In this important volume two philosophers with interests in bioethics and law make the case for the moral worth of the human embryo from non-religious grounds. The case instead is made with a combination of science (biology, embryology, genetics) and moral philosophy.
Thus this book covers a wide range of topics, and deals with the various technologies that threaten the human embryo, from abortion to cloning and embryonic stem cell research. Much of the discussion focuses on the scientific questions: what is an embryo, how is it formed and developed, and so on.
The authors show that at fertilisation a new and distinct human organism comes into existence. The newly formed zygote is genetically unique, and its sex is established. This newly formed zygote is genetically distinct from either of its two parents.
When sperm and oocyte unite, there is a new human individual which comes into existence. It is a “single, unified, and self-integrated biological system”, argue the authors, which is on a “developmental trajectory” toward a mature stage of human being.
The authors remind us that the zygote is no longer some functional part of either parent, but a “unique organism, distinct and whole, albeit at the very beginning of a long process of development to adulthood”. All the mother does from now on is provide nutrition and a safe environment for the embryo to grow.
And this growth is internally directed. It contains within itself all the “genetic programming and epigenetic characteristics necessary to direct its own biological growth”. It is a complete or whole organism, in the very early stages of development. And the changes from embryo to fetus to child to adult, etc., are simply changes in degree, not changes in kind.
Thus the scientific question is easily answered. This is a wholly new and distinct genetic individual. And it of course is fully human. But questions arise as to whether this new human embryo is in fact a person. Here the authors move from science to philosophy.
For science cannot answer these sorts of questions. Thus the need for moral philosophy. And here the authors take on all the leading critics of the personhood of the human embryo. Peter Singer, Lee Silver, Judith Jarvis Thompson, Michael Tooley and others are all interacted with.
Drawing on a rich history of philosophical discussion, going back at least to Plato, the authors seek to establish the substance or essence of an entity, in distinction to its various characteristics or properties. Distinction, in other words, must be made between the kind of thing an entity is, and its accidental or contingent properties. For example, being left-handed or red-haired is not an essential feature of personhood, but is simply an accidental property.
Utilitarian and consequentialist definitions of personhood fail to make this important distinction. Thus personhood is tied up with functionality and activity, instead of one’s innate nature or essence. So persons are described as those with sentience, or self-consciousness, or various other functions. But the authors argue that the utilisation of these accidental properties is not the same as our fundamental nature or substance.
The various abilities to reason, communicate, make free choices, and perform other functions of course are not fully formed in the embryo, or even in a young child. They take time to mature and properly develop. But the capacity to perform such functions is with us from the very beginning. Each new human being “comes into existence possessing the internal resources to develop such capacities”.
Thus human beings live personal lives, argue the authors. These lives are “characterised by a certain range of potentialities, which need not be fully instantiated or realized all at once or to the same degree in all cases”.
The bulk of this book then takes on the various arguments made against the personhood of the embryo, and these functionalist definitions of personhood. Various philosophical and moral challenges and objections are carefully dealt with. Specific issues such as brain death, twinning, natural embryo loss, lifeboat ethics, surplus embryos, and other problems are discussed in detail. Challenges from cloning and other new reproductive technologies are also addressed. Finally, political, technological and cultural recommendations are made, based on this understanding of the complete humanity and personhood of the human embryo.
This is a very fine book that covers most of the bases in what is often a highly emotive and controversial debate. The scientific, moral and philosophical case for the worth of the embryo is here clearly and dispassionately made. The authors have produced a welcome addition to the growing body of pro-life literature.