Re: A calculus of personal identity

From: Brent Meeker <>
Date: Wed, 12 Jul 2006 17:25:07 -0700

Stathis Papaioannou wrote:
> Brent Meeker writes:
>> I would say that what makes a statement like "we're the same person from moment to moment" true
>> is that it's an inference from, or a part of, a model of the world that is "true" in the
>> provisional sense of scientific theories, i.e. it subsumes and predicts many emprically
>> verified observations (e.g. if I wake you up in the middle of the night and ask you your name
>> you'll reply 'Stathis') and it has not made any falsified predictions. So in this sense we
>> could say that our model of personhood is better than that of the day-people - not in the sense
>> that we can show theirs is false, but in the sense that ours has greater predictive power and
>> scope.
> If I were a day-person and you woke me in the middle of the night, I would say that the person
> who went to bed last night was Stathis-1 and the person now awake is Stathis-2. I would agree
> that Stathis-1 and Stathis-2 are comprised of mostly the same matter and have similar mental
> attributes, but the fact remains, the brains of my species have evolved so that waking up from
> sleep makes them believe they are a new person. This isn't a model or a theory; it's more like
> reporting that I'm hungry, or frightened. Philosophical problems arise when this feeling of
> continuity of identity (or lack of it) is equated with some empirical fact. It happens that in
> our own evolution physical and mental continuity has been strongly correlated with the subjective
> feeling of continuity of identity, and it is tempting to say that therefore physical and mental
> continuity is equivalent to or (slightly weaker) necessitates continuity of identity. However,
> this default model that we all use day to day is flawed on two counts. Firstly, the correlation
> is not necessary, but contingent on evolutionary circumstances. It is easy enough to imagine
> rational beings like the day-people who have a completely different approach to personal
> identity. Secondly, the default model is not even internally consistent, as shown in duplication
> thought experiments. If I am to be duplicated tomorrow and one of the copies tortured, I am
> worried; but when tomorrow comes, and I am not tortured, I am relieved. How is it that I "become"
> one or other copy when my mental continuity with both is the same? There is no ambiguity in the
> empirical facts, but there is ambiguity in how I experience continuity of identity - because
> these are two different things and there is no simple, consistent relationship between them.

Well, the default model, personal continuity, is consistent absent duplications...and there ain't
any yet.

My example of waking you up and asking your name was a weak one. I agree with Lee that the test of
a model is in the behavoir it predicts (and not just the vocal behavoir). And on that basis I think
the model of personal continuity would be a better one, and you might even convince a day-person of
it; Just the reverse of trying convince people here that there isn't *really* continuity. Of course
if they didn't act as if there were personal continuity, their physical continuity would likely end.

Brent Meeker

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Received on Wed Jul 12 2006 - 20:26:10 PDT

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