Are you positive about the negative feedback?

[From Rick Marken (960112.1400)]

Bruce Abbott (960112.1040 EST) --

It [the engine analogy of the Killeen model] is a positive feedback loop,
and would lead to catastrophic runaway of the engine RPM were it not for
limiting factors that increase even more rapidly with RPM than the increase
in rate of energy input and thus lead to an equilibrium of forces at some
particular RPM... Killeen's system will behave in this fashion.

Now I'm confused (as usual). I had said:

If Killeen's model actually is a closed loop model then it is either a
positive feedback model (which is stable only when the loop gain is less
than 1.0) or a negative feedback model. If it is the latter, then it's a
control of perception model

And you [Bruce Abbott (960111.1145 EST)] replied to this with:

Well, Rick, don't let a mathematical proof get in the way of your
assertions; if it proves you wrong, just ignore it.

Killeen's 1995 JEAB model is a control system in the outer loop.

So in your post of (960112.1040 EST) you say that Killeen's model is a
positive feedback system that is in equilibrium (which means a loop
gain < 1.0). But in your earlier post (960111.1145 EST) you scold me for
ignoring your mathematical proof that Killeen's model is a control system
(suggesting a negative feedback system with high loop gain). Is Killeen's
model both a positive and a negative feedback system all at once? Is
it like god: father, son and holy spirit all rolled into one?

Best

Rick