Re: self-producing
Don Mikulecky (mikulecky%VCUVAX.BITNET@letterbox.rl.ac.uk)
Tue, 22 Aug 1995 09:14:14 -0400
>> >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
>WWW. http://bruce.edmonds.name/bme_home.html
>
Been really busy getting through finals, etc for two summer courses and
getting ready for classes that start this week. I had to wonder about the
discussion of "dissipative" processes. Being a thermodynamicist, I naturally
see all real processes as "dissipative". Prigogine coined the term
"dissipative structures" to single out a distinct subcategory, namely
things like Benard cells, the Zhabotinsky reaction, the Oregonator,
the Brusselator, etc. What makes these unique is not that they are
dissipative so much (since all non-equilibrium processes are) but that their
NONLINEARITY led to self organization. We also have many examples of this
idea in enzyme systems. I hope this helps.
Best wishes, Don Mikulecky