When philosophers discuss personal identity they are not talking about such down-to-earth concerns as ethnicity and multiculturalism.  Instead, they are referring to the more abstractly metaphysical question of what makes each of us the same person he or she was last week.  Ever since the great English philosopher John Locke kicked off the conversation back in the seventeenth century by telling a perplexing story about a prince and a cobbler whose bodies were switched while they slept, the philosophical investigation of personal identity has largely revolved around bizarre imaginary cases.  At one point in the early 1990s the apparent craziness of the whole thing drove philosopher Kathleen Wilkes to write her book, Real People: Personal Identity Without Thought Experiments.  Nevertheless, the steady flow of new and weirder imaginary cases continues unabated.

Shoemaker’s book offers a relatively painless entry into this abstruse area of philosophy, but it does so with a twist: he is primarily interested in how the problem of personal identity relates to matters of practical human interest.  While this take might sound surprising, it is in a way, quite traditional.  When he first tackled personal identity, John Locke himself defined person as a “forensic term”; we have to be able to re-identify persons in order to hold them responsible for their past actions and commitments. 

Shoemaker engages with some rather down to earth problems: can an adult be held responsible for something he did in his childhood?  Is he still really the same person?  And what a healthy middle aged woman whose advanced medical directives will gravely affect the life of her future aged and demented self?  In what sense can those two very different modes of existence be said to belong to one and the same person?  Personal identity is also important for the heated debate over abortion.  Is it correct to say, “I once was an embryo”?  And if that statement is correct, does it imply that it would have been just as wrong to put an end to my embryonic existence as it would be to put an end to my present adult human existence?  Things get even more complicated when Shoemaker addresses the treatment of criminals suffering from multiple personality disorders.  If one personality committed murder, is it fair to imprison the innocent personalities as well?  Another set of problems involves issues of self-concern.  Why should an eighteen year old be worried about how his present actions will affect the life of his distant grumbling future self?  If there is such a thing as life after death, is there any reason for us to identify ourselves with the disembodied souls that might survive our deaths? These are the kinds of problems with which Shoemaker grapples.

The theories that Shoemaker applies to these issues come in two basic flavors: biological and psychological.  The biological criteria of personal identity say that we can keep track of who someone is by keeping track of him as an organism: “same organism, same person.”  The psychological brand of criteria points to continuity of memories, personality traits, and the like as constituting the backbone of a person’s continued existence as a particular person.  Beyond these mainstream views he also grants space to two less popular theories: “narrative identity,” which says that actions can be attributed to me when they constitute part of the biographical narrative I have constructed to unify my life into an intelligible whole, and the “Identity Doesn’t Matter” approach, which tries to deny moral relevance to the metaphysical question of personal identity.  Shoemaker explains the important philosophical arguments for and against each approach and tries to apply them to the kinds of practical issues mentioned above. 

All-in-all, this is a very clearly written book and it manages to present a great deal of philosophical material quickly and relatively painlessly — including more technical issues in ethical theory (such as Derek Parfit’s defense of utilitarianism) whose complexity is not amenable to description in this short review.  People looking for straightforward solutions to the puzzles brought up in the book will, however, be somewhat disappointed.  Shoemaker takes care to point out the advantages and disadvantages of each approach but finally adopts a position of principled fence-straddling, suggesting that different ideas about personal identity will be useful for dealing with different concerns and situations.  As he puts it: “This is all fairly complicated, messy, and disunified, but it could well be that the truth about the relation between personal identity and ethics, like persons themselves, is complicated, messy, and disunified (p. 284).

© 2009 Berel Dov Lerner

Berel Dov Lerner teaches philosophy at the Western Galilee College in Israel.

Keywords: philosophy