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Article 2243 of comp.ai.philosophy:
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>From: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: comp.ai.philosophy
Subject: Re: Scaled up slug brains
Message-ID: <60637@netnews.upenn.edu>
Date: 18 Dec 91 16:42:49 GMT
References: <60372@netnews.upenn.edu> <349@idtg.UUCP> <60435@netnews.upenn.edu> <351@idtg.UUCP>
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Reply-To: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
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In-reply-to: dow@idtg.UUCP (Keith Dow)

In article <351@idtg.UUCP>, dow@idtg (Keith Dow) writes:
>Simple, only infinite systems have a phase transition.

Finite cellular automata can exhibit phase transitions.

>The n->oo is a real infinity.

Says who?  I've yet to see a statistical mechanics textbook make the
claim that there are really infinitely many molecules in their ideal
gases.

>Yes, please give the reference to the experiment.  Too bad it does not
>exist.

I've posted the same reference on pumped phonons condensations three
times now.  They exist, but maybe not at your site.

>Hardly, it is my two cents worth.  Also chemsists, like others, can be 
>fooled if you get them out of their field.

Froehlich is not a chemist.  He's a physicist.  He's not a biologist,
though, which is why others do the relevant experiments.

>>>The few claims I have heard for Bose-Einstein condensation are for materials
>>>below 10 degrees kelvin.

>>Then you simply have not heard enough.  Laser light is a pumped photon
>>condensation, as originally proposed by Dicke before lasers were invented.

>Your homework assignment is to write down a thousand times.
>"Statistical mechanics and thermodynamics apply only to systems
>in or near thermal equilibrium."

I guess you never got past the undergraduate courses.  They didn't
give homework so slugbrained in the graduate courses I took.

Perhaps you might write to Stockholm and explain to the people there
the awful mistake they made when they gave Ilya Prigogine some money
and a cute little medallion with an Alfred Nobel engraving in honor
of his seminal work in non-equilibrium thermodynamics?

>Since laser are described with negative temperatures,

You contradict yourself.  Negative temperatures show up when talking
about finite systems, not the n->oo that you say is a real infinity.

>						       and they are
>hardly near thermal equilibrium, they are not a candidate for
>Bose-Einstein condensation.

A Bose-Einstein condensation is what the rest of us call a collection
of bosons in the ground state.  No more, no less.  If they stay there
on their own (equilibrium) good.  If they stay there because something
keeps pushing them there (non-equilibrium) good.

The proper way to describe the thermodynamics of laser light is irrelevant.
The pumped photon condensation exists in a 300K environment whether you
view the temperature of the laser light via infinite, negative, imaginary,
quaternionic or elvish temperature scales.  A pumped phonon condensation
could survive 300K just as well, no problem.

>>"Bose-Einstein condensation" is a noun phrase used to describe a certain
>>quantum mechanical state.  Its usage in no way shape or form requires that
>>the associated verb "to condense" be applicable.

>>Try and come up with more sophisticated arguments than irrelevant etymology.

>Not true.  Bose-Einstein condensation refers to bosons occupying the lowest
>energy state.

What I said.  It does not refer to how they got there, whether by phase
transition or pair formation or pixie intervention or too much keyboard
drool.  Either the bosons are all in the ground state, or they aren't.

>>>Since humans evolved from the level of slugs and other lower life forms 
>>>(i.e. graduate students), what is the problem with the idea that gradual
>>>improvements lead to what we are now?

>>It sometimes doesn't explain enough.

>Like what doesn't it explain?  If a process with no intelligence can create
>humans after a billion years, it should be little problem for homo-sapiens to
>understand how it was done in less than one tenth of one percent of that 
>time.

Indeed.  But who said it was gradual all the way?

>Fine, then we all agree that the brain is a machine which will soon
>be understood.

The question has been *what* kind of machine.  "Soon?"  AI folks have
been singing that tune for three decades now.  Soon on geologic time
scales, for sure.
-- 
-Matthew P Wiener (weemba@libra.wistar.upenn.edu)


