Subject: Flows (was Feedback Loops)

Posted by John Gunkler on 2/9/2006
In Reply To:Feedback Loops Posted by Prof. Dr. Niall Palfreyman on 12/9/2006

Message:

In Niall's chemical reaction example, I certainly understand "flows" to be happening. At a fairly macro level, a portion of each of the elements hydrogen, oxygen, sodium, and chlorine are "flowing" from certain states (namely, being in compounds we call hydrochloric acid and sodium hydroxide) into other states (namely, being in the different compounds salt and water.)

I wonder if Niall, and perhaps others, are a bit hung up on the ordinary language connotations of the word "flow." In system dynamics, we use this word in a clearly defined technical sense. We could have used other words, and sometimes we do ("state change" or "rate" or "policy" depending upon the context, for instance.)

Does it match my intuition or mental image to say that numbers "flow" from, say, inventory counts into annual totals? Not really. But in a system dynamics sense, they certainly do. (And, if it helps me, I can even stretch my imagination enough to see these counts acting like little particles "flowing" into a reservoir that is their total.)


John Gunkler

Follow Ups:

Flows (was Feedback Loops) - Bill Braun 2/9/2006