In this article, I present a new interpretation of the pro-life view on the status of early human embryos. In my understanding, this position is based not on presumptions about the ontological status of embryos and their developmental capabilities but on the specific criteria of rational decisions under uncertainty and on a cautious response to the ambiguous status of embryos. This view, which uses the decision theory model of moral reasoning, promises to reconcile the uncertainty about the ontological status of (...) embryos with the certainty about normative obligations. I will demonstrate that my interpretation of the pro-life view, although seeming to be stronger than the standard one, has limited scope and cannot be used to limit destructive research on human embryos. (shrink)

The articles in this issue cover a wide range of topics, including the moral status of human embryos and human-animal chimeras and hybrids, the determination of death, theories of human cognition, and policies on the identity of mitochondrial donors. Despite this variety, there are two underlying questions that tie the articles together: what is a human being? And, what is the basis of moral status? First, I discuss these two questions and why they are important for bioethics. Then I provide (...) summaries of the six articles in this issue and explain how each of them is connected to the questions of human nature and moral status. (shrink)

Marquis’ future-like-ours argument against the morality of abortion assumes animalism—a family of theories according to which we are animals. Such an assumption is theoretically useful for various reasons, e.g., because it provides the theoretical underpinning for a reply to the contraception-abstinence objection. However, the connection between the future-like-ours argument and one popular version of animalism can prove lethal to the former, or so I argue in this paper.

It has been argued that the possibility of monozygotic twinning disproves the conservative position on foetal personhood that defines the foetus as a person from conception. This article will canvass arguments for and against this proposition, in order to arrive at a conclusion as to the relative strength of this finding.

This essay serves as an introduction to this issue of the Journal of Medicine and Philosophy. The five articles in this issue address a range of topics from the human embryo and substantial change to conceptions of disability. They engage claims of moral status, defense of our humanity, and argue for an accurate and just classification of persons of different communities within a healthcare system. I argue in this essay that though their concerns are diverse, the authors in this issue (...) help to answer a common question: “Who counts as one of us?” Reading these articles through the lens of membership and the themes of dignity illustrates this commonality and bears fruit for further reflection on many of the challenging issues addressed in the subsequent papers. (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)

In various places we have defended the position that a new human organism, that is, an individual member of the human species, comes to be at fertilization, the union of the spermatozoon and the oocyte. This individual organism, during the ordinary course of embryological development, remains the same individual and does not undergo any further substantial change, unless monozygotic twinning, or some form of chimerism occurs. Recently, in this Journal Jason Morris has challenged our position, claiming that recent findings in (...) reproductive and stem cell biology have falsified our view. He objects to our claim that a discernible substantial change occurs at conception, giving rise to the existence of a new individual of the human species. In addition, he objects to our claim that the embryo is an individual, a unified whole that persists through various changes, and thus something other than a mere aggregate of cells. Morris raises a number of objections to these claims. However, we will show that his arguments overlook key data and confuse biological, metaphysical, and ethical questions. As a result, his attempts to rebut our arguments fail. (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)

This paper presents an account of how human spontaneous embryonic chimeras are formed. On the prevalent view in the philosophical literature, it is said that chimeras are the product of two embryos that fuse to form a new third embryo. We call this version of fusion synthesis. In contrast to synthesis, we present an alternative mechanism for chimera formation called incorporation, wherein one embryo incorporates the cells of a second embryo into its body. We argue that the incorporation thesis explains (...) other types of chimera formation, which are better understood, and is more consistent than synthesis with what is known about embryological development. Incorporation also has different implications than synthesis and so avoids the philosophical puzzles that are often said to accompany embryonic chimera formation—puzzles which pose problems to the human embryo’s persistence from fertilization to the fetal stage of human development. (shrink)

While most theorists agree with the claim that human beings have high and equal moral standing, there are strong disagreements about how to justify this claim. These disagreements arise because there are different ways of managing the difficulty of finding a basis for this claim, which is sufficiently substantial to do this justifying work, but not vary in degree in order to not give rise to inequality of moral considerability. The aim of this paper is to review previous attempts to (...) address this difficulty and to demonstrate why they fail and then to defend another way of dealing with this challenge by applying two views: the substance view on the human person and the natural-law account of morality. My claim is that this approach has comparative advantages because it provides a binary and a normatively significant basis of justification for equality without being implausibly inclusive. (shrink)

Consider the following two metaphysical questions about pregnancy: (1) When does a new organism of a certain kind start to exist? (2) What is the mereological and topological relationship between the pregnant organism and with what it is pregnant? Despite assumptions made in the literature, I take these questions to be independent of each other, such that an answer to one does not provide an answer to the other. I argue that the way to connect them is via a maximality (...) principle that prevents one organism being a proper part of another organism of the same kind. That being said, such a maximality principle need not be held, and may not apply in the case of pregnancy. The aims of this paper are thus to distinguish and connect these metaphysical questions, in order to outline a taxonomy of rival mereotopological models of pregnancy that result from the various combinations of their answers. (shrink)

Moral status ascribes equal obligations and rights to individuals on the basis of membership in a protected group. Substance change is an event that results in the origin or cessation of individuals who may be members of groups with equal moral status. In this paper, two substance changes that affect the moral status of human embryos are identified. The first substance change begins with fertilization and ends with the formation of the blastocyst, a biological individual with moral status comparable to (...) that ascribed to human organs. The second substance change begins at implantation and ends late in embryological development with the formation of the human body, an organism with moral status as a human being. The bioethical implications of each substance change are explored. The Two Substance Change theory is contrasted with continuity theories, which recognize no substance change in embryological development and with fertilization-only substance change theories. (shrink)

En este artículo presento una clasificación de las teorías éticas acerca del aborto provocado. En esa clasificación utilizo dos criterios que, aunque inseparables, se pueden tratar relativamente disociados uno del otro. En primer lugar, presento las teorías ordenadas según el estatuto ontológico y ético que otorgan a los gametos, cigotos, preembriones, embriones, fetos y neonatos, y discuto las teorías basadas en la idea de potencialidad. En segundo lugar, me refiero a las teorías centradas en la libertad de la madre. En (...) las consideraciones finales reconozco explícitamente el partidismo de la teoría de teorías propuesta. (shrink)

This paper analyzes the transformation from the human zygote to the implanted embryo under the prism of substantial change. After a brief introduction, it vindicates the Aristotelian ideas of substance and accident, and those of substantial and accidental change. It then claims that the transformation from the multicelled zygote to the implanted embryo amounts to a substantial change. Pushing further, it contends that this substantial change cannot be explained following patterns of genetic reductionism, emergence, and self-organization, and proposes Gustavo Bueno’s (...) idea of anamorphosis as a means to encapsulate criticism against such positions. (shrink)