What is PCT for?

From [Shannon Williams 19 March 2004 19:00]

Goal [Identify a procedure for self moderation]

[From Bryan Thalhammer (2004.03.19.1505)]

I propose a "moderated" forum, one where the contributors "moderate
themselves" according to a code of behavior

Should behavior be moderated or should the goal of the behavior be
moderated?

Perhaps we start each email with:

From [John Doe time]

Goal [desired result of message]

Shannon

[From Bryan Thalhammer (2004.03.19.2105 CST)]

Shannon,

One of the goals of the behavior should be the perception of m�derate
behavior on CSGnet.

It's like this, just watching from the sidelines, I feel that certain
contributors have taken unfair advantage, regardless of other people's
abilities to put up a defense. One notion of a bully is someone who riles up
a victim so that he or she finally hauls off and pops the offender. Then the
bully calls attention to this last frame of the interaction, and says,
"Well, now see who is violent?!"

I really don't want there to be forced moderation (sorry Rick), but
self-enforced moderation, which is far better and in accordance with what we
really want (ok, Rick?!). That is just to say, let's everyone deal with this
as responsible colleagues, using implicit goals of posting, learning,
sharing, collaborating, and evangelizing PCT.

[insert graphic here]

If I were able to draw a graphic here, I would draw a big arrow. Inside, I
would draw little arrows, and all of the arrows would be generally pointing
in the same direction as the big arrow, and all going about the same speed
as the big arrow, driving it along to somewhere we can't see. Now, each of
those arrows inside are US, and the vectors of those arrows are the actions
of each person represented. Most of the time, the arrows are approximately
the same size and shape, and they all are generally distributed. But it
would be possible at times for one arrow to change its shape, velocity and
direction, and for groups of arrows to gather together into separate groups.
But in this little whiteboard drawing, I would say that we don't want to see
them turn into bumper cars or killer whales, making a hard time for the
other little arrows and impacting the outline, direction, and velocity of
that big arrow.

[insert a wink here]

This should not be very difficult, yet some very intelligent folks here are
turning their arrows into bumper cars with spikes and killer whales with
teeth, banging the heck out of the whole graphic. So...? If a little arrow
does not play nice, what do we do, let the arrow continue to wreak havoc? Or
should we help that arrow become more like the others? Failing that, could
we reasonably take the little arrow out and put it in some other graphic?
Just asking...

Shannon, I just don't want to lose the idea that people here should
understand that being here in CSGnet has both responsibilities and
consequences, and that if one does not take responsibility for his/her
actions, then the game is over. It is not worth it. As it happens, I am
wasting far more time on this monolog that I should, but I feel so darned
passionate about PCT, that not being able to see beyond the NOISE when
someone starts wrecking the dialog, I get so frustrated.

TY.

--Bryan

···

-----Original Message-----
From: Control Systems Group Network (CSGnet)
[mailto:CSGNET@listserv.uiuc.edu]On Behalf Of Shannon Williams
Sent: Friday, March 19, 2004 8:46 PM
To: CSGNET@listserv.uiuc.edu
Subject: Re: [CSGNET] What is PCT for?

From [Shannon Williams 19 March 2004 19:00]

Goal [Identify a procedure for self moderation]

[From Bryan Thalhammer (2004.03.19.1505)]

I propose a "moderated" forum, one where the contributors "moderate
themselves" according to a code of behavior

Should behavior be moderated or should the goal of the behavior be
moderated?

Perhaps we start each email with:

From [John Doe time]

Goal [desired result of message]

Shannon

From[Bill Williams 20 March 2004 6:20 AM CST]

[Bryan Thalhammer (2004.03.19.2105 CST)] argues that

One of the goals of the behavior should be the
perception of m�derate behavior on CSGnet.

I am not objecting to what you are saying, but I have no idea what you mean
by "moderate behavior."

It's like this, just watching from the sidelines, I feel that > certain

contributors have taken unfair advantage,

regardless of other people's abilities to put up a
defense. One notion of a bully is someone who riles up
a victim so that he or she finally hauls off and pops the > offender.

Then the bully calls attention to this last frame > of the interaction, and
says, "Well, now see who is

violent?!"

Instead of "bully" I think a more accurate term would be "tease."

Byran goes on to say that with intelligent people it should be possible for
CSGnet to be a place where people can carry on moderate (whatever this
means) reasonable, productive discussions.

This should not be very difficult,

It might not be "very difficult." However, I think that it does require
conditions that are different in some important respects from those that
have been characteristic of the conditions typical of CSGnet.

Bryan goes on to say that,

yet some very intelligent folks here are
turning their arrows into bumper cars with spikes and
killer whales with
teeth, banging the heck out of the whole graphic.

I think this is an excellent description of what has been happening.

So...? If a little arrow
does not play nice, what do we do, let the arrow
continue to wreak havoc? Or
should we help that arrow become more like the others? Failing that, could
we reasonably take the little arrow out and put it in
some other graphic?

Just asking...

Your use in the above of "we" invokes an undefined term. Who in the CSGnet
"non-community" is this "we?" I don't perceived that there has been on the
CSGnet forum an adaquate sense of "we" or community so what your idea about
providing "help" at this point doesn't appear to me to have any basis in any
recognizable reality.

There is another issue involved here as well. Your discussion implicitly
assumes that your "we" is at all competent to make decisions such as
regarding the question of "what if the little arrow does not play nice."
What if the "we" is a bit crazy? In my opinion the possiblity that the
"we" might not be entirely sane is not at all improbable.

Shannon, I just don't want to lose the idea that people here should
understand that being here in CSGnet has both responsibilities

But, to whom or to what are these "responsiblities" owed to?

and

consequences, and that if one does not take responsibility for his/her
actions, then the game is over. It is not worth it.

I think a decision about whether "the game is over" and
whether "it isn't worth it, " is something that each of the participants on
the CSGnet, and in CSG will make for themselves. I don't think any one
individual, or even any partial collection of indivdiduals is in a position
to make a decision that "the game is over" for everyone else. Nor whether
it "isn't worth it" for everyone or anyone else.

As it happens, I am
wasting far more time on this monolog that I should,

I may not agree with all that you are saying, but I am puzzled as to why you
would feel what you are doing or attempting to do by this post would be a
"waste of time."

but I feel so darned
passionate about PCT, that not being able to see
beyond the NOISE when
someone starts wrecking the dialog, I get so
frustrated.

I don't find it at all hard to see why you might feel this way.

[From Bill Powers (2004.03.20.0821 MST)]

Bill Williams 20 March 2004 6:20 AM CST--

Instead of "bully" I think a more accurate term would be "tease."

My definition of a bully is someone who has the ability to hurt others,
uses it, and is proud of it,

Best,

Bill P. .

From[Bill Williams 20 March 2004 10:20 AM CST]

[From Bill Powers (2004.03.20.0821 MST)]

Bill Williams 20 March 2004 6:20 AM CST--

>Instead of "bully" I think a more accurate term would be "tease."

My definition of a bully is someone who has the ability > to hurt others,

uses it, and is proud of it,

Like Humpty Dumpty you are free to use words to mean whatever you wish them
to mean.

My definition of a bully would be a person who uses an advantage to do
something that is unfair to other people. Sometimes it can be difficult to
tell when a fight is going on just who started it. Was there first a sly
pinch, that drew forth an open punch? Or is something malicious being said,
or implied?

In case there is any question about the situation, I do not regard my
postings to the CSGnet as "unfair." However, hurting other people, I would
like to point out, is not always necessarily unfair.

But let me expand upon your definition. People might think that when you say
that "My definition of a bully is
someone who has the ability to hurt others, and uses
it, and is proud of it." you were making a comment about me. OK. I think I
have demonstrated a capacity to say stuff that other people find painful.
And, I don't think there is any doubt that I have used such a capacity. And,
if there is any doubt about it, I take pride in having done so. In my own
view, however, I have done what I have done for a reason, and I have done so
for a good reason. Rick doesn't have to pick fights with me. Neither do
you.

I say, I suspect that indirectly by your post you may have been implying
that I have behaved badly. If that is what you wish to say, then why not
say so explicitly? If not you can indicate that in providing a definition of
the meaning of the term "bully" you were not in anyway implying anything at
all about me.

Bill Williams

[From Bill Powers (2004.03.20.15239 MST)]

Bill Williams 20 March 2004 10:20 AM CST --

But let me expand upon your definition. People might think that when you say
that "My definition of a bully is someone who has the ability to hurt
others, and uses it, and is proud of it." you were making a comment about me.

I was. Also about anyone else who shows those characteristics, and I could
(but won't) name others. And I must say that I wouldn't know so much about
bullies if I hadn't found myself in that role once or twice.

OK. I think I
have demonstrated a capacity to say stuff that other people find painful.
And, I don't think there is any doubt that I have used such a capacity. And,
if there is any doubt about it, I take pride in having done so.

Then you are acting exactly in accord with my definition of a bully.

In my own view, however, I have done what I have done for a reason, and I
have done so for a good reason.

Of course. Every bully does, in his own view. If he did not feel justified,
he would not act that way. The same goes for every person. You, me, Rick,
and everyone else.

Rick doesn't have to pick fights with me. Neither do you.

I know. Nor do you have to retailiate massively for minor or imagined
slights. We do as we intend to do, for what we consider to be
good higher-order reasons.

I say, I suspect that indirectly by your post you may have been implying
that I have behaved badly. If that is what you wish to say, then why not
say so explicitly?

All right, in my opinion you have, in the past, behaved like a bully (and
I'm grateful to Bryan for putting his finger on the exact term). However,
we have not talked about whether being a bully is good or bad. I can think
of a number of reasons for which being a bully is a bad idea. For one
thing, unless other people exert considerable self-restraint by not
defending themselves against false characterizations, malicious
distortions, and so on, it is likely to result in massive opposition that,
one way or another, puts an end to the bullying.

If not you can indicate that in providing a definition of
the meaning of the term "bully" you were not in anyway implying anything at
all about me.

But I was, about you among others, so your inference is correct. I can't
guess why you have chosen this policy, which seems to be "Anything bad you
do to me I will do back to you ten times worse." This sort of policy is
only remotely practical if just one person adopts it. If two or more people
adopt it, you have immediate escalation of conflict to the maximum possible
level. I don't think we need a model to verify that point. If you choose
to reactivate this policy in retaliation for my calling you a bully
(despite your admission that you do in fact behave according to my
definition), then this tentative rapprochement will be destroyed
immediately. Your call.

There was once a rather famous person who said, "Let him among you who is
without sin cast the first stone." Not one of us can claim to have behaved
without error in the past, nor can we promise to be perfect in the future.
What we can do is decide to be tolerant and lower the gain, so we do not
overreact to small disturbances and go unstable, or deliberately put the
worst interpretation on what we read or hear and push back against
nonexistent forces.

I am sick to death of spending so much time talking about sociology when
far more interesting subjects are waiting to be discussed. Aren't you, too?

Best,

Bill P.

From[Bill Williams 20 March 2004 6:30 PM CST]

[From Bill Powers (2004.03.20.15239 MST)]

Bill Williams 20 March 2004 10:20 AM CST --

Earlier today one of my supporters called me, to congratulate me upon my
recent performance. The supporter is a long time CSG member who has, is,
and will continue to make a "substantial" contributor to the CSG community.
While my caller didn't wish to become personally involved in the recent
disputes they wished to say that their choosing not to become involved was
in no way an indication that they disaproved of me or my participation.
Rather they expressed a warm approval for what I have been doing. Silence
in their case was due to their recognition that becoming involved would
destroy their role and the work they were doing which they percieved as
important in their life and also to the functioning of CSG. They trusted
me enough to talk openly with me about their view of recent disputes, but
they did so over the phone. They did so, I believe, in large part because
they did not wish to create a record of a candid conversation. You by your
behavior have created a threatening situation in which people fear that
being associated with me would damage their standing and role in CSG. Now,
you may think that this is another instance, as you say of "shocking
stupidity." How , you might think, could anyone think that you ever act
out anything but the best of motives? Before moving on, I want to say
that I perceive of you as being, for the most part, a reflective, person who
engages in self-criticism. So, I would ask that you accept what I am saying
in the above as something other than a malicious dig.

One of the things my caller suggested was that a line by line mode of
communication was one of the traits of email that tend to escalate disputes.
And, it seems to me the my caller has a point, and a good one. So, in this
communication I am not for the most part going to go line by line through
your message. If as a result I ignore some part of your posting that you
perceive as being sufficiently important that I need to respond to it, bring
it to my attention and I will attend to it.

Now, the main point of your posting is that I am a "bully."
OK. By the dictionary definition the common meaning that people have
assigned to the term "bully" is, and I take the definition from my 1950 _New
College_ 50 cent book sale dictionary, "1 [Pop] Excellent; admirable."
Now, you have in Humpty Dumpty fashion chosen to use your own definition of
the term, an unfortunate definition and first apply this unfortunate
definition to me first indirectly, and then when querried, directly. You
are continuing an attack upon my character.

You say, "I can't guess why you have chosen this policy, which seems to be
"Anything bad you do to me I will do to you ten times worse."

Isn't this just what a fight is about. What is it that you find so strange
that you can't guess why I have chosen this policy? It seems perfectly
ordinary to me. You and I, and Rick and I have been having fights. Actually
all the fights amount to is our talking trash to each other. So, as far as
I can see, all your complaint amounts to when a fight starts I can handle
myself pretty well. Yours is basicly a loser's complaint.

Then you make a threat.

If you choose to reactivate this policy in retaliation for > my calling

you a bully (despite your admission that you > do in fact behave according
to my definition), then this > tentative rapprochement will bedestroyed
immediately.

And, then you issue a challenge.

> Your call.

So, after having been defeated, you are going to try and convert a loss
into a victory? There hasn't yet been a rapprochement. You are continuing
the fight. You want to be the victor. You want this to end with your being
the winner on moral terms.

Why not retract your insistence that I am morally inferior. Then maybe we
might be in a better position to talk to each other like reasonable people.

You close by saying,

I am sick to death of spending so much time talking

> about sociology

When were we ever talking about sociology?

when far more interesting
subject are waiting to be discussed.

Aren't you, too?

Well, I would be happy enough to talk about other things, after you decide
that it isn't worth it to continue the fight.
But, you are still in the "I am a winner." and "You are a loser." mode.

You know, it occurs to me, why would anyone want to talk to a loser? And,
why would I want to talk to you?
Why, if there were alternative choices, would anyone want to talk to
someone who as a condition of discussion insisted upon defining things in
terms of winners and losers?

You talk about "tolerance" and at the same time insist upon calling me a
"bully." Maybe this looks to you like a good starting point for a
discussion?

May I say that it doesn't appear to me that you have a good understanding of
a control theory analysis of conflict. You are probably tired. Why not give
it a rest for a while and rethink the problem. Maybe you can come up with
some basis for a discussion other than one which starts with you win and I
lose.

By-the-way, what's RIck been up to recently?

Bill Williams

From[Bill Williams 20 March 2004 6:00 PM CST]

[From Bill Powers (2004.03.20.15239 MST)]

Bill Williams 20 March 2004 10:20 AM CST --

Talking on the phone today with an active member of the CSGnet community who
no one question makes a substantial communication

>Rick doesn't have to pick fights with me. Neither do you.

I know. Nor do you have to retailiate massively for minor or imagined
slights. We do as we intend to do, for what we consider to be
good higher-order reasons.

>I say, I suspect that indirectly by your post you may have been implying
>that I have behaved badly. If that is what you wish to say, then why not
>say so explicitly?

All right, in my opinion you have, in the past, behaved like a bully (and
I'm grateful to Bryan for putting his finger on the exact term). However,
we have not talked about whether being a bully is good or bad. I can think
of a number of reasons for which being a bully is a bad idea. For one
thing, unless other people exert considerable self-restraint by not
defending themselves against false characterizations, malicious
distortions, and so on, it is likely to result in massive opposition that,
one way or another, puts an end to the bullying.

>If not you can indicate that in providing a definition of
>the meaning of the term "bully" you were not in anyway implying anything

at

>all about me.

But I was, about you among others, so your inference is correct. I can't
guess why you have chosen this policy, which seems to be "Anything bad you
do to me I will do back to you ten times worse." This sort of policy is
only remotely practical if just one person adopts it. If two or more

people

adopt it, you have immediate escalation of conflict to the maximum

possible

level. I don't think we need a model to verify that point. If you choose
to reactivate this policy in retaliation for my calling you a bully
(despite your admission that you do in fact behave according to my
definition), then this tentative rapprochement will be destroyed
immediately. Your call.

There was once a rather famous person who said, "Let him among you who is
without sin cast the first stone." Not one of us can claim to have behaved
without error in the past, nor can we promise to be perfect in the future.
What we can do is decide to be tolerant and lower the gain, so we do not
overreact to small disturbances and go unstable, or deliberately put the
worst interpretation on what we read or hear and push back against
nonexistent forces.

I am sick to death of spending so much time talking about sociology when
far more interesting subjects are waiting to be discussed. Aren't you,

too?

···

Best,

Bill P.

[From Bill Powers (2004.03.21.0626 MST)]

Bill Williams 20 March 2004 6:30 PM CST --

You are probably tired. Why not give it a rest for a while and rethink
the problem. Maybe you can come up with some basis for a discussion other
than one which starts with you win and I lose.

Excellent idea. Let's both do that.

I think I may have come closer to understanding how Keynes arrived at his
idea that savings equals investment. If you're still working on your
exposition, perhaps you can check this out to see if you agree.

While I'm at it, I'll discuss some general ideas about modeling, as you
previously suggested I do. In particular, I think we need to talk about the
"test bed" idea in which we separate properties of the human agents from
properties of the objective environment in which they operate, where
"objective" means only that the characteristics of this environment are
independent of the observer. It is always important in PCT modeling to have
a model of the control system AND a model of its environmment. I hope the
meaning of that will become clearer as we go along.

In Chapter 6, Keynes begins (p. 52) with some bookkeeping. "During any
period of time, an entrepreneur will have sold finished output to consumers
or other entrepreneurs for a certain sum which we will designate as A. He
will also have spent a certain sum, designated by A1, on purchasing output
from other entrepreneurs. And he will end up with a capital equipment,
which terms includes both his stocks of unfinished goods or working capital
and his stocks of finished goods, having a value G."

He then goes into the problem that part of the value of G comes from "the
capital equipment which he had at the beginning of the period." So he sees
a problem in defining income, which he proceeds to attack in a way that
seems unneccessarily complex. This is the section where he introduces the
idea of User Cost, which seems to involve estimates of how much more the
production equipment would have been worth if it had not been used for
production of output. I have finally realized what he was talking about: he
was talking about the cost of maintaining capital equipment against the
deterioration due to its use (a cost proportional to the amount of goods
produced, to a first approximation), plus other costs which are simply a
function of elapsed time whether the equipment is used or not. There are a
few savings from using the machinery, which would exist only if the
equipment were not used, such as mothballing machinery in cosmoline which
would not have to be purchased and applied if the machines were in use, and
some savings, in that not using the equipment would reduce the costs of
maintenance and change the kind of maintenance, which savings are foregone
by using the machinery. So estimating the value of the capital equipment
can get quite complicated.

The key idea that got things going again for me was the realization that
Keynes was including two different kinds of things in the term "value". For
modeling purposes, monetary value is particularly simple to calculate: it
is a quantity of money, either in cash or in some other form which has a
fixed monetary value (for example, a deposit slip from a bank indicating
that you have $250 in your account means that the monetary value of your
account is, and will remain until you change it or the bank adds interest
and subtracts fees, $250). The monetary value of money is an objective fact
-- i.e., not dependent on who is observing it. This is not the case for
other measures of value, which are dependent on who is observing, what that
observer knows, and how that observer reasons.

Since Keynes does not mention stores of money in his definition of G, I
conclude that he considers money simply another form of value comparable,
say, to possession of machinery or buildings or raw materials for
production. If everything is always reduced to an equivalent monetary
value, that would make sense.

However, for modeling it does not work. Charlotte Bruun has said
essentially the same thing. In a model of the environment, the monetary
value of a machine, a building, or a ton of sand is not known after the
moment of purchase until it is sold, and then it is computed as the number
of goods of each type bought/sold times the unit price for each type of
good. The price is set by interactions among agents as part of their
actions on the common economic environment; price is a variable of the
model. Thus the test bed requires keeping track of physical goods (or any
non-monetary assets) as goods rather than as monetary value, leaving their
money equivalents to be determined as prices are varied through time. The
"test bed" model, in other words, deals only in actualities, not in
estimates or predictions. Estimates and predictions are things that the
human agents do in their heads, things that influence their actions but
which have no other effect on what exists outside the agents until actions
take place.

Under this principle, we can legitimately deduct from income A the amount
of money actually spent on purchase, maintenance, or improvement of
equipment during the period in question. Those are objective expenses and
they actually subtract from net income. However, we can't deduct any
subjective estimate of what the cost would have been if the equipment had
not been used, because that is part of a model of an agent, a person, and
not of economic transactions per se. An entrepreneur may take that
alternative cost into account in determining what his actual profit is or
might be, but that calculation belongs in a model of the entrepreneur, not
the test bed.

So we can trivially compute the monetary values of any cash reserves
maintained by the producer, but not the values of any material goods or
other assets for which a value is not set until a price is established in a
transaction. Whether we speak of raw materials, machinery, partly finished
goods, or finished goods held in inventory prior to sale, we have to carry
them in the model simply as counts of goods of each kind. Some goods, such
as production machinery, have direct effects on productivity, which will
make productivity a function of the amount of money spent on maintaining or
improving such machinery. The machinery, even without a specific monetary
value assigned to it, will play a part in determining production quantities
and production costs. But the value of the machinery remains undetermined,
unless of course it is sold at a specific price. Then its monetary value is
known for a specific moment in time.

The "income" of the entrepreneur, Keynes says, comes down to the value of
finished output sold (actually sold at a specific price) during the period
in question, minus his prime cost, prime cost consisting of (actual) factor
costs (money actually spent on production) and User Costs, which are partly
actual and partly subjective estimates.

And this income is, according to the previous discussion, exactly the net
change in G that has occurred during the accounting period.

Skipping over numerous details, I hope safely, we come at last to saving
and investment. Keynes says, "Income we have defined above. Expenditure on
consumption during any period must mean the value of goods sold to
consumers during that period ...". Savings, he says, is the excess of
income over expenditure, and according to the previous discussion, it is
therefore equal to the change in the net value of G during the period in
question, after deduction of production costs. This shows us that savings
is measured by Keynes not in monetary terms alone, but in terms of the
change in "value" of the "capital equipment" defined at the beginning of
the chapter. This term "value" thus includes not only actual money held in
reserve, but the entrepreneur's best estimate of the market value of all
his assets.

Keynes eventually goes on: "Our definition of income also leads at once to
the definition of _current investment_. For we must mean by this the
current addition to the value of the capital equipment which has resulted
from the productive activity of the period." In other words, the same G,
less costs. He then goes on to sum up, and naturally concludes that income
equals investment, as must be the case if they are both defined as the
change in G minus costs.

However, this does not mean that the amount of money held in liquid cash
form or its equivalent is equal to the amount of money spent on the
purchase and upkeep of physical production machinery, buildings, or raw
materials -- physical assets. If we think of savings as actual cash held
back and not spent, and of investment as the actual purchase and upkeep of
capital machinery, then savings is clearly different from investment: cash
that is saved is not spent for investment; what is spent on investment is
not saved. The sum of cash held back and cash spent on investment remains
the total amount taken from income in addition to costs of production, of
course. But that, apparently, would be a nonstandard usage of these terms,
even though it is a common usage.

I hope this is an acceptable solution to the controversy over savings and
investment.

···

========================================================================
In the test-bed model, it is easy to keep track of goods and money
separately, with price being the conversion factor when actual transactions
take place. Rather than use the term "Savings", knowing that it has a
special meaning to economists or at least to Keynes, I used the term
"reserve" to mean holdings of cash or equivalent. "Investment" is not yet
part of the model, although I have provided for an "investment fund" which
is built up from current income to some desired level and maintained there.
Later, money will be withdrawn from that fund and used to maintain
machinery, or rather to maintain the productivity factor at whatever level
is desired. Some assumptions (or measurements!) will have to be made about
the effect of money on productivity by this route.

I noticed a problem in Keynes' expositions that arises from a confusion
between what Forester calls "stocks and flows." Consider the idea of
income. I think of my income in terms of a rate or a flow: so many dollars
per month, which converts to so many dollars per day, a handy number to
keep in mind. However, when Keynes speaks of income he refers to the total
quantity received during an accounting period (it's true that he says "any
period," so he is almost there). The idea of carrying over value of capital
equipment from a previous period seems to be handled awkwardly, because of
thinking only in terms of total amounts rather than stocks and flows.

In modeling, it is essential to know the difference between a variable and
its time integral, which is what we're talking about. Let's say that the
entrepreneur calculates the value of his capital equipment (given modern
computers) every day (or even every minute). The value at the start of one
day is the value at the end of the previous day plus any changes in value
due to purchases, sales, and expenses occuring during that day. By adding
up all these changes, recalculating the total value every day, the
entrepreneur can compute the cumulative value at any time after the initial
conditions were set -- say, at the end of a monthly or quarterly accounting
period. This is a simple way of handling the problem that Keynes seemed to
pose so awkwardly.

Income and expenses can fluctate rapidly and widely every day, but the
total value changes much more slowly, since it's a cumulative quantity. So
there is a built-in lag which means that not every variable in the whole
system changes simultaneously, in proportion. Keynes writes about these
lags and seems to have an intuitive idea about their consequences, one of
which is a tendency to oscillations ("cycles"). When the model is set up
properly as a simulation based on differential equations, such oscillations
and their causes will be easily understood.

I think that much of the confusion here will be resolved by going to
"accounting periods" that are short enough to make all the relationships
appear continuously variable - in the test bed, I use a period of 0.001
day. Then cumulative variables will be seen to change on a slow time scale
while rate or flow variable fluctate more rapidly. This will eventually
open the way to a hierarchical model in which higher systems operate much
more slowly than lower ones (Richard Kennaway seems to have shown that a
speed ratio of about 4 to 1 from one level to the next is optimal for
certain kinds of hierarchical control).

I look forward to seeing your discussion of income, savings, and investment,\

Best,

Bill P.