This paper examines the reductive arguments about personhood in bioethics in order to illustrate a relational aspect of the concept of a person. First, the paper investigates Michael Tooley's claim that we cannot resolve the problem of abortion unless we define the concept of a person that entitles an individual to the right to life. According to him, self-consciousness is the crucial ingredient of that definition. Thus, a severely disabled child or a fetus might not have the right to life because it is unable to be aware of itself. Second, this paper, by focusing on analytic-philosophical approaches to John Locke's conception of a person, shows an interdependent relationship between the first-person authority and the third-person criterion in our ascribing consciousness to another person. Analytic-philosophical approaches suggest (1) that self-consciousness is not necessary to express oneself, and (2) that the first-person authority for expressing oneself must be judged from the third-person criterion which consists in an observable behavior. This suggestion implies that we should pay attention to the interdependent relationship when we ascribe consciousness to children in bioethical and educational contexts.