Tuesday, December 28, 2004

Systems, Open & Closed

In systems theory, systems are described as being open or closed. Hall and Fagen's "Definition of a System" says "organic systems are open" when "they exchange materials, energies, or information with their environments. A system is closed if there is not import or export of energies in any of its forms as information..."

The "conceptual shift from energy to information is essential to the almost vertiginous development in the philosophy of science since the end of World War II, and it has had a particular impact on our knowledge of man," write Watzlawick, et al, in Pragmatics of Human Communication, 1967.

I kick a pebble. Energy is transferred from my foot to the pebble. The pebble is displaced and will move and come to rest again in a position which is determined by the amount of energy transferred, the surface on which it rolls, the size and shape of the pebble, the wind, etc.

I kick a dog and the dog bites me. The relationship between the kick and the bite is very different than the relationship between the kick and the displacement of the pebble. The energy for the dog's reaction does not come from my kick but from his metabolism. What is transferred is thus not energy but information, and the bite is the feedback to the information, which is my kick.

A kick of a pebble is a transfer of energy, but a kick to a living system is a transfer of information.

We may view the boundaries of a given system along a continuum from closed to open. A completely closed system would be one which accepts no input and gives no output. A completely open system is one which accepts and gives all.

Feedback within systems is positive or negative. Positive feedback leads to "amplification" (e.g., turning the volume knob on the stereo clockwise to increase volume). Negative feedback decreases (or is intended to decrease) "output deviation from a set norm or bias" (e.g., decreasing volume by turning the volume knob counterclockwise). With feedback, "part of a system's output is reintroduced into the system as information about the output." Feedback helps to both change and maintain the system. In a closed system there is "no change of components" within the system (Hall & Fagen).

1 Comments:

Blogger Bright_Abyss said...

Hey Jim. just checking out your blog. My name is Michael, but you might know me better as Pathos. I was wondering: I'm trying to set up a forum-ish blog at my own site, but I'm just now starting off by posting some random thoughts, interesting media blurbs, etc., and was wondering if you would let me post your "Systems, Open & Closed" blog on my site? Or I might do my typical quasi-dialogue treatment with this post, just to expand with my own thoughts... Let me know what you think.

PS~ keep doing what you are doing out there your posts, blogs, and I can imagine, your work is very much appreciated...

Thx.

Friday, April 22, 2005  

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