Re: measuring complexity

Don Mikulecky (mikulecky@VCUVAX.BITNET)
Thu, 13 Jul 1995 09:30:51 -0400

>The following message was sent to me from Hans-Cees Speel.
>I assume he wants me to post it on PCP.
>Jeff Prideaux
>
>
>From: NET%"hanss@sepa.tudelft.nl" 13-JUL-1995 03:54:38.42
>To: NET%"JPRIDEAUX@Gems.VCU.EDU" "Jeff Prideaux"
>CC:
>Subj: RE: measuring complexity
>
> Perhaps "complexity", like "quality", is of
>> such a nature that it is illusive to conventional methods.
>
>I think you are right in ther way that we use complexity as meaning
>complicated to look at, as Bruce does I think.
>Quality is often seen as 'the difference of standards'. If you switch a
>standard you have to compute differently, etc. So to compare
>greenness with length is difficult. Humans do seem to have this
>difficulty with quality, because they are lazy thinkers, and want things
>to add up [literally] in out western society [imho].
>So I do not agree that you can't measure complexity if you have a
>standard agreed upon. Of course, if you don't undwerstand a lot of the
>complexity, you can't make a good standard, and you can't measure it.
I wish Bruce would clear this point up..I read his rejection of the Rosen
approach to complexity as a clear sttement that complexity is a property of
nature, not the way we look at it. He cites "Anticipitory Systems" when he
does this. I use the definition of complexity in Anticipatory Systems as my
working definition. Stated simply " A system is complex if we can describe it
in a variety of ways, each of which corresponds to a distinct subsystem.
Complexity then ceases to be an intrinsic property of a system, but it is
rather a function of the number of ways in which we can interact with the
system and the number of separate descriptions required to describe these
interactions.
Therefore a system is simple to the extent that a single description
suffices to account for our interactions with the system; it is complex to
the extent that this fails to be true."

Note carefully that the modeling relation is central to putting these words
into
context. If you try to interpret them out of that context, things get
hopelessly confused.
>
>..perhaps
>> requiring a different way of looking at it...perhaps it is
>> necessary not to look at it as an object (something you can attach
>> a number to)...but as something that can only be approached by
>> looking at the relationships or organization of certain interacting
>> components.
>
>Sure, and if you give these things a number [like the exponents they
>use in chaos-theory] y0u can measure it. Of course every language is
>reeducing everything eventually.
>
A numer assigned to a QUALITY is an arbitrary scale, not a measurement.
A measurement requires a metric. This is tough. We never had a
metric for thermodynamics until Network thermodynamics provided one!
I refer you to Rosen's book "Fundamentals of Measurement" which deals with
this issue in great depth and leaves little room for ambiguity.
>..and perhaps the distinguishing thing separating the
>> "complex" from the "non-complex" is the existance of a closed
>> causal loop, self-reference, strange loop, inpredicativity, or
>> vicious circle (all terms for the same thing). This is what Rosen
>> claims.
>
>These are very specific ways of defining complexity, but that's alright
>to me.
>
>Theories come and go, the frog stays [F. Jacob]
>-------------------------------------------------------
>|Hans-Cees Speel School of Systems Engineering, Policy Analysis and management
>|Technical University Delft, Jaffalaan 5 2600 GA Delft
> PO Box 5015 The Netherlands
>|telephone +3115785776 telefax +3115783422 E-mail hanss@sepa.tudelft.nl
>HTTP://www.sepa.tudelft.nl/~afd_ba/hanss.html featuring evolution and memetics!
>
The reason for repeating these things is that there is really meat in them
(sorry to the vegitarians). As I said before, Rosen is a master at using
reductionist methodology and the myth of objectivity to show the system's
intrinsic limitations. I have yet to see anyone tackle this in depth.
It can be very rewarding!
Best wishes, Don Mikulecky
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