To: Charles C.
From: Geoffrey Klempner
Subject: Criteria for personal identity over time
Date: 30 June 2003

Dear Charley,

Thank you for your e-mail of 19 June, with your third essay for the Philosophy of Mind program, on the question, 'My Identity Through Time'.

The first question on the sheet of essay questions for units 7-9 states:

"Can one give adequate criteria for the identity of a person over time? Illustrate your answer with thought experiments describing 'problem cases' of personal identity."

I appreciate your claim that thought experiments describing problem cases might not be the best way to approach the question of personal identity. Not all philosophers are agreed that this is the best way to approach the question. But what exactly is your argument for dismissing the relevance of thought experiments?

We need to separate two questions: First, how do we, in fact, establish questions of personal identity? Sometimes this is not always possible. In a film, which (I think) was called, 'The Return of Martin Guerre' a man 'returns' to his wife, after fighting in the war. However, no-one, not even her, is sure that he is her husband, rather than an impostor. This could happen. The best knowledge available from all existing records, and human memory, might be insufficient to decide a particular question of personal identity.

I also remember once seeing a play with a similar theme, 'The Man in the Glass Case' about a Jewish man who pretends to be Eichmann, and is put on trial. At the climax of the play, his true identity is revealed.

The second question, is what personal identity *consists in*. In other words, what is the *question* we are trying to decide when deciding a person's 'true identity', as in the above examples?

Natural and social facts collude together to make a pretty robust concept of personal identity, though its robustness admittedly depends on the contingent fact that the only 'problem cases' we actually encounter are ones of limitations of knowledge - as in the above scenarios - rather than those described in the imaginations of science fiction authors.

We can go further and make the point that it is not just social *facts* that we are considering, but rather the moral implications of those facts. It is above all the moral nature of interpersonal relations that determines what 'persons' are. (I am only restating here the point made by John Locke that personal identity is a 'forensic' notion.)

I gather that you are against a 'neuroscientific' or 'neurophilosophical' theory of personal identity. However, you do not attempt to state how personal identity would be defined in neurological terms. How does a neurological account differ from Locke's 'memory criterion' of personal identity?

Thirty years ago, you were hurt in a sailing accident. Someone was hurt, the possessor of your social security number, the son of your parents, the man whose birth certificate bears the name 'Charles Countryman', and so on. These are all common facts that are hardly likely to be disputed. Today, genetics provides a pretty conclusive way of checking these things. But is that all there is to say about persons?

It would still be open for a philosopher, like Derek Parfit, to argue that we attach too much *importance* to the concept of a person, and draw the appropriate ethical conclusions.

I do take your point that our respect for persons, certainly our feelings of emotional attachment do not necessarily depend on an 'inner' identity being preserved. The car crash victim reduced to a human vegetable does not cease to be the object of feelings of 'love' despite the fact that all that remains is a living body. Switching off the life support machine without the proper authorization would still be murder.

However, for that reason I would emphasize the equal importance we attach to the first person perspective when addressing the problem of personal identity. Consider the case of the British Moors murderer Myra Hindley, who died recently in prison. Hindley participated in the torturing and killing of several young children. There was public outrage every time her case was discussed. Yet there were people convinced that she had totally reformed, found religion, become a 'different' person. I am not asking you to form an opinion on this question, one way or the other. The question is *what is at issue*? How do we decide, and on what principle? Shouldn't we be asking this kind of question when we address the philosophical issue of personal identity?

All the best,

Geoffrey