> Date: Thu, 20 Aug 2009 12:23:51 -0700
> Subject: Re: Emulation and Stuff
> From: david.ny...@gmail.com
> To: email@example.com
> On 20 Aug, 10:09, Flammarion <peterdjo...@yahoo.com> wrote:
> > > > OK. It's invalid because you can't have computaiton with zero phyiscal
> > > > activity.
> > > But that is **precisely** the conclusion of the reductio that MGA
> > > proposes. MGA claims precisely that - as you say - since it is
> > > implausible to justify the ascription of computation to zero physical
> > > activity, if you still want to claim that there is computation 'going
> > > on', then it can't be attached to physical activity. Are you
> > > questioning that MGA constitutes a valid instantiation of a physical
> > > TM? What about Olympia?
> > I should have added that you can;t have computaton with zero
> > computational activity.
> One more time then, using Olympia as the reductio ad absurdum: this
> relies on radical minimisation of physical activity to render
> implausible the notion of the attachment of instantiation-invariant
> consciousness-as-computation to PM.
I don't think the Olympia argument is really the final nail in the coffin for
the notion that computations can only be instantiated by the right sorts of
physical processes; there might be other ways of defining when a physical
process counts as an "instantiation" of a given abstract computation that don't
lead to the same problems. See my speculations about a physical process needing
to have the same "causal structure" as the abstract computation, with causal
structure defined *not* in terms of counterfactuals but rather in terms of
which facts imply which other facts, in the posts at
...this notion of causal structure isn't totally developed and probably has
holes in it, but I don't see any reason to rule out the idea that it couldn't
be developed into a coherent notion of "instantiation" that wouldn't lead to
weird reductio ad absurdums like Olympia does for computations defined in terms
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