It is often argued that certain metaphysical complications surrounding the phenomenon of monozygotic twinning force us to conclude that, prior to the point at which twinning is no longer possible, the zygote or early embryo cannot be considered an individual human organism. In this essay, I argue, on the contrary, that there are in fact several ways of making sense of monozygotic twinning that uphold the humanity of the original zygote, but also that there is no easy answer to what (...) happens when the human zygote twins. All of the options available carry with them one or more surprising, alarming, or otherwise counterintuitive implications. All things considered, I conclude that the “budding option,” according to which the original human organism present before twinning carries on as one of the resulting embryos but not the other, is the most plausible explanation of what happens when a human zygote twins. (shrink)

Recent scientific advances have indicated that it may be technically feasible to sustain human embryos in vitro beyond 14 days. Research beyond this stage is currently restricted by a guideline known as the 14-day rule. Since the advances in embryo culturing there have been calls to extend the current limit. Much of the current debate concerning an extension has regarded the 14-day rule as a political compromise and has, therefore, focused on policy concerns rather than assessing the philosophical foundations of (...) the limit. While there are relevant political considerations, I maintain that the success of extension arguments will ultimately depend on the strength of the justifications supporting the current 14-day limit. I argue that the strongest and most prevalent justifications for the 14-day rule—an appeal to individuation and neural development—do not provide adequate support for the limit of 14 days. I instead suggest that an alternative justification based on sentience would constitute a more defensible basis for embryo protection and that a consideration of such grounds appears to support an amendment to the current limit, rather than the retention of it. While these conclusions do not establish conclusively that the current limit should be extended; they do suggest that an extension may be warranted and permissible. As such, this paper offers grounds on which a reassessment of the 14-day rule may be justified. (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)

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)

There is no issue more central to the abortion debate than the controversial issue of whether the fetus is a moral person. Abortion-rights opponents almost universally claim that abortion is murder and should be legally prohibited because the fetus is a moral person at the moment of conception. Abortion-rights proponents almost universally deny the crucial assumption that the fetus is a person; on their view, whatever moral disvalue abortion involves does not rise to the level of murder and hence does (...) not rise to the level of something that should be legally prohibited.In this essay, I argue that, under dualist assumptions about the nature of mind, the fetus is not a person until brain activity has begun.i First, I argue it is a necessary condition for a thing to be a moral person that it is a self. Second, I argue it is a necessary condition for a fetus to be a self, under dualist assumptions, that there has been some electrical activity in the brain. I conclude that a dualist can take the position that abortion ought to be legally permitted at least until the beginning of brain activity in the fetus. (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)

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.

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.