Complexity Theory vs Complex Systems

From: Richard Loosemore (
Date: Wed Sep 21 2005 - 07:37:20 MDT

Not to be picky or anything, but people are starting to use the phrase
"complexity theory" as if it were synonymous with "complex systems".

My understanding is that "complexity theory" already has a strongly
entrenched usage: it refers to the calculation of algorithmic complexity.

Okay, so I just checked the Wikipedia, and apparently there is now
ambiguity in the usage (don't you just hate it when the language starts
to shift around underneath you?).

It would help though, to stick to the standard, since in our context
both meanings could be relevant, and someone coming fresh to this
discussion is sooner or later going to be completely confused about what
we are talking about.

[I won't even *begin* to discuss the fact that when people say
"complexity theory" and yet mean "complex systems" they *then* often
proceed to talk about chaos theory instead. Sigh :-) ]

Complexity theory (from Wikipedia)

"Complexity theory can refer to more than one thing:

     * Computational complexity theory: a field in theoretical computer
science and mathematics dealing with the resources required during
computation to solve a given problem
     * The theoretical treatment of descriptive complexity (or
Kolmogorov complexity) of a string is studied in algorithmic information
theory by identifying the length of the shortest binary program which
can output that string.
     * Systems theory (or systemics or general systems theory): an
interdisciplinary field including engineering, biology and philosophy
that incorporates science to study large systems
     * Complexity theory is sometimes used as a broad term addressing
the study of complex systems, including subjects such as chaos theory,
artificial life, and genetic algorithms."

This archive was generated by hypermail 2.1.5 : Wed Jul 17 2013 - 04:00:52 MDT