# Description and explanation

**URL:** <http://discourse.iapct.org/t/description-and-explanation/3442>\
**Category:** CSG1996\
**Created:** [October 24, 1996, 4:16pm UTC](http://discourse.iapct.org/t/description-and-explanation/3442 "1996-10-24T16:16:16Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Bruce\_Gregory9](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/43a26b/32.png) [@Bruce\_Gregory9](http://discourse.iapct.org/u/Bruce_Gregory9)\
**Post date:** [October 24, 1996, 4:16pm UTC](http://discourse.iapct.org/t/description-and-explanation/3442/1 "1996-10-24T16:16:16Z")

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[From Bruce Gregory (961024.1115)]

> From Rick Marken (961023.1320)

> Have you seen Bill Powers' "Gatherings" program in action? I think it's  
> available on Dag's PCT Demos disk. Anyway, in one scenario (called "guru" I  
> think) a bunch of dots (representing individuals) converge toward and  
> eventually encircle a stationary dot -- the "guru". I am thinking that a plot  
> of the dynamical pattern of movements of these dots resembles an "attractor".  
> I presume that are a set of dynamical equations -- the attractor "theory" or  
> equations -- which (with the appropriate parameter settings) can generate an  
> approximation to the dynamical behavior of the set of dots. These equations  
> do not (to my mind) provide an explanation of the behavior of the dots; they  
> simply describe the behavior of the dots.

Indeed. But this is not what Martin is talking about. Martin,  
like Kent, is talking about the behavior of control systems.  
Both are using the same "dynamical equations." Bill's "guru"  
exists as an "attractor" in real space (or at least in a  
two-dimensional representation of real space). Martin is  
talking about behavior in a more abstract phase space. The  
paths of the individuals in this phase space look different  
than the paths of the individuals in 3-space. In the phase  
space the paths may or may not reveal the presence of an  
attractor. This attractor is not a new "force" or principle. It  
is simply a way of describing the trajectories in phase space.  
You can certainly prefer not to look at what is happening in  
phase space. It is not something that I find illuminating  
either. Martin is fond of phase space. He finds it  
illuminating.

Bruce