ABSTRACT
Bioethicists sometimes neglect or outright reject metaphysics as useless for offering conclusive arguments about the beginning and end of human life. Nevertheless, various positions regarding issues related to the limits of human life often presuppose some metaphysical understanding of human nature. Hence, there is at least a tacit need to adopt a metaphysical account of human nature for the sake of addressing certain types of bioethical issues. In this chapter and the following, I will provide Thomistic metaphysical conclusions to the questions of when a human person’s life begins and ends. These conclusions provide a foundation for responding to issues such as embryonic stem cell research, abortion and the use of abortifacient contraceptives, cloning, care for patients who are in a persistent vegetative state or who are terminally ill, and organ procurement. Complete responses to these issues, though, require combining such metaphysical conclusions with a particular ethical theory and taking various values into account. I will accomplish this task in Chapters 4 and 5.
