From: Anders Sandberg (nv91-asa@nada.kth.se)
Date: Tue Jan 14 1997 - 05:40:12 MST
On Mon, 13 Jan 1997, Lee Daniel Crocker wrote:
> > 2) An analog computer MUST have an infinite number of internal states, so it
> > must be built with infinite precision, but quantum mechanics tells us that
> > is impossible.
>
> It says no such thing. It says only that the precision of our outputs is
> limited by what we choose to observe--no limit at all on the unobservable
> precision, nor is it a contraint on what we may choose to measure.
What about the Bekenstein Bound?
> > 3) If your analog computer is operating at any temperature above absolute
> > zero (and it will be) it will be subjected to thermal vibrations further
> > reducing it's precision.
>
> Unless those thermal vibrations /are/ its computational facility.
By definition thermal noise is a source of high entropy. It seems
unlikely it could be used for computation (if you use thermal signals
above this level, its just a normal computer).
> > 4) Unlike digital machines, any errors in a analog machine are cumulative.
> > This is very serious in all but the simplest calculations.
>
> This is true to an extent, but negative feedback mechanisms for error
> correction are possible in the analog domain.
But this negative feedback would also counteract the "infinite precision"
of analog computation by shrinking the phase space. At best you could do
your computations on a strange attractor.
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