Lennart Nilsson wrote:
> Bruno says:
>
> "...the notion of computability is absolute."
>
> David Deutsch says:
>
> "We see around us a computable universe; that is to say, of all
> possible mathematical objects and relationships, only an infinitesimal
> proportion
> are ever instantiated in the relationships of physical objects and physical
> processes. (These are essentially the computable functions.)
But if there is inherent randomness in QM that is not computable. So Deutsch and others insist on the MWI so that everything happens computably and then they turn around and conclude that the universe is computable. A clearly circular argument.
Brent Meeker
>Now it might
> seem that one approach to explaining that amazing fact, is to say "the
> reason
> why physical processes conform to this very small part of mathematics,
> 'computable mathematics,' is that physical processes really are computations
> running on a computer external to what we think of as physical reality." But
> that relies on the assumption that the set of computable functions -- the
> Turing computable functions, or the set of quantum computable operations
> -- is somehow inherently privileged within mathematics. So that even a
> computer
> implemented in unknown physics (the supposed computer that we're
> all simulations on) would be expected to conform to those same notions of
> computability, to use those same functions that mathematics designates as
> computable. But in fact, the only thing that privileges the set of all
> computational
> operations that we see in nature, is that they are instantiated by
> the laws of physics. It is only through our knowledge of the physical world
> that we know of the difference between computable and not computable. So
> it's only through our laws of physics that the nature of computation can be
> understood. It can never be vice versa."
>
> http://www.qubit.org/people/david/Articles/PPQT.pdf
>
>
> If it is only through our knowledge of the physical world
> that we know of the difference between computable and not computable, and I
> donīt see any flaw in Davidīs argument that leads up to that statement, then
> the notion of computability definitely is not absolute.
>
> LN
>
>
>
> >
>
>
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Received on Fri Aug 31 2007 - 13:12:17 PDT