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From: pindor@gpu.utcc.utoronto.ca (Andrzej Pindor)
Subject: Re: Knowledge and reasoning
Message-ID: <D5Jonr.As2@gpu.utcc.utoronto.ca>
Organization: UTCC Public Access
References: <738635033wnr@dolphsys.demon.co.uk> <795081420snz@chatham.demon.co.uk>
Date: Thu, 16 Mar 1995 17:59:50 GMT
Lines: 55

In article <795081420snz@chatham.demon.co.uk>,
Oliver Sparrow <ohgs@chatham.demon.co.uk> wrote:
>.. but the problem with reductionism is that it doesn't work very well when
>applied to every day experience. HIgh order systems possess properties which
>are lost when they are considered as the sum of their components. Physicists
>tend to accept - for example - self-organising criticality as an example of
>an emergent system which has properties which do not map down to its 
>components, but those who deal with organisms, systems and organisations
>(that is to say, the rest of us!) have to deal with irreducible systems as
>a permanent component of our everyday lives. 
>
I think that you misrepresent physicists' version of reductionism. Physicsts
know very well (not "tend to accept"), that ensembles of large numbers of
elements have new (emergent?) properties, which have a meaning only for the
ensembles and not individual elements. Individual molecules of gas do not 
have pressure - pressure is a property of the whole ensemble; liquid has
a surface tension, not its constituent molecules. Reductionism here means
being able to trace how these new properties of ensembles spring from 
the properties of individual elements. This no different than in the case of
"organisms, systems and organisations".
For physical systems it may be sometimes very difficult to make such 
a connection - it took 49 years from a discovery of superconductivity (1908)
to BCS theory (1957), which connected microscopical properties of electrons
to the macroscopic phenomenon. High-temperature superconductivity discovered
over 10 years ago still is not understood in terms of microscopic properties
of atoms. There is no reason to think that "organisms, systems and 
organisations" are irreducible in the above sense. They definitely are very 
complex (organisms in particular), so understanding how their (emergent)
properties spring from properties of the constituents is much more difficult.

>The Aristotelian tradition is splendid and powerful when applied to that
>which is the sum of its parts: the broad tradition of science to the end of 
>the Eighteenth century and the taxonomic tendencies of the C19th. Rather as 
>Newtonian physics works fine in its own particular domain, so this tradition
>functions helpfully where it is appropriate. There is, alas, no Young's slit
>experiemnt of the emergent domain: the detector which has to be used is our
>own understanding. We do not, for much of the time, know whether reductionism
>does not work because we are not looking at things in the right way or because
>it simply does not work like that.
>
I do not understand what you mean by "Young's slit experiemnt of the emergent 
domain". I know what "Young's slit experiemnt" is. To interpret it one needs
understanding too. How is understanding a detector in "emergent domain"?
Could you elaborate?

>
>  Oliver Sparrow
>  ohgs@chatham.demon.co.uk

Andrzej
-- 
Andrzej Pindor                        The foolish reject what they see and 
University of Toronto                 not what they think; the wise reject
Instructional and Research Computing  what they think and not what they see.
pindor@gpu.utcc.utoronto.ca                           Huang Po
