>From a "lurker"...
>>So, I again submit that there usually (always?) is bi-directionality in
>>living systems, but perhaps others will have examples where
>>mono-directionality (As Robert said: " The cause-and-effect arrow of
>>implication is one-way.") is the only case.<<
Isn't "mono vs. bi" directionality dependent upon model "grain" or or the bias
of scale. I would think all one-way causal relationships can become
bidirectional as perspective zooms in or out.
Bidirectionality can be represented by a causal *loop* diagram where the
cause-and-effect arrow is always one-way.
Lou
----- Original Message -----
From: Robert Howard
To: 'The Friday Morning Applied Complexity Coffee Group' ; 'Tom Johnson'
Sent: Monday, June 04, 2007 6:23 PM
Subject: Re: [FRIAM] Re-named topic to: Mono- and bi-directionality in systems
…then things change simply because they are dynamic
Yes. Change and Dynamic are synonyms.
What if the "30-cent collective" were capable of deciding...
I don’t know what it means for a collective to decide. I know what it means
for an individual to decide. I know how voting systems work. I know what it
means for two (or more) people to agree on a contracted future based on
unforeseen triggers. Is this what you are referring to?
"Hey, the nickel and the quarter are fine, but wouldn't the collective be
better off if our rules required two dimes, a nickel and five pennies
Then the rules (the dynamics; the functions) still depend on the coins (the
statics). As for “better”, I only imagine you or I deciding—not the coins.
Then what/who determines the flight direction of the flock.
I think that question presupposes a determiner. It’s like asking “why did the
planet decide to orbit the sun?” It presupposes that planets decide. “Who
caused the universe?” presupposes God. “I think, therefore I am” presupposes
“I”, which presupposes “exists”, which is a tautology.
Do three birds constitute a flock?
Only if you and I agree on the constraints of the model—the rules of play—the
definition of flock! We’re the authority!
Lot’s of intellectual progress occurs when someone like you says “Let’s
assume that three birds constitutes a flock”, and I say “ok, let’s” – and then
attempt to deduce new knowledge from those assumptions.
When Langton wrote Boids, he put all the rules inside the birds—not inside
the flock. The flocking dynamics were directly caused by the birds. The flock
is nothing without the birds, but each bird is something without the flock.
I realize that not everyone in Arizona is a cowboy
Everyone in Arizona is a cowboy. It’s state law! I really only see pictures
of cows but still…
behavior of a cow-calf "unit" can influence the collective herd
The cow-calf unit is interesting. But the so called emergent behavior for
herd flow is the execution of rules inside the brains of each cow. Each cow’s
rule set is mostly like the others (called the abstract part, or the
collective) and partly unique (called the concrete part or the individual).
However, the predicates that decide which element of one cow’s rule set is also
a member of another cow’s rule set (i.e. the union) are define by the observer
according to a model. We decide if two cows are acting similarly or
differently. And we call the similar part the herd and each dissimilar part a
cow. Just as we see constellation in the stars, we see the collective in the
parts!
Each cow sees itself as part of a group, and each view is a spanning
tree—which is unidirectional.
So I submit again in different words, that to model a complex system properly
with minimum pain and maximum comprehension, define the system to be the
superposition of many unidirectional spanning trees rather than one big
bi-directional graph, and then iterate across each spanning tree (or fork
threads) for each agent in the model.
And from what I see from the Redfish Group, this is exactly what their code
does internally when they make these really impressive simulations.
Robert Howard
Phoenix, Arizona
------------------------------------------------------------------------------
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Johnson
Sent: Monday, June 04, 2007 3:23 PM
To: [EMAIL PROTECTED]
Subject: Re-named topic to: Mono- and bi-directionality in systems
[The conversation topic seems to have moved on to a much higher plane than
Robert's and my original discussion ( describe ABM (and IBM) methodologies. ),
hence I've taken the liberty of re-naming the topic.]
It seems to me that the conversation started with discussing adaptive
(dynamic) living systems, as contrasted with conceptual systems and their
taxonomies. Your [Robert's] 30-cent collective, for example. And I grant you
that case as being mono-directional.
However, when we turn to dynamic systems -- the birds, for example -- then
things change simply because they are dynamic. What if the "30-cent
collective" were capable of deciding, "Hey, the nickel and the quarter are
fine, but wouldn't the collective be better off if our rules required two
dimes, a nickel and five pennies. Then we could have a greater range of
'purchasing' power because the collective would have more options for exact
payment?"
Or, in the case of the birds, "How many birds does the system require to
constitute a flock?" Is two a flock? Probably not, as i"flock" is commonly
understood. But let's say the threshold of flock sufficiency is reached. Then
what/who determines the flight direction of the flock. Is there a leader,
unconsciously recognized and acknowledged by all the members of the flock? Or
is the flock's behavior -- and that of its individual members -- also
influenced by, say, rainfall or wind direction, and each member "deciding" to
seek the closest refuge in a tree or under an eave? Ergo, the "environment" --
the context -- is driving the action. And when members of the flock recognize
that one of their peers -- and not necessarily the "leader" -- has veered off
and taken refuge, that individual will do like wise. Eventually the flock --
the system -- could take a dramatically different form, all because one of its
original members decided to take a deviant action.
Another example: I realize that not everyone in Arizona is a cowboy, but
anyone who has herded cattle in the spring -- when mother cows have young
calves at their side -- will recognize how behavior of a cow-calf "unit" can
influence the collective herd. For example, cattle can be herded if the
individual units (essentially the mother cows) recognize and follow a lead cow,
the alpha cow. However, if for some reason, a cow and her calf become
separated, that can generate a type of herd chaos, usually limited. The cow
will stop trailing the leader and literally stop and mill about until she can
reunite with her calf. That stopping action can at the least jam up the flow
of the herd ( especially depending on the terrain; thick forest, narrow canyon,
etc.), which in itself, can have a ripple effect as other cows get separated
from their calves. Consequently, a good trail boss -- a cowboy, not a cow --
will periodically stop the moving herd to let the cows and calves "mother up,"
re-establishing the system that is the herd. (There are also cows that move
much faster than others, which adds a whole new dimension to the herd/system,
but that's another story.)
So, I again submit that there usually (always?) is bi-directionality in
living systems, but perhaps others will have examples where mono-directionality
(As Robert said: " The cause-and-effect arrow of implication is one-way.") is
the only case.
-tom
On 6/3/07, Robert Howard <[EMAIL PROTECTED]> wrote:
Tom,
But is there really such thing as a collective—physically? If I have a nickel
and a dime in my pocket, the collective total is 30 cents. But where is the
object whose value is thirty cents? Both the nickel and the dime can exist
independently of the 30 cent thingy; but not the other way around. Do not the
birds define a flock, and not the other way around? We can talk about a
plurality of things, but only if deductively consistent with the
characteristics of every part. Is it the collective that generates and governs
data flow? Or is it merely one object sending data to another repeated many
times?
I always get tripped up in this type of philosophy! J And when I get tripped
up, I've learned to check my assumptions and retreat to the fundamental
principles I hold dearly: that implication flows one way.
Did you have an example that you were thinking about?
Robert Howard
Phoenix, Arizona
------------------------------------------------------------------------------
From: [EMAIL PROTECTED] [mailto: [EMAIL PROTECTED] On Behalf Of Tom Johnson
Sent: Sunday, June 03, 2007 8:18 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Fwd: ABM
Robert:
It seems to me that there is usually (always?) bi-directionality involved in
a dynamic system, especially between the individual and the collective. The
collective often (Usually? Always?) provides a context that generates and
governs data flow, a time frame, rugged landscapes or not, etc. Such data
flows can hinder or enhance the individual's decisions and actions and,
possibly, those of the collective.
-Tom
On 6/3/07, Robert Howard <[EMAIL PROTECTED]> wrote:
Interesting paper!
I do like seeing the phrase:
Individual-based models (IBMs) allow researchers to study how system level
properties emerge from the adaptive behaviour of individuals
The collective presupposes the individual.
Information and properties of the part flow to the whole—not the other way
around.
The cause-and-effect arrow of implication is one-way.
Robert Howard
Phoenix, Arizona
------------------------------------------------------------------------------
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Douglas Roberts
Sent: Friday, June 01, 2007 11:25 AM
To: The Friday Morning Applied Complexity Coffee Group
Subject: [FRIAM] Fwd: ABM
FRIAMers,
I received this today from several of my co-workers and thought I'd pass it
on.
I still can't help but feeling that in general, *way* too many words are
being used to describe ABM (and IBM) methodologies. The underlying concept of
object-oriented software design as the basis for ABM simulation architecture is
just so straight forward and intuitive that I am repeatedly amazed at how
people continue to make such a big, mysterious deal out of it.
But, I suppose that's just me, and my opinion...
--Doug
--
Doug Roberts, RTI International
[EMAIL PROTECTED]
[EMAIL PROTECTED]
505-455-7333 - Office
505-670-8195 - Cell
****************************************************
This is a very interesting resource re: Agent Based Modeling.
http://www.openabm.org/site/
Note also the current efforts re: ODD (Overview, Design Concepts and Details)
–based descriptions (cf. attached manuscript).
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FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
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--
==========================================
J. T. Johnson
Institute for Analytic Journalism -- Santa Fe, NM USA
www.analyticjournalism.com
505.577.6482(c) 505.473.9646(h)
http://www.jtjohnson.com [EMAIL PROTECTED]
"You never change things by fighting the existing reality.
To change something, build a new model that makes the
existing model obsolete."
-- Buckminster Fuller
==========================================
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
--
==========================================
J. T. Johnson
Institute for Analytic Journalism -- Santa Fe, NM USA
www.analyticjournalism.com
505.577.6482(c) 505.473.9646(h)
http://www.jtjohnson.com [EMAIL PROTECTED]
"You never change things by fighting the existing reality.
To change something, build a new model that makes the
existing model obsolete."
-- Buckminster Fuller
==========================================
------------------------------------------------------------------------------
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
