Abstract

The primary task of my dissertation is to develop non-circular necessary and sufficient conditions for personal identity. Personal identity refers to cross-temporal numerical identity. Before constructing criteria of the identity of a person, I first defend my method of using thought experiments. Then I examine various such attempts to determine the necessary and sufficient conditions for personal identity by reductionist philosophers from John Locke to Derek Parfit and Sydney Shoemaker. An analysis of each of their theories yields important flaws, but consequently leads me to develop my own. I maintain that A and B are cross-temporally identical persons if and only if the following conditions are met: There is either psychological continuity between A and B, or else, if there is a break in continuity, B, the later person, must have over fifty percent psychological connectedness to A; There must be no person other than B who also has either psychological continuity or over fifty percent connectedness to A; The cause, as long as it is not copying, of either the continuity or the connectedness is irrelevant; and Continuity and connectedness include not only memories, but personality characteristics, etc. ;Before any theory of personal identity is complete, it is essential that it explain how we can identify a person as a single person. We cannot understand how the persons at two temporal stages of a life are identical unless we can understand how the mental components of a person at a single time hold together in one person. Thus, I address what should be called 'the unity of a person's mental life'. I argue that this unity exists because of a functional integration of stimuli within the person. This integration comes about due to a single interpreter within the person, rather like a central processing unit in a computer. ;Finally I argue that Parfit's belief that persons are not what truly matters is not well founded, and his subsequent contention that his theory renders utilitarianism more plausible is consequently unsubstantiated