The 14-day rule restricts the culturing of human embryos in vitro for the purposes of scientific research for no longer than 14 days. Since researchers recently developed the capability to exceed the 14-day limit, pressure to modify the rule has started to build. Sophia McCully argues that the limit should be extended to 28 days, listing numerous potential benefits of doing so. We contend that McCully has not engaged with the main reasons why the Warnock Committee set such a limit, (...) and these still remain valid. As a result, her case for an extension of the 14-day rule is not persuasive. (shrink)

Catholic opponents of abortion and embryonic stem cell research usually base their position on a hylomorphic account of ensoulment at fertilization. They maintain that we each started out as one-cell ensouled organisms. Critics of this position argue that it is plagued by a number of intractable problems due to fission (twinning) and fusion. We're unconvinced that such objections to early ensoulment provide any reason to doubt the coherence of the hylomorphic account. However, we do maintain that a defense of ensoulment (...) at fertilization must deny that we're essentially organisms. (shrink)

Do pregnant mothers have fetuses as parts? According to the “parthood view” they do, while according to the “containment view” they don’t. This paper raises a novel puzzle about pregnancy: if mothers have their fetuses as parts, then wherever there is a pregnant mother, there is also a smaller thinking being that has every part of the mother except for those that overlap with the fetus. This problem resembles a familiar overpopulation puzzle from the personal identity literature, known as the (...) “Thinking Parts Problem”, but it’s not merely a special case of that problem. Rather, the fact that late-term fetuses have a mental life of their own makes the Problem of Pregnant Thinkers, as I will call it, a sui generis and especially recalcitrant problem. (shrink)

A number of philosophers maintain that the destruction of an embryo in the first 2 weeks after fertilization is not morally problematic as it is metaphysically impossible for any human organism to then have existed. We contend that the typical adult human organism was once a zygote so there is no metaphysical shortcut to justify early abortion. We show that five arguments against human organisms ever having been zygotes fail. All of the arguments have to do with one variant or (...) another of the zygote or early embryo dividing. They do not provide any reason to believe that since some adult organisms are not identical to zygotes due to earlier divisions, none could have been. (shrink)