A higher order potential analysis of moral status clarifies the issues that divide Human Being Theorists who oppose embryo research from Person Theorists who favor embryo research. Higher order potential personhood is transitive if it is active, identity preserving and morally relevant. If the transition from the Second Order Potential of the embryo to the First Order Potential of an infant is transitive, opponents of embryo research make a powerful case for the moral status of the embryo. If it is (...) intransitive, then the Person Theorist can draw lines between levels of moral status that permit embryo research to proceed. (shrink)

When does a human being begin to exist? We argue that it is possible, through a combination of biological fact and philosophical analysis, to provide a definitive answer to this question. We lay down a set of conditions for being a human being, and we determine when, in the course of normal fetal development, these conditions are first satisfied. Issues dealt with along the way include: modes of substance-formation, twinning, the nature of the intra-uterine environment, and the nature of the (...) relation between fetus and mother (connection, parthood, dependence). (shrink)