organism must happen earlier; closer to conception. This article makes a radically different claim: if we accept Smith and Brogaard’s ontological commitments, then human organisms start, on average, roughly nine months after conception. The main point of contention is (...) whether the fetus is or is not part of the maternal organism. Smith and Brogaard argue that it is not; I demonstrate that it is. This claim in combination with Smith and Brogaard’s own criteria commits to the view that human organisms begin, precisely, at birth. (shrink)

I have argued that substance ontology cannot be used to determine the moral status of embryos. Patrick Lee, Christopher Tollefsen, and Robert George wrote a Reply to those arguments in this Journal. In that Reply, Lee, Tollefsen, and George defended and clarified their position that their substance ontology arguments prove that the zygote and the adult into which it develops are the same entity that share the same essence. Here, I show the following: Even using the substance ontology framework to (...) which Lee, Tollefsen, and George subscribe, we cannot know when in development substance changes cease. Substance ontology cannot therefore be used to assign moral status to embryos. The Lee, Tollefsen, and George substance ontology framework should not be applied to the study of development or to biological discourse in general, because this framework depends on premises that do not apply. (shrink)

Do fetuses have a right to life in virtue of the fact that they are potential adult human beings? I take the claim that the fetus is a potential adult human being to come to this: if the fetus grows normally there will be an adult human animal that was once the fetus. Does this fact ground a claim to our care and protection? A great deal hangs on the answer to this question. The actual mental and physical capacities of (...) a human fetus are inferior to those of adult creatures generally thought to lack a serious right to life, and the mere fact that a fetus belongs to our species in particular seems morally irrelevant. Consequently, a strong fetal claim to protection rises or falls with the appeal to the fetus's potentiality, for nothing else can justify it. (shrink)

How can the abortion issue be resolved? Many believe that the issue can be resolved if, and only if, we can determine when human life begins. Those opposed to abortion choice typically say that human life begins at conception. Many who favor abortion choice say that we will never know when human life begins. The importance of the when-does-human-life-begin issue is not so much argued for as it is taken to be self-evident. Furthermore, belief that this issue is fundamental is (...) taken for granted – at least outside of philosophy – by many of the people who seem to disagree about almost everything else concerning abortion. It has been my experience that – with rare exceptions – even those who insist that the issue of abortion should focus on the interests of pregnant women believe that this focus is warranted because fetuses are either not yet fully alive or not yet fully human. (shrink)

Francis Beckwith’s Defending life: a moral and legal case against abortion choice defends the pro-life position on moral, legal and political grounds. In this critical notice I consider three key issues and argue that Beckwith’s treatment of each of them is unpersuasive. The issues are: (1) whether abortion is politically justified by the principle that we should err on the side of liberty in the face of reasonable disagreement over the moral status of the fetus; (2) whether the fetus’s natural (...) capacity or genetic propensity to develop rationality and communication is sufficient to give it a moral right to life; and (3) whether abortion is morally justified on the basis of bodily rights. I also show that Beckwith’s book fails to consider several important issues and arguments. (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)

It is sometimes suggested that if a moral theory implies that infanticide can sometimes be permissible, that is sufficient to discredit the theory. I argue in this article that the common-sense belief that infanticide is wrong, and perhaps even worse than the killing of an adult, is challenged not so much by theoretical considerations as by common-sense beliefs about abortion, the killing of non-human animals, and so on. Because there are no intrinsic differences between premature infants and viable fetuses, it (...) is difficult to accept that an abortion performed after the point of viability can be permissible while denying that infanticide can be permissible for a comparably important reason. This and other challenges to the consistency of our intuitions exert pressure on us either to accept the occasional permissibility of infanticide or to reject liberal beliefs about abortion. (shrink)

In vitro embryology not only makes possible the growing of human tissue to remedy infertility but also for many other experimental purposes. This paper examines the ethical issues involved in such work and outlines the circumstances in which such work is morally permissible and those in which it is not.

abstract This paper re‐examines some well‐known and commonly accepted arguments for the non‐individuality of the embryo, due mainly to the work of John Harris. The first concerns the alleged non‐differentiation of the embryoblast from the trophoblast. The second concerns monozygotic twinning and the relevance of the primitive streak. The third concerns the totipotency of the cells of the early embryo. I argue that on a proper analysis of both the empirical facts of embryological development, and the metaphysical importance or otherwise (...) of those facts, all three arguments are found wanting. None of them establishes that the embryo is not an individual human being from the moment of conception. (shrink)

The process of embryogenesis poses numerous philosophical puzzles. Conceptual difficulties encountered while attempting to clarify the ontological and moral status of the fertilized ovum, for example, are compounded in the minds of some philosophers by the possible occurrence of monozygotic twinning during the earliest stages of embryological development. In light of certain conceptual complexities engendered by this possibility, G.E.M. Anscombe, for example, has come to believe that the pivotal metaphysical query in need of an adequate response is the following: Is (...) the human zygote a single human? The answer to this question is of interest to Anscombe primarily for the role it would play in solving the following puzzle: Suppose that zygote A divides into twins B and B1, such that neither B nor B1 is identical with its twin or with A. It then seems clear that either A, prior to its division, was somehow already B and B1; or A was a single human out of which another human grew ; or A, which was a single human, became two humans, much like an amoeba becomes two amoebae; or A is a "whole human substantial entity". (shrink)