[extropy-chat] Role of Observer is not Relevant
lcorbin at rawbw.com
Sun Apr 8 01:56:16 UTC 2007
> Eugen argues that you can't simulate a brain by hand;
> Frank Tipler in "The Physics of Immortality" calculates
> that the energy requirements alone would forbid such
> a thing, at least in real time. But, as I think you see,
> that misses the point of the argument.
Yes. To me these dismissals have the air of protests
given to Bruno's ideas in 1600 that the stars are really
just suns, only very very far away. A critic could have
said, "such distances simply would have no practical
consequences in our lives, even if they were conceivable,
which they are not". And his conjecture that there are
infinitely many stars would likewise have been dismissed
on the *exact* same grounds that some people want to
dredge up to dispatch our extremely theoretical notions
of what could constitute a calculation.
> Extreme difficulty despite purposeful effort is a different
> situation to extreme improbability given random processes.
> An example of the latter would be a Turing-equivalent
> machine implementing my brain being realised by cosmic
> dust clouds.
You're often very good about giving proper lip service even
to theories you disagree with, but I cannot help reminding
readers that dust clouds are static arrangements of particles,
no dust cloud being causally related to any other, and no
information flow between them being performed in real time.
> It's far from clear that this could never happen (what if the
> universe is very large, or long-lived? what if there are multiple
> universes? what about the fact that there are multiple different
> abstract machines implementing a particular computation,
> each multiply realisable?), but even if it could be shown
> that it was as close to impossible as doesn't matter, that
> doesn't invalidate it as a thought experiment which says
> interesting things about functionalism and personal identity.
I agree, except for the proviso that I insist on causality in order
for a process to be said to be a computation. Note that my
statement is much stronger than it would have been five years
ago; many people who are giving up on string theory are
turning to causal-based theories, in which causality is viewed
as fundamental or axiomatic. (Smolin's recent book aludes to
several of these.)
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