Jacques Mallah wrote:

> >From: "Saibal Mitra" <[EMAIL PROTECTED]>
> >There are different versions of QTI (let's not call it FIN).
>
>     I'm certainly not going to call it a "theory".  Doing so lends it an a
> priori aura of legitimacy.  Words mean things, as Newt Gingrich once said
in
> one of his smarter moments.
>
> >The most reasonable one (my version, of course) takes into account the
> >possibility that you find yourself alive somewhere else in the universe,
> >without any memory of the atomic bomb that exploded. I totally ignore the
> >possibility that one could survive an atomic bomb exploding above one's
> >head.  My version doesn't imply that your a priory expected lifetime
should
> >be infinite.
>
>     Your version may not imply immortality, but I don't really see how
it's
> different from other versions (and thus why it doesn't).

As I have written before, a person is just a computation being implemented
somewhere. Suppose that the person has discovered that he suffers from a
terminal ilness and he dies (the computation ends). Now in principle the
person in question could have lived on if he wasn't diagnosed with this
terminal ilness. Somewhere in the multiverse this person exists. Some time
ago I wrote (I think on the FoR list) that the transformation from the old
dying person to the new person is a continuous one. The process of death
must involve the destruction of the brain. At some time the information
that the person is dying will be lost to the person. The person might even
think he is 20 years old while in reality he is 92. Anyway, the point is
that his brain had stored so much information that adding new information
would lead to an inconsistency. By dumping some of the information, the
information left  will be identical to the information in a similar brain
somewhere else of a younger person, free from disease.

>
> >I say:
> >1) If you are hurt in a car accident and the surgeon performes brain
> >surgery and you recover fully, then you are the same person.
>
>     OK, that's merely a matter of definition though.
>
> >2) You would also be the same person if the surgeon made a new brain
> >identically to yours.
>
>     I'm not sure what you mean here.  The new brain would be the same as
the
> old you, the old one would remain the same, the old one was destroyed, or
> what?
>

Well, suppose that the damaged brain contains enough information to
reconstruct the original one. It doesn't matter if you repair the old one or
create a new one.

> >3) From 2) it follows that if your brain was first copied and then
> >destroyed, you would become the copy.
>
>     A matter of definition agin, but let me point out something important.
> If your brain is copied, then there is a causal link between the old brain
> and any copies.  Thus it's quite possible for an extended implementation
of
> a computation to start out in the old brain and end up in the copy,
without
> violating the requirement that implementations obey the proper direct
causal
> laws.
>
> >4) From 3) you can thus conclude that you will always experience yourself
> >being alive, because copies of you always exist.
>
>     I don't see how 4 is supposed to follow from 3.  In any case, it's
> certainly not true that copies of you always exist.  Rather, people who
are
> structurally identical do exist, but they are not copies as they are not
> causally linked.  Even if they were linked in the past, they have diverged
> on the level of causal relationships between your brain parts vs. their
> brain parts.


I don't understand why it is necessary for one person to qualify as a copy
of another iff there is a causal link.

>
> >5) It doesn't follow that you will experience surviving terrible
accidents.
>
>     If 4 were true, I don't see how 5 could be true.
5) is true because you can survive with memory loss (see above). You would
be killed, but copies of you exist that never experienced the accident.

Saibal



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