Abstract

This thesis analyzes and critiques the influential work of Derek Parfit. Parfit has argued that the mere numerical identity of persons is unimportant and that the concept of person can be reduced, without sacrifice, to the continuity of consciousness over time. Parfit reaches his conclusions by considering logically possible, but scientifically impossible examples in which the scientifically determined existence and persistence conditions for humans in our world are violated. This thesis argues that Parfit's attempt to analyze the ontological status of persons in our world through the use of other possible worlds is inherently illegimate and that in our world humans form an ontologically fundamental category of things. Ontological questions are logically prior to possible world analysis. In addition, it is argued that Parfit's reductionism should be rejected because it leads to the unacceptable conclusions that persons have no autonomy or responsibility and that different persons cannot even be discriminated from one another at a given instant in time. Further, this thesis also contends that Parfit's reductionism is inconsistent with any coherent concept of morality. Assuming arguendo that Parfit's reductionism is, at least in theory, consistent with a coherent concept of morality, it is argued that Parfit's reductionism implies highly implausible normative ethical conclusions. The critique of Parfit's position is furthered by demonstrating that one can construct possible worlds in which even the most basic ontological and ethical truths in our world are violated. In challenging Parfit's analysis, certain current controversies in the philosophy of biology are discussed, as is the philosophical nature of beliefs, desires, capacities, and personality traits. Finally, the nature of mental illness is analyzed and the highly relevant real world example of multiple personality is discussed. It is argued that a multiple personality sufferer only qualifies as mentally ill because he is a single person who is disposed to harm himself; he is not, as a reductionist is forced to conclude, two or more reductionist "persons" who share the same body