Re: self-producing

Bruce Edmonds (B.Edmonds@MMU.AC.UK)
Tue, 22 Aug 1995 08:23:14 GMT

> >Computer systems are, in general, necessarily dissapative. There is
> >a subset of (mechanistic) computational processes ('reversible
> >computations') that are not, but most software and computation is not
> >restricted to this subset. Most computation involves a loss of
> >information - this is necessarily so if you are using a finite
> >computer for many computations.
>
> It is important to realize that what goes on on a computer screen is an
illusion
> arranged in the mind of conscious observers. The program "Tierra" is no more

..... much deleted ......

> independent of each other. They do not interact. Any "dissipation" and
> "information loss" are therefore purely illusory.

My comments are not based on any output by the computer. Necessarily
there is a dissipation of energy when information is erased in a
computational machine. This is not so if the information is merely
moved, so that the computation is reversible, i.e. given its end
state the computer can work backwards through its steps and
eventually reach its starting state. There is a quantum limit to the
minimimum amount of energy used to erase 1 bit of information.

Thus any finite computational device, which keeps on doing
computations will be necessarily dissipative, almost regardless of
the nature of that computation.

----------------------------------------------------------
Bruce Edmonds
Centre for Policy Modelling,
Manchester Metropolitan University, Aytoun Building,
Aytoun Street, Manchester M1 3GH. UK.
e-mail b.edmonds@mmu.ac.uk
Tel no. +44 161 247 6479 Fax no +44 161 247 6802
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