A socially constructed moral category that denotes the inclusion criteria and salient characteristics that distinguish human beings from other forms of life, thus specifying the individuals to whom we owe particular moral obligations, i.e., those obligations we have to others due to their status as persons. In general, there are two ways of defining personhood. Philosophically, personhood is generally defined by some list of essential properties by which we recognize a human being as a person. Though these lists vary, they often include such characteristics as consciousness, the ability to reason, self-movement, self-awareness and a capacity to communicate. The second way of defining personhood is more theologically oriented and entails some relational interpretation of what it means to be a person. In this sense, personhood is often conceived of in terms of one’s ability to have relationships with other human beings and the special relationship human beings have with God.
It is crucial to note that the moral doctrine and teaching of the Catholic Church does not depend on or entail any specific concept of personhood in the sense considered above. Rather, in the Catholic moral tradition, normative obligations owed to individual persons arise from their status as human beings. Thus, when considering the principle of respect for persons from the Catholic perspective, one need not meet any socially constructed criteria included in one or another philosophical or theological definitions of personhood. Considered in this way, "human person" should be understood as synonymous with "human being." Nonetheless, the concept of "human being" presupposes biological, as well as philosophical and theological criteria. This point is critical for appropriately understanding the Catholic moral perspective on beginning- and end-of-life issues, though it does not resolve all of the relevant moral questions involved. [See Donum Vitae: Instruction on Respect for Human Life in its Origins and on the Dignity of Procreation (especially Part I, n.1, paragraph four).]