[Bulk] Re: a chemical equation of equilibrium and
negativ
[Martin Taylor 2006.05.09.11.33]
{From Bjorn Simonsen (2006.05.09,14:50
EUST)]
From Bill Powers (2006.05.06.0810
MDT)Of course if a control system operates to change
position or
angle, there are inertial forces that result from
linear or angular
accelerations (as you point out), so a
gravity-like force is involved
– but that’s just a property of the world the
control system lives
in, and I can’t see any special connection with
the principles of
control. Gravity isn’t needed for control systems
to work.I agree that Gravity isn’t needed for control
systems to work. But people living today have two feet. Those limbs I
think are specialized to keep people upright. When you go to the
fridge for a beer (it is a warm summer day today) you walk on your
feet. If gravity didn’t exist, I don’t think you would have had
feet. I think you still would have had fins and nobody would have
generated beer. Or maybe you would have had four arms to avoid
collisions with the roof…I think Martin would not hear the secretary asking him
his name. No gravity, no sound. (the air molecules would have left the
earth long ago).I think gravity is one of the reasons for all
perceptions I control.I enjoyed your example about the ph of blood. I will
come back with an example of the equation of
equilibrium.
If the
only point of Jim’s quetion was to assert that all living control
systems evolved in a gravitational field, there wuld have been no
argument. It’s too obvious for that to have been at
issue.
The way I
understood the question was not that organisms always live in a
gravitational field (other than those in orbit), but whether all
control systems in organisms control for gravitational effects. It’s
this latter question that makes some sense when the questioner is
relatively new to PCT. The answer is that the control systems that
control against gravity are pretty low-level ones, whether or not you
accept the Powers hierarchy. Simple consideration of the necessities
of evolution tells you that much.
So the
question becomes whether all control systems in living organisms are
complexes that control for vectorial (multiple independent) values, of
which one of the values is always related to gravity, or whether there
exist control systems, complex or not, in living organisms that do not
include gravity among the components of the perceptions for which they
control.
If you
accept that there exist simple scalar control systems (the ones that
are the very foundation of PCT, which control the value of a single
numerical variable), then it is obvious that there exist control
systems that don’t include gravity as a component of the controlled
perception. The alternative is that ALL living control systems control
ONLY for gravitational effects, and that clearly isn’t the case. A
trivial counter-example is controlling for being neither too hot nor
too cold.
If you
think of an organism as being A single control system, it’s a very
complex one, and one which necessarily includes gravity among the
aspects of its controlled perceptions. PCT asserts that this very
complex control system is actually constructed of a lot of simple
ones, few of which are in any way related to gravitational effects.
HPCT (Hierarchic PCT) describes a particular organization of this
kind, but HPCT is not required in order to conclude that there exist
control systems that don’t involve gravity.
I think
that the point Jim may have missed is that what is controlled is
independent of the actions that may be effective in influencing the
value of the controlled perception. When you control for the
temperature perception, the action is simply to invoke (change
references for) other controlled perceptions: you might take off a
sweater, move to a cooler room, walk to and change a thermostat, etc.
All of those actions are EXTERNAL to the temperature control system.
They form part of its enviromnetal feedback loop. Those actions, in
turn, influence control of perceptions such as “perceiving
oneself to be not wearing a sweater”, which in their turn evoke
(set reference values for) other perceptions external to the evoking
perceptual control systems. Eventually, in that cascade of reference
settings, it is almost inevitable that references are set for control
systems whose actions are indeed working with or against gravity. But
gravity is an element only of the perceptions those peripheral control
systems control.
At the end
of this, I might admit to some scepticism as to whether gravity itself
is ever perceived, separately from the perceptions of the muscular
forces that act to influence the peripheral perceptions that are
controlled. One can indeed see falling objects, and feel weight, but
it took one of the greatest scientists of the last millenium to INFER
the existence of gravity, and another equally great one to provide a
better conception of why we do perceive falling objects and feel
weight.
Martin