> Anders Sandberg wrote:
>
> > I somewhat envy the protagonists in _Permutation City_, who have
> > literally unlimited computing power...
>
> As I recall, this was the part in Permutation City which didn't work for
> me. The people uploaded into progressively more computationally complex
> worlds, and convienently forgot that somewhere there was a physical
> machine running all of this.
Remember the "dust theory" - Permutation City was not run on any specific
physical computer, but on the general substrate of reality. So if this
substrate is finite (the Bekenstein Bound for the entire spacetime is
finite), then Permutation City will eventually stop growing, while if it
is infinite (like in an open universe) then it can (and will) run
forever.
There is a slight complication here; the laws of physics in the City would
imply with mathematical certainty that their cubical universe would expand
forever. If there isn't enough computing stuff in reality, then we have a
contradiction that cannot be resolved - unless we assume that strong
platonic materialism holds, and the substrate of computation isn't really
the physical universe but mathematical reality. This is just another way
of saying that if we ignore Egan's inconsistencies near the end, strong
platonic materialism or an infinite universe holds.
I like this book for the way Egan takes an ontology and develops it
beyond its limits.
> If as an upload your "clock" is running ever more
> slowly, you won't notice, so with limited physical hardware, a simulated
> second of time might take a million physical years....
Which doesn't matter to a member of Solipsist Nation...
-----------------------------------------------------------------------
Anders Sandberg Towards Ascension!
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