ABSTRACT
The conundrum turns on one's acceptance of extrinsic relations as making a difference to personal identity and upon a non-derivative notion of personal identity as being contributed by literal survival. Although concern with the problem of personal identity in the contemporary period certainly antedated the work of Derek Parfit, it is Parfit's article 'Personal Identity' along with his book Reasons and Persons that has given great impetus to a large body of work during the last twenty years. Parfit, thought experiments feature fission of the brain with the severed hemispheres being placed in two different cranial cavities and 'teletransportation' of a person from one planet to another via replication of the person's body, with different kinds of scenarios all designed to call the concept of personal identity into question. Harold Noonan in Personal Identity suggests that Parfit tries to cast doubt on the 'only x and y' principle by the use of thought experiments.
