[ExI] The Reality of Categories

Stathis Papaioannou stathisp at gmail.com
Tue Jul 17 04:00:01 UTC 2007

On 17/07/07, Lee Corbin <lcorbin at rawbw.com> wrote:

> > What would you actually say to an alien who thought you were crazy to
> > assert that the rock was the same rock as yesterday?
> I would first make sure that there was not a communication
> problem.  Then I would ask him why the two rocks were
> not the same.  He might say that one was a "today-rock"
> and one was a "yesterday-rock", but that would probably
> indicate nothing more than a communication or language
> difficulty. He might say that extremely fine changes had
> occurred to the rock that were important to his people
> or whatever. Still, I would refuse to believe him if he said
> that the lake today has more in common with the rock
> yesterday than the rock today has in common with the
> rock of yesterday. (of course, it's possible that he's been
> artificially created by scientists to mouth absurdities, just
> like many programs we too have written).

The point is, it is a different rock from day to day, but for certain
practical purposes (which a naturally evolved being would know about)
it is reasonable to ignore the differences and call it the same rock.

In the context of personal identity, it is not just the degree of
similarity that matters. I am roughly as similar to the person I was
yesterday as I will be to the person who identifies as being me
tomorrow, and yet I don't anticipate surviving in my yesterday
incarnation, not even if he exists in a timeless block universe.

Stathis Papaioannou

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