To say that some human beings are not persons is to say that only achievers, only successful functioners, only sufficiently intelligent performers, qualify as persons and have a right to life. And who is to say what “sufficient” is? The line can be drawn at will – the will of the stronger. Nature, reason, and justice are then replaced by artifice, prejudice, and power. When it is in the self interest of certain people to kill certain other people, whether fetuses, or the dying, or enemies of the state, or Jews, or Armenians, or Cambodians, or heretics, or prophets, the killers will simply define their victims as non-persons by pointing out that they do not meet certain criteria. Who determines the criteria? Those in power, of course. Whenever personhood is defined functionally, the dividing line between persons and non-persons will be based on a decision by those in power, a decision of will. Such a decision, given the fallenness of human nature, will inevitably be based on self-interest. Where there is an interest in killing persons, they will be defined as non-persons.
Human Personhood Begins at Conception