[From Bill Powers (2011.06.04.0045 MDT)]
Gavin Ritz 2011.06.04.15.02NZT –
BP: Gavin, it’s really time to
switch to real physics if you’re going to try to apply advanced
mathematics to all these ideas.
GR: Bill that is
exactly what Im doing. I dont understand why you would say I should
apply real physics, when that is what Im doing. Please dont patronize
me. If you are going to teach me something I expect to be
respected.
I think that PCT is
an extremely elegant concept, and if Im to understand (and deeply) it
fully it requires me to do so from me own creative inner sets of
knowledge.
BP: You’re using laymen’s
terms for physical processes, instead of the careful and internally
consistent language worked out by thousands of scientists over hundreds
of years. “Blocking” and “resisting” are vague terms
for vague ideas, as is the way “energy” is used by you and most
nonscientists.
GR: This is a
not true, I use energy in the strictest sense of the word. Im am a
professional engineer (I have got a post graduate and undergrad
engineering degree from one of the top engineering schools in the
world), I have designed some of the most sophisticated structures
using hard engineering science, where energy is in the strictest sense of
the word energy and nothing non scientific. When I talk about energy Im
talking about energy in the physics and chemistry sense of energy,
nothing less nothing else.
I cannot understand why you would say this.
BP: Then please reconsider all this talk about energy this and
energy that, because it is not how perception works. Yes, energy is used
during perceptual processes, but energy does not make the difference
between one perception and another one, and no energy is transported
along with neural signals from one point to another. There are not
different kinds of energy from one perception to another. The perceptual
system does not take energy into the body; in fact perceiving requires
the expenditure of energy from the body’s stores. If you measured the
energy used up in one kind of perceptual process, it would be
indistinguishable from the energy used in another kind. I’m talking about
the kind of energy physicists mean.
I don’t dispute your education. I simply object to the way you are using
the terms of physics, in a way that shows little of the deep grasp of
physics that you undoubtedly have.
BP earlier: Sometimes vague
terminology is all you need because you’re not trying to communicate some
deep principle, but when you are trying to do that, or work toward doing
it, you had better take advantage of whatever specific and precise tools
there are.
GR: That is why Im
saying if one says its a variable, my question is in the strictest sense
what quality are you measuring. Show me the identities of those qualities
so we can measure them.
BP: In the environment, they are simply the ordinary quantities of
physics, but most particularly those that have sensory representations in
the nervous system. In a tracking experiment, they are the positions of
images on a computer screen (and the retinas), and the positions and
motions of an arm and hand holding a mouse.
BP earlier: Yes, a disturbance can
block the effect of a controlling action, or resist it, but it can also
cause some other alteration of the form of a connection between action
and controlled quantity, and it can occur in the form of any physical
process that affects the controlled quantity, as perceived, directly. If
I am controlling the distance between A and B, but can affect only the
position of B, a disturbing effect applied to B is a disturbance that can
change the perceived distance (if my action doesn’t change), but so is a
change in A. If I want just one light out of two to be lit to save
electricity (A and not B, or B and not A), then lighting both lights (by
any means) constitutes a disturbance of that perception. In general, a
disturbance is anything that can alter a perception other than an action
of the control system itself.
GR: We have
potential disturbing influences all the time it seems to me that the only
time its really called a disturbance is when we are in trying to control
it. Like gravity when we walk or the sunlight is too strong so we put on
a pair of sun glasses.
GR: My question is a valid one;
disturbances may be a set, what are the identities of the set or sets.
I guess you are saying Im at liberty to make these choices
myself.
BP: We do not often control disturbances; we control perceptions.
Disturbances are seldom counteracted directly and are seldom detectable
except through their effects (mostly canceled by a control system). Most
often the action that does the controlling acts directly on the
controlled quantity and does nothing to the disturbing quantity or the
connection between the disturbing quantity and the perception being
affected.
Occasionally we do try to anticipate disturbances so as to avoid them or
to be braced to meet them. But that does not lead to accurate control.
Accurate control requires that action vary as the disturbance varies even
when the changes in the disturbing variable can’t be anticipated or even
seen, as in the case of a sailor casually strolling down an interior
passageway of a ship rolling in the the waves.
When it comes to disturbances, you can divide them into different
categories if you like, but the most important thing is to recognize them
when you see or feel them. Little disturbances are happening all the
time, starting with gravity as you say, but including variations in the
world and your body that influence your movements (such as winds and
inertia) and little inaccuracies in your own behavior that move your
limbs and body not quite as you had intended. If psychologists had
noticed all the obvious little disturbances, stimulus-response theory
would have been abandoned as soon as it was proposed.
You simply have to ask what all the influences in the environment are
that can affect the world where your sensors are and that do not arise
from your own muscle tensions. That is the set of all disturbances. Of
course they must affect aspects of the world that you are controlling, to
be labeled that way.
GR: In conceptual mathematics a set
is required to have an identity so the disturbance is a variable (that is
elements of a set) what are the identities of the sets or set that
contains these variables.
BP: If the sun comes out from behind a cloud, that changes the light flux
reaching the ground. The increased light flux might reduce the contrast
on a portable television screen at a picnic, so the viewer will reach out
and turn the contrast up. Or it might make the sun too hot on the skin of
a sunworshipper, who puts the reflector aside that was being used to
increase the radiation reaching the skin. Or it might cause increased
evaporation from a plant’s leaves, and the plant will close some of the
pores to hold the water in. Or it might overheat the sand at a beach, so
the bathers hop gingerly as they walk to minimize the duration of contact
with the sand, and the crabs burrow deeper to where the sand is cooler.
Any physical variable has multiple effects, and can disturb many
different things that people or other control systems are controlling (as
well as a vastly greater number of uncontrolled physical variables). You
can’t know whether a given physical variable is a disturbance until you
find it disturbing some variable that a person is controlling.
BP earlier: That’s up to you; you can
define a set any way you want to. You can also make up whatever rules you
like for manipulating sets. Sets aren’t physical things that exist
outside us; they’re just ways of looking at collections of things, ideas,
forces, tastes, pieces of lint, anything you pay attention to. A set is a
perception. I call the level concerned with that sort of thing the
“category” level, not in any formal sense of the term, but in
the sense of “things you could throw into a bucket and treat as if
they were the same.”
GR: Ok, so
does your category have the same rules as mathematical categories then?
Qualitatively a category in conceptual mathematics is a very all
encompassing concept.
GR: The set of all stars are
not the same as the set may contain different elements in a set of
stars big stars, Cepheid stars, bright stars, red stars, neutron stars.
One cant just throw things into a bucket and call it a
category.
BP: I haven’t tried to devise any rules for categories. My basic concept
is simply the OR of all the variables that give rise to the same category
perception. There may well be more to it than that, but we would have to
study real category perception to find out.
BP: Of course one can. What about the category of all things in my left
trouser pocket (keys and a comb)? I can refer to the “contents”
of my pocket as causes of holes, without specifying which element of the
category I mean. That’s all I mean by the word. I know it’s customary to
suppose that elements of a category must have some feature in common, but
I would see that as a special case, with many other cases being possible.
How about “the set of all things that have nothing in common?”
Looking up writings on category theory on the Web, I find all sorts of
arbitrary definitions, which is OK with me, but the idea that this is the
only way to define a category seems unreasonable. Or to put that another
way, what they’re defining as a category isn’t what I mean by the word,
though I guess they have a right to their own definition. To claim that
theirs is the ONLY way to think of a category, however, goes against my
grain. How do they justify these definitions? Isn’t this basically a
game, in which you state some rules and then try to play according to
them just to see if you can?
GR: There are
mathematical rules for sets and functions and how we apply them to
identities and associations.
What was it Stafford Beer said I think it went something like this the
parsimony of natural invariance
Stafford Beer is a master of almost meaningless prose, presented so
convincingly that when I first spoke with him I called him “Sir
Stafford,” feeling sure I had heard that he was knighted. He
corrected me. He believes in the Law of Requisite Variety, which says
nothing of any importance.
GR: I dont understand how a
controlled variable can also be a function.
BP earlier: Who suggested that it could? I didn’t see any such claim.
Rick said so
in his last email.
BP: Where? I’m looking at the post of 2011.05.31.1810 from Rick, and
don’t see it.
Cite it, please.
BP earlier; A variable can be one
argument of a function,
GR: My point
exactly.
BP earlier: or the value of a
function can be a variable,
but the function itself is a
formula,
GR: My point
exactly
BP: Fine, that’s how we have all learned to speak of variables and
functions. Who is arguing with that?
BP earlier: a set of operations which
combines variables and constants to generate a value.
GR: A function in conceptual mathematics is the transformation formula.
Can you explain to me please
how a variable is also a function? A variable in conceptual mathematics
is an element of a set.
BP earlier: I don’t know what you are referring to – who said a variable
is also a function?
Rick said so
in his last email.
BP: All right, I’ll say it: no, he didn’t. So quote from the post and
show me I’m wrong.
GR: The second question is more
important (too me anyway) how do these external circuitry of the Control
system interact with other external circuitry of other control systems.
That is how do multiple external circuitries interact?
BP earlier: What do you mean by “external circuitry”?
GR: I have
just lumped all the external parts of the control circuit into one
concept.
BP: I thought you said " One cant just throw things into a bucket
and call it a category." You have just proven that you can.
BP earlier: The way I use the term
circuitry, it means neural networks inside the organism,
GR: Yes, well
it is also a sort of circuitry outside the organism although it doesnt
have the neural part; the energy is still transduced to other energies
like mechanical, sound etc.
There you go with the “energies” bit again. Variables are
transduced into variables, but energy is not transduced into energy in
the nervous system. The energy flow can go either way – consider a cold
receptor, which fires when it loses heat to its surroundings. Consider
black print on a white background. “A sort of circuitry outside the
organism” is what I mean about misusing physical terms.
BP earlier: An object with mass, for
example, converts a force applied to it into an acceleration. So we might
diagram that as
f → MASS → a
The descriptive formula would be a = f/M.
That isn’t a “circuit,” it’s just a physical process in the
environment.
GR: Im just
being a bit sloppy, it sort of is, instead of being an electrical signal
(neural etc) it is sound, heat, pressure etc that can be potentially
transduced into a neural signal (inside the organism) again in the
circular feedback process.
GR: Very simply it seems to me
that disturbances are just the perceptual blockages of these energies.
BP: The term isn’t “a bit” (sloppy), it’s “HORRIBLY.”
It “sort of is?”
BP; Well, they aren’t. They aren’t even “sort of” what
you say. They are variables that can alter controlled variables
independently of the actions of the organism. They tend to alter
variables, not “energies”. Another example of the sloppy use of
physical terms. A disturbance can increase a variable as well as decrease
its value; its effect will still be resisted.
Sorry, Gavin. I’m being mean. I’m sure you’re really a great guy, but in
this discussion you’re irritating the hell out of me. Yes, I know who is
irritating me, but it’s more satisfactory when I say it that
way.
Bill P.
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