Philosophers approach the concept of a person from two directions. In ethics and political philosophy it often is taken as primitive, or at least familiar and not requiring elucidation, but persistent inquiry and difficult problems make a deeper look inevitable. In discussing abortion, for example, one can hardly invoke principles about rights and welfare of persons concerned, without facing the question about which concerned parties are, in fact, persons, and what that means. One moves remorselessly from issues of rights and responsibilities to questions of consciousness, self-awareness, and identity - from the moral to the metaphysical.