Subject: Feedback Loops

Posted by Prof. Dr. Niall Palfreyman on 2/8/2006
In Reply To:Feedback Loops Posted by Jay W. Forrester on 2/7/2006

Message:

I certainly think feedback loops are ubiquitous, but I'm not sure I'd say they "control" all change. In fact given the discussion of the last few days I'm not even sure we have a shared definition of feedback loops. Are they something that happens between a flow and a stock, or between two stocks?

I'm thinking of the reaction of hydrochloric acid with sodium hydroxide to produce salt and water. This isn't a strict "flow" from one stock to another, but rather a _process_ which depletes the two stocks hydrochloric acid and sodium hydroxide, and fills the two stocks salt and water. And all four compounds contribute to the rate of this process, so there is certainly feedback between them and the process, but is "loop" the right word for this? I think of it rather as a dance, or narrative, in which all four compounds take part. So for me a "feedback loop" is an extremely useful, but nevertheless somewhat artificial, way of analysing this dance into individual interactions between the compounds and the reaction in which they participate.

Hopefully more circumspectly than my last attempt, Niall.

Follow Ups:

Feedback Loops - Bill Braun 2/9/2006 
Feedback Loops - Florence Duarte 2/9/2006
Feedback Loops - John Gunkler 2/9/2006 
Feedback Loops - Bill Ellis 2/9/2006
Feedback Loops - Ford, Andy 2/8/2006 
Feedback Loops - Jay W. Forrester 2/9/2006