Revision with unchanged content. Identity, Potential and Design addresses the metaphysics of personal identity and the question of the moral permissibility of abortion. This book begins by discussing personal identity, arguing that a generally-Thomistic hylomorphic approach is most acceptable. It then moves to a discussion of the moral significance of potentiality, arguing that certain types of potentiality carry with them the same rights to protection as possessed by those individuals who have manifest these traits. It then examines the concept of health, arguing that appeals to species-norms are not helpful in determining health, proper function, or moral status, and thus arguing that we must appeal to divine design to salvage commonsense ethics. Finally, it addresses the issue of the degree of sacrifice required to live a moral life, concluding that when another person will certainly die if I do not make some sacrifice to sustain his or her life, I am required to sacrifice up to just short of my own life to save his or her life. Identity, Potential and Design comes to the ultimate conclusion that abortion is always morally wrong.